Laser treatment of chitosan/biopolymer materials of different molecular weight coated with ZnO for antimicrobial surface development

Creating novel temporary "platforms" for effective integration of engineered tissues has been extensively researched and innovated in order to obtain scaffolds fulfilling all requirements for seeding different types of cell cultures and improving the cells' adhesion, proliferation and differentiation. A perfect scaffold should mimic the native porous environment of the cells – interconnected pores with well-defined sizes providing the normal functioning of the cells, as they can significantly influence not only the cells behavior, but also the integration of the implants with the surrounding "host" tissues. The biopolymer-based scaffolds still need additional modification in order to impart complete biological cellular functioning and communication. In this study, a femtosecond laser-based method for surface modification was applied to improving the morphological properties of chitosan-based ZnO magnetron sputtered blends and chitosan matrices of different molecular weight, thus achieving different levels of morphological structures for creation of enhanced antibacterial cell surface environment. The microstructured scaffolds were investigated by SEM, EDX and FTIR. Wettability measurements were performed in order to determine the hydrophilicity of the treated surfaces. Changes in the water contact angle (WCA) values were monitored in the range from 120° to 70° by introducing diverse laser patterning conditions. Modifying the topography/morphology of the sputtered biopolymer blends can essentially improve their bioactivity properties; moreover, creating hierarchical porosity will affect its antibacterial features, which will enable their successful applications in tissue engineering. (paper)