Ultrasonic deposition of cells on a surface

Bacteria in water have been driven to a glass surface by all ultrasonic standing wave. On an antibody coated surface Capture of Bacillus subtilis var niger (BG) spores (6.6 x 10(6) ml(-1)) was increased more than 200-fold over above the efficiency in the absence of ultrasound. In microfluidic (non-turbulent) systems detection of particles by sensors operating at a surface is diffusion limited. This results in very low detection abilities particularly for particles with diameters greater than 1 mum. Ultrasound is used here to drive bacterial spores to a wall and overcome this limitation. The results confirm: (I) pressure nodes can be formed close to the water-glass interface when the glass thickness is near half the ultrasonic wavelength (2) the antibody used was able to capture spores in the presence Of all ultrasonic standing wave. (C) 2003 Elsevier B.V. All rights reserved.