Before the modification process, the microneedle device was placed in the PECVD for 15 minutes (200 sccm O2, 260mTorr, 100W) to remove all carbon content from the surface and to generate silanol groups on the SiNPs. In a glovebox under an Ar atmosphere, the device was placed in 200μL of 95% APDMES solution for 2h. The device was then submerged in 160μL of toluene to remove any remaining APDMES solution, extensively washed with IPA, and heated at 115°C for 30 minutes to completely evaporate any remaining solvents and to fully stabilize and enhance the covalent bonds between the APDMES and the surface.