Toward Subcutaneous Electrochemical Aptasensors for Neuropeptide Y

Subcutaneous sensors, similar to the continuous glucose monitor, are advantageous for identifying healthy and pathological patterns of circulating biomarkers. A biosensor for the detection of neuropeptide Y (NPY), a marker of stress, has been designed and tested for operation in a flexible microneedle form factor. The biosensing principle used is affinity binding of NPY to a DNA aptamer-functionalized electrode. A gold microelectrode was functionalized by formation of a self- assembled monolayer (SAM) of a thiol-modified NPY-binding aptamer and poly(ethylene glycol) methyl ether thiol (PEG). The sensors were evaluated by cyclic voltammetry and electrochemical impedance spectroscopy, resulting in a response to NPY over 400 pM to 200 nM when tested in KCl and K3[Fe(CN)6]/K4[Fe(CN)6], and PBS.