A hybrid poly(dimethylsiloxane) microsystem for on-chip whole blood filtration optimized for steroid screening

Abstract

Miniaturized biochemical devices in glass, silicon and polymer materials are starting to find their way from the academic laboratories to real-life applications. However, most attention has been given to miniaturize the downstream functions of various microfluidic systems, leaving the sample introduction and preparation steps to more conventional, bulkier solutions. For point-of-care diagnostics in particular, it becomes crucial to be able to handle complex human samples in a miniaturized format.In this work, we report on a microsystem for on-chip sample preparation that is able to remove blood cells from whole blood. The hybrid system consists of a commercially available membrane filter incorporated into a poly(dimethylsiloxane) (PDMS) casted device. Membrane materials were evaluated on the bases of low nonspecific adsorption of free and protein-bound testosterone as analyte substance. The hybrid system including a hydrophilic polypropylene filter successfully removed blood cells from diluted human whole blood. Surface oxidation was sufficient to make the plasma filtrate flow through the membrane filter and the channel system by capillary force alone and thus no external pumping source was needed.

Characterization of thermoplastic microfiltration chip for the separation of blood plasma from human blood

“…That device used commercial membranes made of polyethersulfone (PES), polypropylene and polyvinylidene fluoride, cellulose acetate, polycarbonate, and polyvinylpyrrolidone (PVP)/polyethersulfone. 9 Multiple experiments have been conducted on hybrid microfluidic chips to understand how different membranes affect blood plasma extraction. In one study, Wang et al developed a disposable four-layer microfluidic chip to separate blood plasma and viruses from whole human blood.…”

“…Thorslund et al 9 reported leakage at the interface between the polyvinylpyrrolidone (PVP)/polyethersulfone (PES) membrane and the PDMS substrates. Homsy et al 12 adopted the method of Thorslund et al 9 but changed the substrate material from PDMS to PC and NOA 81 in an attempt to prevent leakage between the two heterogeneous materials. In the current study, we used a two-step injection and curing procedure of UV adhesive to fabricate a fully thermoplastic microfiltration chip for separating blood plasma from human blood, and this chip had ring-shaped structural features on the both poly(methyl methacrylate) (PMMA) substrates around the microchannels and a commercial polycarbonate membrane was sandwiched between the top and bottom substrates.…”

“…Microfluidic devices can even be integrated with other components toward a lab-on-a-chip (LOC). Blood analysis [2][3][4][5][6][7][8][9][10][11][12][13] involves separating blood plasma from whole human blood to prevent blood cells from affecting final assay results. The conventional approach for plasma separation involves fitting commercial centrifuge tubes with a filter to separate the blood plasma from the whole human blood; however, the centrifugal forces induced by high speed rotation are difficult to be realized on microfluidic platforms.…”

“…Fax: 886-2-27376460. chips. [7][8][9][10][11] Examples of the different microfiltration approaches are described over subsequent paragraphs.…”

Direct detection of cancer biomarkers in blood using a “place n play” modular polydimethylsiloxane pump

“…Numerous reports have described on-chip plasma separation using microfluidic approaches, such as centrifugation, 24,25 filtration, 26 magnetophoresis, 27 flow bifurcation, 28 and membrane integration. [29][30][31] However, these chips require external power sources or sophisticated fabrication which hinders their widespread application, especially in developing countries. Recently, Dimov et al demonstrated a self-powered, integrated, microfluidic blood analysis system that performed on-chip cell removal and multiple protein binding assays.…”