Search Results (32)

pH-sensitive hydrogels are important soft biomaterials as they mimic biological organisms by altering their properties in response to small pH changes in biological fluids. In this work, novel chitosan (Cs) hydrogels were developed using an innovative dual curcumin (Cur) encapsulation system. Cur was loaded into poloxamer 407 micelles and incorporated into citric acid (CA) cross-linked Cs hydrogels using a central composite design. The hydrogels were characterized using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), rheological tests, and in vitro experiments, such as hemolysis and cytotoxicity assays. FTIR confirmed cross-linking between Cs and CA, while DSC suggested interactions between Cur-loaded micelles and the hydrogel matrix. Rheological analysis revealed gel-like behavior, with G′ consistently higher than G, and temperature influenced hydrogel properties. SEM showed a denser network when Cur-loaded micelles were incorporated, slowing Cur release. At physiological pH (7.4), 75% of Cur was released after 7 days, while 84% was released at pH 5.5, showing pH-responsive behavior. Cytotoxicity tests showed over 80% viability of VERO CCL-81 cells (0.2–20 ppm hydrogel). This dual-encapsulation system provides a simple and effective platform for loading lipophilic drugs into pH-responsive hydrogels. Full article

Triboelectric nanogenerators (TENGs) are ideal for meeting the global demand for sustainable energy in energy harvesting and wearable electronics. While biomaterials like polysaccharides are well studied in TENGs, the potential of polyphenols and the role of phenolic groups in contact electrification remain underexplored. This study bridges the gap by using tannic acid (TA) to rapidly prepare TA-Fe³⁺ complex-coated particle films in 1.2 min. Analysis reveals that phenolic hydroxyl groups are strong electron donors, with Fe³⁺ enhancing electron affinity by restricting their mobility and lowering molecular orbital energy levels. Adjusting the pH to control complex states enables the regulation of triboelectric charging behavior between positive and negative. Investigations into film micromorphology and particle size further optimize performance, with the tris-complex exhibiting negative charging behavior achieving exceptional stability and a high charge density of 92.5 μC·m⁻². Additionally, integrating biomaterials into bio-TENGs and exploring the film’s pH and ion sensitivity broaden its applications, demonstrating versatile properties. This study clarifies the triboelectric properties of phenolic groups and proposes methods to regulate charging behavior, offering novel insights for developing biomaterials in TENGs. Full article

Bone defects caused by various traumas and diseases such as osteoporosis, which affects bone density, and osteosarcoma, which affects the integrity of bone structure, are now well known. Given this situation, several innovative research projects have been reported to improve orthopedic methods and technologies that positively contribute to the regeneration of affected bone tissue, representing a significant advance in regenerative medicine. This review article comprehensively analyzes the transition from existing methods and technologies for implants and bone tissue regeneration to innovative biomaterials. These biomaterials have been of great interest in the last decade due to their physicochemical characteristics, which allow them to overcome the most common limitations of traditional grafting methods, such as the availability of biomaterials and the risk of rejection after their application in regenerative medicine. This could be achieved through an exhaustive study of the applications and properties of various materials with potential applications in regenerative medicine, such as using magnetic nanoparticles and hydrogels sensitive to external stimuli, including pH and temperature. In this regard, this review article describes the most relevant compounds used in bone tissue regeneration, promoting the integration of these biomaterials with the affected area’s bone structure, thereby allowing for regeneration and preventing amputation. Additionally, the types of interactions between biomaterials and mesenchymal stem cells and their effects on bone tissue are discussed, which is critical for developing biomaterials with optimal regenerative properties. Furthermore, the mechanisms of action of the various biomaterials that enhance osteoconduction and osteoinduction, ensuring the success of orthopedic therapies, are analyzed. This enables the treatment of bone defects tailored to each patient’s condition, thereby avoiding limb amputation. Consequently, a promising future for regenerative medicine is emerging, with various therapies that could revolutionize the management of bone defects, offering more efficient and safer solutions. Full article

