Metal Nanoparticle Modified Carbon-Fiber Microelectrodes Enhance Adenosine Triphosphate Surface Interactions with Fast-Scan Cyclic Voltammetry

Adenosine triphosphate(ATP) is an important rapid signaling moleculeinvolved in a host of pathologies in the body. Historically, ATP isdifficult to directly detect electrochemically with fast-scan cyclicvoltammetry (FSCV) due to limited interactions at bare carbon-fibers.Systematic investigations of how ATP interacts at electrode surfacesis necessary for developing more sensitive electrochemical detectionmethods. Here, we have developed gold nanoparticle (AuNP), and platinumnanoparticle (PtNP) modified carbon-fiber microelectrodes coupledto FSCV to measure the extent to which ATP interacts at metal nanoparticle-modifiedsurfaces and to improve the sensitivity of direct electrochemicaldetection. AuNP and PtNPs were electrodeposited on the carbon-fibersurface by scanning from -1.2 to 1.5 V for 30 s in 0.5 mg/mLHAuCl(4) or 0.5 mg/mLK(2)PtCl(6). Overall,we demonstrate an average 4.1 & PLUSMN; 1.0-fold increase in oxidativeATP current at AuNP-modified and a 3.5 & PLUSMN; 0.3-fold increase atPtNP-modified electrodes. Metal nanoparticle-modified surfaces promotedimproved electrocatalytic conversion of ATP oxidation products atthe surface, facilitated enhanced adsorption strength and surfacecoverage, and significantly improved sensitivity. ATP was successfullydetected within living murine lymph node tissue following exogenousapplication. Overall, this study demonstrates a detailed characterizationof ATP oxidation at metal nanoparticle surfaces and a significantlyimproved method for direct electrochemical detection of ATP in tissue.

Automated summary

The study developed gold nanoparticle and platinum nanoparticle-modified carbon-fiber microelectrodes coupled with FSCV to measure ATP interactions and improve sensitivity. Metal nanoparticle-modified surfaces promoted the electrocatalytic conversion of ATP oxidation products, enhanced adsorption strength and surface coverage, significantly improving sensitivity.