PNNL

Abstract

Microarrays printed on glass slides are often constructed by covalently linking oligomer probes to a derivatised surface. These procedures typically require amino- or thiol-modified oligomer probes that can add considerable expense to larger arrays. We describe a system by which unmodified oligomer probes are noncovalently bound to a nonderivatised glass slide. Biotinylated PCR products are heat denatured before hybridization and detected using an enzymatic amplification system. Noncovalent probe attachment is robust between pH 1 and 10 after which hybridization signal declines rapidly. High temperature and low ionic strength does not weaken noncovalently attached probes so the system will accommodate a wide range of hybridization stringencies. Unmodified oligomer probes also adhere to epoxy-silane derivatised slides and produce a stronger hybridization signal compared with the same probes attached to acid washed slides. We illustrate kinetics of room temperature hybridizations for unpurified PCR products and demonstrate that unmodified probes produce hybridization signals equal to amine-modified, covalently bound probes. Our method provides a cost effective alternative to conventional attachment strategies that is particularly ideal for microarrays that are designed for PCR based genotyping.