A Novel Suspension Detection of DNA Based on Quantum Dot Encoded Microbeads and Fluorescence Amplifying

Researchers pay close attentions to suspension arrays in high-throughput bioassays, in which biomolecules are detected in a solution with advantages such as convenient separation, flexibility in target selection, higher quality of results, etc. In this study, we designed a novel suspension DNA detection based on magnetic nanoparticles and quantum dot (QD) encoded microbeads, in which detection signals were amplified by bio-barcode technology. Two different QDs were integrated into polystyrene (PS) microspheres that were used as supports for different DNA sequences. A FITC labeled DNA was designed as reporting signal probe and fluorescence signal was amplified by the bio-barcode technology. Results indicated that the fluorescence wavelengthes for the QD encoded microbeads and fluorescence labels could be distinguished without interference. The target DNAs at concentrations about 50 nm were effectively detected, and the ratio of background-subtracted fluorescence intensities for complementary DNA to single-base mismatched DNA was 4.15:1. This suspension system can be extended to suspension array for detection of biomolecules such as DNAs and proteins.