Surface engineering of spongy bacterial cellulose via constructing crossed groove/column micropattern by low-energy CO laser photolithography toward scar-free wound healing.

Bacterial cellulose (BC) is a bio-derived polymer, and it has been considered as an excellent candidate material for tissue engineering. In this study, a crossed groove/column micropattern was constructed on spongy, porous BC using low-energy CO laser photolithography. Applying the targeted immobilization of a tetrapeptide consisting of Arginine-Glycine-Aspartic acid-Serine (H-Arg-Gly-Asp-Ser-OH, RGDS) as a fibronectin onto the column platform surface, the resulting micropatterned BC (RGDS-MPBC) exhibited dual affinities to fibroblasts and collagen. Material characterization of RGDS-MPBC revealed that the micropattern was built by the column part with size of ~100 × 100 μm wide and ~100 μm deep, and the groove part with size of ~150 μm wide. Hydrating the MPBC did not result in the collapse of the integrity of the micropattern, suggesting its potential application in a highly hydrated wound environment. Cell culture assays revealed that the RGDS-MPBC exhibited an improved cytotoxicity to mouse fibroblasts L929, as compared to the pristine BC. Meanwhile, it was observed that the RGDS-MPBC was able to guide the ordered aggregation of human skin fibroblast (HSF) cells on the column platform surface, and no HSF cells were found in the groove channels. Over time, it was found that a dense network of collagen was gradually established across the groove channels. Furthermore, the in-vivo animal study preliminarily demonstrated the scar-free healing potential of the micropatterned BC materials. Therefore, this RGDS-MPBC material exhibited its advantages in guiding cell migration and collagen distribution, which could present a prospect in the establishment of "basket-woven" organization of collagen in normal skin tissue against the formation of dense, parallel aggregation of collagen fibers in scar tissue toward scar-free wound healing outcome.