Gold nanoparticles and [PEDOT-poly(D,L-lactic acid)] composite: Synthesis, characterization and application to H₂O₂ sensing

Biocompatible electrochemical devices are challenging to develop due to the toxicity of many advanced electrode materials and the difficulty to degrade the discarded material. Few recent advances were made in the synthesis of conducting biodegradable composites of polymers for electrode materials. In this article we describe the synthesis of two new inorganic/organic nanocomposites of Au nanoparticles and conducting polymers based on the biodegradable polymer poly(D,L-lactic acid) (PDLLA): Au nanoparticles/oligomers of 3,4-ethylenedioxythiophene (EDOT)-PDLLA and Au nanoparticles with poly(3,4-ethylenedioxythiophene) (PEDOT)-PDLLA. The nanocomposites were carefully analyzed; the gold nanoparticles mean sizes were 8 ± 3 and 7 ± 2 nm, respectively. ¹H and ¹³C nuclear magnetic resonance (NMR) demonstrated the polymerization of EDOT-PDLLA made through one-pot reaction with Au^III precursor. Raman spectra show that PEDOT-PDLLA is formed in the synthesis of Au/PEDOT-PDLLA. The immobilization of Au/PEDOT-PDLLA on glassy carbon electrodes is easy and more stable than the immobilization of simple PEDOT. Au/PEDOT-PDLLA catalyzes the reduction of H₂O_2(aq), which was detected by chronoamperometry. The sensor is stable and presents sensitivity of 8.36 × 10^-3 A mol^-1 L cm^-2, linear range of 1-45 mmol L^-1 and limit of detection of 0.17