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In the management of accelerating wound healing, moist environments play an important role. Compared with other scaffolds of various forms, hydrogels can maintain a moist environment in the wound area. They are cross-linked hydrophilic polymeric networks that resemble natural soft tissues and extracellular matrices. Among them, injectable hydrogels have attracted great attention in wound repair, as they can be injected into irregular-shaped skin defects and formed in situ to shape the contour of different dimensions. The excellent compliance makes hydrogels easy to adapt to the wound under different conditions of skin movement. Here, we oxidized hydroxyethyl starch (O-HES) and modified carboxymethyl chitosan (M-CMCS) to fabricate an in situ forming hydrogel with excellent self-recoverable extensibility–compressibility, biocompatibility, biodegradability, and transparency for accelerating wound healing. The oxidation degree of O-HES was 74%. The amino modification degree of M-CMCS was 63%. M-CMCS/O-HES hydrogels were formed through the Schiff base reaction. The physicochemical properties of M-CMCS/O-HES hydrogels with various ratios were investigated, and M-CMCS/O-HES hydrogel with a volume ratio of 5:5 exhibited appropriate gelation time, notable water-retaining capacity, self-recoverable conformal deformation, suitable biodegradability, and good biocompatibility for wound-healing application. Then, skin wound-healing experimental studies were carried out in Sprague–Dawley rats with full-thickness skin defects. Significant outcomes were achieved in the M-CMCS/O-HES hydrogel-treated group including higher wound closure percentage, more granulation tissue formation, faster epithelialization, and decreased collagen deposition. These findings demonstrate that using the obtained M-CMCS/O-HES hydrogels is a promising therapeutic strategy for wound healing.

Sodium alginate and carboxymethyl chitosan have been extensively applied in tissue engineering and other relative fields due to their low price and excellent biocompatibility. In this paper, we oxidized sodium alginate with sodium periodate to convert 1,2-hydroxyl groups into aldehyde groups to get aldehyde-sodium alginate (ASA). Carboxymethyl chitosan was modified with ethylenediamine (ED) in the presence of water-soluble N-(3-Dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride (EDC) to introduce additional amino groups to get amino-carboxymethyl chitosan (A-CS). Upon mixing the A-SA and A-CS aqueous solutions together, a gel rapidly formed based on the Schiff’s base reaction between aldehyde groups in A-SA and amino groups in A-CS. FTIR analysis confirmed the characteristic peak of Schiff’s base group in the hydrogel. It was confirmed that the gelation time be dependent on the aldehyde group content in A-SA and amino group content in A-CS. The fasted hydrogel formation takes place within 10 min. The data of bonding strength and cytotoxicity measurement also showed that the hydrogel had good adhesion and biocompatibility. All these results support that this gel has the potential as soft tissue adhesive.

Curcumin exhibited excellent properties including antioxidant, antiinflammatory, antiviral, antibacterial, antifungal, anticancer, and anticoagulant activities. In this study, curcumin was incorporated into silk fibroin (SF)/poly(L-lactic acid-co-e-caprolactone) (P(LLA-CL)) nanofibrous scaffolds via electrospinning, and changes brought about by raising the curcumin content were observed: SEM images showed that the average nanofibrous diameter decreased at the beginning and then increased, and the nanofibers became uniform; FTIR showed that the conformation of SF transforming from random coil form to β-sheet structure had not been induced, while SF conformation converted to β-sheet after being treated with 75% ethanol vapor; XRD results confirmed that the crystal structure of (P(LLA-CL)) had been destroyed; The mechanical test illustrated that nanofibrous scaffolds still maintained good mechanical properties. Further, curcumin-loaded nanofibrous scaffolds were evaluated for drug release, antioxidant and antimicrobial activities in vitro. The results showed that curcumin presented a sustained release behavior from nanofibrous scaffolds and maintained its free radical scavenging ability, and such scaffolds could effectively inhibit S. aureusgrowth (> 95%). Thus, curcumin-loaded SF/P(LLA-CL) nanofibrous scaffolds might be potential candidates for wound dressing and tissue engineering scaffolds.

