Amplification of Protein Adsorption on Micro/Nanostructures for Microarray Applications
E.P. Ivanova, Y.V. Alekseeva, D.K. Pham, L. Filipponi and D.V. Nicolau
Swinburne University, AU
Keywords: microarrays, protein arrays, microstructures, AFM
The fabrication and operation of biodevices require the accurate control of the concentration of the bioactive molecules on the surface, as well as the preservation of their bioactivity, in particular proteins that have a significant propensity for surface-induced denaturation. A method that allows the adsorption of proteins on 'combinatorial' micro/nano-surfaces fabricated via laser ablation of a thin metal layer deposited on a polymer has been recently proposed1. The present study investigates the relationship between the amplification of the protein adsorption and their molecular characteristics (total molecular surface; and charge- and hydrophobicity-specific surface). The adsorption of five proteins with very different molecular characteristics, i.e. alpha-chymotrypsin, human serum albumin, human immunoglobulin, lysozyme, and myoglobin, has been characterized using quantitative fluorescence measurements and atomic force microscopy. It has been found that the 'combinatorial' nature of the micro/nano-channels surface allows for the increased adsorption of molecularly different proteins, comparing with the adsorption on flat surfaces. This amplification increases for proteins with lower molecular surface which can capitalize better on the newly created surface and nano-environments. Importantly, the adsorption on micro/nano-fabricated structures appears to be less dependent on the local molecular descriptors, i.e. hydrophobicity and charges, due to the combinatorialization of the nano-areas presented to the proteins. The amplification of adsorption is important, ranging from 3- to 10-fold, with a higher amplification for smaller, globular proteins.
Nanotech 2004 Conference Technical Program Abstract