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Gels, Volume 9, Issue 8 (August 2023) – 78 articles

Cover Story (view full-size image): Three-dimensional (3D) neuronal cultures are valuable models for studying brain complexity in vitro, and the choice of the bulk material in which the neurons grow is a crucial factor in establishing successful cultures. Indeed, neuronal development and network functionality are influenced by the mechanical properties of the selected material; in turn, these properties may change due to neuron–matrix interactions that alter the microstructure of the material. To advance our understanding of the interplay between neurons and their environment, here we utilized a PEGylated fibrin hydrogel as a scaffold for mouse primary neuronal cultures and carried out a rheological characterization of the scaffold over a three-week period, both with and without cells. View this paper
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14 pages, 3893 KiB  
Article
Bovine Serum Albumin Molecularly Imprinted Electrochemical Sensors Modified by Carboxylated Multi-Walled Carbon Nanotubes/CaAlg Hydrogels
by Letian Cheng, Zhilong Guo, Yuansheng Lin, Xiujuan Wei, Kongyin Zhao and Zhengchun Yang
Gels 2023, 9(8), 673; https://doi.org/10.3390/gels9080673 - 20 Aug 2023
Cited by 1 | Viewed by 1131
Abstract
In this paper, sodium alginate (NaAlg) was used as functional monomers, bovine serum albumin (BSA) was used as template molecules, and calcium chloride (CaCl2) aqueous solution was used as a cross-linking agent to prepare BSA molecularly imprinted carboxylated multi-wall carbon nanotubes [...] Read more.
In this paper, sodium alginate (NaAlg) was used as functional monomers, bovine serum albumin (BSA) was used as template molecules, and calcium chloride (CaCl2) aqueous solution was used as a cross-linking agent to prepare BSA molecularly imprinted carboxylated multi-wall carbon nanotubes (CMWCNT)/CaAlg hydrogel films (MIPs) and non-imprinted hydrogel films (NIPs). The adsorption capacity of the MIP film for BSA was 27.23 mg/g and the imprinting efficiency was 2.73. The MIP and NIP hydrogel film were loaded on the surface of the printed electrode, and electrochemical performance tests were carried out by electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV) using the electrochemical workstation. The loaded MIP film and NIP film effectively improved the electrochemical signal of the bare carbon electrode. When the pH value of the Tris HCl elution solution was 7.4, the elution time was 15 min and the adsorption time was 15 min, and the peak currents of MIP-modified electrodes and NIP-modified electrodes reached their maximum values. There was a specific interaction between MIP-modified electrodes and BSA, exhibiting specific recognition for BSA. In addition, the MIP-modified electrodes had good anti-interference, reusability, stability, and reproducibility. The detection limit (LOD) was 5.6 × 10−6 mg mL−1. Full article
(This article belongs to the Special Issue Alginate-Based Gels: Preparation, Characterization and Application)
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18 pages, 3639 KiB  
Article
Bromelain- and Silver Nanoparticle-Loaded Polycaprolactone/Chitosan Nanofibrous Dressings for Skin Wound Healing
by Yasaman Saghafi, Hadi Baharifar, Najmeh Najmoddin, Azadeh Asefnejad, Hassan Maleki, Sayed Mahmoud Sajjadi-Jazi, Alireza Bonkdar, Forough Shams and Kamyar Khoshnevisan
Gels 2023, 9(8), 672; https://doi.org/10.3390/gels9080672 - 19 Aug 2023
Cited by 6 | Viewed by 1979
Abstract
A cutaneous wound is caused by various injuries in the skin, which can be wrapped with an efficient dressing. Electrospinning is a straightforward adjustable technique that quickly and continuously generates nanofibrous wound dressings containing antibacterial and anti-inflammatory agents to promote wound healing. The [...] Read more.
A cutaneous wound is caused by various injuries in the skin, which can be wrapped with an efficient dressing. Electrospinning is a straightforward adjustable technique that quickly and continuously generates nanofibrous wound dressings containing antibacterial and anti-inflammatory agents to promote wound healing. The present study investigated the physicochemical and biological properties of bromelain (BRO)- and silver nanoparticle (Ag NPs)-loaded gel-based electrospun polycaprolactone/chitosan (PCL/CS) nanofibrous dressings for wound-healing applications. Electron microscopy results showed that the obtained nanofibers (NFs) had a uniform and homogeneous morphology without beads with an average diameter of 176 ± 63 nm. The FTIR (Fourier transform infrared) analysis exhibited the loading of the components. Moreover, adding BRO and Ag NPs increased the tensile strength of the NFs up to 4.59 MPa. BRO and Ag NPs did not significantly affect the hydrophilicity and toxicity of the obtained wound dressing; however, the antibacterial activity against E. coli and S. aureus bacteria was significantly improved. The in vivo study showed that the wound dressing containing BRO and Ag NPs improved the wound-healing process within one week compared to other groups. Therefore, gel-based PCL/CS nanofibrous dressings containing BRO and Ag NPs could be a promising solution for healing skin wounds. Full article
(This article belongs to the Special Issue Gel-Based Materials for Biomedical Engineering)
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19 pages, 1980 KiB  
Review
Emergence of Nano-Based Formulations for Effective Delivery of Flavonoids against Topical Infectious Disorders
by Khusbu Dwivedi, Ashok Kumar Mandal, Obaid Afzal, Abdulmalik Saleh Alfawaz Altamimi, Ankit Sahoo, Manal A. Alossaimi, Waleed H. Almalki, Abdulaziz Alzahrani, Md. Abul Barkat, Tahani M. Almeleebia, Shehla Nasar Mir Najib Ullah and Mahfoozur Rahman
Gels 2023, 9(8), 671; https://doi.org/10.3390/gels9080671 - 18 Aug 2023
Cited by 2 | Viewed by 1946
Abstract
Flavonoids are hydroxylated phenolic substances in vegetables, fruits, flowers, seeds, wine, tea, nuts, propolis, and honey. They belong to a versatile category of natural polyphenolic compounds. Their biological function depends on various factors such as their chemical structure, degree of hydroxylation, degree of [...] Read more.
Flavonoids are hydroxylated phenolic substances in vegetables, fruits, flowers, seeds, wine, tea, nuts, propolis, and honey. They belong to a versatile category of natural polyphenolic compounds. Their biological function depends on various factors such as their chemical structure, degree of hydroxylation, degree of polymerization conjugation, and substitutions. Flavonoids have gained considerable attention among researchers, as they show a wide range of pharmacological activities, including coronary heart disease prevention, antioxidative, hepatoprotective, anti-inflammatory, free-radical scavenging, anticancer, and anti-atherosclerotic activities. Plants synthesize flavonoid compounds in response to pathogen attacks, and these compounds exhibit potent antimicrobial (antibacterial, antifungal, and antiviral) activity against a wide range of pathogenic microorganisms. However, certain antibacterial flavonoids have the ability to selectively target the cell wall of bacteria and inhibit virulence factors, including biofilm formation. Moreover, some flavonoids are known to reverse antibiotic resistance and enhance the efficacy of existing antibiotic drugs. However, due to their poor solubility in water, flavonoids have limited oral bioavailability. They are quickly metabolized in the gastrointestinal region, which limits their ability to prevent and treat various disorders. The integration of flavonoids into nanomedicine constitutes a viable strategy for achieving efficient cutaneous delivery owing to their favorable encapsulation capacity and diminished toxicity. The utilization of nanoparticles or nanoformulations facilitates drug delivery by targeting the drug to the specific site of action and exhibits excellent physicochemical stability. Full article
(This article belongs to the Special Issue Research on Hydrogels for Controlled Drug Delivery)
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19 pages, 5461 KiB  
Article
Mercury Bonding to Xerogel: The Interface Fractal Dynamics of the Interaction between Two Complex Systems
by Maria-Alexandra Paun, Vladimir-Alexandru Paun and Viorel-Puiu Paun
Gels 2023, 9(8), 670; https://doi.org/10.3390/gels9080670 - 18 Aug 2023
Viewed by 692
Abstract
This study describes novel solid substances founded on chitosan and TEGylated phenothiazine that have a high ability for hydrargyrum recovery from watery liquid solutions. These compounds were taken into account, consisting of two distinct entity interactions inside of the classic fractal dynamics conjecture [...] Read more.
