Localized biomolecules immobilization in optical microbubble resonators

In order to optimize the performance of an optical microbubble resonator (OMBR) as biosensor, the chemical functionalization of its inner surface plays a key role. Here we report on a spatially selective photo - chemical procedure able to bind fluorescent biomolecules only in correspondence of the OMBR inner surface. This abruptly reduces the occurrence of an undesired specific biochemical bond event all along the microfluidic section of the device. The evidence of this method, which maintains high Q factor (> 10(5)) for the OMBR in buffer solution, is proved by fluorescence microscopy and real time measurement of the resonance broadening.