Target-regulated photoactivities of CdS/Ni-MOF heterojunction with [Ru(bpy)2dppz]2+ intercalator: a bisphenol A photoelectrochemical aptasensor

Nanoencapsulated Optical Fiber-Based PEC Microelectrode: Highly Sensitive and Specific Detection of NT-proBNP and Its Implantable Performance

Microelectrodes offer exceptional sensitivity, rapid response, and versatility, making them ideal for real-time detection and monitoring applications. Photoelectrochemical (PEC) sensors have shown great value in many fields due to their high sensitivity, fast response, and ease of operation. Nevertheless, conventional PEC sensing relies on cumbersome external light sources and bulky electrodes, hindering its miniaturization and implantation, thereby limiting its application in real-time disease monitoring. To overcome these limitations, we developed a nanoencapsulated optical fiber (OF)-based PEC microelectrode. The microelectrode features TiO2/CdS nanocrystals and bis (2,2'-bipyridine) (10-methylphenanthroline [3,2-a:2'3'-c] pyridine ruthenium(II) dichloride ([Ru(bpy)2dppz]2+) @dsDNA/Au@epigallocatechin gallate nanoparticle (EGCG NP) layers. And its application for the detection of N-terminal pro-brain natriuretic peptide (NT-proBNP) as a biomarker of cardiovascular diseases was explored. An extensive linear range of 1-5000 pg mL-1 combined with a low detection limit of 0.36 pg mL-1 was achieved. This range covers not only the recommended threshold for excluding cardiovascular diseases in the clinical diagnosis of individuals across all age groups but also the prognostic target value. The sensor exhibited excellent selectivity and stability and notable labeling recovery capability in serum tests. Critically, the sensor successfully discriminated the alterations in NT-proBNP secretion levels within human smooth muscle cells, comparing pre- and poststimulation by platelet-derived growth factor-BB. Even more significantly, the skin puncture experiment conducted in mice demonstrated the remarkable implantability and biological compatibility of the OF-PEC microelectrode. This addresses critical challenges commonly faced by microelectrodes when used as implanted devices, such as minimizing invasive trauma, mitigating inflammation, and preventing biofouling, thereby firmly establishing their suitability for the development of advanced implantable sensing devices. Therefore, the present OF microelectrode PEC biosensor is not only cost-effective, easy to operate, and miniaturized but also holds significant potential for enabling more precise, more minimally invasive, and continuous monitoring of biological markers without causing inflammation. This capability is crucial for early disease detection, tracking disease progression, and facilitating personalized treatment strategies, which expands the practical application of PEC sensors.

Gold Nanoparticle-Modified Molecularly Imprinted Polymer-Coated Pencil Graphite Electrodes for Electrochemical Detection of Bisphenol A

The sensitive Bisphenol A (BPA) detection by an electrochemical sensor based on gold nanoparticle-doped molecularly imprinted polymer was successfully improved. This study describes the development of a method for BPA detection in both aqueous solution and real water samples using N-methacroyl-(L)-cysteine methyl ester and N-methacryloyl-(L)-phenylalanine methyl ester coated pencil graphite electrodes modified with AuNPs by differential pulse voltammetry (DPV). Importantly, AuNPs, which increase the electroactivity, were used to increase the surface area of a BPA-imprinted pencil graphite electrode (MIP PGE) sensor. Scanning electron microscopy and spectrophotometry analysis were used for the characterization. The DPV response of the synthesized electrode showed distinguished electrical conductivity. The MIP PGE and nonimprinted pencil graphite electrode (NIP PGE) sensor were evaluated for selective and sensitive detection of BPA in aqueous solutions. Five different BPA concentrations (1.5, 3.0, 4.5, 6.0, and 7.5 μM) were applied to the MIP PGE, and the DPV recognized signal responses with a correlation coefficient value of 0.9965. The modified electrode demonstrated good electrocatalytic activity toward BPA for the linear concentration range of 1.5-7.5 μM, and a low limit of detection was found as 0.1610 μM. The results show that the MIP PGE sensor has excellent potential for selective and sensitive detection of BPA in real water samples.

Self-shedding MOF-nanocarriers modulated CdS/MoSe2 heterojunction activity through in-situ ion exchange: An enhanced split-type photoelectrochemical sensor for deoxynivalenol

Deoxynivalenol (DON), a mycotoxin produced by Fusarium, poses a significant risk to human health and the environment. Therefore, the development of a highly sensitive and accurate detection method is essential to monitor the pollution situation. In response to this imperative, we have devised an advanced split-type photoelectrochemical (PEC) sensor for DON analysis, which leverages self-shedding MOF-nanocarriers to modulate the photoelectric response ability of PEC substrate. The PEC sensing interface was constructed using CdS/MoSe2 heterostructures, while the self-shedding copper peroxide nanodots@ZIF-8 (CPNs@ZIF-8) served as the Cu2+ source for the in-situ ion exchange reaction, which generated a target-related signal reduction. The constructed PEC sensor exhibited a broad linear range of 0.1 pg mL-1 to 500 ng mL-1 with a low detection limit of 0.038 pg mL-1, demonstrating high stability, selectivity, and proactivity. This work not only introduces innovative ideas for the design of photosensitive materials, but also presents novel sensing strategies for detecting various environmental pollutants.

MOF-derived sandwich-structured dual Z-Scheme Co9S8@ZnIn2S4/CdSe hollow nanocages heterojunction: Target-induced ultrasensitive photoelectrochemical sensing of chlorpyrifos

Exploring efficient photoactive material presents an intriguing opportunity to enhance the analytical performance of photoelectrochemical (PEC) sensor in the environmental analysis. In this work, a sandwich-structured multi-interface Co9S8@ZnIn2S4/CdSe QDs dual Z-Scheme heterojunction, derived from metal-organic framework (MOF), was synthesized as a sensing platform for chlorpyrifos detection, by integrating with enzyme-induced in situ insoluble precipitates strategy. The meticulously designed Co9S8@ZnIn2S4/CdSe QDs exhibited enhanced charge separation efficiency and was proved to be a highly effective sensing platform for the immobilization of biomolecules, attributing to the intrinsic dual Z-Scheme heterojunction and the distinctive hollow structure. The proposed PEC sensing platform combined with enzyme-induced in situ precipitate signal amplification strategy achieved superior performance for sensing of chlorpyrifos (CPF), showing in wide linear range (1.0 pg mL-1-100 ng mL-1), with a limit of detection (0.6 pg mL-1), excellent selectivity, and stability. This work offers valuable insights for the design of novel advanced photoactive materials aimed at detecting environmental pollutants with low level concentration.