An inexpensive, facile, and environmentally benign method has been developed for the preparation of multiresponsive, dynamic, and self-healing chitosan-based hydrogels. A dibenzaldehyde-terminated telechelic poly(ethylene glycol) (PEG) was synthesized and was allowed to form Schiff base linkages between the aldehyde groups and the amino groups in chitosan. Upon mixing the telechelic PEG with chitosan at 20 °C, hydrogels with solid content of 4-8% by mass were generated rapidly in <60 s. Because of the dynamic equilibrium between the Schiff base linkage and the aldehyde and amine reactants, the hydrogels were found to be self-healable and sensitive to many biochemical-stimuli, such as pH, amino acids, and vitamin B6 derivatives. In addition, chitosan could be digested by enzymes such as papain, leading to the decomposition of the hydrogels. Encapsulation and controlled release of small molecules such as rhodamine B and proteins such as lysozyme have been successfully carried out, demonstrating the potential biomedical applications of these chitosan-based dynamic hydrogels.

Biocompatible fluorescent organic nanoparticles with tunable photoluminescence were prepared via the one-pot oxidation of polydopamine and subsequently utilized for cell imaging.

A straightforward method to prepare a novel magnetic self-healing hydrogel has been successfully developed.

Porous silica nanofibers containing catalytic silver nanoparticles have been synthesized by a new method that combines sol−gel chemistry and electrospinning technique. Tetraethyl orthosilicate (TEOS), poly[3-(trimethoxysily)propyl methacrylate] (PMCM), and silver nitrate (AgNO3) were used as precursors for the production of silica−PMCM hybrid fibers containing AgNO3. Calcination of the hybrid fibers at high temperatures results in porous silica fibers because of thermal decomposition of PMCM polymer and in conversion of AgNO3 to silver nanoparticles. The color of the fiber mats changed from white to dark golden yellow due to the surface plasma resonance of the silver nanoparticles embedded in the fibers. The size and density of the silver particles in the silica fibers could be tuned by varying the size of the fibers, amount of AgNO3 introduced, and the thermal treatment conditions. The silica fibers containing silver particles were characterized with environmental scanning electron microscopy, transmission electron microscopy, X-ray diffraction, UV−vis spectroscopy, and thermogravimetric analysis. The catalytic activity of the silver containing fiber mats was assessed by a reduction reaction of methylene blue dye.