Polymer Microfluidic Chips with Integrated Waveguides for Reading Microarrays

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• 作者：Feng Xu ; Proyag Datta ; Hong Wang ; Sitanshu Gurung ; Masahiko Hashimoto ; Suying Wei ; Jost Goettert ; Robin L. McCarley ; Steven A. Soper
• 刊名：Analytical Chemistry
• 出版年：2007
• 出版时间：December 1, 2007
• 年：2007
• 卷：79
• 期：23
• 页码：9007 - 9013
• 全文大小：344K
• 年卷期：v.79,no.23(December 1, 2007)
• ISSN：1520-6882

文摘

A microfluidic chip with an integrated planar waveguidewas fabricated in poly(methyl methacrylate), PMMA,using a single-step, double-sided hot-embossing approach. The waveguide was embedded in air on threesides, the solution being interrogated on the fourth. DNAprobes were covalently attached to the waveguide surfaceby plasma activating the PMMA and the use of carbodiimide coupling chemistry. Successful hybridization eventswere read using evanescent excitation monitored by animaging microscope, which offered high spatial resolution(2 m) and a large field-of-view (20 mm diameter field-of-view), providing imaging of the entire array withoutscanning. The application of the microfluidic/waveguideassembly was demonstrated by detecting low abundantpoint mutations; insertion C mutations in BRCA1 genesassociated with breast cancer were analyzed using auniversal array coupled to an allele-specific ligation assay.DNA probes consisting of amine-terminated oligonucleotides were printed inside the microfluidic channel usinga noncontact microspotter. Mutant and wild-type genomicDNAs of BRCA1 were PCR (polymerase chain reaction)amplified, with the amplicons subjected to ligation detection reactions (LDRs). LDR solutions were allowed to flowover the microarray positioned on the polymer waveguidewith successful ligation events discerned through fluorescence signatures present at certain locations of thearray. The microfluidic/waveguide assembly could detectpolymorphisms present at <1% of the total DNA content.