Nanobiophotonics

Nanoscale sensors have the potential for ultrasensitive and highly parallel bioanalytical applications. Bottom up methods like gas-phase self assembly allow for the controlled and cost-efficient preparation of numerous functional units with nanometer dimensions. Their use in sensoric instruments, however, requires the defined integration into sensoric setups such as electrode arrays. We show here how to use alternating electrical fields (dielectrophoresis DEP) in order to address this micro nano integration problem. Nanoscale units such as metal nanoparticles or semiconductor nanowires are thereby polarized and moved into the direction of higher electrical field gradients. As result, these particles bridge an electrode gap and can so be used for electrical sensoric using the electrical resistance through this structure as value correlated to the presence of molecules at the sensor surface. In order to achieve high selectivity, capture molecules (such as complementary DNA or antibodies) are used.