Vol. 41, Issue 2, pp. 403-408

Abstract

In general flow cytometry enables the characterization of individual cells/microparticles. When a sample is injected into a flow cytometer, the randomly distributed cells are ordered into a stream of single cells. Hence, they can be individually analyzed in the detection system. In this paper, an optoelectronic compact and portable system for bacteria cells detection is described. The system consists of PDMS (polydimethylsiloxane) microfluidic chip, a duralumin holder with microfluidic connectors – inlets/outlets, as well as optic fiber connectors and waveguides for laser diode and photodetectors (avalanche photodiode BPYP 59 or photomultiplier 9658B). The fluorochrome is excited by light beam of an appropriate wavelength coming from a light source, e.g., the laser diode. The excitation light passes through hydrodynamically focused cells in the middle of the channel. After optical filtering, the light emitted by the fluorochrome is detected by a photodetector. Electrical signals from the selective nanovoltmeter are amplified and collected by the computer electronic system. Since in the real sample bacteria cells are selectively labeled with the fluorophores or antibodies conjugated with fluorochrome, in our experiments to evaluate lower detection limits of the developed detection system, exemplary fluorescent dye solutions of sodium fluorescein were used as testing solutions.