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Kitsara M.,Biomedical Diagnostics Institute | Ducree J.,Biomedical Diagnostics Institute
Journal of Micromechanics and Microengineering | Year: 2013

The opportunity for the commercialization of microfluidic systems has surged over the recent decade, primarily for medical and the life science applications. This positive development has been spurred by an increasing number of integrated, highly functional lab-on-a-chip technologies from the research community. Toward commercialization, there is a dire need for economic manufacture which involves optimized cost for materials and structuring on the front-end as well as for a range of back-end processing steps such as surface modification, integration of functional elements, assembly and packaging. Front-end processing can readily resort to very well established polymer mass fabrication schemes, e.g. injection molding. Also assembly and packaging can often be adopted from commercially available processes. In this review, we survey the back-end processes of hybrid material integration and surface modification which often need to be tailored to the specifics of miniaturized polymeric microfluidic systems. On the one hand, the accurate control of these back-end processes proves to be the key to the technical function of the system and thus the value creation. On the other hand, the integration of functional materials constitutes a major cost factor. © 2013 IOP Publishing Ltd.

Kent N.J.,Biomedical Diagnostics Institute | Kent N.J.,Dublin Institute of Technology | O'Brien S.,Royal College of Surgeons in Ireland | Basabe-Desmonts L.,Royal College of Surgeons in Ireland | And 5 more authors.
IEEE Transactions on Biomedical Engineering | Year: 2011

We report a microfluidic chip-based hydrodynamic focusing approach that minimizes sample volume for the analysis of cell-surface interactions under controlled fluid-shear conditions. Assays of statistically meaningful numbers of translocating platelets interacting with immobilized von Willebrand factor at arterial shear rates (∼1500 s-1) are demonstrated. By controlling spatial disposition and relative flow rates of two contacting fluid streams, e.g., sample (blood) and aqueous buffer, on-chip hydrodynamic focusing guides the cell-containing stream across the protein surface as a thin fluid layer, consuming ∼50 μL of undiluted whole blood for a 2-min platelet assay. Control of wall shear stress is independent of sample consumption for a given flow time. The device design implements a mass-manufacturable fabrication approach. Fluorescent labeling of cells enables readout using standard microscopy tools. Customized image-analysis software rapidly quantifies cellular surface coverage and aggregate size distributions as a function of time during blood-flow analyses, facilitating assessment of drug treatment efficacy or diagnosis of disease state. © 2006 IEEE.

Nwankire C.E.,Biomedical Diagnostics Institute | Czugala M.,Dublin City University | Burger R.,Biomedical Diagnostics Institute | Diamond D.,Dublin City University | Ducree J.,Biomedical Diagnostics Institute
17th International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2013 | Year: 2013

This paper describes the first use of a compact, integrated and automated centrifugal microfluidic platform equipped with paired emitter detector diodes (PEDD) for carrying out a 5-parameter enzymatic liver assay panel with colorimetric end-point and kinetic detection (Fig. 1). Starting with single-step pipetting of finger prick blood, this "Lab-on-a-Disc" (LoaD) system [1, 2] controls multi-stage sample preparation and flow distribution into six outer reaction chambers by an array of dissolvable film (DF) valves [3]. The measurements on albumin (ALB), alkaline phosphatase (ALP), gamma glutamyl transferase (GGT) and total (TBIL) bilirubin show good quantitative correlation with standard benchtop and hospital laboratory results.

Yuk J.S.,Biomedical Diagnostics Institute | Trnavsky M.,Biomedical Diagnostics Institute | McDonagh C.,Biomedical Diagnostics Institute | MacCraith B.D.,Biomedical Diagnostics Institute
Biosensors and Bioelectronics | Year: 2010

We have carried out a human IgG immunoassay on a novel disposable optical array biochip using surface plasmon-coupled emission (SPCE) detection. The work successfully combines the advantages of the highly directional SPCE emission profile and enhanced surface plasmon excitation with the high light collection efficiency achieved using supercritical angle fluorescence (SAF). This is achieved using an array of transparent paraboloid polymer elements which have been coated with a thin gold layer to facilitate SPCE. Moreover, since only the emission of molecules which are close to the metal surface couple into the surface plasmon, the detection is highly surface-specific leading to background suppression and increased signal-to-noise ratio. Theoretical calculations have been carried out in order to match the surface plasmon resonance angles and SPCE emission angles to the paraboloid array features for light collection. A sandwich assay format was used and a dose response curve was obtained in the concentration range 2 ng/ml to 200 μg/ml yielding a limit of detection of 20 ng/ml. This is the first demonstration of an SPCE-based assay on a disposable biochip platform and indicates the potential of SPCE-based arrays for high-throughput analysis of biomolecular interactions. Crown Copyright © 2009.

Siegrist J.,Biomedical Diagnostics Institute | Burger R.,Biomedical Diagnostics Institute | Kirby D.,Biomedical Diagnostics Institute | Zavattoni L.,Biomedical Diagnostics Institute | And 2 more authors.
15th International Conference on Miniaturized Systems for Chemistry and Life Sciences 2011, MicroTAS 2011 | Year: 2011

This paper presents a refined centrifugo-magnetophoretic platform enabling 2-dimensional separation of cancer cells from background cells [1]. The multi-force, stopped-flow separation combines centrifugal sedimentation with lateral magnetic deflection. In this way, hydrodynamic stresses and variations typical in pressure-driven microfluidic platforms [2][3] are minimized, and collisions between cells and chamber walls, a common disadvantage of stand-alone magnetic separation systems, is avoided. In this work, basic separation of magnetic particles from a background of non-magnetic particles is shown first. Then, magnetic particles functionalized with anti-EpCAM antibodies are used to successfully capture and separate MCF-7 breast cancer cells from background HeLa cells.

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