Low level epifluorescent detection of nanoparticles and DNA on dielectrophoretic microarrays

Abstract

Common epifluorescent microscopy lacks the sensitivity to detect low levels of analytes directly in clinical samples, such as drug delivery nanoparticles or disease related DNA biomarkers. Advanced systems such as confocal microscopes may improve detection, but several factors limit their applications. This study now demonstrates that combining an epifluorescent microscope with a dielectrophoretic (DEP) microelectrode array device enables the detection of nanoparticles and DNA biomarkers at clinically relevant levels. Using DEP microarray devices, nanoparticles and DNA biomarkers are rapidly isolated and concentrated onto specific microscopic locations where they are easily detected by epifluorescent microscopy. In this study, 40nm nanoparticles were detected down to 2–3 × 103/ul levels and DNA was detected down to the 200 pg/ml level. The synergy of epifluorescent microscopy and DEP microarray devices provides a new paradigm for DNA biomarker diagnostics and the monitoring of drug delivery nanoparticle concentrations. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Electrokinetic device design and constraints for use in high conductance solutions

“…Simulations correlate with behavior seen in devices, e.g. and Fig. , where thermal effects are minimal and positive‐DEP particles accumulate on the electrode circumference, where the electric field gradients are highest.…”

“…None of these solutions are ideal. This said, examples of commercial planar electrode arrays (Biological Dynamics, San Diego, CA), are seen in , which shows that this architecture has found success with high conductance solutions, and provides an empirical reference for further designs. Nevertheless, even these devices, designed to operate with high conductance solutions, have performance limitations due to adverse electrochemical effects when driven above recommended voltages or below recommended frequency of operation.…”

Recovery of Drug Delivery Nanoparticles from Human Plasma Using an Electrokinetic Platform Technology

“…This means that using DEP parameters that were consistent with the conductivity regime of classical DEP theory were most effective at creating a positive DEP force that pulled these particles down to the electrodes. [ 27 ] If the driving frequency was too high then the permittivity regime would dominate because the particles were less polar than water. This would not result in the nanoparticles being pulled down to the electrodes.…”

DNA dielectrophoresis: Theory and applications a review

“…Continuous flow concentration according to our definition was not found for DNA dielectrophoresis. However, several groups presented DNA concentration at fixed locations, for example, .…”