Search Results (202)

Developing a rapidly gel-forming, in situ sprayable hydrogel with wound dressing functionality is essential for enhancing the wound healing process. In this study, a novel sprayable hydrogel-based wound dressing was developed by combining thermo- and pH- responsive polymers including Pluronic F127 (PF127) and N-succinyl chitosan (NSC). NSC was prepared by modifying chitosan with succinic anhydride, as confirmed by Fourier-transform infrared spectroscopy and nuclear magnetic resonance spectroscopy. The NSC synthesized using a succinic anhydride-to-chitosan molar ratio of 5:1 exhibited the highest degree of substitution, resulting in a water-soluble polymer effective over a broad pH range. The formulation process of the PF127:NSC sprayable hydrogel was optimized and evaluated based on its sol–gel phase transition behavior, clarity, gelation time, liquid and moisture management, stability, and cytotoxicity. These properties can be suitably tailored by adjusting the concentrations of PF127 and NSC. Moreover, the antioxidant capacity of the hydrogels was enhanced by incorporating Azadirachta indica (neem) extract, a bioactive compound, into the optimized sprayable hydrogel. Both neem release and antioxidant activity increased in a dose-dependent manner. Overall, the developed sprayable hydrogel exhibited favorable sprayability, appropriate gelation properties, controlled drug release, and antioxidant activity, underscoring its promising translational potential as a wound dressing. Full article

Poly(trimethylene terephthalate) (PTT) is a thermoplastic polyester with a unique structure due to having three methylene groups in the glycol unit. PTT competes with poly(ethylene terephthalate) (PET) and poly(butylene terephthalate) (PBT) in carpets, textiles, and thermoplastic materials, primarily due to the development of economically efficient synthesis methods. PTT is widely utilized in textiles, carpets, and engineering plastics because of its advantageous properties, including quick-drying capabilities and wrinkle resistance. However, its low melting point, resistance to chemicals, and brittleness compared to PET, have limited its applications. To address some of these limitations for targeted applications, PTT nanocomposites incorporating clay, carbon nanotube, silica, and ZnO have been developed. The distribution of nanoparticles within the PTT matrix remains a significant challenge for its potential applications. Several techniques, including sol–gel blending, melt blending, in situ polymerization, and in situ forming methods have been developed to obtain better dispersion. This review discusses advancements in the synthesis of various PTT nanocomposites and the effects of nanoparticles on the isothermal and nonisothermal crystallization of PTT. Full article

The interest in macromolecular alkoxysilyl-functionalized hybrids (self-assembling or nanostructured), which could be used as precursors in biomimetic silica precipitation and for the synthesis of hollow spherical silica particles, is growing. Nevertheless, reports on all-organosilicon systems for bioinspired silica precipitation are scarce. Therefore, a new kind of polyalkoxysilane macromonomer–linear polysilsesquioxane (LPSQ) of ladder-like backbone, functionalized in side chains with trimethoxysilyl groups (LPSQ-R-Si(OMe)₃), was designed following this approach. It was obtained by photoinitiated thiol-ene addition of 3-mercaptopropyltrimethoxysilane to the vinyl-functionalized polysilsesquioxane precursor, carried out in situ in tetraethoxysilane (TEOS). The mixture of LPSQ-R-Si(OMe)₃ and TEOS (co-monomers) was used in a sol–gel process conducted under acidic conditions (0.5 M HCl/NaCl) in the presence of Pluronic^® F-127 triblock copolymer as a template. LPSQ-R-Si(OMe)₃ played a key role for the formation of microparticles of a spherical shape that were formed under the applied conditions, while their size (as low as 3–4 µm) was controlled by the stirring rate. The hybrid materials were hydrophobic and showed good thermal and oxidative stability. Introduction of zinc acetate (Zn(OAc)₂) as an additive in the sol–gel process influenced the pH of the reaction medium, which resulted in structural reinforcement of the hybrid microparticles owing to more effective condensation of silanol groups and a relative increase of the content of SiO₂. The proposed method shows directions in designing the properties of hybrid materials and can be translated to other silicon–organic polymers and oligomers that could be used to produce hollow silica particles. The established role of various factors (macromonomer structure, pH, and stirring rate) allows for the modulation of particle morphology. Full article

