Researchers K. C. Gupta (left) and P. K. R. Kumar. 
The researchers coated a glass substrate with a gold layer sandwiched between two chromium layers using thermal evaporation. This was irradiated with energetic gold ions, which gave rise to latent tracks on the surface. On etching by hydrofluoric acid vapour, nanosized holes (20 nm, 50 nm and 80 nm) were created. The surface of the film was then modified with complex organic compounds including streptavidin and biotin.
On being bathed with laser light, each interaction between biomolecules gives shows a distinct change in reflectivity. The changes in the measurement of angle between incident and reflected light signal the identity of the biomolecules. "This evanescent-field-coupled (EFC) waveguide-mode sensor will facilitate detection of small molecular interactions for developing common platform for a wide range of biomolecules," says co-researcher Penmetcha Krishna Rajendra Kumar.
The authors of this work are from: Center for Applied Near Field Optics Research (CAN-FOR), National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, Waseda University, Shinjuku, Tokyo; Tandem Accelerator Complex, University of Tsukuba, Tsukuba, Japan; Institute for Genomics and Integrative Biology, Mall Road, Delhi University Campus, Delhi, India and Institute for Biological Resources and Functions, AIST, Tsukuba, Ibaraki, Japan.