This study investigates the synthesis and properties of innovative poly(oligo(alkylene glycol)) methacrylate hydrogels synthesized via gamma radiation-induced copolymerization and the crosslinking of oligo(ethylene glycol) methacrylate (OEGMA) and oligo(propylene glycol) methacrylate (OPGMA) at varying mole fractions. Our primary objective is to investigate the impact of copolymerization on the swelling properties of P(OEGMA/OPGMA) hydrogels compared to their homopolymeric counterparts, namely, POEGMA and POPGMA, which exhibit distinct volume phase transition temperatures (VPTTs) of around 70 and 13 °C, respectively, under physiological conditions. To this end, a comprehensive library of smart methacrylate-based hydrogel biomaterials was developed, featuring detailed data on their swelling behavior across different copolymer molar ratios and physiological temperature ranges. To achieve these objectives, we conducted swelling behavior analysis across a wide range of temperatures, assessed the pH sensitivity of hydrogels, utilized scanning electron microscopy for morphological characterization, performed in vitro biocompatibility assessment through cell viability and hemolysis assays, and employed diclofenac sodium as a model drug to control drug delivery testing. Our findings demonstrate that the newly synthesized P(OEGMA₄₀/OPGMA₆₀) copolymeric hydrogel exhibits desirable characteristics, with VPTT close to the physiological temperatures required for controlled drug delivery applications. Full article

The study aims to determine how chitosan impacts pectin hydrogel’s ability to attach peritoneal leukocytes, activate complement, induce hemolysis, and adsorb blood proteins. The hydrogels PEC-Chi0, PEC-Chi25, PEC-Chi50, and PEC-Chi75 were prepared by placing a mixture solution of 4% pectin and 4% chitosan in a ratio of 4:0, 3:1, 2:2, and 1:3 in a solution of 1.0 M CaCl₂. Chitosan was found to modify the mechanical properties of pectin–calcium hydrogels, such as hardness and cohesiveness-to-adhesiveness ratio. Chitosan in the pectin–calcium hydrogel caused pH-sensitive swelling in Hanks’ solution. The PEC-Chi75 hydrogel was shown to adsorb serum proteins at pH 7.4 to a greater extent than other hydrogels. PEC-Chi75’s strong adsorption capacity was related to lower peritoneal leukocyte adherence to its surface when compared to other hydrogels, showing improved biocompatibility. Using the optical tweezers approach, it was shown that the force of interaction between pectin–chitosan hydrogels and plasma proteins increased from 10 to 24 pN with increasing chitosan content from 0 to 75%. Thus, the properties of pectin–calcium hydrogel, which determine interactions with body tissues after implantation, are improved by the addition of chitosan, making pectin–chitosan hydrogel a promising candidate for smart biomaterial development. Full article

Colon-targeted drug delivery is gradually attracting attention because it can effectively treat colon diseases. Furthermore, electrospun fibers have great potential application value in the field of drug delivery because of their unique external shape and internal structure. In this study, a core layer of hydrophilic polyethylene oxide (PEO) and the anti-colon-cancer drug curcumin (CUR), a middle layer of ethanol, and a sheath layer of the natural pH-sensitive biomaterial shellac were used in a modified triaxial electrospinning process to prepare beads-on-the-string (BOTS) microfibers. A series of characterizations were carried out on the obtained fibers to verify the process–shape/structure–application relationship. The results of scanning electron microscopy and transmission electron microscopy indicated a BOTS shape and core–sheath structure. X-ray diffraction results indicated that the drug in the fibers was in an amorphous form. Infrared spectroscopy revealed the good compatibility of the components in the fibers. In vitro drug release revealed that the BOTS microfibers provide colon-targeted drug delivery and zero-order drug release. Compared to linear cylindrical microfibers, the obtained BOTS microfibers can prevent the leakage of drugs in simulated gastric fluid, and they provide zero-order release in simulated intestinal fluid because the beads in BOTS microfibers can act as drug reservoirs. Full article

