Dependence of cellular activity at protein adsorbed biointerfaces with nano- to microscale dimensionality.

Abstract

Protein adsorption is one of the first-few events that occur when a biomedical device comes in contact with the physiological system. The adsorption process is subsequently followed by communication with cells and formation of tissue. Given the strong interest in nanostructured surfaces, we describe here the impact of grain structure from nanograined (NG) regime to coarse-grained (CG) regime on the self-assembly of proteins (bovine serum albumin) and consequent functional response of osteoblasts. The objective is accomplished using the innovative concept of "phase reversion" that enables a wide range of grain size (from NG to CG regime) to be obtained using an identical set of parameters, besides additional attributes of high strength/weight ratio and wear resistance. Depending on the grain structure a consistent and significant change in the adsorption characteristics of protein was observed at biointerface, such that the cell density was statistically different. The high surface coverage and leaf-like conformation of adsorbed protein on NG surface as compared to bare branch-like structure with low surface coverage on the CG surface, was beneficial in favorably modulating cellular activity (osteoblast functions: cell attachment, proliferation, actin, vinculin, and fibronectin expression). This is the first report that elucidates the impact of grain structure from NG to CG regime on cellular activity.