The removal of iron deposits on shipwreck surfaces by mechanical cleaning is labour-intensive work. This study develops an in situ gel and peeling cleaning method, utilising a carboxymethyl chitosan/tannic acid (CMCS/TA) colloidal solution spray on the surface of ferruginous deposits, promoting their removal by adhesion, chelation, and electrostatic bonding processes. The investigation confirmed that the CMTA-2 sample exhibited a sprayable viscosity of 263 mPa/s, the largest single removal thickness of 1.01 mm, a significant reduction in the fe/s atomic ratio by 2.53 units, and enhanced the deposit removal homogeneity. The field testing of the Nanhai I cultural relic showed a 14.37% reduction in iron concentration and a significant decrease in red colour (Δa* = 4.36). The synergistic mechanism involves TA chelating Fe²⁺/Fe³⁺ ions, while the CMCS gel network facilitates interfacial adhesion and mechanical peeling, hence promoting efficient and controllable cleaning. Full article

Postoperative adhesions are a prevalent complication following abdominal surgeries, often leading to significant clinical challenges. This study introduces an innovative solution utilizing a polyethylene glycol (PEG)-based triblock copolymer to form an injectable, self-healing hydrogel aimed at preventing these adhesions. The hydrogel, formulated with temperature-responsive and self-healing properties through the incorporation of poly (N-isopropyl acrylamide) (PNIPAM) and anion–pi interactions, was synthesized using reversible addition–fragmentation chain transfer (RAFT) polymerization. The hydrogel’s physical properties, biocompatibility, hemostatic effect, and anti-adhesive capabilities were rigorously tested through in vitro and in vivo experiments involving rat models. It demonstrated excellent biocompatibility, effective tissue adhesion, and robust hemostatic properties. Most notably, it exhibited significant anti-adhesive effects in a rat abdominal wall–cecum model, reducing adhesion formation effectively compared to controls. The PEG-based injectable hydrogel presents a promising approach for postoperative adhesion prevention. Its ability to gel in situ triggered by body heat, coupled with its self-healing properties, provides a substantial advantage in clinical settings, indicating its potential utility as a novel anti-adhesion material. Full article

Tomato spotted wilt virus (TSWV) is a highly destructive plant pathogen and transmitted by several thrips including the western flower thrips, Frankliniella occidentalis. A structural N protein encoded in the viral genome represents the nucleocapsid protein by binding to the viral RNA genome. However, it remains unknown how the RNA-binding protein specifically interacts with the viral RNA from host RNAs in the target cells. To study the molecular basis of N function, we produced the protein in Escherichia coli and the resulting purified recombinant protein was used to investigate the protein–RNA interactions. The recombinant N protein migrated on agarose gel to the anode in the electric field due to its high basic isoelectric point. This electrostatic property led N protein to bind to DNA as well as RNA. It also bound to both single-stranded (ssRNA) and double-stranded RNA (dsRNA). However, when the total RNA was extracted from plant tissues collected from TSWV-infected host, the RNA extract using the recombinant N protein was much richer in the TSWV genome compared to that without the protein. To investigate the specificity of N protein to ssRNA, the three-dimensional structure was predicted using the AlphaFold program and showed its trimeric oligomerization with the binding pocket for ssRNA. This was supported by the differential susceptibility of N protein with ssRNA and dsRNA against RNase attack. Furthermore, a thermal shift assay to analyze the RNA and protein interaction showed that ssRNA strongly interacted with N protein compared to dsRNA. In addition, the N gene was expressed along with the multiplication of the viral RNA genome segments from the segment-specific fluorescence in situ hybridization analysis in different tissues during different developmental stages of the virus-infected F. occidentalis. These results suggest that the functional trimeric N proteins bind to the viral RNA to form a basic nucleocapsid structure at a specific virus-replicating compartment within the host cells. Full article

