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Updated: Feb 16, 2026

Hollow Microneedle-based Sensor for Multiplexed Transdermal Electrochemical Sensing
Published on: June 1, 2012
An electronic device based on gold nanoparticles and tetraruthenated porphyrin as an electrochemical sensor for
Luana M Sousa1, Luana M Vilarinho1, Gabriel H Ribeiro2
1Faculdade de Ciências Integradas do Pontal, Universidade Federal de Uberlândia, Rua vinte, 1600, CEP 38304-402, Ituiutaba, Minas Gerais, Brazil.
Abstract:
The aim of this study was to obtain an electrochemical device between the electrostatic interaction of the electropolymerized porphyrin {CoTPyP[RuCl3(dppb)]4}, where TPyP = 5,10,15, 20-tetrapyridilphorphyrin and dppb = 1,4-bis(diphenylphosphino)butane, and gold nanoparticles (AuNPsn-), to be used as a voltammetric sensor to determine catechol (CC). The modified electrode, labelled as [(CoTPRu4)n8+-BE]/AuNPsn- {where BE = bare electrode = glassy carbon electrode (GCE) or indium tin oxide (ITO)}, was made layer-by-layer. Initially, a cationic polymeric film was generated by electropolymerization of the {CoTPyP[RuCl3(dppb)]4} onto the surface of the bare electrode to produce an intermediary electrode [(CoTPRu4)n8+-BE]. Making the final electronic device also involves coating the electrode [(CoTPRu4)n8+-BE] using a colloidal suspension of AuNPsn- by electrostatic interaction between the species. Therefore, a bilayer labelled as [(CoTPRu4)n8+-BE]/AuNPsn- was produced and used as an electrochemical sensor for CC determination. The electrochemical behaviour of CC was investigated using cyclic voltammetry at [(CoTPRu4)n8+-GCE]/AuNPsn- electrode. Compared to the GCE, the [(CoTPRu4)n8+-GCE]/AuNPsn- showed higher electrocatalytic activity towards the oxidation of CC. Under the optimized conditions, the calibration curves for CC were 21-1357 µmol l-1 with a high sensitivity of 108 µA µmol l-1 cm-2. The detection limit was 1.4 µmol l-1.
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