Microfluidic cell counter with embedded optical fibers fabricated by femtosecond laser ablation and anodic bonding

Abstract

A simple fabrication technique to create all silicon/glass microfluidic devices is demonstrated using femtosecond laser ablation and anodic bonding. In a first application, we constructed a cell counting device based on small angle light scattering. The counter featured embedded optical fibers for multiangle excitation and detection of scattered light and/or fluorescence. The performance of the microfluidic cell counter was benchmarked against a commercial fluorescence-activated cell sorter.

Fig. 1

Fiber placement in a femtosecond laser ablated groove.

Fig. 2

(a) White light image of the fluid channel (horizontal) with four fiber grooves: one above at 14 degrees from normal and three below at −45, 0, and 45 degrees from normal. (b) Nanoport connectors were attached to either end of the fluid channel. In these experiments, light was delivered through the fiber at 0 degrees from normal and collected through the fiber opposite it at 14 degrees from normal.

Fig. 3

An illustration of the experimental setup.

Fig. 4

Overlap of the illumination region with the anticipated detection region was determined by filling the fluid channel with a fluorescent dye and then imaging the fluorescence. Lineouts along the center of the fluid channel (parallel to the x axis) show the overlap of the illumination region (A) with the detection region (B).

Fig. 5

Sample data set showing the peaks from light scattered by passing HeLa cells.