David Schwartz, Ping Gong, and K. L. Shepard, “Time-resolved Forster-resonance-energy-transfer DNA assay on an active CMOS microarray,” Biosensors and Bioelectronics 24, 3 (November 15, 2008), pp. 383-390
We present an active oligonucleotide microarray platform for time-resolved F ¨ orster-resonance-energy transfer (TR-FRET) assays. In these assays, immobilized probe is labeled with a donor fluorophore and analyte target is labeled with a fluorescence quencher. Changes in the fluorescence decay lifetime of the donor are measured to determine the extent of hybridization. In this work, we demonstrate that TR-FRET assays have reduced sensitivity to variances in probe surface density compared with standard fluorescence-based microarray assays. Use of an active array substrate, fabricated in a standard complementarymetal- oxide-semiconductor (CMOS) process, provides the additional benefits of reduced system complexity and cost. The array consists of 4096 independent single-photon avalanche diode (SPAD) pixel sites and features on-chip time-to-digital conversion.We demonstrate the functionality of our system by measuring a DNA target concentration series using TR-FRET with semiconductor quantum dot donors.