A label-free optical detection method for biosensors and microfluidics

A label-free detection method is developed for biosensors and for microfluidic applications. Multiple optical modes, including a conventional surface plasmon resonance (SPR) mode and many bulk modes, are created in a microfluidic channel with metallic coatings on top and bottom. The bulk modes are bulk sensitive and detect analytes in the channel with 20 times higher sensitivity than the SPR, which is particularly suitable for microfluidic devices. The method can be operated either in the SPR mode for detection of molecular binding on a surface or in one of the bulk optical modes for monitoring analytes in the channel. (C) 2008 American Institute of Physics.