Polylysine coated bacterial cellulose nanofibers as novel templates for bone-like apatite deposition

The study on bacterial cellulose (BC) nanofibers used as templates for hydroxylapatite (HAp) deposition has been investigated by our group and many other researchers. However, BC is only microscopically similar to natural collagen but not molecular structure. If protein could be introduced to the surfaces of BC nanofibers, the BC nanofibers could mimic the natural collagen fibers in terms of both shape and molecular structure. In this work, our latest results concerning the preparation of polylysine (PLL) coated BC nanofibers are reported. It is found that the ε-polylysine (PLL), a natural coming peptide, was introduced to the surfaces of BC nanofibers via crosslinking method by using procyanidins as crosslinker. The bioactivity of PLL coated BC nanofibers was demonstrated by the bone-like HAp deposition throughout the scaffold in a simulated body fluid (SBF). To initiate mineralization the PLL coated BC nanofibers were immersed in 1.5 times simulated body fluids (1.5 SBF) at 37 °C for 7 days. The deposited minerals on the nanofiber surfaces were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), and fourier transformed infrared spectroscopy (FTIR). These PLL coated BC nanofibers were proved to act as nano templates to induce the formation of nano-sized platelet-like, calcium-deficient, B-type carbonated HAp of which the features was closed to those of biological apatite.