This study describes novel solid substances founded on chitosan and TEGylated phenothiazine that have a high ability for hydrargyrum recovery from watery liquid solutions. These compounds were taken into account, consisting of two distinct entity interactions inside of the classic fractal dynamics conjecture of an “interface”. They were assimilated through fractal-type mathematical objects and judged as such. The bi-stable behavior of two fractally connected objects was demonstrated both numerically and graphically. The fractal character was demonstrated by the fractal analysis made using SEM images of the xerogel compounds with interstitial fixed hydrargyrum. For the first time, SEM helped to verify such samples from two distinct bodies, with the multifractal parameter values being listed in continuation. The fractal dimension of the rectangular mask is D1 = 1.604 ± 0.2798, the fractal dimension of the square mask is D2 = 1.596 ± 0.0460, and the lacunarity is 0.0402. Full article
(This article belongs to the Special Issue Advances in Xerogels: From Design to Applications (2nd Edition))
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30 pages, 4210 KiB  
Review
Fluorescent-Nanoparticle-Impregnated Nanocomposite Polymeric Gels for Biosensing and Drug Delivery Applications
by Kumaraswamy Gandla, K. Praveen Kumar, P. Rajasulochana, Manoj Shrawan Charde, Ritesh Rana, Laliteshwar Pratap Singh, M. Akiful Haque, Vasudha Bakshi, Falak A. Siddiqui, Sharuk L. Khan and S. Ganguly
Gels 2023, 9(8), 669; https://doi.org/10.3390/gels9080669 - 18 Aug 2023
Cited by 3 | Viewed by 1672
Abstract
Nanocomposite polymeric gels infused with fluorescent nanoparticles have surfaced as a propitious category of substances for biomedical purposes owing to their exceptional characteristics. The aforementioned materials possess a blend of desirable characteristics, including biocompatibility, biodegradability, drug encapsulation, controlled release capabilities, and optical properties [...] Read more.
Nanocomposite polymeric gels infused with fluorescent nanoparticles have surfaced as a propitious category of substances for biomedical purposes owing to their exceptional characteristics. The aforementioned materials possess a blend of desirable characteristics, including biocompatibility, biodegradability, drug encapsulation, controlled release capabilities, and optical properties that are conducive to imaging and tracking. This paper presents a comprehensive analysis of the synthesis and characterization of fluorescent-nanoparticle-impregnated nanocomposite polymeric gels, as well as their biomedical applications, such as drug delivery, imaging, and tissue engineering. In this discourse, we deliberate upon the merits and obstacles linked to these substances, encompassing biocompatibility, drug encapsulation, optical characteristics, and scalability. The present study aims to provide an overall evaluation of the potential of fluorescent-nanoparticle-impregnated nanocomposite polymeric gels for biomedical applications. Additionally, emerging trends and future directions for research in this area are highlighted. Full article
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18 pages, 5209 KiB  
Article
Effect of the Preparation Method on the Properties of Eugenol-Doped Titanium Dioxide (TiO2) Sol-Gel Coating on Titanium (Ti) Substrates
by Julia Both, Anita-Petra Fülöp, Gabriella Stefania Szabó, Gabriel Katona, Alexandra Ciorîță and Liana Maria Mureșan
Gels 2023, 9(8), 668; https://doi.org/10.3390/gels9080668 - 18 Aug 2023
Cited by 2 | Viewed by 1010
Abstract
The focus of this study was the preparation of sol–gel titanium dioxide (TiO2) coatings, by the dip-coating technique, on Ti6Al4V (TiGr5) and specific Ti implant substrates. In order to confer antibacterial properties to the layers, Eugenol was introduced in the coatings [...] Read more.
The focus of this study was the preparation of sol–gel titanium dioxide (TiO2) coatings, by the dip-coating technique, on Ti6Al4V (TiGr5) and specific Ti implant substrates. In order to confer antibacterial properties to the layers, Eugenol was introduced in the coatings in two separate ways: firstly by introducing the Eugenol in the sol (Eug–TiO2), and secondly by impregnating into the already deposed TiO2 coating (TiO2/Eug). Optimization of Eugenol concentration as well as long term were performed in orderboth short- and long-term Eugenol concentration was performed to investigate the prepared samples thoroughly. The samples were investigated by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization curves (PDP). To investigate their resistance against Gram-negative Escherichia coli bacteria, microbiological analysis was performed on coatings prepared on glass substrates. Structural studies (FT-IR analysis, Raman spectroscopy) were performed to confirm Eugenol–TiO2 interactions. Coating thicknesses and adhesion were also determined for all samples. The results show that Eug–TiO2 presented with improved anticorrosive effects and significant antibacterial properties, compared to the other investigated samples. Full article
(This article belongs to the Special Issue Advances in Functional Gel)
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14 pages, 5575 KiB  
Article
Wettability of HPMC/PEG/CS Thermosensitive Porous Hydrogels
by Li Ma, Tong Shi, Zhaoyun Zhang, Xixi Liu and Hui Wang
Gels 2023, 9(8), 667; https://doi.org/10.3390/gels9080667 - 18 Aug 2023
Cited by 1 | Viewed by 1321
Abstract
Thermosensitive hydrogels have been receiving attention in the development of fire extinguishing agents due to their stimuli responsivity. Conventional hydrogels are limited by their slow response rate, and their wettability has not been studied systematically. In the present study, a concentrate of a [...] Read more.
Thermosensitive hydrogels have been receiving attention in the development of fire extinguishing agents due to their stimuli responsivity. Conventional hydrogels are limited by their slow response rate, and their wettability has not been studied systematically. In the present study, a concentrate of a thermosensitive porous system has been successfully synthesized by adding Na2CO3/CH3COOH as a foaming agent into the mixture of hydroxypropyl methylcellulose (HPMC)/polyethylene glycol (PEG)/chitosan (CS). The systems with different concentrations were obtained by diluting the concentrate with water. Thermosensitivity, surface tension and contact angle were characterized. In addition, spreadability, wettability and adhesivity were investigated systematically. Results showed that the systems with a concentration greater than 15 wt% exhibited outstanding performance of thermosensitivity and coagulability. A total of 20 wt% of the system has the best spreadability and wettability on the wood surface, most likely due to favorable contributions brought by both adequate viscosity and hydrophilicity. The adhesive force and surface-free energy of the pre-gel droplet that reached deposition on the wood surface decreased by 46.78% and 20.71%, respectively. The gel has a great capacity of water retention over a long period of time, which makes this porous gel the best system when it comes to its wettability and adhesiveness towards the chosen wood surface. The equilibrium surface tension decreased by 45.50% compared with water. HPMC/PEG/CS thermosensitive porous hydrogel with excellent wettability presented wide-ranging possibilities for the further development of fire suppression agents of fast phase-transition thermosensitive hydrogel. Full article
(This article belongs to the Section Gel Chemistry and Physics)
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20 pages, 4896 KiB  
Review
Insights into the Potential of Biopolymeric Aerogels as an Advanced Soil-Fertilizer Delivery Systems
by H. P. S. Abdul Khalil, Kanchan Jha, Esam Bashir Yahya, Sandeep Panchal, Nidhi Patel, Arindam Garai, Soni Kumari and Mohammed Jameel
Gels 2023, 9(8), 666; https://doi.org/10.3390/gels9080666 - 17 Aug 2023
Cited by 3 | Viewed by 2104
Abstract
Soil fertilizers have the potential to significantly increase crop yields and improve plant health by providing essential nutrients to the soil. The use of fertilizers can also help to improve soil structure and fertility, leading to more resilient and sustainable agricultural systems. However, [...] Read more.
Soil fertilizers have the potential to significantly increase crop yields and improve plant health by providing essential nutrients to the soil. The use of fertilizers can also help to improve soil structure and fertility, leading to more resilient and sustainable agricultural systems. However, overuse or improper use of fertilizers can lead to soil degradation, which can reduce soil fertility, decrease crop yields, and damage ecosystems. Thus, several attempts have been made to overcome the issues related to the drawbacks of fertilizers, including the development of an advanced fertilizer delivery system. Biopolymer aerogels show promise as an innovative solution to improve the efficiency and effectiveness of soil-fertilizer delivery systems. Further research and development in this area could lead to the widespread adoption of biopolymer aerogels in agriculture, promoting sustainable farming practices and helping to address global food-security challenges. This review discusses for the first time the potential of biopolymer-based aerogels in soil-fertilizer delivery, going through the types of soil fertilizer and the advert health and environmental effects of overuse or misuse of soil fertilizers. Different types of biopolymer-based aerogels were discussed in terms of their potential in fertilizer delivery and, finally, the review addresses the challenges and future directions of biopolymer aerogels in soil-fertilizer delivery. Full article
(This article belongs to the Special Issue Functional Gels for Agricultural and Environmental Applications)
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20 pages, 9641 KiB  
Article
Carbon Gels–Green Graphene Composites as Metal-Free Bifunctional Electro-Fenton Catalysts
by Lilian D. Ramírez-Valencia, Esther Bailón-García, Adriana I. Moral-Rodríguez, Francisco Carrasco-Marín and Agustín F. Pérez-Cadenas
Gels 2023, 9(8), 665; https://doi.org/10.3390/gels9080665 - 17 Aug 2023
Cited by 6 | Viewed by 2583
Abstract
The Electro-Fenton (EF) process has emerged as a promising technology for pollutant removal. However, the EF process requires the use of two catalysts: one acting as an electrocatalyst for the reduction of oxygen to H2O2 and another Fenton-type catalyst for [...] Read more.
The Electro-Fenton (EF) process has emerged as a promising technology for pollutant removal. However, the EF process requires the use of two catalysts: one acting as an electrocatalyst for the reduction of oxygen to H2O2 and another Fenton-type catalyst for the generation of ·OH radicals from H2O2. Thus, the search for materials with bifunctionality for both processes is required for a practical and real application of the EF process. Thus, in this work, bifunctional electrocatalysts were obtained via doping carbon microspheres with Eco-graphene, a form of graphene produced using eco-friendly methods. The incorporation of Eco-graphene offers numerous advantages to the catalysts, including enhanced conductivity, leading to more efficient electron transfer during the Electro-Fenton process. Additionally, the synthesis induced structural defects that serve as active sites, promoting the direct production of hydroxyl radicals via a 3-electron pathway. Furthermore, the spherical morphology of carbon xerogels enhances the accessibility of the reagents to the active sites. This combination of factors results in the effective degradation of Tetracycline (TTC) using metal-free catalysts in the Electro-Fenton process, achieving up to an impressive 83% degradation without requiring any other external or additional catalyst. Full article
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36 pages, 8851 KiB  
Review
Chitosan Hydrogels for Water Purification Applications
by Mariana Chelu, Adina Magdalena Musuc, Monica Popa and Jose M. Calderon Moreno
Gels 2023, 9(8), 664; https://doi.org/10.3390/gels9080664 - 17 Aug 2023
Cited by 9 | Viewed by 4425
Abstract
Chitosan-based hydrogels have gained significant attention for their potential applications in water treatment and purification due to their remarkable properties such as bioavailability, biocompatibility, biodegradability, environmental friendliness, high pollutants adsorption capacity, and water adsorption capacity. This article comprehensively reviews recent advances in chitosan-based [...] Read more.
Chitosan-based hydrogels have gained significant attention for their potential applications in water treatment and purification due to their remarkable properties such as bioavailability, biocompatibility, biodegradability, environmental friendliness, high pollutants adsorption capacity, and water adsorption capacity. This article comprehensively reviews recent advances in chitosan-based hydrogel materials for water purification applications. The synthesis methods, structural properties, and water purification performance of chitosan-based hydrogels are critically analyzed. The incorporation of various nanomaterials into chitosan-based hydrogels, such as nanoparticles, graphene, and metal-organic frameworks, has been explored to enhance their performance. The mechanisms of water purification, including adsorption, filtration, and antimicrobial activity, are also discussed in detail. The potential of chitosan-based hydrogels for the removal of pollutants, such as heavy metals, organic contaminants, and microorganisms, from water sources is highlighted. Moreover, the challenges and future perspectives of chitosan-based hydrogels in water treatment and water purification applications are also illustrated. Overall, this article provides valuable insights into the current state of the art regarding chitosan-based hydrogels for water purification applications and highlights their potential for addressing global water pollution challenges. Full article
(This article belongs to the Special Issue Recent Advances in Hydrogel-Based Biomaterials)
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14 pages, 3161 KiB  
Article
Silica Gels Doped with Gold Nanoparticles: Preparation, Structure and Optical Properties
by Dimitar Shandurkov, Nina Danchova, Tony Spassov, Vesselin Petrov, Roumen Tsekov and Stoyan Gutzov
Gels 2023, 9(8), 663; https://doi.org/10.3390/gels9080663 - 17 Aug 2023
Cited by 3 | Viewed by 1268
Abstract
A novel, one-pot sol–gel preparation scheme leading to reproducible incorporation of 20–40 nm sized gold nanoparticles (AuNPs) in SiO2 gels is developed based on in situ reduction during gelation using chloroauric acid and ascorbic acid. Variation in the preparation conditions affects the [...] Read more.
A novel, one-pot sol–gel preparation scheme leading to reproducible incorporation of 20–40 nm sized gold nanoparticles (AuNPs) in SiO2 gels is developed based on in situ reduction during gelation using chloroauric acid and ascorbic acid. Variation in the preparation conditions affects the chemical composition, optical properties and size distribution of the AuNPs incorporated in the silica gels. Different organic dopants, i.e., oleic acid, acetic acid or dodecanethiol, are applied to modify the final composite material and to control the rate of reduction and growth of the AuNPs in the gels. The synthesized samples are characterized by UV/Vis/NIR spectroscopy, X-ray diffraction, transmission electron microscopy, thermal conductivity measurements and DTA/TG measurements. The optical properties of the obtained composites are explained using Mie theory. The incorporation of AuNPs leads to an increase in the thermal conductivity of the silica gels. The best process method in this contribution is the use of NaOH as a gelation catalyst and oleic acid as an organic modifier, leading to 20 nm AuNPs dispersed in the silica matrix. Full article
(This article belongs to the Special Issue Gel Formation and Processing Technologies for Material Applications)
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20 pages, 2575 KiB  
Review
Advances in the Research and Application of Smart-Responsive Hydrogels in Disease Treatment
by Juan Cao, Ping Yuan, Bo Wu, Yeqi Liu and Cheng Hu
Gels 2023, 9(8), 662; https://doi.org/10.3390/gels9080662 - 17 Aug 2023
Cited by 3 | Viewed by 1412
Abstract
Smart-responsive hydrogels have been widely used in various fields, particularly in the biomedical field. Compared with traditional hydrogels, smart-responsive hydrogels not only facilitate the encapsulation and controlled release of drugs, active substances, and even cells but, more importantly, they enable the on-demand and [...] Read more.