Hydrogels are three-dimensional networks with a variety of structures and functions that have a remarkable ability to absorb huge amounts of water or biological fluids. They can incorporate active compounds and release them in a controlled manner. Hydrogels can also be designed to be sensitive to external stimuli: temperature, pH, ionic strength, electrical or magnetic stimuli, specific molecules, etc. Alternative methods for the development of various hydrogels have been outlined in the literature over time. Some hydrogels are toxic and therefore are avoided when obtaining biomaterials, pharmaceuticals, or therapeutic products. Nature is a permanent source of inspiration for new structures and new functionalities of more and more competitive materials. Natural compounds present a series of physico-chemical and biological characteristics suitable for biomaterials, such as biocompatibility, antimicrobial properties, biodegradability, and nontoxicity. Thus, they can generate microenvironments comparable to the intracellular or extracellular matrices in the human body. This paper discusses the main advantages of the presence of biomolecules (polysaccharides, proteins, and polypeptides) in hydrogels. Structural aspects induced by natural compounds and their specific properties are emphasized. The most suitable applications will be highlighted, including drug delivery, self-healing materials for regenerative medicine, cell culture, wound dressings, 3D bioprinting, foods, etc. Full article

For biomedical applications, gelatin is usually modified with methacryloyl groups to obtain gelatin methacryloyl (GelMA), which can be crosslinked by a radical reaction induced by low wavelength light to form mechanically stable hydrogels. The potential of GelMA hydrogels for tissue engineering has been well established, however, one of the main disadvantages of mammalian-origin gelatins is that their sol-gel transitions are close to room temperature, resulting in significant variations in viscosity that can be a problem for biofabrication applications. For these applications, cold-water fish-derived gelatins, such as salmon gelatin, are a good alternative due to their lower viscosity, viscoelastic and mechanical properties, as well as lower sol-gel transition temperatures, when compared with mammalian gelatins. However, information regarding GelMA (with special focus on salmon GelMA as a model for cold-water species) molecular conformation and the effect of pH prior to crosslinking, which is key for fabrication purposes since it will determine final hydrogel’s structure, remains scarce. The aim of this work is to characterize salmon gelatin (SGel) and salmon methacryloyl gelatin (SGelMA) molecular configuration at two different acidic pHs (3.6 and 4.8) and to compare them to commercial porcine gelatin (PGel) and methacryloyl porcine gelatin (PGelMA), usually used for biomedical applications. Specifically, we evaluated gelatin and GelMA samples’ molecular weight, isoelectric point (IEP), their molecular configuration by circular dichroism (CD), and determined their rheological and thermophysical properties. Results showed that functionalization affected gelatin molecular weight and IEP. Additionally, functionalization and pH affected gelatin molecular structure and rheological and thermal properties. Interestingly, the SGel and SGelMA molecular structure was more sensitive to pH changes, showing differences in gelation temperatures and triple helix formation than PGelMA. This work suggests that SGelMA presents high tunability as a biomaterial for biofabrication, highlighting the importance of a proper GelMA molecular configuration characterization prior to hydrogel fabrication. Full article

In 2020, we published a review on the study of semi-crystalline thermoplastic polyurethane elastomers and composites based on the shape memory effect. The shape recovery ability of such polymers is determined by their sensitivity to temperature, moisture, and magnetic or electric fields, which in turn are dependent on the chemical properties and composition of the matrix and the nanofiller. Nanocellulose is a type of nanomaterial with high strength, high specific surface area and high surface energy. Additionally, it is nontoxic, biocompatible, environmentally friendly, and can be extracted from biomass resources. Thanks to these properties, nanocellulose can be used to enhance the mechanical properties of polymer matrices with shape memory effect and as a switching element of shape memory. This review discusses the methods for producing and properties of nanocellulose-based thermo-, moisture-, and pH-sensitive polyurethane composites. The synergistic effect of nanocellulose and carbon nanofillers and possible applications of nanocellulose-based thermoplastic polyurethane biocomposites with shape memory effect are discussed. A brief description of nanocellulose terminology is also given, along with the structure of shape memory thermoplastic polyurethanes. There is significant interest in such materials for three primary reasons: the possibility of creating a new generation of biomaterials, improving the environmental friendliness of existing materials, and exploiting the natural renewability of cellulose sources. Full article

