Direct and Sensitive Detection of Dopamine Using Carbon Quantum Dots Based Refractive Index Surface Plasmon Resonance Sensor

Abstract

Abnormality of dopamine (DA), a vital neurotransmitter in the brain’s neuronal pathways, causes several neurological diseases. Rapid and sensitive sensors for DA detection are required for early diagnosis of such disorders. Herein, a carbon quantum dot (CQD)-based refractive index surface plasmon resonance (SPR) sensor was designed. The sensor performance was evaluated for various concentrations of DA. Increasing DA levels yielded blue-shifted SPR dips. The experimental findings revealed an excellent sensitivity response of 0.138°/pM in a linear range from 0.001 to 100 pM and a high binding affinity of 6.234 TM−1. The effects of varied concentrations of DA on the optical characteristics of CQD thin film were further proved theoretically. Increased DA levels decreased the thickness and real part of the refractive index of CQD film, according to fitting results. Furthermore, the observed reduction in surface roughness using AFM demonstrated that DA was bound to the sensor layer. This, in turn, explained the blue shift in SPR reflectance curves. This optical sensor offers great potential as a trustworthy solution for direct measurement due to its simple construction, high sensitivity, and other sensing features.

Emerging Trends in Nanomedicine: Carbon-Based Nanomaterials for Healthcare

“…Eddin et.al. reported a novel CQD-based biosensor for the ultrasensitive detection of dopamine, an important neurotransmitter [63]. The sensor demonstrated a wide linear range and a low detection limit of 62 nM, indicating its potential for biomolecule sensing [64].…”

The potential of a novel enzyme-based surface plasmon resonance biosensor for direct detection of dopamine

“…For this purpose, surface plasmon resonance (SPR) biosensing method is introduced as one of the most powerful approach for monitoring of affinity binding of biomolecules, and primary screening of druggable molecules. This analytical technique monitors the refractive index changes based on biomolecular interaction with good sensitivity that occurring at a thin metal surface (gold or silver), act exactly as a real time operating system, with no need to label or complex procedures for sample preparation 8 – 12 . This novel method can be utilized for therapeutic detection of dopamine in medical and clinical application.…”