Smart-responsive hydrogels have been widely used in various fields, particularly in the biomedical field. Compared with traditional hydrogels, smart-responsive hydrogels not only facilitate the encapsulation and controlled release of drugs, active substances, and even cells but, more importantly, they enable the on-demand and controllable release of drugs and active substances at the disease site, significantly enhancing the efficacy of disease treatment. With the rapid advancement of biomaterials, smart-responsive hydrogels have received widespread attention, and a wide variety of smart-responsive hydrogels have been developed for the treatment of different diseases, thus presenting tremendous research prospects. This review summarizes the latest advancements in various smart-responsive hydrogels used for disease treatment. Additionally, some of the current shortcomings of smart-responsive hydrogels and the strategies to address them are discussed, as well as the future development directions and prospects of smart-responsive hydrogels. Full article
(This article belongs to the Special Issue Biosoursed and Bioinspired Gels for Biomedical Applications)
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18 pages, 8485 KiB  
Article
Upcycling Wool Waste into Keratin Gel-Based Nanofibers Using Deep Eutectic Solvents
by Cláudia Mouro, Rodrigo Martins, Ana P. Gomes and Isabel C. Gouveia
Gels 2023, 9(8), 661; https://doi.org/10.3390/gels9080661 - 17 Aug 2023
Cited by 3 | Viewed by 1432
Abstract
Millions of tons of wool waste are produced yearly by textile industries, which may become a serious environmental hazard in the near future. Given this concern, it is crucial to explore strategies to reduce the amount of wool waste generated worldwide and adopt [...] Read more.
Millions of tons of wool waste are produced yearly by textile industries, which may become a serious environmental hazard in the near future. Given this concern, it is crucial to explore strategies to reduce the amount of wool waste generated worldwide and adopt more sustainable practices for dissolving and regenerating wool keratin (WK) from textile waste. Most traditional methods involve the use of expensive, toxic, harmful, and poorly biodegradable compounds. To overcome these limitations and facilitate the reuse of wool waste through a cascade valorization strategy, researchers have started testing the use of deep eutectic solvents (DES) as a more sustainable and eco-friendly alternative for WK dissolution and regeneration. In this study, the potential of two different DES mixtures, Choline chloride (ChCl): Urea and L-Cysteine (L-Cys): Lactic acid (LA), was explored for dissolving wool waste. Subsequently, the gels obtained based on DES-WK were blended with polyvinyl alcohol (PVA) in different ratios to produce nanofibers using the electrospinning technique. The PVA/L-Cys: LA DES-WK proved to be the most effective DES mixture for fabricating WK gel-based nanofibers. Furthermore, their antioxidant and antimicrobial abilities were evaluated, thus confirming their bioactivity. The results obtained revealed that this approach to valorizing textile waste offers a unique avenue for the development of sustainable functional materials with potential applications in various biomedical and industrial fields. Full article
(This article belongs to the Special Issue Advances in Functional Gel)
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18 pages, 2714 KiB  
Article
Development of Oral In Situ Gelling Liquid Formulations of Garcinia Extract for Treating Obesity
by Kantiya Fungfoung, Rachanida Praparatana, Ousanee Issarachot and Ruedeekorn Wiwattanapatapee
Gels 2023, 9(8), 660; https://doi.org/10.3390/gels9080660 - 16 Aug 2023
Viewed by 2258
Abstract
Novel in situ gelling liquid formulations incorporating garcinia extract were developed to achieve prolonged delivery of hydroxycitric acid (HCA), an active compound displaying anti-obesity function, following oral administration. The optimized formulation was composed of sodium alginate (1.5% w/v), hydroxypropyl methylcellulose [...] Read more.
Novel in situ gelling liquid formulations incorporating garcinia extract were developed to achieve prolonged delivery of hydroxycitric acid (HCA), an active compound displaying anti-obesity function, following oral administration. The optimized formulation was composed of sodium alginate (1.5% w/v), hydroxypropyl methylcellulose (HPMC K100) (0.25% w/v), calcium carbonate (1% w/v) and garcinia extract (2% w/v). The formulation displayed rapid gelation in less than a minute on exposure to 0.1 N hydrochloric acid (pH 1.2) and remained afloat for more than 24 h. The formulations were capable of gradually releasing more than 80% of HCA load over 8 h, depending on the composition. The resulting gels exhibited high values of gel strength by texture analysis, suggesting they would offer resistance to breakdown under the action of stomach content movement. The optimized formulation loaded garcinia extract significantly reduced lipid accumulation in 3T3-L1 adipocyte cells and displayed moderate anti-inflammatory activity by inhibiting the production of nitric oxide (NO) in LPS-stimulated RAW 264.7 macrophage cells. These findings demonstrate that oral in situ gelling liquid formulations based on sodium alginate and HPMC K100 offer much potential for sustained delivery of HCA and other anti-obesity compounds. Full article
(This article belongs to the Special Issue Women’s Special Issue Series: Gels)
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19 pages, 6124 KiB  
Article
Carboxymethyl Chitosan/Sodium Alginate/Chitosan Quaternary Ammonium Salt Composite Hydrogel Supported 3J for the Treatment of Oral Ulcer
by Tao Lin, Dandan Chen, Yan Geng, Jiayu Li, Yanghui Ou, Zhijun Zeng, Canqiang Yin, Xudong Qian, Xiang Qiu, Gang Li, Yali Zhang, Wen Guan, Mengjie Li, Xiaojia Cai, Jiaqiang Wu, Wen-Hua Chen, Yan-Qing Guan and Hongliang Yao
Gels 2023, 9(8), 659; https://doi.org/10.3390/gels9080659 - 16 Aug 2023
Cited by 1 | Viewed by 1556
Abstract
Oral ulcer is a common inflammatory disease of oral mucosa, causing severe burning pain and great inconvenience to daily life. In this study, compound 3J with anti-inflammatory activity was synthesized beforehand. Following that, an intelligent composite hydrogel supported 3J was designed with sodium [...] Read more.
Oral ulcer is a common inflammatory disease of oral mucosa, causing severe burning pain and great inconvenience to daily life. In this study, compound 3J with anti-inflammatory activity was synthesized beforehand. Following that, an intelligent composite hydrogel supported 3J was designed with sodium alginate, carboxymethyl chitosan, and chitosan quaternary ammonium salt as the skeleton, and its therapeutic effect on the rat oral ulcer model was investigated. The results show that the composite hydrogel has a dense honeycomb structure, which is conducive to drug loading and wound ventilation, and has biodegradability. It has certain antibacterial effects and good anti-inflammatory activity. When loaded with 3J, it reduced levels of TNF-α and IL-6 in inflammatory cells by up to 50.0%. It has excellent swelling and water retention properties, with a swelling rate of up to 765.0% in a pH 8.5 environment. The existence of a large number of quaternary ammonium groups, carboxyl groups, and hydroxyl groups makes it show obvious differences in swelling in different pH environments, which proves that it has double pH sensitivity. It is beneficial to adapt to the highly dynamic changes of the oral environment. Compared with single hydrogel or drug treatment, the drug-loaded hydrogel has a better effect on the treatment of oral ulcers. Full article
(This article belongs to the Special Issue Advances in Hybrid Gels Films)
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13 pages, 1750 KiB  
Article
Water-Content-Dependent Switching of the Bending Behavior of Photoresponsive Hydrogels Composed of Hydrophilic Acrylamide-Based Main Chains and Hydrophobic Azobenzene
by Junsu Park, Yuki Shimizu, Xin Zhou, Ryohei Ikura, Go Matsuba and Yoshinori Takashima
Gels 2023, 9(8), 658; https://doi.org/10.3390/gels9080658 - 16 Aug 2023
Viewed by 1696
Abstract
Photoresponsiveness is a promising characteristic of stimulus-responsive materials. Photoresponsiveness can be achieved by incorporating photoresponsive molecules into polymeric materials. In addition, multiple-stimuli-responsive materials have attracted scientists’ interest. Among the numerous multiple-stimuli-responsive materials, moisture- and photoresponsive materials are the focus of this report. These [...] Read more.
