Advances in Polysaccharides for Cartilage Tissue Engineering Repair: A Review.

Cartilage repair has been a significant challenge in orthopedics that has not yet been fully resolved. Due to the absence of blood vessels and the almost cell-free nature of mature cartilage tissue, the limited ability to repair cartilage has resulted in significant socioeconomic pressures. Polysaccharide materials have recently been widely used for cartilage tissue repair due to their excellent cell loading, biocompatibility, and chemical modifiability. They also provide a suitable microenvironment for cartilage repair and regeneration. In this Review, we summarize the techniques used clinically for cartilage repair, focusing on polysaccharides, polysaccharides for cartilage repair, and the differences between these and other materials. In addition, we summarize the techniques of tissue engineering strategies for cartilage repair and provide an outlook on developing next-generation cartilage repair and regeneration materials from polysaccharides. This Review will provide theoretical guidance for developing polysaccharide-based cartilage repair and regeneration materials with clinical applications for cartilage tissue repair and regeneration.

Prospects of Using Chitosan-Based Biopolymers in the Treatment of Peripheral Nerve Injuries.

Peripheral nerve injuries are common neurological disorders, and the available treatment options, such as conservative management and surgical repair, often yield limited results. However, there is growing interest in the potential of using chitosan-based biopolymers as a novel therapeutic approach to treating these injuries. Chitosan-based biopolymers possess unique characteristics, including biocompatibility, biodegradability, and the ability to stimulate cell proliferation, making them highly suitable for repairing nerve defects and promoting nerve regeneration and functional recovery. Furthermore, these biopolymers can be utilized in drug delivery systems to control the release of therapeutic agents and facilitate the growth of nerve cells. This comprehensive review focuses on the latest advancements in utilizing chitosan-based biopolymers for peripheral nerve regeneration. By harnessing the potential of chitosan-based biopolymers, we can pave the way for innovative treatment strategies that significantly improve the outcomes of peripheral nerve injury repair, offering renewed hope and better prospects for patients in need.

Janus mucosal dressing with a tough and adhesive hydrogel based on synergistic effects of gelatin, polydopamine, and nano-clay.

There are many problems and challenges related to the treatment of highly prevalent oral mucosal diseases and oral drug delivery because of a large amount of saliva present in the oral cavity, the accompanying oral movements, and unconscious swallowing in the mouth. Therefore, an ideal oral dressing should possess stable adhesion and superior tough strength in the oral cavity. However, this fundamental requirement greatly limits the use of synthetic adhesive dressings for oral dressings. Here, we developed a mussel-inspired Janus gelatin-polydopamine-nano-clay (GPC) hydrogel with controlled adhesion and toughness through the synergistic physical and chemical interaction of gelatin (Gel), nano-clay, and dopamine (DA). The hydrogel not only exhibits strong wet adhesion force (63 kPa) but also has high toughness (1026 ± 100 J m-3). Interfacial adhesion of hydrogels is achieved by modulating the interaction of catechol groups of the hydrogel with specific functional groups (e.g., NH2, SH, OH, and COOH) on the tissue surface. The matrix dissipation of the hydrogel is regulated by physical crosslinking of gelatin, chemical crosslinking of gelatin with polydopamine (Michael addition and Schiff base formation), and nano-clay-induced constraint of the molecular chain. In addition, the GPC hydrogel shows high cell affinity and favors cell adhesion and proliferation. The hydrogel's instant and strong mucoadhesive properties provide a long-lasting therapeutic effect of the drug, thereby enhancing the healing of oral ulcers. Therefore, mussel-inspired wet-adhesion Janus GPC hydrogels can be used as a platform for mucosal dressing and drug delivery systems. STATEMENT OF SIGNIFICANCE: It is a great challenge to treat oral mucosal diseases due to the large amount of saliva present in the oral cavity, the accompanying oral movements, unconscious swallowing, and flushing of drugs in the mouth. To overcome the significant limitations of clinical bioadhesives, such as weakness, toxicity, and poor usage, in the present study, we developed a simple method through the synergistic effects of gelatin, polydopamine, and nano-clay to prepare an optimal mucosal dressing (Janus GPC) that integrates Janus, adhesion, toughness, and drug release property. It fits effectively in the mouth, resists saliva flushing and oral movements, provides oral drug delivery, and reduces patient discomfort. The Janus GPC adhesive hydrogels have great commercial potential to support further the development of innovative therapies for oral mucosal diseases.

Fabrication of self-healing hydrogel from quaternized N-[3(dimethylamino)propyl]methacrylamide copolymer for antimicrobial and drug release applications.

Self-healing hydrogels have attracted great attention in recent years because of their wide application in bioscience and biotechnology. In this study, P(DMAPMA-stat-DAA) were synthesized by Reversible Addition-Fragmentation Chain Transfer (RAFT) polymerization and quaternized to import antimicrobial properties. Then quaternized P(DMAPMA-stat-DAA) was used to prepare hydrogel containing acylhydrazone groups with Polyethylene oxide (PEO) diacylhydrazide as a cross-linking agent. The acylhydrazone groups imparted a variety of properties, including group responsiveness and self-healing properties to the hydrogel. At the same time, the quaternary ammonium endowed the hydrogel with the antimicrobial property. The mechanical property, self-healing properties, and antimicrobial property of hydrogels were investigated intensively. Results showed hydrogels formed in neutral conditions, and the luminescent property was introduced with PEO23 dinaphthhydrazide (DNH) cross-linking. The hydrogels showed a controlled pH-sensitive DOX·HC l and Ovalbumin (OVA) release profile. In addition, the hydrogel showed the antimicrobial property and may have important applications in the biomedical field in the near future.

Self-healing PEG-poly(aspartic acid) hydrogel with rapid shape recovery and drug release.

Self-healing hydrogels were prepared from hydrazide functionalized poly(aspartic acid) (PAsp). The polymer succinimide (PSI) was reacted with hydrazine and ethanolamine successively to obtain water soluble poly(aspartic acid) derivatives with hydrazide functional groups (PAEH). The hydrogel was prepared by cross-linking PAEH with poly(ethylene glycol) dialdehyde (PEG DA) under mild conditions without addition of catalyst. The rheological property and the self-healing property of the hydrogels were investigated intensively. The in vitro toxicity experiment showed the hydrogels have good bio-compatibility and the doxorubicin (DOX)-loaded hydrogels showed controlled release profile. Importantly, the hydrogel can still be degraded based on poly(aspartic acid) backbone. The bio-degradable poly(amino acid) based on self-healing hydrogel could have great potential application in bioscience including tissue repairing, drug loading and release.