Resonance-enhanced microfluidic impedance cytometer for detection of single bacteria

Abstract

This paper reports on a novel impedance-based cytometer, which can detect and characterize sub-micrometer particles and cells passing through a microfluidic channel. The cytometer incorporates a resonator, which is constructed by means of a discrete inductor in series with the measurement electrodes in the microfluidic channel. The use of a resonator increases the sensitivity of the system in comparison to state-of-the-art devices. We demonstrate the functionality and sensitivity of the cytometer by discriminating E. coli and B. subtilis from beads of similar sizes by means of the resonance-enhanced phase shift of the current through the microfluidic channel. The phase shift can be correlated to size and dielectric properties of the measured objects.

High accuracy particle analysis using sheathless microfluidic impedance cytometry

“…Externally applied forces can also be used to focus particles within the fluid. For example dielectrophoresis 6,23 (DEP) and acoustophoresis 24 have been used to focus particles without the use of a secondary flow. Other novel approaches include combining DEP and inertial microfluidics 25 .…”

“…A voltage is applied at several different frequencies and the change in current is analysed to determine the cell dielectric properties. Microfluidic impedance cytometry has been used to analyse micro-organisms [5][6][7] , erythrocytes 8,9 , leukocytes 10,11 , platelets 12,13 , and animal and human cell lines [14][15][16] . Low frequency (e.g.…”

New Technologies for Rapid Bacterial Identification and Antibiotic Resistance Profiling

“…Recent advances in single-cell monitoring [21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38] may provide new solutions that can speed bacterial analysis by monitoring changes in growth on a cell-bycell level. Single-cell microbioreactors 30 and microscale incubators 27 provide a means to culture bacteria in very small volumes, and new types of single-cell analysis methods 24,25,34 allow rapid readout of bacterial viability.…”

Analyzing Single Giant Unilamellar Vesicles With a Slotline-Based RF Nanometer Sensor

“…The use of resonators [12], [13] and interferometers [14], [15] helps address this issue, but at single frequency points. Broadband [16] and multiple frequency DS [17] are reported with single cell sensitivities.…”