title: DNA microarrays on ultraviolet-modified surfaces for speciation of bacteria.
abstract: In this study, we report an approach to activate inert hydrocarbon monolayers with ultraviolet (UV) light to fabricate DNA microarrays. Unlike traditional microarrays that require reactive functional groups on the surface, our DNA microarray is built on 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 X-ray photoelectron spectroscopy (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 oligonucleotides. By using this approach, we further optimize UV exposure time and oligonucleotide concentration and also reduce agent concentration to achieve a high density of immobilized oligonucleotides up to 0.16 pmol/mm². As a proof of concept, we demonstrate that this microarray can be used for differentiation of different Clostridium species such as Clostridium acetobutylicum, Clostridium butylicum, and Clostridium beijerinkii.
authors.affiliation: Department of Chemical and Biomolecular Engineering, National University of Singapore, Singapore 117576, Republic of Singapore.
authors.forename: Yanyang
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Civil and Environmental Engineering, National University of Singapore, Singapore 117576, Republic of Singapore.
authors.forename: Jianzhong
authors.initials: J
authors.lastname: He
authors.affiliation: Department of Chemical and Biomolecular Engineering, National University of Singapore, Singapore 117576, Republic of Singapore. Electronic address: cheyk@nus.edu.sg.
authors.forename: Kun-Lin
authors.initials: KL
authors.lastname: Yang
mesh_terms: D003013:Clostridium / Q000235:genetics* / Q000302:isolation & purification*; D005898:Glass / Q000737:chemistry; D009693:Nucleic Acid Hybridization; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods*; D015345:Oligonucleotide Probes / Q000737:chemistry / Q000235:genetics; D012821:Silanes / Q000737:chemistry; D013499:Surface Properties; D013997:Time Factors; D014466:Ultraviolet Rays
chemical_list: D015345:Oligonucleotide Probes; D012821:Silanes
keywords: DNA microarray; Surface modification; UV