Electrochemical determination of urinary dopamine from neuroblastoma patients based on Cu nanoplates encapsulated by alginate-derived carbon

Precisely monitoring dopamine (DA) with high sensitivity, selectivity, and low cost from real life biological samples such as urine to investigate the suspected catecholamine-secreting tumor remains a big challenge. Here, for the first time, we synthesize a DA sensor based on Cu nanoplatelets (Cu@CNP) encapsulated by carbon nanoparticles (CNP) that are pre-modified by a benzimidazolium-1-acatate ionic liquid (BAIL). The simple scalable route (freeze-drying followed by a temperature-switchable carbonization process) enables the CNP shells with controlled thickness to form upon the Cu nanoplatelets. Among the resulting products, Cu@CNP-600 (Cu@CNP carbonized at 600 °C) shows a high concentration of exposed {111} Cu crystal planes, surface defects with quadrupole and dipolar plasmons multipoles , and graphitic layers. Once deposited onto the lead pencil electrode (LPE), the Cu@CNP-600 modified with highly conductive BAIL synergistically allows highly sensitive and selective detection of DA. We successfully apply this novel electrode to monitor the DA from the urine of neuroblastoma patients with high sensitivity. The designed electrode can be used not only in the diagnosis of suspected catecholamine-secreting tumors but also in the evaluation of drugs’ efficacy.