Infection is a major problem that increases the normal pH of the wound bed and interferes with wound healing. Natural biomaterials can serve as a suitable environment to acquire a great practical effect on the healing process. In this context, anthocyanin-rich red cabbage (Brassica oleracea var. capitata F. rubra) extract and honey-loaded alginate hydrogel was fabricated using calcium chloride as a crosslinking agent. The pH sensitivity of anthocyanins can be used as an indicator to monitor possible infection of the wound, while honey would promote the healing process by its intrinsic properties. The mechanical properties of the hydrogel film samples showed that honey acts as a plasticizer and that increasing the incorporation from 200% to 400% enhances the tensile strength from 3.22 to 6.15 MPa and elongation at break from 0.69% to 4.75%. Moreover, a water absorption and retention study showed that the hydrogel film is able to absorb about 250% water after 50 min and retain 40% of its absorbed water after 12 h. The disk diffusion test showed favorable antibacterial activity of the honey-loaded hydrogel against both Gram-positive and Gram-negative Staphylococcus aureus and Escherichia coli, respectively. In addition, the incorporation of honey significantly improved the mechanical properties of the hydrogel. 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay proved the antioxidant activity of the honey and anthocyanin-containing hydrogel samples with more than 95% DPPH scavenging efficiency after 3 h. The pH-dependent property of the samples was investigated and recorded by observing the color change at different pH values of 4, 7, and 9 using different buffers. The result revealed a promising color change from red at pH = 4 to blue at pH = 7 and purple at pH = 9. An in vitro cell culture study of the samples using L929 mouse fibroblast cells showed excellent biocompatibility with significant increase in cell proliferation. Overall, this study provides a promising start and an antibacterial/antioxidant hydrogel with great potential to meet wound-dressing requirements. Full article

Hydrogels are intensively investigated biomaterials due to their useful physicochemical and biological properties in bioengineering. In particular, naturally occurring hydrogels are being deployed as carriers for bio-compounds. We used two approaches to develop a plate colourimetric test by immobilising (1) ABTS or (2) laccase from Trametes versicolor in the gelatine-based hydrogel. The first system (1) was applied to detect laccase in aqueous samples. We investigated the detection level of the enzyme between 0.05 and 100 µg/mL and pH ranging between 3 and 9; the stability of ABTS in the solution and the immobilised form, as well as the retention functional property of the hydrogel in 4 °C for 30 days. The test can detect laccase within 20 min in the concentration range of 2.5–100 µg/mL; is effective at pH 3–6; preserves high stability and functionality under storage and can be also successfully applied for testing samples from a microbial culture. The second system with the immobilised laccase (2) was tested in terms of substrate specificity (ABTS, syringaldazine, guaiacol) and inhibitor (NaN₃) screening. ABTS appeared the most proper substrate for laccase with detection sensitivity C_ABTS > 0.5 mg/mL. The NaN₃ tested in the range of 0.5–100 µg/mL showed a distinct inhibition effect in 20 min for 0.5 µg/mL and total inhibition for ≥75 µg/mL. Full article

Bacterial cellulose (BC) is a biopolymer with vast application prospects, and its production demands culture media rich in carbon sources. Here, we researched a modified in situ strategy for preparing composite hydrogels comprising BC and sodium alginate (SA) or sodium hyaluronate (SH), termed as SA-BC and SH-BC, respectively. A new carbon source for BC generation was successfully developed from cassava residue saccharification liquid (CSL), in an attempt to better exploit the residue and decrease the costs of BC production. SA or SH was mechanically hydrogen-bonded with BC nanofibers to form porous nanostructures. Compared to the native BC, the mechanical strength of SH-BC with 1% SH was 61% higher and the thermal stability was also improved. A considerable difference in the cumulative drug-release rate of 93% in 66 h revealed that SA-BC with 0.5% SA exhibited a higher pH sensitivity due to its abundant fibrous layers, the -COO^--electrostatic repulsion, and the weakened hydrogen-bonding at pH 7.4. Such in situ-derived composite hydrogels could provide insights for BC functionalization and advance understanding of polysaccharides’ conversion to biomaterials with favorable biocompatibility and sustainability. Full article

