Corneal neovascularization (CNV) is a heavy attribute of blinding disease changes. Existing medications need numerous infusions and have a limited absorption. Investigating novel drugs with safety, efficacy, and convenience is crucial. In this study, we developed a bone morphogenetic protein 4 (BMP4)-loaded poloxamer-oxidized sodium alginate (F127-OSA) thermosensitive hydrogel. The 14 % F127-OSA hydrogel transformed from sol to gel at 31-32 °C, which might extend the application period on the ocular surface. The hydrogel\'s porous structure and uniform dispersion made it possible for drugs to release gradually. We used a suture-induced rat CNV model to investigate the mechanism of CNV inhibition by hydrogel. We discovered that F127-OSA hydrogel loaded with BMP4 could significantly reduce the length and area of CNV, relieve corneal edema, and stop aberrant epithelial cell proliferation. The hydrogel\'s efficacy was superior to that of the common solvent group. Additionally, BMP4 thermosensitive hydrogel repaired ultrastructure, including microvilli, intercellular junctions, and damaged apical junctional complexes (AJCs), suggesting a potential mechanism by which the hydrogel prevented CNV formation. In conclusion, our investigation demonstrates that F127-OSA thermosensitive hydrogel loaded with BMP4 can repair corneal epithelial AJCs and is a promising novel medication for the treatment of CNV.

In this study, sodium alginate (SA) was oxidized with potassium periodate to produce an alginate-based tanning agent. Using OSA as a biodegradable tanning agent and a nano-hydroxyapatite (nano-HAp) low concentration suspension to give flame retardancy to leather, eco-design concepts were applied to establish a chrome-, aldehyde-, and phenol-free tanning process. Micro-DSC, 1H unilateral nuclear magnetic resonance (NMR), attenuated total reflection mode Fourier transform infrared spectroscopy (FTIR-ATR), and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS) were used to investigate the complex matrix collagen-OSA-nano-HAp. Micro-differential scanning calorimetry (micro-DSC) was used to assess OSA\'s ability to interact with collagen and stabilize the collagen-OSA matrix, while 1H unilateral (NMR) was used to investigate the aqueous environment and its limitations around collagen molecules caused by their association with OSA and nano-HAp. Industrial standard tests were used to assess the mechanical properties and fire resistance of the new leather prototype. The findings reported here indicate that both OSA and nano-HAp are suitable alternatives for cleaner tanning technologies and more sustainable leather.

Here we develop and characterize a dual-cross-linked pH-responsive hydrogel based on the carboxyethyl chitosan-oxidized sodium alginate (CAO) containing silver nanoparticles (Ag NPs) functionalized with tannic acid/red cabbage (ATR). This hybrid hydrogel is formed via covalent and non-covalent cross-linking. The adhesive strength measured in contact with cow skin and compression strength is measured more than 3 times higher than that of CAO. Importantly, the incorporation of 1 ​wt% ATR into CAO significantly enhances the compression strength of CAO from 35.1 ​± ​2.1 ​kPa to 97.5 ​± ​2.9 ​kPa. Moreover, the cyclic compression tests confirm significantly higher elastic behavior of CAO after the addition of ATR-functionalized NPs to CAO. The CAO/ATR hydrogel is pH-sensitive and indicated remarkable color changes in different buffer solutions. The CAO/ATR also shows improved hemostatic properties and reduced clotting time compared to the clotting time of blood in contact with CAO hydrogel. In addition, while CAO/ATR is effective in inhibiting the growth of both Gram-positive and Gram-negative bacteria, CAO is only effective in inhibiting the growth of Gram-positive bacteria. Finally, the CAO/ATR hydrogel is cytocompatible with L929 fibroblasts. In summary, the resulting CAO/ATR hydrogel shows promising results in designing and constructing smart wound bioadhesives with high cytocompatibility, antibacterial properties, blood coagulation ability, and fast self-healing properties.

Supported cross-linked enzyme aggregates were prepared by immobilization of Candida antarctica lipase B onto hydrophobic surface of octyl-modified mesocellular foams (MCFs-C8). Oxidized sodium alginate was used as a substitute for traditional glutaraldehyde. Supported cross-linked enzyme aggregates using oxidized sodium alginate (SA-CLEAs@MCFs-C8) exhibited significantly improved thermal stability and organic solvents tolerance compared to the free lipase, lipase adsorbed onto MCFs-C8 and supported cross-linked enzyme aggregates using glutaraldehyde (G-CLEAs@MCFs-C8). Then immobilized lipases were employed for biodiesel production by transesterification of soybean oil with methanol. In the optimization condition, SA-CLEAs@MCFs-C8 were quite stable and still showed high fatty acid methyl esters (FAME) yield after 5 repeated cycles (from 89% to 78%), whereas MCFs-C8-CALB retained 67% FAME yield (about 72% for G-CLEAs@MCFs-C8).

Oxidized sodium alginate is a handily modifiable polysaccharide owing to the pendant aldehyde groups which can form dynamic covalent bonds with amines, acylhydrazines, etc., providing oxidized sodium alginate-based hydrogels with stimuli-responsive properties. However, due to the stiffness and, in particular, the hydrophobicity of sodium alginate dialdehyde at low pH, the mechanical performance and pH stimuli responsiveness of oxidized sodium alginate-based hydrogels are still strictly limited. Herein, we report a new strategy to build an injectable, dual responsive, and self-healing hydrogel based on oxidized sodium alginate and hydrazide-modified poly(ethyleneglycol) (PEG). The hydrazide-modified PEG, referred to as PEG-DTP, acts as a macromolecule crosslinker. We found that the presence of PEG-DTP reduces the hydrophobicity of oxidized sodium alginate at low pH so effectively that even a pH-induced reversible sol-gel transitions can be realized. Meanwhile, the disulfide bonds in PEG-DTP endows the hydrogel with the other reversible sol-gel transitions by redox stimuli. In particular, due to the softness of PEG-DTP chains, mechanical performance was also enhanced significantly. Our results indicate we can easily integrate multi-stimuli responsiveness, injectability, and self-healing behavior together into an oxidized sodium alginate-based hydrogel merely by mixing an oxidized sodium alginate solution with PEG-DTP solution in certain proportions.

Green polyelectrolytes including chitosan (CS), phytic acid (PA) and oxidized sodium alginate (OSA) were deposited on polyamide 66 (PA66) fabrics in a quadralayer (QL) fashion like (CS-PA-CS-OSA)n (where \"n\" denotes the number of quadra layers) via layer-by-layer (LbL) assembly to improve the flame retardant property. In the vertical burning test, the PA66 fabric with 10 and 15 QL depositions could stop the melt-dripping. Cone calorimetry results showed that a maximum reduction (24%) in the peak heat release rate was achieved for the PA66 fabric with 5 QL depositions. Thermogravimetric analysis indicated that the presence of the polyelectrolytes catalyzed the degradation pathway of virgin PA66 fabric where the initial decomposition temperature was reduced and the char yield was enhanced for all the coated fabrics significantly. Moreover, UV-vis spectroscopy demonstrated that the use of OSA could improve the durability of such a multilayered nanocoating.