A biocompatible electrochemical sensor based on PtNi alloy nanoparticles-coupled N-GQDs for in situ monitoring of dopamine in glioma cells

We report the design and construction of enzyme-free sensor using platinum-nickel (PtNi) bimetallic alloy nanoparticle-conjugated nitrogen-doped graphene quantum dots (N-GQDs) for the highly specific in situ monitoring of dopamine (DA) secreted by glioma cells (C6). PtNi@N-GQDs nanocomposites were synthesized using a simple ultrasonication method. The resulting hybrid material was an excellent electrocatalyst for the redox activity of DA owing to the combined properties of PtNi alloys and highly conductive N-GQDs. The PtNi@N-GQDs-based sensing platform demonstrated substantial sensing ability with a detection range of 0.0125-952 mM, a sensitivity of 0.279 mA/mM/cm2, and a limit of detection of 0.005 mM (S/N 1/4 3). The sensing performance of PtNi@N-GQDs was highly stable, selective, and repro-ducible. We successfully showed the practical application of the PtNi@N-GQDs sensor by quantifying DA in the blood serum and human urine samples. Finally, we used the PtNi@N-GQDs biocompatible platform to quantify DA released from C6 cells.(c) 2022 Elsevier Ltd. All rights reserved.

Automated summary

We designed and constructed an enzyme-free sensor using PtNi bimetallic alloy nanoparticle-conjugated N-GQDs for in situ monitoring of dopamine (DA) secreted by glioma cells. The PtNi@N-GQDs nanocomposites were synthesized through ultrasonication, exhibiting excellent electrocatalytic activity for DA oxidation. The PtNi@N-GQDs-based sensing platform showed substantial sensing ability, stability, selectivity, and reproducibility, with a wide detection range and low detection limit.