High-density fiber-optic DNA random microsphere array

A high-density fiber-optic DNA microarray sensor was developed to monitor m ultiple DNA sequences in parallel. Microarrays were prepared by randomly di stributing DNA probe-functionalized 3.1-mum-diameter microspheres in an arr ay of wells etched in a 500-mum-diameter optical imaging fiber. Registratio n of the microspheres was performed using an optical encoding scheme and a custom-built imaging system. Hybridization was visualized using fluorescent -labeled DNA targets with a detection limit of 10 fM. Hybridization times o f seconds are required for nanomolar target concentrations, and analysis is performed in minutes.