The widespread phase-out of long-chain per- and poly-fluoroalkyl substances (PFASs) has created an urgent need for durable, fluorine-free water-repellent finishes that match the performance of legacy chemistries while minimising environmental impact. Here, the performance of an eco-friendly hybrid organic–inorganic treatment obtained by the in situ hydrolysis–condensation of triethoxy(octyl)silane (OS) in an amino-terminated polydimethylsiloxane (APT-PDMS) aqueous dispersion was investigated. The sol was applied to plain-weave cotton and polyester by a pad-dry-cure process and benchmarked against a commercial fluorinated finish. Morphology and chemistry were characterised by SEM–EDS, ATR-FTIR, and Raman spectroscopy; wettability was assessed by static contact angle, ISO 4920 spray ratings, and AATCC 193 water/alcohol repellence; and durability, handle, and breathability were evaluated through repeated laundering, bending stiffness, and water-vapour transmission rate measurements. The silica/PDMS coating formed a uniform, strongly adherent nanostructured layer conferring static contact angles of 130° on cotton and 145° on polyester. After five ISO 105-C10 wash cycles, the treated fabrics still displayed a spray rating of 5/5 and AATCC 193 grade 7, outperforming or equalling the fluorinated control, while causing ≤5% loss of water-vapour permeability and only a marginal increase in bending stiffness. These results demonstrate that the proposed one-step, water-borne sol–gel process affords a sustainable, industrially scalable route to high-performance, durable, water-repellent finishes for both natural and synthetic textiles, offering a viable alternative to PFAS-based chemistry for outdoor apparel and technical applications. Full article

Cellulose acetate butyrate (CAB) and cellulose acetate propionate (CAP) are biobased materials that are insoluble in water and present a potential alternative to fossil-based plastics. Solvent removal-induced in situ matrices are gaining attention as an innovative dosage form for localized drug delivery for periodontitis therapy. This study aims to develop levofloxacin hemihydrate (Lh)-loaded in situ matrices formed through solvent removal, incorporating various molecular weights (MWs) and concentrations of CAB and CAP. Increased MWs and higher concentrations of these cellulosic esters significantly improved formulation viscosity and injection force, contributing to enhanced phase inversion and greater matrix toughness. Microscopic analysis of interfacial phase changes revealed progressive thickening of the matrix over time, which was influenced by polymer concentration and limited solvent movement. The transformed matrices with high MW CAP and elevated CAB content demonstrated prolonged drug release, predominantly following first-order kinetics, suggesting drug dissolution and diffusion through the scaffold structure. CAB-based in situ matrices containing 15% and 20% polymer exhibited low viscosities suitable for injection, along with optimal gel formation for maintaining their shape, and adhered effectively to periodontal pockets. These matrices provided extended Lh release for up to 120 h and inhibited the growth of periodontopathic bacteria for over 15 days. Therefore, the developed Lh-loaded in situ matrices show promise as an effective treatment for periodontitis, warranting further research to explore their therapeutic potential. Full article

Nasal drug delivery faces numerous challenges related to the ineffectiveness of most nasal formulations without a mucoadhesive nature, prolonging residence time on the nasal mucosa. Another challenge is the low administrable dosage strength, which can be solved via nano-encapsulation techniques, including the utilization of polymeric micelles. In this study, gellan gum–cellulose derivative complex in situ gelling matrices were formulated to test their effect on the colloidal characteristics of polymeric micelles, their respective rheological behavior, and nasal applicability. It has been proven that these complex matrices can form gels upon contact with nasal fluid without disrupting the micellar structure. Changes in the drug release and permeation profile have been shown in a concentration-dependent manner to hinder the burst-like drug release profile of polymeric micelles. Formulations show concentration- and composition-dependent mucoadhesive features under nasal conditions. Most of the hydrogels possess a soft gel characteristic, making them suitable for nasal administration. In conclusion, this descriptive study provides useful insights for conscious, nasal dosage form design. Full article