Photoresponsiveness is a promising characteristic of stimulus-responsive materials. Photoresponsiveness can be achieved by incorporating photoresponsive molecules into polymeric materials. In addition, multiple-stimuli-responsive materials have attracted scientists’ interest. Among the numerous multiple-stimuli-responsive materials, moisture- and photoresponsive materials are the focus of this report. These stimuli-responsive materials responded to the stimuli synergistically or orthogonally. Unlike most stimulus-responsive materials utilizing moisture and light as stimuli, the materials studied herein switch their photoresponsiveness in the presence of moisture. Appropriate copolymers consisting of hydrophilic acrylamide-based monomers for the main chain and hydrophobic azobenzene moieties switched their bending behaviors at 6–9 wt% water contents. At water contents lower than 6 wt%, the polymeric materials bent away from the light source, while they bent toward the light source at water contents higher than 10 wt%. At a low water content, the bending behaviors can be described on the molecular scale. At a high water content, the bending behavior requires consideration of the phase scale, not only the molecular scale. By controlling the balance between hydrophilicity and hydrophobicity, the switching behavior was achieved. This switching behavior may inspire additional strategies for the application of polymeric material as actuators. Full article
(This article belongs to the Special Issue Preparation, Properties and Applications of Functional Hydrogels)
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20 pages, 5110 KiB  
Article
QbD Design, Formulation, Optimization and Evaluation of Trans-Tympanic Reverse Gelatination Gel of Norfloxacin: Investigating Gene-Gene Interactions to Enhance Therapeutic Efficacy
by Amit Budhori, Abhishek Tiwari, Varsha Tiwari, Ajay Sharma, Manish Kumar, Girendra Gautam, Tarun Virmani, Girish Kumar, Abdulsalam Alhalmi, Omar Mohammed Noman, Sidgi Hasson and Ramzi A. Mothana
Gels 2023, 9(8), 657; https://doi.org/10.3390/gels9080657 - 15 Aug 2023
Cited by 3 | Viewed by 1260
Abstract
Traditional otic drug delivery methods lack controlled release capabilities, making reverse gelatination gels a promising alternative. Reverse gelatination gels are colloidal systems that transition from a sol to a gel phase at the target site, providing controlled drug release over an extended period. [...] Read more.
Traditional otic drug delivery methods lack controlled release capabilities, making reverse gelatination gels a promising alternative. Reverse gelatination gels are colloidal systems that transition from a sol to a gel phase at the target site, providing controlled drug release over an extended period. Thermosensitive norfloxacin reverse gelatination gels were developed using a Quality by Design (QbD)-based optimization approach. The formulations were evaluated for their in vitro release profile, rheological behavior, visual appearance, pH, gelling time, and sol–gel transition temperature. The results show that the gelation temperatures of the formulations ranged from 33 to 37 °C, with gelling durations between 35 and 90 s. The drug content in the formulations was uniform, with entrapment efficiency ranging from 55% to 95%. Among the formulations, F10 exhibited the most favorable properties and was selected for a stability study lasting 60 days. Ex-vivo release data demonstrate that the F10 formulation achieved 95.6percentage of drug release at 360 min. This study successfully developed thermosensitive norfloxacin reverse gelatination gels using a QbD-based optimization approach. The selected formulation, F10, exhibited desirable properties in terms of gelling temperature, drug content, and release profile. These gels hold potential for the controlled delivery of norfloxacin in the treatment of ear infections. Full article
(This article belongs to the Special Issue Gels in Medicine and Pharmacological Therapies (2nd Edition))
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16 pages, 5016 KiB  
Article
Polydopamine-Functionalized Bacterial Cellulose as Hydrogel Scaffolds for Skin Tissue Engineering
by Kannan Badri Narayanan, Rakesh Bhaskar, Kuncham Sudhakar, Dong Hyun Nam and Sung Soo Han
Gels 2023, 9(8), 656; https://doi.org/10.3390/gels9080656 - 14 Aug 2023
Cited by 4 | Viewed by 1450
Abstract
Bacterial cellulose (BC) is a natural polysaccharide polymer hydrogel produced sustainably by the strain Gluconacetobacter hansenii under static conditions. Due to their biocompatibility, easy functionalization, and necessary physicochemical and mechanical properties, BC nanocomposites are attracting interest in therapeutic applications. In this study, we [...] Read more.
Bacterial cellulose (BC) is a natural polysaccharide polymer hydrogel produced sustainably by the strain Gluconacetobacter hansenii under static conditions. Due to their biocompatibility, easy functionalization, and necessary physicochemical and mechanical properties, BC nanocomposites are attracting interest in therapeutic applications. In this study, we functionalized BC hydrogel with polydopamine (PDA) without toxic crosslinkers and used it in skin tissue engineering. The BC nanofibers in the hydrogel had a thickness of 77.8 ± 20.3 nm, and they could be used to produce hydrophilic, adhesive, and cytocompatible composite biomaterials for skin tissue engineering applications using PDA. Characterization techniques, namely Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and Raman spectroscopy, were performed to investigate the formation of polydopamine on the BC nanofibers. The XRD peaks for BC occur at 2θ = 14.65°, 16.69°, and 22.39°, which correspond to the planes of (100), (010), and (110) of cellulose type Iα. Raman spectroscopy confirmed the formation of PDA, as indicated by the presence of bands corresponding to the vibration of aromatic rings and aliphatic C–C and C–O stretching at 1336 and 1567 cm−1, respectively. FTIR confirmed the presence of peaks corresponding to PDA and BC in the BC/PDA hydrogel scaffolds at 3673, 3348, 2900, and 1052 cm−1, indicating the successful interaction of PDA with BC nanofibers, which was further corroborated by the SEM images. The tensile strength, swelling ratio, degradation, and surface wettability characteristics of the composite BC biomaterials were also investigated. The BC/PDA hydrogels with PDA-functionalized BC nanofibers demonstrated excellent tensile strength and water-wetting ability while maintaining the stability of the BC fibers. The enhanced cytocompatibility of the BC/PDA hydrogels was studied using the PrestoBlue assay. Culturing murine NIH/3T3 fibroblasts on BC/PDA hydrogels showed higher metabolic activity and enhanced proliferation. Additionally, it improved cell viability when using BC/PDA hydrogels. Thus, these BC/PDA composite biomaterials can be used as biocompatible natural alternatives to synthetic substitutes for skin tissue engineering and wound-dressing applications. Full article
(This article belongs to the Special Issue Designing Gels for Wound Dressing)
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18 pages, 4407 KiB  
Article
Evaluation of Poly(vinyl alcohol)–Xanthan Gum Hydrogels Loaded with Neomycin Sulfate as Systems for Drug Delivery
by Diana Serbezeanu, Manuela Maria Iftime, Gabriela-Liliana Ailiesei, Alina-Mirela Ipate, Alexandra Bargan, Tǎchiţǎ Vlad-Bubulac and Cristina Mihaela Rîmbu
Gels 2023, 9(8), 655; https://doi.org/10.3390/gels9080655 - 14 Aug 2023
Cited by 4 | Viewed by 1319
Abstract
In recent years, multidrug-resistant bacteria have developed the ability to resist multiple antibiotics, limiting the available options for effective treatment. Raising awareness and providing education on the appropriate use of antibiotics, as well as improving infection control measures in healthcare facilities, are crucial [...] Read more.
