Fabrication and characterization of calcium phosphate-reinforced alginate/gelatin composite hydrogels with pH-dependent ciprofloxacin release behavior

A Biomimetic Nanocomposite Hydrogel Cross-Linked by Calcium Phosphate Oligomers for Bone Regeneration.

Conventional gelatin (Gel) and alginate hydrogels possess excellent biocompatibility. Their high water content and three-dimensional porous structure mimic the extracellular matrix, facilitating nutrient transport and metabolic waste removal. However, their application in bone tissue engineering is hindered by insufficient mechanical strength, rapid degradation, and weak osteogenic activity. In this study, we developed a self-cross-linking hydrogel (GOP hydrogel) reinforced with calcium phosphate oligomers (CPO). The network was formed via a Schiff base reaction between periodate-oxidized sodium alginate (OSA) and gelatin, with small-sized CPO acting as an inorganic cross-linker to enhance intermolecular bonding and strengthen the polymeric network. The composite hydrogel was characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD), and its mechanical properties, degradation behavior, and swelling capacity were evaluated. The GOP hydrogel exhibited excellent biocompatibility, supported cell viability and osteogenic differentiation, and promoted vascularized healing in critical-sized calvarial defects in rats. With the incorporation of CPO, the hydrogels exhibited enhanced mechanical strength, regulated degradation and swelling, and improved mineralization and osteogenic activity. These findings indicate that the GOP hydrogel meets the key requirements for bone tissue engineering scaffolds and holds considerable promise for bone regeneration applications.

Tailored Bio‐Based Sodium Alginate/Polyacrylamide Hydrogels With Enhanced Adhesive and Load Bearing Ability

This study focuses on the synthesis of a bio‐based, viscoelastic hydrogel derived from sodium alginate with enhanced adhesive properties suitable for diverse applications. The hydrogel network was formed through free radical polymerization, employing N, N′‐methylene bisacrylamide (MBA) as a crosslinking agent to establish a chemically crosslinked matrix. Comprehensive characterization using Fourier‐transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and simultaneous thermal analysis (STA) confirmed the successful synthesis, morphological features, and thermal stability of the hydrogels. The adhesive performance was systematically evaluated through rheological testing, measuring both adhesive strength and viscoelastic parameters such as storage ( G ′) and loss ( G ″) moduli under varying frequencies and strain conditions. The findings demonstrate that intermolecular interactions within the polymeric network critically influence adhesive efficacy. By modulating sodium alginate concentrations (0.1, 0.2, and 0.3 g), optimal adhesive properties were attained at 0.2 g. Adhesion tests conducted on multiple solid substrates including glass, steel, wood, and textiles revealed superior adherence particularly on metal, wood, and glass surfaces. These results underscore the potential utility of the synthesized hydrogel as a versatile adhesive material for biomedical and industrial applications.

Nanoparticle-reinforced polysaccharide–protein composite hydrogels: synthesis, structural integrity, and sustained release behavior

Fabrication and physicochemical characterization of sodium alginate-based hydrogel incorporated with aloe vera and chitosan for wound dressing applications

Hydrogels are considered as promising polymeric biomaterials for wound dressing due to the desirable properties of wound healing. In this work, the use of natural polymeric biomaterials such as aloe vera (AV), chitosan (CH) in sodium alginate (SA)-based hydrogels, a novel hydrogel was produced and characterized that might be applied to healing wounds. Initially, a neat SA specimen was used as a control. Afterward, the specimens were fabricated via the solvent casting method with varying amounts of CH and AV. Morphological changes were observed in SA after the introduction of AV and CH using X-ray diffraction (XRD). The loss of crystalline nature in the SA–Neat and SA–AV samples were observed after the incorporation of CH was revealed by the loss of peaks that were previously observed in the SA–Neat and SA–AV samples. Fourier transform infrared (FTIR) spectroscopy demonstrated strong bonding between SA and the incorporated materials. The samples containing CH exhibited comparatively higher degradation, whereas the AV samples degraded slowly. The hardness of the tested samples increased with the incorporation of AV, whereas an increase in hardness was observed with the incorporation of CH. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) revealed an increase in thermal stability in samples containing AV followed by samples containing CH.

Silver Nanoparticle-Modified PVA/BС Hydrogels: A Path toward Stable and Functional Biomaterials

This study examines the physicochemical properties of a hydrogel composed of poly(vinyl alcohol) (PVA) and bacterial cellulose (BC), modified with silver nanoparticles (AgNPs) previously synthesised via green methods using Lactobacillus acidophilus UCM B-2691. The effects of composition on moisture content, sorption behavior, and moisture desorption were assessed, and the density of the obtained samples was investigated. Increasing the bacterial cellulose content in hydrogels enhances their hydrophilicity, water-holding capacity, and sorption properties. The incorporated AgNPs are not released from the hydrogels and do not exhibit antimicrobial activity; instead, they promote the formation of a more porous, structurally stable network, which enhances sorption and lowers density. PVA/BC hydrogels containing 40–60% BC and AgNPs showed the best overall performance, combining high hydrophilicity, structural stability, and porosity. The results indicate the high potential of these hydrogel systems for biomedical technologies, particularly in controlled drug delivery and tissue engineering.

Development of stimuli-responsive polymeric hydrogels and their applications

Electro-responsive nanocomposite hydrogels based on gelatin, partially neutralized acrylic acid (PAAc), and acid-functionalized multiwalled carbon nanotubes (MWCNT-COOH) were developed and evaluated as potential smart drug delivery systems. The successful functionalization of pristine MWCNTs was confirmed by the shift in characteristic X-ray diffraction (XRD) peaks, while the presence of MWCNT-COOH peaks in the nanocomposite hydrogel verified their effective incorporation into the polymer matrix. Scanning electron microscopy (SEM) revealed distinct morphological changes following acid functionalization and demonstrated the uniform dispersion of MWCNT-COOH within the hydrogel network, resulting in a smooth and homogeneous surface. Swelling studies showed that increasing MWCNT-COOH content reduced the swelling percentage in the absence of an electric field, whereas the application of a 10 V electric field significantly enhanced swelling, confirming the electro-responsive nature of the hydrogels. In vitro hemolysis assays indicated excellent blood compatibility, highlighting their suitability for biomedical applications. The electro-responsive release of vitamin B12 was strongly influenced by the ionic strength of the release medium, applied voltage, and MWCNT-COOH concentration. Furthermore, drug release behavior was systematically optimized using response surface methodology based on a central composite design. Overall, the developed Gelatin-g-PAAc/MWCNT-COOH nanocomposite hydrogels exhibit favorable structural, swelling, biocompatible, and electro-responsive characteristics, making them promising candidates for the design of advanced electrically controlled drug delivery systems.