Construction and Biocompatibility Evaluation of Fibroin/Sericin-Based Scaffolds.

Because tissue responses to implants determine the success or failure of tissue engineering products, fibroin/sericin-based scaffolds including bionic silk scaffolds, native silk fibers, fibroin fibers, and regenerated fibroin have been fabricated, and their biocompatibility was investigated. Fibroin/sericin-based scaffolds were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). Bionic silk scaffolds were beneficial to silk fiber formation through self-assembly. Histological and immunofluorescent staining analysis demonstrated that bionic silk scaffolds did not show significant inflammatory responses. Immunization analysis showed that soluble fibroin and sericin did not show obvious immunogenicity. This work supplied an effective approach to design fibroin/sericin-based scaffolds for tissue engineering and drug delivery.

Brain-Targeted Dual Site-Selective Functionalized Poly(ß-Amino Esters) Delivery Platform for Nerve Regeneration.

Brain injuries are devastating central nervous system diseases, resulting in cognitive, motor, and sensory dysfunctions. However, clinical therapeutic options are still limited for brain injuries, indicating an urgent need to investigate new therapies. Furthermore, the efficient delivery of therapeutics across the blood-brain barrier (BBB) to the brain is a serious problem. In this study, a facile strategy of dual site-selective functionalized (DSSF) poly(ß-amino esters) was developed using bio-orthogonal chemistry for promoting brain nerve regeneration. Fluorescence colocalization studies demonstrated that these proton-sponge DSSF poly(ß-amino esters) targeted mitochondria through electrostatic interactions. More importantly, this delivery system could effectively accumulate in the injured brain sites and accelerate the recovery of the injured brain. Finally, this DSSF poly(ß-amino esters) platform may provide a new methodology for the construction of dual regioselective carriers in protein/peptide delivery and tissue engineering.

Synthesis and Evaluation of Cytocompatible Alkyne-Containing Poly(ß-amino ester)-Based Hydrogels Functionalized via Click Reaction.

Although poly(ß-amino esters) (PAEs) have been widely applied in nonviral gene transfection, drug delivery systems, and regenerative medicine, the multifunctional modification of PAEs and bio-orthogonal strategies of PAE-based hydrogel functionalization is still a challenge. Herein, a strategy of poly(ß-amino ester)-based hydrogel functionalization was developed via bio-orthogonal reactions in this study. Acrylate-terminated poly(ß-amino esters) containing alkyne groups were synthesized by Michael addition reaction. Alkyne groups on poly(ß-amino esters) could conjugate bioactive molecules with azide of K(N3)RGD via copper-catalyzed azide-alkyne cycloaddition, and terminal acrylate groups could in situ polymerize to prepare a hydrogel. A biomimetic peptide K(N3)RGD functionalized hydrogel was prepared by polymerization of acrylate-terminated poly(ß-amino esters) containing conjugated peptide and polyethylene glycol diacrylate (PEGDA). The storage modulus and mechanical properties exhibited an increased trend with the increased concentration; nevertheless, swelling ratio and surface wetting properties demonstrated a decreased tendency by increased concentrations. Cell proliferation and live/dead staining showed that Schwann cells plated on the hydrogel with an elastic modulus of 25.39 KPa are more suitable for proliferation and function exertion of Schwann cells compared with that of 42.11 and 57.86 KPa, and KRGD-conjugated hydrogel could increase the elongation of Schwann cells relative to nonconjugated hydrogels. This azide-alkyne strategy may be a promising candidate for hydrogel functionalization in tissue engineering and other biomedical applications.