Quantum Dot Fullerene-Based Molecular Beacon Nanosensors for Rapid, Highly Sensitive Nucleic Acid Detection

Abstract

Spherical fullerene (C) can quench the fluorescence of a quantum dot (QD) through energy-transfer and charge-transfer processes, with the quenching efficiency regulated by the number of proximate C on each QD. With the quenching property and its small size compared with other nanoparticle-based quenchers, it is advantageous to group a QD reporter and multiple C-labeled oligonucleotide probes to construct a molecular beacon (MB) probe for sensitive, robust nucleic acid detection. We demonstrated a rapid, high-sensitivity DNA detection method using the nanosensors composed of QD-C-based MBs carried by magnetic nanoparticles. The assay was accelerated by first dispersing the nanosensors in analytes for highly efficient DNA capture resulting from short-distance three-dimensional diffusion of targets to the sensor surface and then concentrating the nanosensors to a substrate by magnetic force to amplify the fluorescence signal for target quantification. The enhanced mass transport enabled a rapid detection (<10 min) with a small sample volume (1-10 μL). The high signal-to-noise ratio produced by the QD-C pairs and magnetic concentration yielded a detection limit of 100 fM (∼10 target DNA copies for a 10 μL analyte). The rapid, sensitive, label-free detection method will benefit the applications in point-of-care molecular diagnostic technologies.

Influence of Quantum Dot Surface on Electrochemical DNA Sensing Mechanism

“…2 below on the criterion of a signalto-noise ratio of 3 its limit of detection (LOD) was found to be 0.45 pg mL À 1 . The obtained genosensor's results are comparable to those reported in the literature [28,38,39,40,41] and show very low detection limit compared to existing DNA assays [Eq. (2)].…”

“…(2)]. [39][40][41] LOD ¼ 3SD Slope (2) In this paper, we further investigate the mechanism of DNA-QD interaction before and after hybridization, Figure 8-10. An important property of quantum dot is that they can easily transfer energy when excited and this form of energy is Scheme 1.…”

Engineering Cellular Signal Sensors based on CRISPR-sgRNA Reconstruction Approaches

“…Currently, many researchers are also developing some CRISPR-endogenous signal sensors that sensed intracellular RNAs, which regulated the "on-off" sensor in response to the expression levels of specific non-coding RNAs with cells. To achieve this, they designed the riboswitch that responses to RNA transcripts (RNA-switch) based on previously reported RNA reaction devices [45], and integrated it into sgRNA. The first approach was to attach the RNA-switch to the 3' end of the sgRNA and rely on the RNA-switch to bind to the spacer region of the sgRNA to form the silent state of the RNA-switchbased CRISPR-endogenous signal sensor ( Figure 6A).…”

Carbon Nanostructure-based Sensors: A Brief Review on Recent Advances

“…Nucleic acid sensing materials have been extensively studied for medical diagnosis allowing planning strategies and early treatment for diseases. Liu et al [149] developed a new sensor for rapid and highly sensitive DNA detection based on the fluorescence-quenching properties of molecular Beacon made of QDs by C 60 FLN carried by magnetic particles (MB@MNP). ese nanosensors were dispersed in analytes solution for DNA capture leading to short-distance diffusion of targets to the sensor surface.…”

“…Other reported systems Responses from other systems GPN/Au-SPR [147] 7.01 nm/(mg/ml) Glucose Sensor only coated with Au [147] 2.98 nm/(mg/ml) QD-C 60 [149] 100 fM (LOD) DNA MB-based DNA detection [166] 4.4 nM to 8.5 nM (LOD) CNTFET [160] 1 used in different nanoparticles. Besides the improvement in the dispersion for the production of hybrid sensors, functionalization of FLN with appropriate groups can also increase their solubility in water, enhancing their biocompatibility [134,137,138,151].…”