Untitled

Abstract

This paper describes a disposable¯ow cytometer that uses an air-liquid two-phase micro¯uidic system to produce a focused high-speed liquid sample stream of particles and cells. The susceptibility of thin liquid columns to instabilities may suggest that focusing of sample liquids with streams of air would be dif®cult. The design of channel geometry, control of¯ow rates, and use of appropriate surface chemistries on the channel walls, however, enabled the generation of thin (15±100 lm) and partially bounded sample streams that were stable and suitable for rapid cell analysis. Using an inverted epi-¯uorescence microscope with a photomultiplier tube, we demonstrated that the system is capable of counting the number of beads and C 2 C 12 myoblast cells. The effects of different¯ow rates and surface chemistries of the channel walls on the air-liquid two-phase¯ows were characterized using optical and confocal microscopy. Use of air instead of liquids as a sheath uid eliminates the need for large sheath liquid reservoirs, and reduces the volume and weight requirements. The low manufacturing cost and high volumetric ef®ciency make the air-sheath¯ow cytometer attractive for use as a stand-alone device or as an integrated component of bio-arti®cial hybrid microsystems.

Acoustically detectable cellular-level lung injury induced by fluid mechanical stresses in microfluidic airway systems

“…Initially, liquid is injected into the plug generator and focused by air flows to form a stable stratification of air and liquid (Fig. 3A) (51,52). When air is valved off, the liquid stream spreads instantaneously and progresses gradually into the culture chamber (Fig.…”

Review Article: Recent advancements in optofluidic flow cytometer

“…Microfluidic systems in this realm offer the benefit of highly predictable behavior that does not depend on sample size desirable qualities for a microfluidic sample positioning system. Numerous structures [17][18][19][20][21][22][23][24][25] have been designed for hydrodynamic flow focusing under this approximation and will be discussed in Sec. II A.…”

“…In a related approach, air can be used as the sheath fluid to confine the sample flow while reducing the volume of the clean water needed. 18 Two-dimensional flow focusing constrains the sample flow in the lateral direction; however, the fluid velocity still exhibits a parabolic velocity profile in the vertical direction.…”

Recent advances in miniaturized microfluidic flow cytometry for clinical use

“…Studies on the enumeration of C2C12 myoblast cells using air pressure [77,78] and of blood cells using a sheathfree transport system [31] are interesting. In addition to an analysis of suspended cell populations (e.g., red blood cells, platelets, lymphocytes, monocytes, and granulocytes), Ferris et al [58] also performed viral analysis, and demonstrated the rapid enumeration of adenovirus, respiratory syncytial virus, and influenza virus.…”