Separation and detection of bacteria using rupture event scanning

We have developed a sensitive and economical method to directly detect bacteria, based on the interaction between the bacteria and specific antibodies attached to an oscillating surface. By monotonously increasing the amplitude of oscillation of a quartz crystal microbalance (QCM) coated with the antibody, the QCM can be used to sensitively detect the acoustic noise produced when the interactions between the bacteria and the surface were broken. We term this process rupture event scanning (REVS). The method is quantitative over at least 6 orders of magnitude and can detect as few as 10 bacteria. We demonstrate here that this approach allows one to arrange separation of bacteria and follow the process completion on the basis of the acoustic signal. Detection is not significantly affected by non-specific binding of sample contaminants and thus can be achieved both in buffer and in serum. (C) 2011 Elsevier B.V. All rights reserved.