Label-free and real-time monitoring of yeast cell growth by the bending of polymer microcantilever biosensors

We demonstrate a new strategy for the label-free monitoring of yeast cell growth and its interaction with drugs using simple bending-mode of polymer microcantilever biosensors. Saccharomyces cerevisiae strains YN94-1 and YN94-19 were deposited onto microcantilever sensor surfaces and the growth curves corresponding to the bending were investigated under different culture conditions. The real-time polymer microcantilever bending signal revealed distinct growth characteristics of cells cultured in Synthetic Complete (SC) medium with and without the addition of uracil and 5′-fluororotic acid, which are indiscernible using conventional screening methods. In addition, cantilever deflection signals of up to ∼7 μm were observed, which can only be explained through surface stress interactions between yeast cells and the polymer cantilevers due to the enhanced sensitivity of the viscoelastic polymer cantilevers. This new method of enhanced sensitivity in static mode microcantilever monitoring of cell growth opens opportunities for highly sensitive applications in the fields of disease diagnosis and drug discovery and testing.