Integration of Multiplexed Microfluidic Electrokinetic Concentrators with a Morpholino Microarray via Reversible Surface Bonding for Enhanced DNA Hybridization

Abstract

PSS) was directly printed and then reversibly surface bonded onto a morpholino microarray for hybridization. Using this electrokinetic trapping concentrator, we could achieve a maximum concentration factor of ∼800 for DNA and a limit of detection of 10 nM within 15 min. In terms of the detection speed, it enabled faster hybridization by around 10-fold when compared to conventional diffusion-based hybridization. A significant advantage of our approach is that the fabrication of the microfluidic concentrator is completely decoupled from the microarray; by eliminating the need to deposit an ion-selective layer on the microarray surface prior to device integration, interfacing between both modules, the PDMS chip for electrokinetic concentration and the substrate for DNA sensing are easier and applicable to any microarray platform. Furthermore, this fabrication strategy facilitates a multiplexing of concentrators. We have demonstrated the proof-of-concept for multiplexing by building a device with 5 parallel concentrators connected to a single inlet/outlet and applying it to parallel concentration and hybridization. Such device yielded similar concentration and hybridization efficiency compared to that of a single-channel device without adding any complexity to the fabrication and setup. These results demonstrate that our concentrator concept can be applied to the development of a highly multiplexed concentrator-enhanced microarray detection system for either genetic analysis or other diagnostic assays.

A Multiwell-Based Detection Platform with Integrated PDMS Concentrators for Rapid Multiplexed Enzymatic Assays

“…S2 in Supplementary Information). This PCF was approximately one order of magnitude higher than that of the previous device with PEDOT:PSS printed on the PDMS channel and bonded to a glass substrate 31 . This increase in PCF can be explained by the increased thickness of PEDOT:PSS membrane in ISAAC, twice as thick as it was before (~3 μm), and thus, higher surface conductance and lower inversed Dukhin number 6 .…”

“…All experiments were run in triplicate. Preconcentration performance data of the same target from previously reported devices, in which PEDOT:PSS was directly printed onto a PDMS chip 31 and then reversibly bonded onto a glass substrate, were used as references.…”

“…Above all, this microflow patterning method limits the integration flexibility of the electrokinetic concentrator device on uneven or spatially confined surfaces such as wells of a microplate. To bypass such limitations, a PDMS preconcentrator with different fabrication method and ion-selective polymer has been developed in our group 31 , 32 . Poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonate) (PEDOT:PSS) dispersion in H 2 O has low viscosity (10–30 cP at 20 °C) and consequently can be directly deposited on a very confined area of a glass or PDMS substrate using a piezoelectrically-actuated micropipette.…”

“…This decoupling fabrication strategy requires no additional substrate surface modification and reduces complexity in the alignment of the concentrator device to the ion-permselective membrane deposited on a flat substrate. In addition, spreading of the PEDOT:PSS solution can be controlled by printing it on a predefined pattern of a PDMS chip to achieve more uniformity in the size of ion-permselective membrane layer 31 . This approach further reduces the risk of compromising the stability of the preconcentration performance due to an incomplete sealing between the PEDOT:PSS membrane and the PDMS chip.…”

Rapid detection of exosomal microRNA biomarkers by electrokinetic concentration for liquid biopsy on chip

“…The concentration plug is in direct contact and spatially above the MO capture probes. In our previous publication, 25 we investigated the DNA concentration plug three-dimensional concentration profile with confocal microscopy along the channel depth in the z-direction. Our finding shows that the fluorescence signal intensity of the DNA plug was maximal near the glass surface and decreased almost linearly as the focal plane moved upward to the top of the channel, where the fluorescence signal intensity value decreased to about one-fourth of the maximal value at the top of the PDMS channel.…”