Microsystems for Optical Cell Detection: Near versus Far Field

Abstract

Optical flow cytometry is a process where physical and (bio‐) chemical parameters of single biological cells can be obtained in a flow‐through setup by optical measurement techniques. Unlike conventional systems, where measurements are conducted in the optical far field, the proposed system senses the cell's optical projection in the near field by using integrated photodiodes. This allows for the attainment of additional parameters, e.g., size and shape, which are usually hidden in the far field. In addition, parameters such as refractive index and absorption of the cell influence the sensor signal. Additionally, with another setup, a different approach is followed to measure similar parameters with external detection using a DVD laser pickup head and a microchannel equipped with a mirror. This low‐cost setup does not measure in the near field, and therefore, is dedicated to different parameters. In this contribution, results from measurements with polystyrene particles and biological cells (yeast and Chinese hamster ovary) are presented and the advantages and limitations of both systems are outlined.

Hacking CD/DVD/Blu-ray for Biosensing

“… 51 Figure 5 illustrates a conventional and an OPU-based cytometer, which integrates a lab-on-chip device. The OPU-based cytometer has been used to count individual polystyrene beads between yeast cells, 52 erythrocytes, 53 Chinese hamster ovary, 54 and cattle erythrocytes 55 by analyzing focus error signal S FE as depicted in Figure 6 .…”

Rapid Prototyping für optofluidische Anwendungen

“…At-Line-Messungen durchzufü hren, um bestimmte Produkteigenschaften bzw. Prozessparameter zu ü berwachen (Kostner, Vellekoop, 2008). Die zytometrische Charakterisierung erfolgt nach der Entnahme der Probenflü ssigkeit (ml -ml) aus dem Produktionsprozess.…”

Non-emissive plastic colour filters for fluorescence detection

“…The latter may be directly incorporated into the microfluidic chip itself or take the form of thin-film components laminated onto the planar faces of the microfluidic chip. In recent years a wide range of optical components have been successfully integrated into microfluidic devices, including both active components such as light-sources 3,5,7,8 and photo-detectors 3,5,7,[9][10][11] and passive components such as prisms, 12 lenses, 13 filters, 4 mirrors, 14 gratings, 15 waveguides, 16,17 and polarisers. 18,19 Optical filters play a particularly important role in microfluidic devices.…”