Long-acting injectable (LAI) formulations have revolutionized veterinary pharmaceuticals by improving patient compliance, minimizing dosage frequency, and improving therapeutic efficacy. These formulations utilize advanced drug delivery technologies, including microspheres, liposomes, oil solutions/suspensions, in situ-forming gels, and implants to achieve extended drug release. Biodegradable polymers such as poly(lactic-co-glycolic acid) (PLGA), and polycaprolactone (PCL) have been approved by the USFDA and are widely employed in the development of various LAIs, offering controlled drug release and minimizing the side effects. Various classes of veterinary medicines, including non-steroidal anti-inflammatory drugs (NSAIDs), antibiotics, and reproductive hormones, have been successfully formulated as LAIs. Some remarkable LAI products, such as ProHeart^® (moxidectin), Excede^® (ceftiofur), and POSILACTM (recombinant bovine somatotropin), show clinical relevance and commercial success. This review provides comprehensive information on the formulation strategies currently being used and the emerging technologies in LAIs for veterinary purposes. Additionally, challenges in characterization, in vitro testing, in vitro in vivo correlation (IVIVC), and safety concerns regarding biocompatibility are discussed, along with the prospects for next-generation LAIs. Continued advancement in the field of LAI in veterinary medicine is essential for improving animal health. Full article

New 3D printing aerogel materials are environmentally friendly and could be used in environmental protection and biomedical fields. There is significant research interest in 3D printing cellulose-based aerogels since cellulose materials are biocompatible and are abundant in nature. The gel-like nature of the cellulose water suspension is suitable for 3D printing; however, the complexity and resolution of the geometry of aerogels are quite limited, mainly due to the inks’ low viscosity that fails to maintain the integrity of the shape after printing. To address this limitation, a carefully optimized formulation incorporating three key ingredients, i.e., nanofibrils (TEMPO-CNFs), 2,2,6,6-tetramethyl-1-piperidinyloxy modified cellulose nanocrystals (TEMPO-CNC), and sodium carboxymethyl cellulose (CMC), is utilized to enhance the viscosity and structural stability of the ink. This combination of cellulose derivatives utilizes the electrostatic repulsive forces between the negatively charged components to form a stable and uniformly distributed suspension of cellulose materials. Our ink formulations improve printability and shape retention during 3D printing and are optimal for DIW printing. We print by employing an all cellulose-based composite ink using a modified direct ink writing (DIW) 3D printing method, plus an in situ freezing stage to form a layer-by-layer structure, and then follow a freeze-drying process to obtain the well-aligned aerogels. We have investigated the rheological properties of the ink formulation by varying the concentration of these three cellulose materials. The obtained aerogels exhibit highly ordered microstructures in which the micropores are well-aligned along the freezing direction. This study demonstrates a strategy for overcoming the challenges of 3D printing cellulose-based aerogels by formulating a stable composite ink, optimizing its rheological properties, and employing a modified DIW printing process with in situ freezing, resulting in highly ordered, structurally robust aerogels with aligned microporous architectures. Full article

Aqueous gel-casting provides a cost-effective and scalable approach for synthesizing nano-spherical Co₃O₄ powders, enabling precise control over particle morphology. In this study, Co₃O₄ powders were prepared using this method and evaluated as a catalyst precursor for the hydrolysis of sodium borohydride (NaBH₄). The effects of the monomer (acrylamide, AM)-to-metal molar ratio and initiator content (ammonium persulphate, APS) on particle size and catalytic performance were systematically explored. X-ray diffraction (XRD) analysis confirmed the formation of the Co₃O₄ phase at 400 °C, while transmission electron microscopy (TEM) images revealed particle sizes ranging from 16 to 85 nm, with higher AM and APS concentrations promoting finer particles. The optimized catalyst achieved a high hydrogen generation rate (HGR) of 28.13 L min⁻¹·cat.⁻¹, demonstrating excellent catalytic activity. Moreover, in situ-formed cobalt boride, derived from Co₃O₄ calcined at 600 °C for 2 h, exhibited an activation energy of 51.81 kJ mol⁻¹, comparable to Ru-based catalysts. This study underscores the aqueous gel-casting technique as a promising strategy for synthesizing efficient and low-cost hydrogen generation catalysts, offering an alternative to noble metal-based materials. Full article

