Double Signal Amplification Strategy for Dual-Analyte Fluorescent Aptasensors for Visualizing Cancer Biomarker Proteins

Abstract

The simultaneous analysis of diversified biomarkers with high sensitivity and in a point-of-care (POC) manner is of great significance for facile and early cancer diagnosis. Herein, we develop a target amplification-assisted ratiometric fluorescence assay (TARFA) platform integrating the dual-amplification strategy and colorimetric readout technology for sensitive and specific detection of two malignancy-associated biomarkers. Meanwhile, the NIR-excited alkaline-earth sulfide nanodots (ASNDs) with an ultrasmall (<10 nm) diameter and tunable emission wavelength are employed to replace commonly UV/visible light-excited fluorescent labels to minimize background interference from the sample matrix. Unique advantages of the ASNDs, together with superiority of consecutive signal amplification of enzymatic target recycling (ETR) and hybridization chain reaction (HCR), realize the pg/mL-range detection limit in specifically recognizing the vascular endothelial growth factor (VEGF) and soluble interleukin-6 receptors (sIL-6R). The combination detection of the dual analyte exhibits an improved sensitivity for cancer diagnosis. The addition of the target biomarkers leads to an increasingly ratiometric RGB signal, and quantification based on the ratio-dependent signal is more reliable rather than measuring the absolute RGB signals. Moreover, perceptible color transformation makes the TARFA platform competent for visual analysis of the target analytes as convenient as reading the pH indicator strip, and hue-based image analysis also improves the method with fine precision by quantitatively identifying the visual color. This work provides a new kind of NIR-excited aptasensing platform with a low detection limit, high throughput, and great portability, which also highlights the potential of the ASNDs in biomolecular fluorescent labeling.

Point-of-Care Immunoassay Based on a Multipixel Dual-Channel Pressure Sensor Array with Visual Sensing Capability of Full-Color Switching and Reliable Electrical Signals

“…Overall, the fabricated immunoassay in this work offers the advantages of the visual signal display, electrical signal output, reversible color adjustment, full-color variation, and power-free, paving the way for practical applications, especially in resource-limited areas (Figure G and Table S1). ,− …”

DNA framework signal amplification platform-based high-throughput systemic immune monitoring

“…Research on HCR probes for cell phenotyping in clinical sample testing has reached a bottleneck for two primary reasons. 24 First, high-dissociation barriers between the aptamer and complementary strands can compromise the structure-switching kinetics of hairpin-structured aptamer probes. 25 It was found that the accessibility of active domains played a crucial role in switching kinetics.…”

Development and Validation of Aptasensor Based on MnO2 for the Detection of Sulfadiazine Residues

“…Aptamers have superior stability, excellent affinity, strong specificity, and easy in vitro screening compared to antibodies [ 12 , 13 , 14 ]. With these advantages, various aptamer-based sensors have been widely developed for environmental monitoring and food safety inspection (e.g., fluorescent, electrochemical, surface-enhanced Raman scattering, and photoelectrochemical sensing signals) [ 15 , 16 , 17 ]. In comparison, fluorescent aptasensors have been widely used in the field of detection for their ability of sensitivity, low cost, and selectivity, which make them particularly useful in monitoring food and environmental samples [ 18 , 19 ], and fluorescent aptamer sensors based on nanomaterials (quantum dots, graphene oxide, nanosilicon, etc.)…”