Biocompatible carboxyethyl chitosan/poly(vinyl alcohol) (CECS/PVA) nanofibers were successfully prepared by electrospinning of aqueous CECS/PVA solution. The composite nanofibrous membranes were subjected to detailed analysis by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and X-ray diffraction (XRD). SEM images showed that the morphology and diameter of the nanofibers were mainly affected by the weight ratio of CECS/PVA. XRD and DSC demonstrated that there was strong intermolecular hydrogen bonding between the molecules of CECS and PVA. The crystalline microstructure of the electrospun fibers was not well developed. The potential use of the CECS/PVA electrospun fiber mats as scaffolding materials for skin regeneration was evaluated in vitro using mouse fibroblasts (L929) as reference cell lines. Indirect cytotoxicity assessment of the fiber mats indicated that the CECS/PVA electrospun mat was nontoxic to the L929 cell. Cell culture results showed that fibrous mats were good in promoting the cell attachment and proliferation. This novel electrospun matrix would be used as potential wound dressing for skin regeneration.

Commercial or clinical tissue adhesives are currently limited due to their weak bonding strength on wet biological tissue surface, low biological compatibility, and slow adhesion formation. Although catechol-modified hyaluronic acid (HA) adhesives are developed, they suffer from limitations: insufficient adhesiveness and overfast degradation, attributed to low substitution of catechol groups. In this study, we demonstrate a simple and efficient strategy to prepare mussel-inspired HA hydrogel adhesives with improved degree of substitution of catechol groups. Because of the significantly increased grafting ratio of catechol groups, dopamine-conjugated dialdehyde–HA (DAHA) hydrogels exhibit excellent tissue adhesion performance (i.e., adhesive strength of 90.0 ± 6.7 kPa), which are significantly higher than those found in dopamine-conjugated HA hydrogels (∼10 kPa), photo-cross-linkable HA hydrogels (∼13 kPa), or commercially available fibrin glues (2–40 kPa). At the same time, their maximum adhesion energy is 384.6 ± 26.0 J m–2, which also is 40–400-fold, 2–40-fold, and ∼8-fold higher than those of the mussel-based adhesive, cyanoacrylate, and fibrin glues, respectively. Moreover, the hydrogels can gel rapidly within 60 s and have a tunable degradation suitable for tissue regeneration. Together with their cytocompatibility and good cell adhesion, they are promising materials as new biological adhesives.

In this study, dynamic imine covalent bonds were introduced into vanillin-based vitrimers networks, endowing thermosets with hot-reprocessing ability and chemical recyclability under acid hydrolysis. First, dialdehyde monomer, which was synthesized from lignin-derived vanillin monomer, was reacted with conventional amine cross-linkers to form dynamic imine bond networks. Even after three hot-processing cycles, the tensile strength and elongation at break of polyschiff vitrimers could be recovered at least up to 71.2 and 72.8%, respectively, through the imine metathesis reaction. Importantly, the dialdehyde monomers showed enhanced recyclability under strong acid solution and could be reused to regenerate polyschiff vitrimers. These characteristics of reprocessablility, recyclablility, and biobased monomer present a feasible way to satisfy the demands of sustainability.