Enhancing the Sensitivity of Photoelectrochemical DNA Biosensing Using Plasmonic DNA Barcodes and Differential Signal Readout

Abstract

Photoelectrochemical biosensors hold great promise for sensitive bioanalysis;h owever,s imilar to their electrochemical analogues,t hey are highly affected by the variable backgrounds caused by biological matrices.W ed eveloped an ew PEC biosensing strategy that uses differential signal generation, combining signals from two separate but correlated binding events on the biosensor,f or improving the limit-ofdetection, sensitivity,a nd specificity of PEC DNAb iosensors in biological samples.I nt his assay, the binding of unlabeled target DNAisfollowed by the capture of asignal amplification barcode featuring aplasmonic nanoparticle.The interaction of the plasmonic barcode with the semiconductive building blocks of the biosensor results in significant signal amplification, and together with differential signal processing enhances the limit of detection and sensitivity of the assay by up to 15and threefold , respectively,c ompared to the previously-used PEC assays with asingle binding event, demonstrating alimit of detection of 3f M.

Light in Electrochemistry

“…In this approach, CdS nanoparticles were used as the semiconductor, and doublestranded DNA-cross-linked CdS nanoparticle arrays on the electrode enhanced the photocurrent generation under irradiation. Recently, high-sensitivity photoelectrochemical sensors for DNA have been developed using approaches, such as wrinkled interfaces [63] and plasmonic nanoparticles [64]. These photoelectrochemical sensors facilitate the screening of biosamples using specific enzymes, antibodies, and aptamers as the targets.…”

Near-Infrared Light-Initiated Photoelectrochemical Biosensor Based on Upconversion Nanorods for Immobilization-Free miRNA Detection with Double Signal Amplification

“…Photoelectrochemical (PEC) sensors are relatively new sensing platforms that implement the separation of the incident light source and detection signal, , resulting in pronounced detection sensitivity as compared to other mothods. , Moreover, PEC sensors are superior in the detection field due to the low cost, simple equipment, and easy miniaturization . However, the current PEC biosensors employing ultraviolet (UV) or visible (vis) laser with high energy as the excitation source still have great challenges to biological signal species determination due to the strong light damage to samples and systems and biological interferences. , In addition, the conventional immobilized methodology that most PEC biosensors use suffers from insufficient sensitivity and repeatability, low reaction rate, and target-recognition efficiency due to the steric hindrance effect on the surface of the modified electrode. − Favorably, upconversion nanoparticles (UCNPs) can absorb NIR light sequentially and emit UV/vis light due to the ladder-like energy levels of Ln 3+ ions, − presenting a series of merits including high chemical and optical stability and low phototoxicity owing to the utilization of the NIR light source. − UCNPs exhibit great competitiveness in PEC sensing fields and photocatalysis, biological imaging, − optical encoding, and photoactive therapy. , More inspiringly, it is mainly in the solid host lattice that the luminescence process of Ln 3+ -doped UCNPs is conducted, which effectively precludes the effects of the external environment (pH, humidity, or buffer) .…”

“…9,10 Moreover, PEC sensors are superior in the detection field due to the low cost, simple equipment, and easy miniaturization. 11 However, the current PEC biosensors employing ultraviolet (UV) or visible (vis) laser with high energy as the excitation source still have great challenges to biological signal species determination due to the strong light damage to samples and systems and biological interferences. 12,13 In addition, the conventional immobilized methodology that most PEC biosensors use suffers from insufficient sensitivity and repeatability, low reaction rate, and targetrecognition efficiency due to the steric hindrance effect on the surface of the modified electrode.…”

Ultrasensitive Photoelectrochemical Biosensor Based on Novel Z-Scheme Heterojunctions of Zn-Defective CdS/ZnS for MicroRNA Assay

“…Photoelectrochemical (PEC) bioanalysis has been extensively explored and developed over the past decade with a higher sensitivity, lower background noise, and faster response compared with traditional electrochemical methods, along with simpler and easier operation in terms of apparatus than the optical methods. − Notably, photoactive materials play important roles in the proposed PEC biosensor as their superior photocurrent intensity and detection sensitivity properties directly determine the efficiency of PEC biosensors . Up to now, numerous inorganic semiconductor materials such as metal oxides, carbon materials, and sulfides have been widely used in PEC assay with excellent photoelectric performance. , Nevertheless, the conversion efficiency of these semiconductor nanomaterials is primarily limited due to a high electron–hole pair recombination rate and poor light absorption capacity in actual analysis. , In recent years, the homojunction strategies using single semiconductor components and heterojunctions by utilizing multiple semiconductor components have been proven to promote the separation of electron–hole pairs and inhibit the recombination of electron–hole pairs. , Compared to homojunctions, heterojunctions could not only overcome the deficiencies of weak light absorption capacity but also exhibit remarkable physicochemical properties .…”