In recent years, multidrug-resistant bacteria have developed the ability to resist multiple antibiotics, limiting the available options for effective treatment. Raising awareness and providing education on the appropriate use of antibiotics, as well as improving infection control measures in healthcare facilities, are crucial steps to address the healthcare crisis. Further, innovative approaches must be adopted to develop novel drug delivery systems using polymeric matrices as carriers and support to efficiently combat such multidrug-resistant bacteria and thus promote wound healing. In this context, the current work describes the use of two biocompatible and non-toxic polymers, poly(vinyl alcohol) (PVA) and xanthan gum (XG), to achieve hydrogel networks through cross-linking by oxalic acid following the freezing/thawing procedure. PVA/XG-80/20 hydrogels were loaded with different quantities of neomycin sulfate to create promising low-class topical antibacterial formulations with enhanced antimicrobial effects. The inclusion of neomycin sulfate in the hydrogels is intended to impart them with powerful antimicrobial properties, thereby facilitating the development of exceptionally efficient topical antibacterial formulations. Thus, incorporating higher quantities of neomycin sulfate in the PVA/XG-80/20-2 and PVA/XG-80/20-3 formulations yielded promising cycling characteristics. These formulations exhibited outstanding removal efficiency, exceeding 80% even after five cycles, indicating remarkable and consistent adsorption performance with repeated use. Furthermore, both PVA/XG-80/20-2 and PVA/XG-80/20-3 formulations outperformed the drug-free sample, PVA/XG-80/20, demonstrating a significant enhancement in maximum compressive stress. Full article
(This article belongs to the Special Issue Innovative Biopolymer-Based Hydrogels)
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20 pages, 10831 KiB  
Article
Composite Hydrogels with Embedded Silver Nanoparticles and Ibuprofen as Wound Dressing
by Irina Popescu, Marieta Constantin, Gheorghe Solcan, Daniela Luminita Ichim, Delia Mihaela Rata, Loredana Horodincu and Carmen Solcan
Gels 2023, 9(8), 654; https://doi.org/10.3390/gels9080654 - 14 Aug 2023
Cited by 3 | Viewed by 1690
Abstract
The wound healing process is often slowed down as a result of complications from bacterial infections and inflammatory reactions. Therefore, it is necessary to develop dressings with fast antibacterial and anti-inflammatory activity that shorten the wound healing period by promoting cell migration and [...] Read more.
The wound healing process is often slowed down as a result of complications from bacterial infections and inflammatory reactions. Therefore, it is necessary to develop dressings with fast antibacterial and anti-inflammatory activity that shorten the wound healing period by promoting cell migration and proliferation. Chitosan (CS)-based hydrogels have been widely studied for their antibacterial and wound healing capabilities. Herein, we developed a composite hydrogel based on CS and PVA embedding silver nanoparticles (AgNPs) with antibacterial properties and ibuprofen (Ib) as an anti-inflammatory agent. The hydrogel prepared by double physical cross-linking, with oxalic acid and by freeze–thawing, loaded with 0.225 wt.% AgNPs and 0.264 wt.% Ib, displayed good mechanical properties (compressive modulus = 132 kPa), a high swelling degree and sustained drug delivery (in simulated skin conditions). Moreover, the hydrogel showed strong antibacterial activity against S. aureus and K. pneumoniae due to the embedded AgNPs. In vivo, this hydrogel accelerated the wound regeneration process through the enhanced expression of TNF alpha IP8, by activating downstream cascades and supporting the healing process of inflammation; Cox2, which enhances the migration and proliferation of cells involved in re-epithelization and angiogenesis; MHCII, which promotes immune cooperation between local cells, eliminating dead tissue and controlling infection; the intense expression of Col I as a major marker in the tissue granulation process; and αSMA, which marks the presence of myofibroblasts involved in wound closure and indicates ongoing re-epithelization. The results reveal the potential healing effect of CS/PVA/AgNPs/Ib hydrogels and suggest their potential use as wound dressings. Full article
(This article belongs to the Special Issue Recent Advances in Hydrogels for Wound Healing)
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17 pages, 1081 KiB  
Review
Self-Assembled Peptide Hydrogels in Regenerative Medicine
by Shuangyang Li, Qixuan Yu, Hongpeng Li, Meiqi Chen, Ye Jin and Da Liu
Gels 2023, 9(8), 653; https://doi.org/10.3390/gels9080653 - 14 Aug 2023
Cited by 1 | Viewed by 1760
Abstract
Regenerative medicine is a complex discipline that is becoming a hot research topic. Skin, bone, and nerve regeneration dominate current treatments in regenerative medicine. A new type of drug is urgently needed for their treatment due to their high vulnerability to damage and [...] Read more.
Regenerative medicine is a complex discipline that is becoming a hot research topic. Skin, bone, and nerve regeneration dominate current treatments in regenerative medicine. A new type of drug is urgently needed for their treatment due to their high vulnerability to damage and weak self-repairing ability. A self-assembled peptide hydrogel is a good scaffolding material in regenerative medicine because it is similar to the cytoplasmic matrix environment; it promotes cell adhesion, migration, proliferation, and division; and its degradation products are natural and harmless proteins. However, fewer studies have examined the specific mechanisms of self-assembled peptide hydrogels in promoting tissue regeneration. This review summarizes the applications and mechanisms of self-assembled short peptide and peptide hydrogels in skin, bone, and neural healing to improve their applications in tissue healing and regeneration. Full article
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13 pages, 11614 KiB  
Article
Comprehensive Optimization of Western Blotting
by Dishiwen Liu, Haoliang Wu, Shengyu Cui and Qingyan Zhao
Gels 2023, 9(8), 652; https://doi.org/10.3390/gels9080652 - 14 Aug 2023
Viewed by 3446
Abstract
Western blotting is one of the most extensively used techniques in the biomedical field. However, it is criticized by many researchers due to its considerable time consumption, multiple steps, and low method results. Therefore, we modified the steps of gel preparation, electrophoresis, electrotransfer, [...] Read more.
Western blotting is one of the most extensively used techniques in the biomedical field. However, it is criticized by many researchers due to its considerable time consumption, multiple steps, and low method results. Therefore, we modified the steps of gel preparation, electrophoresis, electrotransfer, blocking, and gel cutting. First, we simplified the gel preparation step by premixing various reagents and varying the amounts of catalysts or radical generators, which shortened the entire process to 10 min. Second, we shortened the electrophoresis process to 35 min by modifying the formula of the electrophoresis running buffer. Then, we removed the hazard of methanol vapor by replacing methanol with ethanol in the electrotransfer buffer. Finally, the use of polyvinylpyrrolidone-40 shortened the blocking procedure to 10 min. Our modifications shortened the time, improved the experimental productivity, and minimized the experimental cost without hindering compatibility with most existing equipment. The entire experiment up to primary antibody incubation can be completed within 80 min. Full article
(This article belongs to the Special Issue Advances in Acrylate-Based Hydrogels)
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15 pages, 12491 KiB  
Article
One-Pot Sol–Gel Synthesis of Highly Insulative Hybrid P(AAm-CO-AAc)-Silica Aerogels with Improved Mechanical and Thermal Properties
by Akshay A. Ransing, Rushikesh P. Dhavale, Vinayak G. Parale, Uzma K. H. Bangi, Haryeong Choi, Wonjun Lee, Jiseung Kim, Qi Wang, Varsha D. Phadtare, Taehee Kim, Wook Ki Jung and Hyung-Ho Park
Gels 2023, 9(8), 651; https://doi.org/10.3390/gels9080651 - 12 Aug 2023
Cited by 2 | Viewed by 1255
Abstract
Silica aerogels and their derivatives have outstanding thermal properties with exceptional values in the thermal insulation industry. However, their brittle nature restricts their large-scale commercialization. Thus, enhancing their mechanical strength without affecting their thermal insulating properties is essential. Therefore, for the first time, [...] Read more.
