Protein immobilisation on micro/nanostructures fabricated by laser microablation.

The performance of biomedical microdevices requires the accurate control of the biomolecule concentration on the surface, as well as the preservation of their bioactivity. This desideratum is even more critical for proteins, which present a significant propensity for surface-induced denaturation, and for microarrays, which require high multiplexing. We have previously proposed a method for protein immobilisation on micro/nanostructures fabricated via laser ablation of a thin metal layer deposited on a transparent polymer. This study investigates the relationship between the properties of the micro/nanostructured surface, i.e., topography and physico-chemistry, and protein immobilisation, for five, molecularly different proteins, i.e., lysozyme, myoglobin, α-chymotrypsin, human serum albumin, and human immunoglobulin. Protein immobilisation on microstructures has been characterised using quantitative fluorescence measurements and atomic force microscopy. It has been found that the sub-micrometer-level, combinatorial nature of the microstructure translates in a 3-10-fold amplification of protein adsorption, as compared to flat, chemically homogenous polymeric surfaces. This amplification is more pronounced for smaller proteins, as they can capitalize better on the newly created surface and variability of the nano-environments.