Combining multiple optical trapping with microflow manipulation for the rapid bioanalytics on microparticles in a chip.

An array of four independent laser traps is combined with a polydimethylsiloxane microfluidic chip to form a very compact system allowing parallel processing of biological objects. Strong three dimensional trapping allows holding objects such as functionalized beads in flows at speeds near 1 mm/s, enabling rapid processing. By pressure control of the inlet flows, the trapped objects can be put in contact with different solutions for analysis purpose.

Microfluidic patterning of alginate hydrogels.

In this article the authors present techniques which allow the microfluidic design of alginate microgels with layer composition on a chip. The hydrogel is created by combining two laminar flows of the gel precursor solutions-a calcium solution and an alginate solution-in a microchannel. The alginate solution is loaded with particles and by employing a certain fluid handling protocol involving several alginate solutions with different types of particles, a gel bar composed of many layers, each layer filled with a certain particle type, is formed.

Micropatterned surfaces of PDMS as growth templates for HEK 293 cells.

In this paper the easy and reliable preparation of precise micropatterns on PDMS surfaces is described and the growth of HEK 293 cells on those patterns during culture over several days is examined. The first patterning approach described is based on soft-lithography and polyelectrolyte multilayer deposition. Two different soft-lithographic techniques are employed for creating surface patterns of PAH, PSS, untreated and oxidized PDMS.