Electrochemiluminescent CdS Quantum Dots Biosensor for Cancer Mutation Detection at Different Positions on Linear DNA Analytes

Abstract

PCR-based techniques routinely employed for the detection of mutated linear DNA molecules, including circulating tumor DNA (ctDNA), require large nucleotide sections on both sides of the mutation for primer annealing. This means that DNA fragments with a mutation positioned closer to the extremities are unlikely to be detected. Thus, sensors capable of recognizing linear DNA with characteristic mutations closer to the ends would be advantageous over the state-of-the-art approaches. Here, an electrochemiluminescence-resonance energy transfer (ECL-RET) biosensor comprising capped CdS quantum dots and hairpin DNA probes labeled with Au nanoparticles was developed for the detection of epidermal growth factor receptor (EGFR) ctDNA carrying the critical T790M lung cancer mutation. The ECL-RET system detected different DNA molecules including single-stranded 18-nucleotides (nt) and 40-nt as well as double-stranded 100-nt with the single nucleotide polymorphism (SNP) coding for T790M located either in the middle or only 7 nt from one end. For all target DNA, the sensor’s limits of detection (LODs) were in the aM range, with excellent selectivity. It was the case of 100-nt target linear ctDNA fragments with LODs of 8.1 and 3.4 aM when the EGFR T790M SNP was either in the middle or at the end, respectively. These results show that ECL-RET systems can sense mutations in DNA fragments that would remain undetected by standard techniques.

Advancements in semiconductor quantum dots: expanding frontiers in optoelectronics, analytical sensing, biomedicine, and catalysis

“…The process was found to be based on ECL-RET, in which quantifiable variations in electrochemiluminescence were caused by energy transfer between CdS quantum dots and Au nanoparticles, enabling accurate detection. 231 (3) Biomedical application. Semiconducting colloidal carbon quantum dots (CQDs), due to their superior photostability, high photoluminescence quantum yield (PLQY), and high absorption coefficient, have been extensively utilized in several medicinal applications.…”

“…The process was found to be based on ECL-RET, in which quantifiable variations in electrochemiluminescence were caused by energy transfer between CdS quantum dots and Au nanoparticles, enabling accurate detection. 231…”

Self-Assembly-Induced Enhancement of Cathodic Electrochemiluminescence of Copper Nanoclusters for a Split-Type Matrix Metalloproteinase 14 Sensing Platform

“…It relies on the redox processes of electrochemical reactions, where electrons or holes are transferred from the electrode to the luminophore in the reaction system at a specific potential, inducing the excited state luminophore to return to its ground state and release photons . As a significant optoelectronic conversion technology, ECL has found extensive applications in various fields such as clinical medicine, , environmental monitoring, , and food analysis , due to its exceptional sensitivity, minimal interference from background signals, and rapid response time . Nevertheless, the exploration of novel luminophores for ECL remains a crucial research focus within this field. − …”