title: Hydrodynamic optical alignment for microflow cytometry.
abstract: A microfabricated flow cytometer has been developed that is capable of detecting nearly all of the microparticles in an aqueous suspension. Current design allows for integrated coupling between an optical fiber-based detection system and the particle stream via hydrodynamic focusing. By adjusting the relative flow-rates at the auxiliary inputs of the focusing manifold, the particle stream can be steered out-of-plane relative to the illuminating laser, and similarly the particle stream can be squeezed or expanded. The microfabricated device was constructed in polydimethylsiloxane with cross-sectional microfluidic dimensions of 125 µm×125 µm. Using the present device and method, fluorescent microparticles in aqueous solution were counted at an absolute counting efficiency of 91±4%. The coefficient of variation of the fluorescence pulse-heights for far-red fluorescent microparticles was 15%. The device exhibited a linear response to fluorescence intensity calibration microparticles as shown by comparison with a commercial cytometer instrument.
authors.affiliation: Department of Electrical and Computer Engineering, Cornell University, Ithaca, NY 14853, USA.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Kennedy
authors.forename: Scott J
authors.initials: SJ
authors.lastname: Stelick
authors.forename: Lavanya G
authors.initials: LG
authors.lastname: Sayam
authors.forename: Andrew
authors.initials: A
authors.lastname: Yen
authors.forename: David
authors.initials: D
authors.lastname: Erickson
authors.forename: Carl A
authors.initials: CA
authors.lastname: Batt
mesh_terms: D005434:Flow Cytometry / Q000295:instrumentation* / Q000379:methods; D057446:Hydrodynamics; D007834:Lasers; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation / Q000379:methods