(659a) DNA Microarrays On UV-Modified Surfaces for Differentiating Clostridium Species

DNA microarrays are powerful tools for the detection and identification of bacteria. However, commercially available DNA chips are very expensive and each chip often contains a very high density of information. In this study, we report a simple approach to activate inert hydrocarbon monolayers with UV light to fabricate DNA microarrays. Unlike like traditional UV microarrays which require reactive functional groups on the surface, our DNA microarray is built upon an inert layer of N,N-dimethyl-n-octadecyl(3-aminopropyl)trimethoxysilyl chloride silane (DMOAP). This layer is activated by UV (254 nm) just prior to the immobilization of oligonucleotide probes. Our XPS results show that new functional groups such as alcohol (C-O), aldehyde (C=O) and carboxylic acid (O-C=O) form on the surface after the UV exposure. Among them, aldehyde groups are responsible for the immobilization of amine-label oligonucleotide. By using this approach, we further optimize several factors affecting the immobilization of oligonucleotides to obtain a DNA microarray on which the density of oligonucleotide is up to 0.1molecular/nm².This DNA microarray is able to differentiate solventogenic Clostridium sp. such as Clostridium acetobutylicum, Clostridium butylicum, and Clostridium beijerinki.