Glass Capillary based cavity resonator for particle trapping study and bacteria up-concentration

• We have performed particle aggregation characterization on the basis of their material and suspendingmedium in a capillary-based cavity resonator used for acoustophoresis. We have investigated the experimentalaggregation time of 5μm polystyrene and silica particles, size of aggregate, number of trapped particles and upconcentrationfactor in water, 0.01M phosphate buffered saline (PBS) and 0.005M PBS at 1.97MHz and withactuation voltages between 4, 8 and 12Vpp. We have found that there is little difference between using water andPBS as suspension medium, approximately 5-10% longer trapping times with PBS compared with water.However we get approx. 5.5 times faster trapping time for silica than for polystyrene. It is also observed andcalculated that silica particle aggregates have 3.4 times larger area than the polystyrene aggregates using the samestarting particle concentrations, revealing similar amount of difference in trapped number of particles. The upconcentrationfactor for silica is also about 3.2 times higher than that of polystyrene due to larger aggregate areaof silica particles. Based on theoretical predictions and experimental characterization of the particle aggregationpattern, we note that the particle-particle interaction force contribution to the total acoustic radiation force is morepronounced for silica than for polystyrene. Finally as a proof of principle for biomedical sample preparationapplication we demonstrate the capillary-based silica particles mediated bacteria acoustophoretic upconcentration.This setup could potentially be utilized not only for sample preparation application but also forbead based affinity immunoassays.

Subject headings

MEDICIN OCH HÄLSOVETENSKAP  -- Medicinsk bioteknologi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Medical Biotechnology (hsv//eng)

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