Traffic accidents, falls, and many other events may cause traumatic spinal cord injuries (SCIs), resulting in nerve cells and extracellular matrix loss in the spinal cord, along with blood loss, inflammation, oxidative stress (OS), and others. The continuous development of neural tissue engineering has attracted increasing attention on the application of fibrin hydrogels in repairing SCIs. Except for excellent biocompatibility, flexibility, and plasticity, fibrin, a component of extracellular matrix (ECM), can be equipped with cells, ECM protein, and various growth factors to promote damage repair. This review will focus on the advantages and disadvantages of fibrin hydrogels from different sources, as well as the various modifications for internal topographical guidance during the polymerization. From the perspective of further improvement of cell function before and after the delivery of stem cell, cytokine, and drug, this review will also evaluate the application of fibrin hydrogels as a carrier to the therapy of nerve repair and regeneration, to mirror the recent development tendency and challenge.

The materials used in bone tissue engineering (BTE) have been advancing with each passing day. With the continuous development of nanomedicine, gold nanoparticles (GNPs), which are easy to be synthesized and functionalized, have attracted increasing attention. Recent years have witnessed this amazing material, i.e., GNPs characterized with large surface area to volume ratio, biocompatibility, medical imaging property, hypotoxicity, translocation into the cells, high reactivity, and other properties, perform distinct functions in BTE. However, the low stability of GNPs in the biotic environment makes them in the requirements of modification or recombination before being used. After being combined with the advantages of other materials, the structures of GNPs have exhibited great potential in stem cells, scaffolds, delivery systems, medical imaging, and other aspects. This review will focus on the advances in the application of GNPs after modification or recombination with other materials to BTE.

The combination of composite nerve materials prepared using degradable polymer materials with biological or physical factors has received extensive attention as a means to treat nerve injuries. This study focused on the potential application of graphene oxide (GO) composite conductive materials combined with electrical stimulation (ES) in nerve repair. A conductive poly(L-lactic-co-glycolic acid) (PLGA)/GO composite membrane was prepared, and its properties were tested using a scanning electron microscope (SEM), a contact angle meter, and a mechanical tester. Next, neural stem cells (NSCs) were planted on the PLGA/GO conductive composite membrane and ES was applied. NSC proliferation and differentiation and neurite elongation were observed using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, immunofluorescence, and PCR, respectively. The results showed that the PLGA/GO membrane had good hydrophilicity, mechanical strength, and protein adsorption. ES combined with the PLGA/GO membrane significantly promoted NSC proliferation and neuronal differentiation on the material surface and promoted significant neurite elongation. Our results suggest that ES combined with GO-related conductive composite materials can be used as a new therapeutic combination to treat nerve injuries.

At present, the healing of osteopathy, especially the healing of cartilage, has been proven to be difficult. Commonly used treatment methods are autogenous bone grafts and allogeneic bone grafts, but grafts cannot fully meet the clinical treatment requirements due to problems related to the source, price, immunity, and other concerns. Thus, the combination of biomaterials and tissue engineering technology has become a new direction in research. Among studies on tissue engineering bone and cartilage materials, hydrogels that show biological activity, absorbability after degradability, plasticity, and easy preparation have become the focus. Hydrogels are used as extracellular matrix mimics. Although various materials are able to form hydrogels, hyaluronic acid and its derivatives are prominently used. Hyaluronic acid hydrogels have many advantages, such as promoting cell adhesion and proliferation and wound healing. They also demonstrate sufficient biological activity for stimulating a microenvironment for cell survival. However, their disadvantages require further modification and include a poor degradation rate and insufficient mechanical performance. In this paper, hyaluronic acid-based hydrogels, their modifications, applications, and mechanisms, as well as new techniques for processing hyaluronic acid hydrogels in bone and cartilage tissue engineering, are briefly reviewed, and their future prospects and directions for future work are discussed.

Chitosan (CS) has been extensively studied as a natural polymer, in the field of wound repair, due to its useful properties, which include a lack of toxicity and stimulation, excellent biological affinity, degradability, and promotion of collagen deposition. However, inferior mechanical strength and moderate antibacterial properties are the drawbacks restricting its further clinical application. Many researchers have adopted the use of nanotechnology, in particular metallic nanoparticles (MNPs), in order to improve the mechanical strength and specific antibacterial properties of chitosan composites, with promising results. Furthermore, chitosan naturally functions as a reducing agent for MNPs, which can also reduce cytotoxicity. Thus, CS, in combination with MNPs, exhibits antibacterial activity, excellent mechanical strength, and anti‐inflammatory properties, and it has great potential to accelerate the process of wound healing. This review discusses the current use of CS and MNPs in wound healing and emphasises the synergy and the advantages for various applications in wound healing.

Chitosan (CS) is a natural polymer with applications in wound restorations and coatings for artificial implants. However, the lack of antimicrobial activity restricts its further application. Thus, the purpose of this study is to prepare CS/AuNPs film by adding gold nanoparticles (AuNPs) to modify chitosan. Through transmission electron microscopy, we found that the presence of CS can effectively prevent the agglomeration of nanoparticles. Furthermore, through the CCK experiment, we found that AuNPs at a certain concentration can improve the adhesion and proliferation of cells, which has also been proved in animal experiments, including gross appearance, histological observations, and immunofluorescence staining. Such findings support the feasibility of using the film as a promising candidate for tissue engineering of skin in a near future.