Microsphere-Based DNA Biosensor Arrays

摘要

A microsphere-based DNA biosensor array with high packing density and low detection limits has been previously developed. Polymeric 3.1-μm-diameter microspheres are employed as the detection elements, where each microsphere is functionalized with single-stranded oligonucleotide probe sequences. The biosensor array is fabricated by randomly distributing a stock microsphere suspension, containing various oligonucleotide-functionalized microspheres, on the distal end of a chemically etched imaging fiber bundle. By placing the microspheres into wells at the end of each individual fiber, each optical channel is connected to a single microsphere. The microspheres are encoded with a unique combination of dyes in order to determine a particular microsphere's location in the randomized array. Specific fluorescence responses are observed after hybridization with fluorescently labeled complementary targets. Enhancement of the signal to noise ratio is possible because of intrinsic redundancy of sensing elements built into the array. This microsphere-based DNA biosensor has several major advantages over existing platforms including higher sensitivity, micron-sized features, and rapid throughput. Microsphere-based DNA arrays have been successfully applied to genomic discrimination of bacteria, gene expression analysis, and the detection of bioagents.