For the fabrication of the desired sensing areas on the device, the silver and beads were removed using lithography techniques, leaving only the necessary sensor regions covered and protected. AZ-1518 photoresist was spin-coated and baked with the same parameters as before and exposed to a UV light with a dose of 45mJ/cm 2 . The substrate was developed in AZ-726 developer for 1 min, and silver and beads were removed from the unwanted areas using gold etchant (TFE) for 30s and O2 plasma etching (50 sccm O2, 40 mTorr, 30W, 15 min) respectively.