Malancha Gupta

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This article describes FLASH (Fast Lithographic Activation of Sheets), a rapid method for laboratory prototyping of microfluidic devices in paper. Paper-based microfluidic devices are emerging as a new technology for applications in diagnostics for the developing world, where low cost and simplicity are essential. FLASH is based on photolithography, but(More)
This paper describes an analytical system that uses magnetic levitation to measure densities of solids and water-immiscible organic liquids with accuracies ranging from +/-0.0002 to +/-0.02 g/cm(3), depending on the type of experiment. The technique is compatible with densities of 0.8-3 g/cm(3) and is applicable to samples with volumes of 1 pL to 1 mL; the(More)
This paper demonstrates that a hand-powered egg beater can be modified to serve as a centrifuge for separating plasma from human whole blood. Immunoassays used to diagnose infectious diseases often require plasma from whole blood, and obtaining plasma typically requires electrically-powered centrifuges, which are not widely available in resource-limited(More)
Non-planar, three dimensional structures, not possible with conventional microfabrication processes, were achieved using post-fabrication thermal annealing of thin film Parylene-C structures facilitated by a mold (" thermoforming "). We demonstrate thermoforming of Parylene-Parylene and Parylene-metal-Parylene (PMP) structures for increased structural and(More)
The use of delivery templates makes it possible to fabricate shaped, millimeter-thick heterogeneously patterned films of ionotropic hydrogels. These structures include two-dimensional (2-D) patterns of a polymer cross-linked by different ions (e.g., alginic acid cross-linked with Ca2+ and Fe3+) and patterns of step gradients in the concentration of a single(More)
This article describes the use of paper—patterned either by hand or with a color laser printer—to fabricate films of ionotropic hydrogels structured into regular shapes with lateral dimensions from 2 mm to several centimeters, and with thicknesses from 0.2 to 1.3 mm. Water-soluble polymers such as alginic acid (AA) and carboxymethyl cellulose (CMC) form(More)
This article describes a method for patterning certain solids—insoluble salts and reduced metals—in sheets of paper. Chemical reactions that produce these solids as precipitates occur when a stamp of patterned paper inked with an aqueous solution of reagent comes into contact with a paper substrate containing a second reagent. The pattern is determined by a(More)
The translation of batch chemistries onto continuous flow platforms requires addressing the issues of consistent fluidic behaviour, channel fouling and high-throughput processing. Droplet microfluidic technologies reduce channel fouling and provide an improved level of control over heat and mass transfer to control reaction kinetics. However, in(More)
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