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Chip-based microcolumn separation systems often require serpentine channels to achieve longer separation lengths within a compact area. However, analyte bands traveling through curved channels experience an increased dispersion that can reduce the benefit of increased channel length. This paper presents analytical solutions for dispersions, numerical models(More)
The present work is an analytical and experimental study of electroosmotic flow (EOF) in cylindrical capillaries with nonuniform wall surface charge (potential) distributions. In particular, this study investigates perturbations of electroosmotic flow in open capillaries that are due to induced pressure gradients resulting from axial variations in the(More)
At present, point-of-care (POC) diagnostics typically provide a binary indication of health status (e.g., home pregnancy test strip). Before anticipatory use of diagnostics for assessment of complex diseases becomes widespread, development of sophisticated bioassays capable of quantitatively measuring disease biomarkers is necessary. Successful translation(More)
BACKGROUND Periodontitis is the major cause of tooth loss in adults and is linked to systemic illnesses, such as cardiovascular disease and stroke. The development of rapid point-of-care (POC) chairside diagnostics has the potential for the early detection of periodontal infection and progression to identify incipient disease and reduce health care costs.(More)
We describe a microfluidic Western blot assay (μWestern) using a Tris tricine discontinuous buffer system suitable for analyses of a wide molecular mass range (6.5-116 kDa). The Tris tricine μWestern is completed in an enclosed, straight glass microfluidic channel housing a photopatterned polyacrylamide gel that incorporates a photoactive benzophenone(More)
The ability to monitor cell signaling events is crucial to the understanding of immune defense against invading pathogens. Conventional analytical techniques such as flow cytometry, microscopy, and Western blot are powerful tools for signaling studies. Nevertheless, each approach is currently stand-alone and limited by multiple time-consuming and(More)
Little headway has been made in single cell protein analysis, aside from tools that rely solely on antibody-probe based detection (i.e., flow cytometry, immunocytochemistry), which are limited by low specificity and multiplexing capabilities. To address these protein analysis gaps, we have introduced a single-cell western blot (scWestern). The protein assay(More)
We introduce an automated immunoblotting method that reports protein electrophoretic mobility and identity in a single streamlined microfluidic assay. Native polyacrylamide gel electrophoresis (PAGE) was integrated with subsequent in situ immunoblotting. Integration of three PA gel elements into a glass microfluidic chip achieved multiple functions,(More)
Intratumor heterogeneity remains a major obstacle to effective cancer therapy and personalized medicine. Current understanding points to differential therapeutic response among subpopulations of tumor cells as a key challenge to successful treatment. To advance our understanding of how this heterogeneity is reflected in cell-to-cell variations in(More)
Reactive ion etching (RIE) was used to pattern antibodies onto the surfaces of polymer substrates. A low pressure, inductively coupled oxygen plasma was used to anisotropically etch 25-30 mum deep features into poly(methyl methacrylate) (PMMA), Zeonex, and polycarbonate (PC). Scanning electron microscopy and contact angle measurements show that the(More)