Development of a new biodetection system independent of known marker molecules using a novel material for microarrays made from amorphous carbon substrates.

Abstract

A bio-chip substrate made from amorphous carbon was successfully developed as an innovative and practical biodetection system. This peptide-microarray biochip was based on a novel principle for protein detection in diagnostics. The carbon material as a substrate carrier offered significant advantages over conventional glass slides with regard to its surface chemistry. The biochip detection system used the measurement of fluorescent intensity changes caused by the interactions between capture molecules (labelled structured peptides arrayed on the substrate) and analytes. Fluorescent intensity changes with and without analytes were dose-dependent and could be visualized as "protein fingerprints". In this recognition system, interactions are not limited to one-to-one correspondence as in ELISA. Hence, this method can even be applied to analytes containing uncharacterized molecules. Statistical data handling, such as multivariate analyses, enabled discrimination of complex analytes such as body fluids. The present biochip used with an in-house developed detection device could be re-used 10-20 times with the same or different analytes. The captured molecules in this system were immobilized on the chip-surface through stable amide bonds, which allowed washing and even scrub cleaning. This unique material has a potential for dual detection thorough fluorescent intensity changes and mass spectrometric analyses when the chip is used as a sample tray, since this material has high electric conductivity. Thus, this dual detection allows the possibility of discovering marker candidates.