Search

High sensitivity, on-chip calorimeter platform using V 2 O 5 thin film thermistor was developed. Integration of a V 2 O 5 thermistor with a high temperature sensitivity of −2.2%/K with a vacuum insulated, suspended SiN membrane structure enabled a low thermal conductance of 12 μW/K and a direct detection of 10 nW of heat with an estimated detection limit of 570 pW. We also investigated the feasibility of integrating the platform with a microfluidic system, and, suggest that, based on numerical simulations, a further 5-fold lowering of detection limit may be possible. [ABSTRACT FROM AUTHOR]

Abstract: We used the electrostatic deposition (ESD) method to prepare the protein microarray for observation of the stem cell responses to pattern size, space and shapes. The ESD method allows a reduction in spot size, high efficiency of substance transfer, and high rate in fabrication as a result of ability to simultaneously deposit thousands of identical spots. Typical electrospraying conditions for the deposition of proteins were a voltage of 3.5–4.5keV and the humidity under 40%. The patterns of masks have a variety of shapes, spaces, and hole sizes from 10 to 300μm. Collagen is deposited on conducting polymer in a dry state, preserving the functional activity of proteins. The surface morphology of deposited spots was observed using an atomic force microscope and a scanning electron microscope. Human mesenchymal stem cells were cultured on each extracelluar protein patterned sample and cellular morphology was observed by light microscopy. Cell attachment and spreading on the surface are dependent on the deposition conditions by ESD. Protein deposition with short time is effective on the cell culture. However, collagen pattern size, space and shapes in micrometer size seemed to have little effect on cellular response in our design. [Copyright &y& Elsevier]