Foam and hydrogel profile control are commonly utilized water-blocking and profile modification techniques in oil fields. This study integrates a foam system with a gel system, employing an organic titanium crosslinking agent to crosslink polyvinyl alcohol, thereby forming a gel system. Concurrently, a gas-evolving agent is incorporated into the system to induce in situ foaming, thereby creating an environmentally benign foam gel system. The fundamental constituents of this system comprise 2 wt% to 5 wt% polyvinyl alcohol, 2 wt% to 4 wt% crosslinker, and 0.3 wt% to 0.9 wt% gas-generating agent. By varying the amounts of each component, the strength grade, gelation time, and foaming volume of the foam gel can be effectively adjusted. The results of the temperature resistance performance evaluation indicate that within the temperature range of 80 °C to 130 °C, the gelation performance of the foam gel is stable and good. At 90 °C, the foam gel can remain stable for 340 days with minimal strength variation. The plugging experiments indicate that the formulated foam gel system exhibits superior injectability and can effectively seal the sand-filled tube model, achieving a blocking efficiency of up to 96.36%. Full article

Biodiesel was produced via transesterification of canola oil in the presence of a silica xerogel catalyst with deposited gold nanoparticles. The silica-gold catalyst was produced in situ, where gold metal was added to a sodium silicate solution; subsequently, gold nanoparticles were synthesised within the solution. The sodium silicate-gold nanoparticles solution was then turned into a silica-gold gel at pH 8.7 and later dried to form silica-gold nanoparticles xerogel. The produced silica-gold nanoparticles xerogel was characterised by X-ray diffraction (XRD), X-ray fluorescence (XRF), transition electron microscopy (TEM), and nitrogen physisorption. The gel had a silica content of 91.6 wt% and a sodium content of 6.4 wt%, with the added gold content being 99.5% retained. The biodiesel produced in the presence of silica-gold nanoparticles xerogel was characterised by gas chromatography-mass spectroscopy (GC-MS) and its physical properties, such as density, kinematic viscosity, flash point, pour point, and cloud point, were also determined. The silica-gold nanoparticles xerogel catalyst remained solid throughout its usage without leaching into the reaction medium. The produced biodiesel contained mostly monounsaturated fatty acid methyl esters and had a yield of 99.2% at optimum reaction conditions. Full article

The growing need for sustainable biotechnological solutions to address environmental challenges, such as climate change and resource depletion, has intensified interest in microbial-based production systems. Synthetic biofilms, which mimic natural microbial consortia, offer a promising platform for optimizing complex metabolic processes that can convert renewable feedstocks into valuable chemicals. In this context, understanding and harnessing the interactions between co-immobilized microorganisms are critical for advancing bioprocesses that contribute to circular bioeconomy goals. In this study, we investigated the viability and metabolic activity of Clostridium carboxidivorans and Clostridium kluyveri within a synthetic, dual-layered biofilm composed of agar hydrogel. This setup compartmentalized each bacterial species. Embedding the bacteria in a structured biofilm offers numerous opportunities for bioproduction, but the inability to monitor cell growth or movement within the immobilization matrix limits process insights. To address this, we adapted a fluorescence in situ hybridization (FISH) protocol, enabling precise, species-specific visualization of bacterial distribution and growth within the gel matrix. Batch processes with the dual-layered biofilm in anaerobic flasks, designed with a metabolic advantage for C. kluyveri, revealed distinct growth dynamics. C. kluyveri exhibited significant metabolic activity, forming clusters at low initial cell concentrations and converting ethanol and acetate into 1-butyrate and 1-hexanoate, indicating viability and cell growth. C. carboxidivorans remained evenly distributed without significant growth or product formation, suggesting that while the cells were viable, they were not metabolically active under the experimental conditions. Both bacterial species were confined to their respective compartments throughout the process, with C. kluyveri showing enhanced substrate conversion at higher initial cell densities in the hydrogel. The pH drop throughout the batch experiment likely contributed to incomplete substrate consumption, particularly for C. kluyveri, which thrives within a narrow pH range. These findings highlight synthetic biofilms as a promising platform for optimizing microbial interactions and improving bioprocess efficiency, especially in applications involving complex metabolic exchanges between co-immobilized microorganisms. Further research will focus on applying conditions to support the growth and metabolic activity of C. carboxidivorans to explore spatial dynamics of bacterial migration and cooperative relationships in the synthetic biofilm. Full article