Silica aerogels and their derivatives have outstanding thermal properties with exceptional values in the thermal insulation industry. However, their brittle nature restricts their large-scale commercialization. Thus, enhancing their mechanical strength without affecting their thermal insulating properties is essential. Therefore, for the first time, highly thermally stable poly(acrylamide-co-acrylic acid) partial sodium salt is used as a reinforcing polymer to synthesize hybrid P(AAm-CO-AAc)-silica aerogels via epoxy ring-opening polymerization in the present study. Functional groups in P(AAm-CO-AAc) partial sodium salts, such as CONH2 and COOH, acted as nucleophiles for the epoxy ring-opening reaction with (3-glycidyloxypropyl)trimethoxysilane, which resulted in a seven-fold enhancement in mechanical strength compared to that of pristine silica aerogel while maintaining thermal conductivity at less than 30.6 mW/mK and porosity of more than 93.68%. Moreover, the hybrid P(AAm-CO-AAc)-silica aerogel demonstrated improved thermal stability up to 343 °C, owing to the synergetic effect between the P(AAm-CO-AAc) and the silica aerogel, corresponding to the thermal stability and strong covalent bonding among them. These excellent results illustrate that this new synthetic approach for producing hybrid P(AAm-CO-AAc)-silica aerogels is useful for enhancing the mechanical strength of pristine silica aerogel without impairing its thermal insulating property and shows potential as an industrial heat insulation material. Full article
(This article belongs to the Special Issue Synthesis and Application of Aerogel)
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22 pages, 9852 KiB  
Article
Antibacterial Activity of PVA Hydrogels Embedding Oxide Nanostructures Sensitized by Noble Metals and Ruthenium Dye
by Diana Pelinescu, Mihai Anastasescu, Veronica Bratan, Valentin-Adrian Maraloiu, Catalin Negrila, Daiana Mitrea, Jose Calderon-Moreno, Silviu Preda, Ioana Catalina Gîfu, Adrian Stan, Robertina Ionescu, Ileana Stoica, Crina Anastasescu, Maria Zaharescu and Ioan Balint
Gels 2023, 9(8), 650; https://doi.org/10.3390/gels9080650 - 11 Aug 2023
Viewed by 1109
Abstract
Nanostructured oxides (SiO2, TiO2) were synthesized using the sol–gel method and modified with noble metal nanoparticles (Pt, Au) and ruthenium dye to enhance light harvesting and promote the photogeneration of reactive oxygen species, namely singlet oxygen (1O [...] Read more.
Nanostructured oxides (SiO2, TiO2) were synthesized using the sol–gel method and modified with noble metal nanoparticles (Pt, Au) and ruthenium dye to enhance light harvesting and promote the photogeneration of reactive oxygen species, namely singlet oxygen (1O2) and hydroxyl radical (•OH). The resulting nanostructures were embedded in a transparent polyvinyl alcohol (PVA) hydrogel. Morphological and structural characterization of the bare and modified oxides was performed using scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), UV–Vis spectroscopy, and X-ray photoelectron spectroscopy (XPS). Additionally, electrokinetic potential measurements were conducted. Crystallinity data and elemental analysis of the investigated systems were obtained through X-ray diffraction and X-ray fluorescence analyses, while the chemical state of the elements was determined using XPS. The engineered materials, both as simple powders and embedded in the hydrogel, were evaluated for their ability to generate reactive oxygen species (ROS) under visible and simulated solar light irradiation to establish a correlation with their antibacterial activity against Staphylococcus aureus. The generation of singlet oxygen (1O2) by the samples under visible light exposure can be of significant importance for their potential use in biomedical applications. Full article
(This article belongs to the Special Issue Functional Hydrogels for Biomedical Applications)
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16 pages, 2192 KiB  
Article
Characteristics of a Lipid Hydrogel and Bigel as Matrices for Ascorbic Acid Stabilization
by Noèlia Loza-Rodríguez, Aina Millán-Sánchez and Olga López
Gels 2023, 9(8), 649; https://doi.org/10.3390/gels9080649 - 11 Aug 2023
Viewed by 1270
Abstract
Ascorbic acid (AA) has many health benefits, including immune and cardiovascular deficiency protection, prenatal problems, and skin diseases. Unfortunately, AA is easily oxidized and has limited bioavailability. Thus, the development of formulations that stabilize and enhance the efficacy of AA is a challenge. [...] Read more.
Ascorbic acid (AA) has many health benefits, including immune and cardiovascular deficiency protection, prenatal problems, and skin diseases. Unfortunately, AA is easily oxidized and has limited bioavailability. Thus, the development of formulations that stabilize and enhance the efficacy of AA is a challenge. In this study, 4% AA was encapsulated in two recently developed gels, a hydrogel and a bigel. The hydrogel was formed exclusively with lipids and water, and the bigel was a combination of the hydrogel with an oleogel formed with olive oil and beeswax. The effect of AA in gel microstructures was determined using X-ray scattering, rheology, and texture analysis. Additionally, the capacity of these materials to protect AA from degradation upon temperature and sunlight was studied. Results showed that the incorporation of AA into both materials did not affect their microstructure. Moreover, hydrogel-protected AA showed only 2% degradation after three months at 8 °C, while in aqueous solution, it degraded by 12%. Regarding sunlight, bigel showed a good shielding effect, exhibiting only 2% AA degradation after 22 h of exposure, whereas in aqueous solution, AA degraded by 10%. These results suggest that both proposed gels could be used in biomedical applications and the field of food. Full article
(This article belongs to the Special Issue Physical and Mechanical Properties of Polymer Gels)
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25 pages, 7489 KiB  
Review
Bigels as Delivery Systems: Potential Uses and Applicability in Food
by Alyssa Francavilla, Maria G. Corradini and Iris J. Joye
Gels 2023, 9(8), 648; https://doi.org/10.3390/gels9080648 - 11 Aug 2023
Cited by 7 | Viewed by 3484
Abstract
Bigels have been mainly applied in the pharmaceutical sector for the controlled release of drugs or therapeutics. However, these systems, with their intricate structures, hold great promise for wider application in food products. Besides their classical role as carrier and target delivery vehicles [...] Read more.
Bigels have been mainly applied in the pharmaceutical sector for the controlled release of drugs or therapeutics. However, these systems, with their intricate structures, hold great promise for wider application in food products. Besides their classical role as carrier and target delivery vehicles for molecules of interest, bigels may also be valuable tools for building complex food structures. In the context of reducing or even eliminating undesirable (but often highly functional) food components, current strategies often critically affect food structure and palatability. The production of solid fat systems that are trans-fat-free and have high levels of unsaturated fatty acids is one of the challenges the food industry currently faces. According to recent studies, bigels can be successfully used as ingredients for total or partial solid fat replacement in complex food matrices. This review aims to critically assess current research on bigels in food and pharmaceutical applications, discuss the role of bigel composition and production parameters on the characteristics of bigels and further expand the use of bigels as solid fat replacers and functional food ingredients. The hydrogel:oleogel ratio, selected gelators, inclusion of surfactants and encapsulation of molecules of interest, and process parameters (e.g., temperature, shear rate) during bigel production play a crucial role in the bigel’s rheological and textural properties, microstructure, release characteristics, biocompatibility, and stability. Besides exploring the role of these parameters in bigel production, future research directions for bigels in a food context are explored. Full article
(This article belongs to the Special Issue Recent Advances in Food Gels)
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19 pages, 6754 KiB  
Article
Stereo-Complex and Click-Chemical Bicrosslinked Amphiphilic Network Gels with Temperature/pH Response
by Wanying Yang, Jiaqi Wang, Lingjiang Jia, Jingyi Li and Shouxin Liu
Gels 2023, 9(8), 647; https://doi.org/10.3390/gels9080647 - 11 Aug 2023
Cited by 1 | Viewed by 925
Abstract
Stimulus-responsive hydrogels have been widely used in the field of drug delivery because of their three-dimensional pore size and the ability to change the drug release rate with the change in external environment. In this paper, the temperature-sensitive monomer 2-methyl-2-acrylate-2-(2-methoxyethoxy-ethyl) ethyl ester (MEO [...] Read more.
