Ranu Nayak | PubMed Health

PubMed2006

Monolithic media in microfluidic devices for proteomics.

Considerable effort has been invested in the development of integrated microfluidic devices for fast and highly efficient proteomic studies. Among various fabrication techniques for the preparation of analytical components (separation columns, reactors, extractors, valves, etc.) in integrated microchips, in situ fabrication of monolithic media is receiving increasing attention. This is mainly due to the ease and simplicity of preparation of monolithic media and the availability of various precursors and chemistries. In addition, UV-initiated photopolymerization technique enables the incorporation of multiple analytical components into specified parts of a single microchip using photomasks. This review summarizes preparation methods for monolithic media and their application as microfluidic analytical components in microchips.

Microfluidic Analytical Techniques↗

PubMed2003

Influence of spinel substrate and over-layer for enhanced SAW and AO properties with KNbO3 thin film.

Surface acoustic wave (SAW) propagation characteristics have been studied using modeling calculations for a potassium niobate (KNbO3) thin film-layered structure with (001) and (110) orientation on a single crystal spinel (MgAl2O4) substrate, and a spinel buffer layer on silicon. Variation in the electromechanical coupling and acoustic attenuation has been compared. A significantly high value of coupling factor (k2max = 23%) is obtained for the (001)KNbO3/spinel structure by introducing an optimum thickness of spinel over-layer for potential wide bandwidth SAW device applications. The dispersion characteristics with the (110) KNbO3 orientation indicate an initial peak in the coupling coefficient value (k2max = 8.8%) at a relatively low KNbO3 film thickness that appears attractive for fabricating devices with thinner films. The KNbO3 film with (001) orientation is found attractive for efficient acousto-optic (AO) device application with the formation of a symmetric waveguide structure (spinel(0.5 microm)/KNbO3(1.0 microm)/spinel). A high value of k2 = 23.5% with 50% diffraction efficiency has been obtained for the spinel(0.5 microm)/KNbO3(1.0 microm)/spinel structure at 1 GHz SAW frequency and 633 nm optical wavelength at a very low input drive power of 15.4 mW.

Journal Article↗