On-chip organic synthesis enabled using an engine-and-cargo system in an electrowetting-on-dielectric digital microfluidic device

This work describes the interfacing of electrowetting-on-dielectric based digital microfluidic (DMF) sample preparation devices with ambient mass spectrometry (MS) via desorption atmospheric pressure photoionization (DAPPI). The DMF droplet manipulation technique was adopted to facilitate drug distribution and metabolism assays in droplet scale, while ambient mass spectrometry (MS) was exploited for the analysis of dried samples directly on the surface of the DMF device. Although ambient MS is well-established for bio- and forensic analyses directly on surfaces, its interfacing with DMF is scarce and requires careful optimization of the surface-sensitive processes, such as sample precipitation and the subsequent desorption/ionization. These technical challenges were addressed and resolved in this study by making use of the high mechanical, thermal, and chemical stability of SU-8. In our assay design, SU-8 served as the dielectric layer for DMF as well as the substrate material for DAPPI-MS. The feasibility of SU-8 based DMF devices for DAPPI-MS was demonstrated in the analysis of selected pharmaceuticals following on-chip liquid-liquid extraction or an enzymatic dealkylation reaction. The lower limits of detection were in the range of 1–10 pmol per droplet (0.25–1.0 µg/mL) for all pharmaceuticals tested.

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Analytical Models to Determine the Electric Field Characteristics of a Multi-Electrode Impedimetric Immunosensor in a Digital Microfluidic Device

Volume 3: Biomedical and Biotechnology Engineering ◽

10.1115/imece2014-37571 ◽

2014 ◽

Author(s):

Steffen O. P. Blume ◽

Michael J. Schertzer ◽

Ridha Ben Mrad ◽

Pierre E. Sullivan

Keyword(s):

Microfluidic Device ◽

Digital Microfluidics ◽

Electrode Array ◽

Analytical Models ◽

Element Analysis ◽

Numerical Simulation Methods ◽

Mapping Techniques ◽

On Chip ◽

Digital Microfluidic ◽

Impedimetric Immunosensor

The level of integration of digital microfluidics is continually increasing to include the system path from fluid manipulation and transport, on to reagent preparation, and finally reaction detection. Digital microfluidics therefore has the capability to encompass all steps of common biochemical protocols. Reported here is a set of analytical models for the design of a coplanar interdigitated multi-electrode array to be used as an impedimetric immunosensor in a digital microfluidic device for on-chip chemical reaction detection. The models are based on conformal mapping techniques, and are compared to results obtained from finite element analysis to discuss limitations of the model. The analytical models are feasible and inexpensive surrogates for numerical simulation methods.

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Time-Invariant Deformation of Blood During Necking on an Electrowetting Digital Microfluidic Platform

Volume 4: Fluid Measurement and Instrumentation; Micro and Nano Fluid Dynamics ◽

10.1115/ajkfluids2019-5516 ◽

2019 ◽

Author(s):

Curtis Young ◽

Anand K. Ramasubramanian ◽

Melinda Simon ◽

Sang-Joon John Lee

Keyword(s):

Whole Blood ◽

Tensile Tests ◽

Exponential Model ◽

Width Ratio ◽

Electrowetting On Dielectric ◽

Neck Width ◽

On Chip ◽

Digital Microfluidic ◽

Time Invariant ◽

Neck Radius

Abstract Recent developments in electrowetting-on-dielectric (EWOD) technology have expanded the possibilities for testing methods and investigation of blood. This work evaluated the development of necking geometry of whole blood on an EWOD-based digital microfluidic (DMF) platform. This was achieved by performing tensile tests on whole blood on an EWOD-based device, thereby inducing necking. A time-invariant method was used to evaluate the deformation of the tested dilutions, using minimum neck width and neck radius as two characteristic parameters of the necking geometry. Experiments were performed on blood diluted with phosphate-buffered saline (PBS) at dilutions of 1:20 and 1:10 by volume. Parameter measurements were obtained by recording microscope video of on-chip tensile tests and extracting the necking profile. Neck radius and neck width are obtained from the extracted necking profile and evaluated to compare results. Results from tensile tests on blood at different dilutions showed an exponential decrease in neck radius as neck width decreases. A four-parameter exponential model was fit to the collected data, showing that the 1:20 dilution had a higher neck radius to neck width ratio than the 1:10 dilution over a neck width interval of 0.3 mm to 1.7 mm, suggesting a viscosity effect on the necking geometry. The results demonstrate that the concentration of blood influences the necking profile when deformed under tension that is applied by electrowetting forces.

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Direct loading of blood for plasma separation and diagnostic assays on a digital microfluidic device

Lab on a Chip ◽

10.1039/d0lc00302f ◽

2020 ◽

Vol 20 (10) ◽

pp. 1845-1855 ◽

Cited By ~ 1

Author(s):

Christopher Dixon ◽

Julian Lamanna ◽

Aaron R. Wheeler

Keyword(s):

Microfluidic Device ◽

Porous Membranes ◽

Plasma Separation ◽

Diagnostic Assays ◽

Direct Loading ◽

On Chip ◽

Finger Stick ◽

Digital Microfluidic ◽

Free Plasma ◽

Chip Analysis

The integration of 3D porous membranes in a digital microfluidic device enables the generation of cell-free plasma from finger-stick volumes of blood with in-line, on-chip analysis.

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On-chip characterization of cryoprotective agent mixtures using an EWOD-based digital microfluidic device

Lab on a Chip ◽

10.1039/c1lc20111e ◽

2011 ◽

Vol 11 (13) ◽

pp. 2212 ◽

Cited By ~ 31

Author(s):

Sinwook Park ◽

Pavithra A. L. Wijethunga ◽

Hyejin Moon ◽

Bumsoo Han

Keyword(s):

Microfluidic Device ◽

Cryoprotective Agent ◽

On Chip ◽

Digital Microfluidic

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Design and Manufacturing of a Disposable, Cyclo-Olefin Copolymer, Microfluidic Device for a Biosensor †

Sensors ◽

10.3390/s19051178 ◽

2019 ◽

Vol 19 (5) ◽

pp. 1178 ◽

Cited By ~ 2

Author(s):

Jorge Prada ◽

Christina Cordes ◽

Carsten Harms ◽

Walter Lang

Keyword(s):

Microfluidic Device ◽

Heating Temperature ◽

Low Cost ◽

Reaction Chamber ◽

Microfluidic System ◽

Heating Process ◽

Design And Manufacturing ◽

On Chip ◽

Working Parameters ◽

Auto Fluorescence

This contribution outlines the design and manufacturing of a microfluidic device implemented as a biosensor for retrieval and detection of bacteria RNA. The device is fully made of Cyclo-Olefin Copolymer (COC), which features low auto-fluorescence, biocompatibility and manufacturability by hot-embossing. The RNA retrieval was carried on after bacteria heat-lysis by an on-chip micro-heater, whose function was characterized at different working parameters. Carbon resistive temperature sensors were tested, characterized and printed on the biochip sealing film to monitor the heating process. Off-chip and on-chip processed RNA were hybridized with capture probes on the reaction chamber surface and identification was achieved by detection of fluorescence tags. The application of the mentioned techniques and materials proved to allow the development of low-cost, disposable albeit multi-functional microfluidic system, performing heating, temperature sensing and chemical reaction processes in the same device. By proving its effectiveness, this device contributes a reference to show the integration potential of fully thermoplastic devices in biosensor systems.

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