Electrokinetically driven micro flow cytometers with integrated fiber optics for on-line cell/particle detection

Review Article: Recent advancements in optofluidic flow cytometer

“…In a similar approach, another group demonstrated manual sorting of red blood cells by switching the applied voltage potentials ͑300-500 V͒ across the inlet and outlets. 82 Dittrich and Schwille described another electro-osmosis-induced sorting method by Theoretical maximum sort rate.…”

Design of a confocal microfluidic particle sorter using fluorescent photon burst detection

“…Possible solutions could be found in reduction of the channel dimensions, 11,12 rapid scanning of the laser beam 35,36 or by using waveguides. 37,38 At present, the speed of detection and sorting is too low for practical use. If one wants to sort 10 5 -10 6 particles from a biolibrary in a limited period of time, a different approach is required.…”

Low cost micro-Coulter counter with hydrodynamic focusing

“…One particularly important application is the development of cell counters, which can be used as a stand alone device for counting, and sizing, or in more complex Particle counting can be based on two detection methods. Optical methods extract information from light dispersed by particles and from specific fluorescent excitation (Schrum et al 1999;McClain et al 2001;Fu et al 2004), whereas electrical methods (referred to as Coulter counters) extract information from the modulation of the electrical resistance in an orifice due to the passage of the particle (Larsen et al 1997;Koch et al 1999;Ayliffe et al 1999;Saleh and Sohn 2001;. Optical methods have the advantage of being able to incorporate fluorescent markers that are widely used in biology, but at the price of increased integration complexity.…”

“…Electrical methods, on the other hand, present advantages from the point of view of integration, particularly after the demonstration of entirely electrical-based micro-flow cytometers and sorters utilizing electrical impedance methods (Cheung et Micro-Coulter counters, i.e. micro-dimensioned particle counters based on electrical detection methods, have been fabricated using a variety of materials -e. g. silicon (Schrum et al 1999;McClain et al 2001;Fu et al 2004;Larsen et al 1997;Koch et al 1999), glass (Ayliffe et al 1999), glass-polyimide (Cheung et al 2005;Holmes et al 2005;Morgan et al 2005;Gawad et al 2001), polymer , and quartz (Saleh and Sohn 2001)-and with different particle alignment methods -geometric (Saleh and Sohn 2001;, hydrodynamic (Larsen et al 1997) and electrokinetic (Schrum et al 1999;McClain et al 2001;Fu et al 2004;Holmes et al 2005;Morgan et al 2005;Cheung et al 2005). Particles with diameters from several micrometers down to tens of nanometers (Saleh and Sohn 2001; have been examined with detection ratios varying from a few counts per second, if electrophoretic forces are utilized for particle manipulation (Saleh and Sohn 2001), to hundreds of counts per second, if pressure forces are utilized (Morgan et al 2005;Gawad et al 2001).…”