Cell detection and discrimination by a microfluidic-integrated broadband microchamber

RF MEMS control of planar microchamber for adaptive biosensing applications

“…3 shows that even though the untuned microchamber achieves better than 16 dB return loss between 0.1 and 3 GHz, this does not insure enough sensitivity around 2 GHz-a frequency that is of interest for cell status identification [3]. Indeed, with |S 11 | measurement fluctuations being of the order of 0.05 dB [3], the untuned biosensor response is well below the noise threshold. On the other hand the response from the microchamber with adaptive tuning exceeds the noise threshold significantly over a 250 MHz range.…”

“…Nevertheless, current challenges in impedance matching [2], sensitivity [3] and calibration [4] harness the potential for fast electrical detection.…”

“…Adaptive control of the impedance environment is attractive since it would not only address drift related issues; it would also allow minimizing the detected parasitic susceptance, thus increasing the sensitivity to biologically relevant parameters. For example small capacitance variations when single cells are trapped across planar electrodes in a~100 µm wide channel can be correlated with cellular status and type [3]. Improving the return loss performance is also of interest if the microchamber is used for cell irradiation instead of, or in addition to sensing [1].…”

Modelling and Measurements of the Microwave Dielectric Properties of Microspheres

“…The cultivation stadium of a yeast culture was monitored to detect the permittivity changes. In [12] and [13], broadband microwave measurements and sensing of single Jurkat and HEK cells were used to overcome electrode polarization, with ac dielectrophoresis used to precisely place cells between narrowly spaced electrodes, and relatively wide microfluidic channels incorporated to prevent cell clogging.…”