Silk fibroin (SF) is a kind of natural polymers with a great potential in biomedical application. Due to its good biocompatibility, biodegradability and minimal inflammatory reaction, SF is an excellent candidate for generating tissue engineering scaffolds. Electrospinning is a simple and effective method to fabricate nanofibers, which has several amazing characteristics such as very large surface area to volume ratio, flexibility in surface functionalities, and superior mechanical performance. The electrospun nanofibers from SF and its blends have been used for varied tissue engineering. This paper will give a brief review about the structure, properties and applications of SF and blend nanofibers via electrospinning.

In our previous study, oxidized dextran/amino gelatin (ODex/MGel) self-crosslinking hydrogels have been successfully prepared. Though their potential applications as in situ forming scaffolds for tissue engineering have been verified, the subcellular porosities of hydrogel networks which were induced by the intensity chemical crosslinking still pose a barrier for cells migration and proliferation within the hydrogels. The objective of this study was to develop an approach to accelerate cellular remodeling by preparing semi-interpenetrating networks (semi-IPNs) composed of ODex, MGel, and sodium hyaluronic (HA). Results showed that the addition of HA at the concentrations of 0.09% and 0.18% can greatly promote pre-osteoblast (MC3T3-E1) cells spreading throughout the ODex/MGel hydrogel networks. Therefore, these semi-IPNs hydrogels could be useful matrixes for cell transplantation in a variety of tissue engineering applications.

In order to improve water-resistant ability silk fibroin (SF) and SF/P(LLA-CL) blended nanofibrous scaffolds for tissue engineering applications, methanol vapor were used to treat electrospun nanofibers. SEM indicated SF and SF/ P(LLA-CL) scaffolds maintained nanofibrous structure after treated with methanol vapor and possessed good water-resistant ability. Characterization of 13C NMR clarified methanol vapor induced SF conformation from random coil or α- helix to β-sheet. Moreover, treated SF/ P (LLA-CL) nanofibrous scaffolds still kept good mechanical properties. Methanol vapor could be ideal method to treat SF and SF/ P(LLA-CL) nanofibrous scaffolds for biomedical applications.

In this study, regenerated silk fibroin (RSF, from Bombyx mori) nanofibers with smooth surface had been successfully prepared via electrospinning, as shown by SEM and then as-spun fibers were induced under 75% ethanol vapor. We aimed to investigate the morphology and structure change of 75% ethanol vapor-induced silk fibroin nanofibers. To determine any difference in surface topographies, the nanofibers were inspected using atomic force microscope (AFM) and the results showed that after inducement of 75% ethanol vapor for 24 h, the surface of fibers became rough. Differential Scanning Calorimetry (DSC) analysis indicated that electrospun SF nanofibrous membranes typically took silk I form and 75% ethanol vapor-induced SF nanofibrous membranes took silk II structure. These results suggested that 75% ethanol vapor inducement could be an attractive alternative to expand the application of RSF.

Arterial bypass and heart valve replacements are two of the most common surgical treatments in cardiovascular surgery today. Currently, artificial materials are used as substitute for these cardiac tissues. However, these foreign materials do not have the ability to grow, repair or remodel and are thrombogenic, leading to stenosis. With the aid of tissue engineering, it is possible to develop functional identical copies of healthy heart valves and arteries, which are biocompatible. Although much effort has been made into this area, there are still inconsistencies with respect to endothelialisation and cell retention on synthetic biological grafts. These variations may be attributed to differences in factors such as cell seeding density, incubation periods and effects of shear stress. In this study, we have compared the endothelialisation and cell retention between gelain chitosan-coated electrospun polyurethane (PU), poly (lactide-co-glycolide) (PGA/PLA) and collagen-coated pericardium. Endothelial cells adhered to all of the materials as early as 1–day post seeding. After 7-day of seeding, the coverage on PU was almost 45% and that on PGA/PLA was about 25% and the least was on collagen-coated pericardium of approximately 15%. It was observed that the PU showed superior cell coverage and cell retention in comparison to the PGA/PLA and collagen-coated pericardium.