Gold Nanoparticles Photosensitization towards 3,4,9,10-Perylenetetracarboxylic Dianhydride Integrated with a Dual-Particle Three-Dimensional DNA Roller: A General “ON–OFF–ON” Photoelectric Plasmon-Enhanced Biosensor

Abstract

A high initial signal for the sensitive detection of analytes is critical in photoelectrochemical (PEC) biosensing systems. As a semiconductor, 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA) possesses an appropriate optical band gap of 2.5 eV and inherently intense and stable PEC response. When gold nanoparticles (Au NPs) are electrodeposited on the surface of PTCDA to form a Schottky junction (Au NPs/PTCDA), a surprising and satisfactory PEC performance is unfolded before our eyes. Considering the outstanding PEC behaviors of Au NPs/PTCDA and the great quenching effect of gold nanoclusters (Au NCs), the “ON–OFF–ON” PEC sensing platform has been developed for microRNA 1246 (miRNA 1246) detection combined with the cascaded quadratic amplification strategy of the polymerization/nicking reaction and dual-particle 3D DNA roller. The higher initial PEC signals of the system can be acquired by regulating the deposition time for 35 s (−0.2 V), which is derived from the synergetic effect of localized surface plasmon resonance of Au NPs and the formation of a Schottky junction. The dual-particle 3D DNA roller has been designed to guarantee wide walking space, remarkable operation performances, and inhibition of derailment. The proposed biosensor shows a dynamic range from 10 aM to 1 pM at a low detection limit of 3.1 aM and exhibits good analytical behaviors while analyzing miRNA 1246 in healthy human serum samples. This work not only expands the application of organic photoelectric materials in bioanalysis but also provides potential possibility of detecting other biomarkers by choosing appropriate target units.

Novel Aggregation-Enhanced PEC Photosensitizer Based on Electrostatic Linkage of Ionic Liquid with Protoporphyrin IX for Ultrasensitive Detection of Molt-4 Cells

“…Then, 20 μL of the homogeneous PPIX-[BMIm] aggregate suspension (0.5 mg mL −1 ) was dropped onto the ITO electrode and dried at room temperature, referred to as PPIX-[BMIm] aggregates/ITO for simplicity. Next, the PPIX-[BMIm] aggregates/ITO was put into the phosphate-buffered solution (PBS, 0.1 M, pH 7.4) containing 2.0 mM HAuCl 4 and then electrodeposited by chronoamperometry at −0.2 V for 400 s according to the previous work with minor modification, 33 accompanied by washing with water, forming the Au NP-modified electrode (denoted as Au NPs/PPIX-[BMIm] aggregates/ITO).…”

Ultrasensitive MicroRNA Photoelectric Assay Based on a Mimosa-like CdS-NiS/Au Schottky Junction

“…p-Type NiS (0.4 eV) and n-type CdS (2.4 eV) in transition metal sulfides have been used to design a p-n semiconductor heterojunction to promote the separation rates of photogenerated carriers. , The recombination of carriers can be reduced by accumulating electrons/holes in the p-type/n-type zone. Moreover, coupling with high activity noble metal nanoparticles to form a Schottky junction is another powerful channel . Due to the existence of a Schottky junction at the interface of metal–semiconductor, electrons and holes near this region will be driven to the opposite directions .…”

“…Moreover, coupling with high activity noble metal nanoparticles to form a Schottky junction is another powerful channel. 14 Due to the existence of a Schottky junction at the interface of metal−semiconductor, electrons and holes near this region will be driven to the opposite directions. 15 In addition, noble metals display significant optical ability that can effectively harness long wavelength photons to produce "hot electrons" and promote quick electron transfer from metal to semiconductors, 16 which can promote the photoelectric conversion efficiency.…”

“…18 When the size is reduced to the range of a few nanometers or less (noble metal nanoclusters), they no longer show photoactive properties but a quenching effect due to molecular-like electronic transitions induced by small size limitation. 14,19 MicroRNAs (miRNAs) are important non-coding gene regulators of genome, and they are associated with various diseases in life processes and deemed as significant biomarkers for early prevention of tumors. 20 However, due to the sequence homology and inherent ultralow abundance, accurate determination of miRNAs has been an issue.…”

“…Interestingly, the light absorption properties of noble metals depend primarily on their size . When the size is reduced to the range of a few nanometers or less (noble metal nanoclusters), they no longer show photoactive properties but a quenching effect due to molecular-like electronic transitions induced by small size limitation. , …”