Jafar Hasan*, Kaushik Chatterjee*

 

Department of Materials Engineering
Indian Institute of Science Bangalore
Bengaluru, Karnataka, India

 

Biofilms are a cause of great concern particularly in device associated infections and hospital environments. An array of nanomaterials was designed to study bactericidal activity inspired from the natural surfaces for use in biomedicine and healthcare sectors. Firstly, nanostructured silicon wafers were produced by deep RIE technique and the surfaces were found to be superhydrophobic with static contact angle of 153° and self-cleaning with contact angle hysteresis value of 8.3°. Using microscopy techniques, the nanostructured silicon surfaces were found to be bactericidal against Escherichia Coli and Staphylococcus aureus cells. However, the nanostructured silicon surfaces were not conducive to the mammalian cell lines of mouse pre-cursor osteoblast as the cells became non-viable on contact.

Secondly, the nanostructured patterns were fabricated on titanium surfaces using reactive ion etching technique. The surfaces were characterized for their bactericidal activity and human mesenchymal stem cell biocompatibility. Later, the osteogenesis capability of stem cell on nanostructured surfaces was also confirmed. The in-vivo analysis of the nanostructured titanium was also evaluated. Thirdly, aluminium surfaces were fabricated using wet etching technique where multi-scale roughness was induced and the surfaces were found to be bactericidal against wide ranging drug resistant bacterial cells obtained from the hospital environments.

Based on this study, the ideal surface with optimum surface topography that would be harmful for the bacterial cells but support the mammalian cell attachment were designed and fabricated (Figure 1). Therefore, the study provides a noteworthy understanding about the impact of surface micro- and nano-scale topography on the behaviour of bacterial and mammalian cell attachment for the design of ideal biomedical surfaces.

Figure 1: The race for the surface as the stem cells is compatible and differentiates into bone-like cells whereas the bacterial cells are getting ruptured upon contact with the nanostructured surface.