PDMS micro-membrane capacitance-type surface stress biosensors for biomedical analyses

Display Omitted The analyte-induced surface stress can cause the change of capacitance.The capacitive variation tendency is similar to a reciprocal function.The biosensor can be used as the device to examine the medical treatment effect. Surface stress biosensor is one of the most promising ways to solve some of the problems concerning the increasing need to develop highly sensitive, fast and economic methods of analysis in medical diagnostics and high throughput screening of bioprocess for candidate drug screening and therapeutic effect monitor. Micro cantilever and micro membrane are two commonly used transducer structures of surface stress biosensors. The physical transducer often determines the limits of detection. Micro membrane-type surface stress biosensors can improve the signal-to-noise ratio. This paper presents PDMS (polydimethylsiloxane) micro membrane capacitance-type surface stress biosensors. The whole analyte-induced surface stress on the micro membrane is efficiently transduced to the membrane deflection and detected as the capacitive signal. The detection to Staphylococcus aureus (S. aureus) is realized based on this PDMS micro-membrane capacitance-type surface stress biosensor. For the state of S. aureus, the higher capacitive value corresponding to the less live S. aureus concentration, the maximum resolution of the biosensor is about 0.73fF/bacterium in this study. S. aureus test result proves that the biosensor can be used as the device to examine the medical treatment effect. The biosensor is easy to form an ordered array, which has more potential biological and medical applications.