Sensitive and direct detection using rupture event scanning (REVS (TM))

We have developed a sensitive and economical method to directly detect particles. The technique, which we term rupture event scanning (REVS(TM)), is based on rapidly oscillating a surface to which a particle has been attached. The oscillation can be achieved with an acoustic wave device, such as a quartz resonator, coated with particle-specific receptors. As the magnitude of oscillation of the surface is increased, there is increasing acceleration of adherent particles. This in turn results in a larger force exerted by the surface on the particle that ultimately causes rupture of the bonds attaching the particle to the surface. Using the same device, we can very sensitively monitor the excitation of vibrations in the piezoelectric substrate produced by bond rupture, which are converted into an electrical signal. The signal indicates not only the presence of specifically bound particles and their affinity for the receptor, but also the number of particles present. The method works in air, water and complex biological fluids, is quantitative over at least six orders of magnitude of particle titer, and in affinity from sub-mM to pM. For selected particle-receptor systems the sensitivity can be as low as a few fg/mm(2) (10(-15) g/mm(2)). The entire assay currently takes less than one hour to perform

Direct and sensitive detection of a human virus by rupture event scanning

We have developed a sensitive, economical method that directly detects viruses by making use of the interaction between type 1 herpes simplex virus (HSV1) and specific antibodies covalently attached to the oscillating surface of a quartz crystal microbalance (QCM). The virions were detached from the surface by monotonously increasing the amplitude of oscillation of the QCM, while using the QCM to sensitively detect the acoustic noise produced when the interactions were broken. We term this process rupture event scanning (REVS). The method is quantitative over at least six orders of magnitude, and its sensitivity approaches detection of a single virus particle