Surface modification of titanium-coated glass substrate embedded acrylate-based hydrogel film for optical metal clad leaky waveguide (MCLW) biosensors

For the highly-sensitive optical MCLW biosensor, the stability of the acrylate-based hydrogel waveguiding sensing layer deposited onto the Ti (titanium)-coated glass substrate depends on the quality of surface modification between the interfaces. This study demonstrates an optimised silanization technique to form covalent bonds across the interface between the modified Ti-coated glass substrate and the deposited acrylate-based hydrogel waveguiding film, to prevent detachment. The optical characteristics of the MCLW device outcome depend on the refractive index changes on the cover medium. Hence, the device sensitivity fabricated on the surface modified substrate generated a strong signal at 250 A.U which is 45% better than previously reported agarose-based hydrogel MCLW sensor. The signal proved to have excellent stability throughout the detection for at least 3 hours without any background noise.