Assembly of osteoblastic cell micro-arrays on diamond guided by protein pre-adsorption

We investigate the role of fetal bovine serum (FBS) proteins in the assembly of osteoblastic cells (SAOS-2) in McCoy's 5A medium on synthetic monocrystalline and nanocrystalline diamonds having H- and O-terminated array patterns. We characterize i) adhesion of proteins and cells to diamond by shaking experiments (1000 rpm), fluorescence, and atomic force microscopy, ii) distribution of FBS proteins by micro-Raman spectroscopy, and iii) influence of pre-adsorbed specific FBS proteins (albumin, fibronectin, vitronectin) on the cell assembly. There is 40% lower adhesion of cells on H-terminated diamond with adsorbed FBS compared to this surface without FBS as well as to O-terminated surfaces. Spatially resolved Raman spectroscopy of C―H stretching bands around 2900 cm− 1 showed uniform coverage of H/O-diamond by the albumin in more than 50 nm thick FBS layers. The other FBS proteins were not detectable by Raman. Pre-adsorption of the specific proteins prior to cell plating indicated that the cell preference to O-terminated diamond is controlled by the fibronectin rather than by the albumin. We discuss the data with a view to the cell preferential assembly on H/O-diamond micro-arrays.