High-speed particle detection in a micro-Coulter counter with two-dimensional adjustable aperture.
This article presents the fabrication and characterisation of a high-speed detection micro-Coulter counter with two-dimensional (2D) adjustable aperture and differential impedance detection. The developed device has been fabricated from biocompatible and transparent materials (polymer and glass) and uses the principle of hydrodynamic focusing in two dimensions. The use of a conductive solution for the sample flux and non-conductive solutions for the focalising fluxes provides an adjustable sample flow where particles are aligned and the resistive response concentrated, consequently enhancing the sensitivity and versatility of the device. High-speed counting of 20 microm polystyrene particles and 5 microm yeast cells with a rate of up to 1,000 particles/s has been demonstrated. Two-dimensional focusing conditions have been used in devices with physical cross-sectional areas of 180 microm x 65 microm and 100 microm x 43 microm, respectively, in which particles resulted undetectable in the absence of focusing. The 2D-focusing conditions have provided, in addition, increased detection sensitivity by a factor of 1.6 as compared to 1D-focusing conditions.
Institut de Bioenginyeria de Catalunya (IBEC), C/ Baldiri Reixac 13, 08028 Barcelona, Spain. romen@el.ub.es
Romen
R
Rodriguez-Trujillo
Oscar
O
Castillo-Fernandez
Miquel
M
Garrido
Martin
M
Arundell
Antoni
A
Valencia
Gabriel
G
Gomila
D002452:Cell Count / Q000295:instrumentation*; D004581:Electronics / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005434:Flow Cytometry / Q000295:instrumentation*; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity