Ethyl 2-Cyanoacrylate as a Promising Matrix for Carbon Nanomaterial-Based Amperometric Sensors for Neurotransmitter Monitoring

Dopamine (DA) is a critical catecholaminergic neurotransmitter that facilitates signal
transduction across synaptic junctions and modulates essential neurophysiological pro
cesses, including motor coordination, motivational drive, and reward-motivated behav
iors. The fabrication of cost-effective, miniaturized, and high-fidelity analytical platforms
is imperative for real-time DA monitoring. Due to its inherent electrochemical activity,
carbon-based amperometric sensors constitute the primary modality for DA quantifica
tion. In this study, graphite, multi-walled carbon nanotubes (MWCNTs), and graphene
were immobilized within an ethyl 2-cyanoacrylate (ECA) polymer matrix. ECA was se
lected for its rapid polymerization kinetics and established biocompatibility in electro
chemical frameworks. All fabricated composites demonstrated robust electrocatalytic ac
tivity toward DA; however, MWCNT- and graphene-based sensors exhibited superior an
alytical performance, characterized by highly competitive limits of detection (LOD) and
quantification (LOQ). Specifically, MWCNT-modified electrodes achieved an interesting
LOD of 0.030 ± 0.001 µM and an LOQ of 0.101 ± 0.008 µM. Discrepancies in baseline cur
rent amplitudes suggest that the spatial orientation of carbonaceous nanomaterials within
the cyanoacrylate matrix significantly influences the electrochemical surface area and re
sulting baseline characteristics. The impact of interfering species commonly found in bio
logical environments on the sensors’ response was systematically evaluated. The best
performing sensor, the graphene-based one, was used to measure the DA intracellular
content of PC12 cells.