Testing the bio-compatibility of the piezoelectric ceramics and biological media

Trying to make a SAW microfluidic micromixer we studied the compatibility between the piezoelectric ceramic substrate and a biological cell suspension. Two aspects were studied: (i) the influence of this kind of substrate on the cell population and (ii) the influence of the cell suspension on the piezoelectric ceramic substrate. A niobium substituted PZT wafer with 40 mm diameter and 0.5 mm thickness was used in our experiments. First, the wafer surface was analyzed by optical microscopy and the surface roughness was estimated by AFM measurements. Then the wafer was put in a Petri dish containing a cell suspension. A second Petri dish containing the same biological medium but without ceramic wafer was kept as reference. Both Petri dishes were observed for 4 days in order to see the cell population development. Both the cell cultures developed in the same manner, the experimental cell culture having some initial time delay (in the first day). Finally, the ceramic wafer was treated with HBSS in order to remove the cells. The ceramic surface was not affected excepting that the remains of dead cells on the wafer surface were rather difficult to clean out.