As proteins from the human body are mostly non-fluorescent, to first show the ability of the device, a modification of the anti-green fluorescence protein (GFP) antibody was conducted. In order to enable transdermal monitoring of different biomarkers and proteins, a chemical modification of the SiNPs surface is conducted as schematically illustrated in Figure . First, the needles were dipped in 3aminopropyldimethylethoxysilane (APDMES) solution, an amino-silane derivative, for 2 hours in an inert environment. Followed by a thorough wash in toluene and IPA, and placed on a heating plate at 115°C for 30 minutes for full dehydration to fully stabilize and enhance the covalent bonds stability between the APDMES and the surface and evaporate all solvents . Subsequently, the needles were immersed in a solution consisting of 160μL of a 10% glutaraldehyde solution in phosphate buffer containing 50mg of cyanoborohydride, acting as a reduction agent, for the duration of 1 hour followed by a thorough wash in deionized water (DIW). The needles were then modified overnight with 40μg/mL anti-GFP solution in phosphate buffer with 50mg of cyanoborohydride at 4°C. The yield of the binding between the antibody and the glutaraldehyde is low, as some of the glutaraldehyde on the surface remains unbound. To prevent non-specific binding, blocking of unreacted aldehyde was performed by dipping the needles for 2 hours in 160μL of ethanolamine solution (400μL in 25mL phosphate buffer containing 50mg of cyanoborohydride) . An additional 2 hours blocking step is performed by dipping the needle in 160μL of skim milk in phosphate buffer silane (PBS) to minimize non-specific adsorption to the biosensor surface that can interfere with detecting the target analyte .