Poly(2-oxazoline)s are the synthetic polymers that are the products of the cationic ring-opening polymerization (CROP) of 2-oxazoline monomers. Due to their beneficial properties, from which biocompatibility, stealth behavior, high functionalization possibilities, low dispersity, stability, nonionic character, and solubility in water and organic solvents should be noted, they have found many applications and gained enormous interest from scientists. Additionally, with high versatility attainable through copolymerization or through post-polymerization modifications, this class of polymeric systems has been widely used as a polymeric platform for novel biomedical applications. The chemistry of polymers significant expanded into biomedical applications, in which polymeric networks can be successfully used in pharmaceutical development for tissue engineering, gene therapies, and also drug delivery systems. On the other hand, there is also a need to create ‘smart’ polymer biomaterials, responsive to the specified factor, that will be sensitive to various environmental stimuli. The commonly used stimuli-responsive biomedical materials are based mostly on temperature-, light-, magnetic-, electric-, and pH-responsive systems. Thus, creating selective and responsive materials that allow personalized treatment is in the interest of the scientific world. This review article focuses on recent discoveries by Polish scientists working in the field of stimuli-responsive poly(2-oxazoline)s, and their work is compared and contrasted with results reported by other world-renowned specialists. Full article

Many concerns are being expressed about the biodegradability, biocompatibility, and long-term viability of polymer-based substances. This prompted the quest for an alternative source of material that could be utilized for various purposes. Starch is widely used as a thickener, emulsifier, and binder in many food and non-food sectors, but research focuses on increasing its application beyond these areas. Due to its biodegradability, low cost, renewability, and abundance, starch is considered a “green path” raw material for generating porous substances such as aerogels, biofoams, and bioplastics, which have sparked an academic interest. Existing research has focused on strategies for developing biomaterials from organic polymers (e.g., cellulose), but there has been little research on its polysaccharide counterpart (starch). This review paper highlighted the structure of starch, the context of amylose and amylopectin, and the extraction and modification of starch with their processes and limitations. Moreover, this paper describes nanofillers, intelligent pH-sensitive films, biofoams, aerogels of various types, bioplastics, and their precursors, including drying and manufacturing. The perspectives reveal the great potential of starch-based biomaterials in food, pharmaceuticals, biomedicine, and non-food applications. Full article

Limited tissue selectivity and targeting of anticancer therapeutics in systemic administration can produce harmful side effects in the body. Various polymer nano-vehicles have been developed to encapsulate therapeutics and prevent premature drug release. Dually responsive polymeric vesicles (polymersomes) assembled from temperature-/pH-sensitive block copolymers are particularly interesting for the delivery of encapsulated therapeutics to targeted tumors and inflamed tissues. We have previously demonstrated that temperature-responsive poly(N-vinylcaprolactam) (PVCL)-b-poly(dimethylsiloxane) (PDMS)-b-PVCL polymersomes exhibit high loading efficiency of anticancer therapeutics in physiological conditions. However, the in-vivo toxicity of these polymersomes as biocompatible materials has not yet been explored. Nevertheless, developing an advanced therapeutic nanocarrier must provide the knowledge of possible risks from the material’s toxicity to support its future clinical research in humans. Herein, we studied pH-induced degradation of PVCL₁₀-b-PDMS₆₅-b-PVCL₁₀ vesicles in-situ and their dually (pH- and temperature-) responsive release of the anticancer drug, doxorubicin, using NMR, DLS, TEM, and absorbance spectroscopy. The toxic potential of the polymersomes was evaluated in-vivo by intravenous injection (40 mg kg⁻¹ single dose) of PVCL₁₀-PDMS₆₅-PVCL₁₀ vesicles to mice. The sub-acute toxicity study (14 days) included gravimetric, histological, and hematological analyses and provided evidence for good biocompatibility and non-toxicity of the biomaterial. These results show the potential of these vesicles to be used in clinical research. Full article