Immobilized quantum dots as donors in fluorescence resonance energy transfer for solid-phase assay within microfluidic channels

Lu Chen

The Edward S. Rogers Sr. Department of Electrical and Computer Engineering (Photonics)

Abstract:

The optical properties and surface area of quantum dots (QDs) have made them an attractive platform for the development of biosensors based on fluorescence resonance energy transfer (FRET). Solid-phase assays based on FRET using mixtures of immobilized QD biosensors have been developed. The typical challenges associated with solid-phase detection strategies include
non-specific adsorption, slow kinetics of reaction, and sample manipulation.  

The work here has considered the immobilization of QD biosensors onto the surfaces of microfluidic channels in order to address these challenges. Microfluidic flow can be used to deliver target to the channel surface to speed reaction, amelioration of adsorption, and regeneration of the sensing surface. Microfluidic flow can also be used to deliver (for immobilization) and remove QD biosensors. QDs that were conjugated with two different oligonucleotide sequences were used to demonstrate feasibility. One oligonucleotide sequence on the QD was available as a linker for immobilization via hybridization with complementary oligonucleotides located on a glass surface within a microfluidic channel. A second oligonucleotide sequence on the QD served as a probe to transduce hybridization with target nucleic acid in a sample solution. A Cy3 label on the target was excited by FRET using green-emitting CdSe/ZnS QD donors and provided an analytical signal to explore this detection strategy. The immobilized QDs could be removed under denaturing conditions by disrupting the duplex that was used as the surface linker and thus allowed a new layer of QD biosensors to be re-coated within the channel for re-use of the microfluidic chip.

 

Biography:

Lu Chen is currently a postdoctoral fellow at the department of Electrical and Computer engineering, University of Toronto, working with Prof. Stewart Aitchison. He obtained the Ph.D. from University of Toronto, and M.Sc. from Queen's University both in Chemistry.