Composite Microneedle Arrays Modified With Palladium Nanoclusters for Electrocatalytic Detection of Peroxide

Abstract

The fabrication of conductive composite microneedle (MN) patches modified with palladium clusters for the electrocatalytic detection of peroxide is described in this letter. Micromolding techniques are utilized in which carbon nanoparticles are bound within a polystyrene matrix resulting in the production of a 10 × 10 array of needles of length 700 μm. Electrochemical anodization of the carbon particles increases the interfacial carboxyl group population which facilitates the capture of Pd <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2+</sup> ions. Their subsequent electroreduction yields a catalytic interface with a high sensitivity toward the electroreduction of peroxide (-0.3 V:49.7+/-2.8 μA·mM <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> ·cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-2</sup> ; -0.5 V:102.1+/-2.32 μA·mM <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> ·cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-2</sup> ). The MN sensing system and the various modification stages has been characterized using mechanical testing (fracture testing), cyclic voltammetry, and high-resolution X-ray photoelectron spectroscopy.