Temperature and time-resolved total internal reflectance fluorescence analysis of reusable DNA hydrogel chips.

Total internal reflection fluorescence (TIRF) coupled with hydrogel-DNA droplet microarrays covalently bound on PMMA substrates presents a reusable, sensitive platform for evaluating DNA hybridization and for rapid biochip development. Hydrogel microarrays, which contain covalently bound DNA probes, are created via a simple printing and photocross-linking process. TIRF measurements of the arrays display robust reusability, show linear sensitivity down to 5 fmol of fluorescently labeled target DNA, and are sensitive to single basepair mismatches.

The design of thin polymer membranes filled with magnetic particles on a microstructured silicon surface.

In this paper we present the fabrication and characterization of polymer nanomembranes filled with magnetic nanoparticles and attached covalently to a periodic array of free-standing silicon walls, forming an array of micro-channels with the membrane as a cover. The width of a micro-channel of about 1.4 microm sets a characteristic lateral size and the thickness of the polymer membrane ranges between 100 and 300 nm.