Self-powered Aptasensors Made with the In₂O₃–In₂S₃–Ti₃C₂ Composite for Dual-mode Detection of Microcystin-LR

Abstract

A dual-mode self-powered aptasensing platform of photoelectrochemical (PEC) and photofuel cell (PFC) was constructed for Microcystin-LR (MC-LR) detection. Specifically, the In2O3–In2S3–Ti3C2 (IO–IS–TC) composite was facilely assembled on the base of MOF-derived In2O3 hollow tubulars, and the integrated mechanism and photoconversion efficiency are proposed and discussed in detail. Herein, a promising dual-mode sensing platform was constructed using the IO–IS–TC composite as a photoanode matrix with higher output power and obvious photocurrent response. Moreover, the dual-mode sensing platform did not require external bias and the addition of sacrificial agents under visible light irradiation. The enhanced PEC properties can be attributed to the matched energy level of ternary components and the improved separation of photogenerated carriers. Moreover, aptamer-based recognition was adopted to catch MC-LR molecules, which realized the highly sensitive and selective detection. The PFC aptasensor was exhibited at 50–5 × 105 pmol/L with a detection limit of 17.4 pmol/L, and the PEC aptasensor was realized from 0.5 to 4 × 105 pmol/L with a detection limit of 0.169 pmol/L. The proposed aptasensing platform showed good specificity, reproducibility, and stability, which paved the way for the construction of a fast and ultrasensitive PEC sensing methodology for environmental analysis.

Phase Modulation of Ti3O/R-TiO2 Nanocomposites for the Self-Powered Photoelectrochemical Sensing of Tetracycline

“…The electron transfer forms an electron depletion layer around the interface between Ti 3 O and R -TiO 2 , resulting in a built-in electric field (IEF) oriented from Ti 3 O to R -TiO 2 . Following that, when exposed to light irradiation, the photogenerated electrons will be excited from the valence band (VB) to the CB of R -TiO 2 and then transfer to Ti 3 O due to the influence of the built-in electric field and band bending . The mechanism demonstrates that Ti 3 O with good electronic conductivity acts as an electron collector, and the built-in electric field is beneficial for the interfacial separation and transfer of photogenerated charge and inhibits the recombination of photogenerated electrons and holes.…”

Recent Trends in Self-Powered Photoelectrochemical Sensors: From the Perspective of Signal Output

“…Single Photoelectrode System. Based on the characteristic dual function effect of PFCs, which break down persistent organic compounds and use wastewater to generate electricity, 48 Yan et al 49 proposed a self-powered sensor using a Pt cathode, graphitic carbon nitride (g-C 3 N 4 ), and molecularly imprinted polymer (MIP) modified fluoride doped tin oxide (FTO) as the photoanode. Under the irradiation of visible light only, the PFC generated different output power densities for different concentrations of targets with good selectivity and photocatalytic activity at the same time.…”

“…This system generated a significant signal response by catalyzing H 2 O 2 , resulting in an extremely low sensor detection limit. Wei and co-workers 48 proposed a dual-mode self-powered sensor with PEC and PFC analysis by utilizing In 2 O 3 −In 2 S 3 −Ti 3 C 2 (IO-IS-TC) composites as the photosensitive materials. The PEC sensing mode with photocurrent as the output signal adopted the classical three-electrode system, which enabled the accurate and sensitive detection of trace targets, while the PFC sensing mode with power as the output signal adopted a simplified two-electrode device (with Pt as the cathode).…”

An ultrasensitive photo-driven self-powered aptasensor for microcystin-RR assay based on ZnIn2S4/Ti3C2 MXenes integrated with a matching capacitor for multiple signal amplification

“…The attendant environmental toxins like microcystin-RR (MC-RR) and microcystin-LR (MC-LR), released during cyanobacterial blooms, are highly toxic and have the highest content of microcystins. 1 MC-RR and MC-LR are both cyclic hepta-peptide metabolites, and they differ only at position 2 of the molecule with arginine (R) in the structure of MC-RR and leucine (L) in MC-LR. 2 Several investigations 3,4 have confirmed that consumption of freshwater organisms ( e.g.…”