Evaluation of Electrochemically Active Surface Area in rGO/Au Nanoparticle-Modified MIP Sensors for Enhanced Dopamine Detection Tania Amara Dewi1, a *, Henry Setiyanto1,b
Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology
Jalan Ganesha 10, Bandung 40132, Indonesia
Abstract
This research aimed to develop cheap and fast electrochemical sensors for early diagnosis of neurodegenerative diseases and assessment of Mental Health through point-of-care testing with dopamine detection. Evaluation of the Electrochemically Active Surface Area (ECSA) was carried out on the development of a molecularly imprinted polymer (MIP) sensor based on reduced graphene oxide (rGO) composites and gold nanoparticles (AuNPs) for dopamine detection. Electrode modification is performed in stages through the electrodeposition of rGO and AuNPs, followed by electrochemical polymerization of polypyrrol as a MIP matrix. The determination of the ECSA was carried out using the Randles-Sevcik equation through the cyclic voltammetry (CV) technique in a redox prob solution
Electrode modification with rGO/Au Nanoparticle and MIP matrix succeeded in significantly increasing the electrochemical active surface area by 73%, from 6.11 mm2 on a plain electrode to 10.57 mm2. This nearly twofold increase confirms the effectiveness of integrating nanomaterial in providing more active sites for dopamine redox reactions This increase proves the synergistic role of rGO and AuNPs in providing a wider active site and accelerating electron transfer, albeit enclosed by a polymer layer. The developed sensor shows good linearity in the range of nanomolar to micromolar concentrations as well as very high selectivity against interfering compounds such as uric acid, glucose, and ascorbic acid with a ratio of up to 1:1000. This study provides important insights into the correlation between the active surface area of the electrode and the sensitivity and stability of MIP-based electrochemical sensors for biomedical applications.