Stimulus-responsive hydrogels have been widely used in the field of drug delivery because of their three-dimensional pore size and the ability to change the drug release rate with the change in external environment. In this paper, the temperature-sensitive monomer 2-methyl-2-acrylate-2-(2-methoxyethoxy-ethyl) ethyl ester (MEO2MA) and oligoethylene glycol methyl ether methacrylate (OEGMA) as well as the pH-sensitive monomer N,N-Diethylaminoethyl methacrylate (DEAEMA) were used to make the gel with temperature and pH response. Four kinds of physicochemical double-crosslinked amphiphilic co-network gels with different polymerization degrees were prepared by the one-pot method using the stereocomplex between polylactic acid as physical crosslinking and click chemistry as chemical crosslinking. By testing morphology, swelling, thermal stability and mechanical properties, the properties of the four hydrogels were compared. Finally, the drug release rate of the four gels was tested by UV–Vis spectrophotometer. It was found that the synthetic hydrogels had a good drug release rate and targeting, and had great application prospect in drug delivery. Full article
(This article belongs to the Special Issue Hydrogels in Action: Self-Assembly, Responsivity and Sensing)
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13 pages, 2640 KiB  
Article
Green Synthesized Silver Nanoparticles Loaded in Polysaccharide Hydrogel Applied to Chronic Wound Healing in Mice Models
by Fahad M. Aldakheel, Dalia Mohsen, Marwa M. El Sayed, Mohammed H. Fagir and Dalia K. El Dein
Gels 2023, 9(8), 646; https://doi.org/10.3390/gels9080646 - 11 Aug 2023
Cited by 1 | Viewed by 1259
Abstract
The prevalence of chronic wounds is increasing owing to the expanding population and the growing number of individuals suffering from diabetes. Such a chronic wound continues to be a significant healthcare burden for diabetic patients because it frequently carries a high chance of [...] Read more.
The prevalence of chronic wounds is increasing owing to the expanding population and the growing number of individuals suffering from diabetes. Such a chronic wound continues to be a significant healthcare burden for diabetic patients because it frequently carries a high chance of limb loss due to amputation and reduces survival as a result. Development of innovative wound dressing materials with the potential to stop bacterial infections and accelerate the process of tissue regeneration is needed to increase the effectiveness of diabetic wound healing. In the current study, a co-polymerization process based on a free radical reaction was used to create a hydrogel of polysaccharides blend graft acrylamide (PsB-g-Am). Starch, chitosan, and alginate make up the polysaccharides blend (PsB). The produced hydrogel’s structure was characterized using FTIR spectroscopy. The antibacterial activities of silver nanoparticles synthesized through the green method using garlic bulb (Allium sativum) is reported. The silver nanoparticles’ physical characteristics were examined using scanning electron microscopy, transmission electron microscopy analysis, and UV-visible spectroscopy and they were found to range in size from 50 to 100 nm. The agar well diffusion technique is used to investigate the antibacterial characteristics. Inclusion of silver nanoparticles in the hydrogels demonstrated concentration-dependent antibacterial behavior against Gram-negative Klebsiella pneumoniae and Gram-positive Staphylococcus aureus during antimicrobial testing of the hydrogels. When hydrogels were applied to diabetic mice, the system was examined for its healing abilities, and positive therapeutic results were obtained in as little as 14 days. Thus, it can be inferred that graft copolymer of chitosan-AgNPs hydrogels can promote healing in chronic wounds over time and can be utilized as an alternative to conventional therapies for chronic wounds (such as those brought on by diabetes) in mouse models. Full article
(This article belongs to the Special Issue Hydrogel for Sustained Delivery of Therapeutic Agents)
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12 pages, 1749 KiB  
Systematic Review
Comparative Study of In Situ Gel Formulation Based on the Physico-Chemical Aspect: Systematic Review
by Insan Sunan Kurniawansyah, Taofik Rusdiana, Iyan Sopyan, Insi Farisa Desy Arya, Habibah A. Wahab and Dela Nurzanah
Gels 2023, 9(8), 645; https://doi.org/10.3390/gels9080645 - 10 Aug 2023
Cited by 4 | Viewed by 2528
Abstract
In recent years, in situ gel delivery systems have received a great deal of attention among pharmacists. The in situ gelation mechanism has several advantages over ointments, the most notable being the ability to provide regular and continuous drug delivery with no impact [...] Read more.
In recent years, in situ gel delivery systems have received a great deal of attention among pharmacists. The in situ gelation mechanism has several advantages over ointments, the most notable being the ability to provide regular and continuous drug delivery with no impact on visual clarity. Bioavailability, penetration, duration, and maximum medication efficacy are all improved by this mechanism. Our review systematically synthesizes and discusses comparisons between three types of in situ gelling system according to their phase change performance based on the physicochemical aspect from publications indexed in the Pubmed, ResearchGate, Scopus, Elsevier, and Google Scholar databases. An optimal temperature-sensitive in situ gelling solution must have a phase change temperature greater than ambient temperature (25 °C) to be able to be readily delivered to the eye; hence, it was fabricated at 35 °C, which is the precorneal temperature. In a pH-sensitive gelling system, a gel develops immediately when the bio-stimuli come into contact with it. An in situ gelling system with ionic strength-triggered medication can also perhaps be used in optical drug-delivery mechanisms. In studies about the release behavior of drugs from in situ gels, different models have been used such as zero-order kinetics, first-order kinetics, the Higuchi model, and the Korsmeyer-Peppas, Peppas-Sahlin and Weibull models. In conclusion, the optimum triggering approach for forming gels in situ is determined by a certain therapeutic delivery application combined with the physico-chemical qualities sought. Full article
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18 pages, 3944 KiB  
Article
Rheological Study of the Formation of Pullulan Hydrogels and Their Use as Carvacrol-Loaded Nanoemulsion Delivery Systems
by Esther Santamaría, Leticia Anjinho de Barros, Carme González and Alicia Maestro
Gels 2023, 9(8), 644; https://doi.org/10.3390/gels9080644 - 9 Aug 2023
Cited by 4 | Viewed by 1433
Abstract
Hydrogels have been extensively studied as delivery systems for lipophilic compounds. Pullulan hydrogels were prepared, and their gelation kinetics were studied over time. Pullulan exhibited a relatively slow gelling reaction in basic medium (KOH) using trisodium metaphosphate (STMP) as a cross-linking agent, so [...] Read more.
Hydrogels have been extensively studied as delivery systems for lipophilic compounds. Pullulan hydrogels were prepared, and their gelation kinetics were studied over time. Pullulan exhibited a relatively slow gelling reaction in basic medium (KOH) using trisodium metaphosphate (STMP) as a cross-linking agent, so capsules cannot be obtained by dripping as easily as in the case of alginate and chitosan. The kinetics of pullulan gelation were studied through rheological analysis over time. An optimal [Pullulan]/[KOH] ratio was found for a fixed [Pullulan]/[STMP] ratio. For this given relationship, gelling time measurements indicated that when the concentration of pullulan increased, the gelation time decreased from 60 min for 6% w/w pullulan to 10 min for 10% w/w. After the gel point, a hardening of the hydrogel was observed over the next 5 h. The formed hydrogels presented high degrees of swelling (up to 1800%). Freeze-dried gels were capable of being rehydrated, obtaining gels with rheological characteristics and visual appearance similar to fresh gels, which makes them ideal to be freeze-dried for storage and rehydrated when needed. The behavior of the hydrogels obtained as active ingredient release systems was studied. In this case, the chosen molecule was carvacrol (the main component of oregano oil). As carvacrol is hydrophobic, it was incorporated into the droplets of an oil-in-water nanoemulsion, and the nanoemulsion was incorporated into the hydrogel. The release of the oil was studied at different pHs. It was observed that as the pH increased (from pH 2 to pH 7), the released amount of carvacrol for the gel with pullulan 10% w/w reached 100%; for the other cases, the cumulative release amount was lower. It was attributed to two opposite phenomena in the porous structure of the hydrogel, where more porosity implied a faster release of carvacrol but also a higher degree of swelling that promoted a higher entry of water flow in the opposite direction. This flow of water prevented the active principle from spreading to the release medium. Full article
(This article belongs to the Special Issue Synthesis and Applications of Hydrogels)
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