Coupling confocal fluorescence detection and recirculating microfluidic control for single particle analysis in discrete nanoliter volumes

Abstract

The recent proliferation of platforms designed to handle arrays of nano- and picolitre volumes is in response to the need to perform biological assays on discrete entities, such as single cells. However, a critical challenge associated with this trend for in vitro compartmentalization is the need for highly sensitive, yet low-volume detection platforms. In this paper, we coupled confocal fluorescence detection with recirculating microfluidic control to perform single particle DNA assays within five nL chambers. The performance of this low-volume assay was shown to match that of traditional single molecule detection platforms. However, volume requirements per measurement were nearly 3 orders of magnitude less than conventional systems, enabling future integration with lab-on-a-chip systems that require discrete or digitalized sample processing.

Applications, techniques, and microfluidic interfacing for nanoscale biosensing

“…1c), with their superior optical, electrical, and thermal properties, have been applied to enhance the functionality of various microfluidic biosensing platforms. Several optical detection schemes based on metal nanoparticles, such as surface plasmon resonance and colorimetric assays, have been incorporated into microfluidic systems (Hosokawa et al 2004;Park et al 2006;Puleo et al 2008;Sato et al 2008). For instance, Au nanoparticle-labeled antibodies were used to amplify the signal of DNA-encoded antibody libraries (DEAL) for multiplexed cell sorting and detection (Bailey et al 2007).…”

“…Microfluidic control provides enhanced capabilities for QD biosensors. A recalculating microfluidic system has recently been coupled with a confocal fluorescence detection system (Puleo et al 2008). The inclusion of the circulating channel reduces the volume requirement per measurement nearly three orders of magnitude compared to conventional approaches.…”

FRET for lab-on-a-chip devices — current trends and future prospects

“…36 The key innovation behind this advance was the development of an integrated closed loop microfluidic rotary pump system, eliminating extra fluidic couplings and their associated dead volumes. In a subsequent refinement, it was possible to increase sensitivity further using an integrated 10Â evaporative concentrator on the chip.…”

Fully integraed droplet based point-of-care platform for molecular detection from crude biosamples

“…A fully functional and easily accessible miniaturized total analysis system (μTAS) that is able to operate with minimum resource requirement is highly desired for timely clinical decision and intervention, hence better therapeutic outcome. Recently, droplet microfluidic platform has been demonstrated for bimolecular detection with enhanced throughput and sensitivity [1][2][3]. In addition, the platform can also be implemented to enhance molecular assays through integration with sample preparation and target amplification [4,5].…”