Microfluidic Ratiometric Photoelectrochemical Biosensor Using a Magnetic Field on a Photochromic Composite Platform: A Proof-of-Concept Study for Magnetic-Photoelectrochemical Bioanalysis

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An innovative self-powered microfluidic photoelectrochemical (PEC) aptasensor was developed that uses photoactive AgBr/CuBi2O4 (ACO) composites as the photocathode matrix for ultrasensitive detection of ciprofloxacin (CIP) and ofloxacin (OFL). The formation of direct Z-scheme heterojunctions in ACO composites greatly aided electron/hole pair separation. Meanwhile, ZnIn2S4-decorated CdS nanorod arrays (CZIS) as the photoanode were used instead of a platinum counter electrode to provide electrons. The “signal-off” CIP detection was accomplished through the steric hindrance effect in the photoanode due to the combination of aptamer(CIP) and CIP. To increase the cathodic photocurrent intensity for OFL determination, controlled release of luminol was first used. Luminol molecules were successfully embedded in the porous structure of silicon dioxide nanospheres (PSiO2) by the electrostatic adsorption between PSiO2 and aptamer(OFL). The luminol released by specific recognition between OFL and aptamer(OFL) could not only react with •O2 – but also produce chemiluminescence emission, resulting in the “signal-on” state. Because of the signal “on–off–on”, the proposed aptasensor exhibited wide linear ranges for CIP (0.001–100 ng/mL) and OFL (0.0005–100 ng/mL) detection. Furthermore, the low detection limits of CIP (0.06 pg/mL) and OFL (0.022 pg/mL) could achieve the ultrasensitive analysis.

Section: Introductionmentioning

confidence: 99%

A Direct Z-Scheme AgBr/CuBi₂O₄ Photocathode for Ultrasensitive Detection of Ciprofloxacin and Ofloxacin by Controlling the Release of Luminol in Self-Powered Microfluidic Photoelectrochemical Aptasensors

Dai

et al. 2022

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“…1−3 Nevertheless, the lack of miniaturization and portability extremely limits its application in actual sample testing. 4,5 In addition, ultrasensitive and efficient biomarker analysis has great significance for early diagnoses and treatment of disease. 6 Therefore, in this paper, an innovative analytical platform was successfully established, which integrated a microfluidic chip possessing superiorities of less sample consumption, easy integration, and miniaturization with a PEC sensor, and could achieve accurate detection of cytokeratin 19 fragments (CYFRA21−1).…”

Section: ■ Introductionmentioning

confidence: 99%

“…The photoelectrochemical (PEC) sensor, which possesses alluring advantages of low background noise, rapid responses, and high sensitivity, has attracted continuously growing scientific interest in the field of bioanalysis, food analysis, and environmental pollutant monitoring. − Nevertheless, the lack of miniaturization and portability extremely limits its application in actual sample testing. , In addition, ultrasensitive and efficient biomarker analysis has great significance for early diagnoses and treatment of disease . Therefore, in this paper, an innovative analytical platform was successfully established, which integrated a microfluidic chip possessing superiorities of less sample consumption, easy integration, and miniaturization with a PEC sensor, and could achieve accurate detection of cytokeratin 19 fragments (CYFRA21–1).…”

Section: Introductionmentioning

confidence: 99%

Catalytic Decomposition of the Hole-Derived H₂O₂ by AgBiS₂@Ag Nanozyme to Enhance the Photocurrent of Z-Scheme BiVO₄/ZnIn₂S₄ Photoelectrode in Microfluidic Immunosensing Platform

Song

Ren

et al. 2022

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A novel microfluidic photoelectrochemical (PEC) analytical device based on AgBiS2@Ag nanozyme-mediated signal amplification was developed for ultrasensitive detection of cytokeratin 19 fragment 21–1 (CYFRA 21–1). First, a brand new Z-scheme BiVO4/ZnIn2S4 (BZIS) photoactive material was utilized as a sensing matrix to supply a stable photocurrent. Under anodic bias, the photoexcited holes in BiVO4 could oxidize water to produce hydrogen peroxide (H2O2), which markedly enhanced the separation efficiency of the electron–hole pairs. Besides, the Z-scheme heterojunction formed between BiVO4 and ZnIn2S4 further accelerated the transport of the electron. Second, for improving the sensitivity of the PEC sensor, a new strategy of catalytic dissociation of the hole-derived H2O2 by AgBiS2@Ag nanozyme was proposed to amplify the PEC signal. AgBiS2@Ag composites, possessing an excellent peroxidase-mimicking feature, could efficiently catalyze the H2O2 to produce hydroxyl radicals (•OH) and lead to the significant enhancement of the photocurrent. Third, automatic sample injection and detection were successfully realized by integrating the photoelectrode into microfluidic chips. Based on this advanced sensing strategy, the designed microfluidic PEC sensor displayed a wide linear range (0.1 pg/mL – 100 ng/mL) and a low detection limit of 35 fg/mL (S/N = 3), which could be efficiently applied to the ultrasensitive determination of CYFRA 21–1 in a human serum sample.

“…A complete and refined biosensing protocol should have good analyte response and stability, but more importantly, portable design and low cost and scale of production are of higher concern to the researchers and testers. , Based on the principle that less is more, researchers have replaced traditional PEC test systems with components such as auto-sampling devices, − microfluidic platforms, − and 3D printing equipment − to meet the demand for miniaturized and portable assays. More meaningfully, with the booming development of microcontroller technology, more studies have proposed microcontroller-based signal transduction and processing as an alternative to electrochemical workstations, providing a portable and good user-interactive platform for achieving sensitive and multichannel real-time analysis.…”

mentioning

confidence: 99%

Exploiting Photoelectric Activities and Piezoelectric Properties of NaNbO₃ Semiconductors for Point-of-Care Immunoassay

Gong

et al. 2022

188

Point-of-care testing (POCT) technology has made major breakthroughs in community medicine and physician office situations, in tandem with the more ubiquitous and intensive usage of highly integrated quick detection equipment for illness diagnosis, personal care, and mobile healthcare. Although the photoelectrochemical (PEC)-based POCT platform offers the benefits of cheap cost and good user engagement, its commercialization is still limited by the photodetection components’ downsizing and mobility, among other factors. In this work, a novel highly integrated PEC biosensor aided by piezophototronics to enhance the efficiency of PEC testing was reported for flexible detection of cancer-associated antigens in biological fluids (prostate-specific antigen, PSA, used as an example). Multiple signal enhancement strategies, including a magnetic bead-linked enzyme-linked immune system catalyzing the production of ascorbic acid from the substrate and a piezoelectric-assisted enhancement strategy, were used for sensitive detection of the analyte to be tested in human body fluids. Unlike the electron transfer mechanism in heterojunctions, piezoelectric semiconductors promote the transfer of electrons and holes by generating piezoelectric potentials in the ultrasonic field, thus contributing to the performance of the PEC testbed. Under optimized conditions, the test platform achieves good correspondence for PSA at 0.02–40 ng mL–1. Impressively, the test devices are comparable to or even superior to gold standard ELISA kits in terms of cost approval and batch testing. This research demonstrates the potential of piezoelectric semiconductors for POC applications in revolutionary PECs and offers innovative thoughts for the development of new PEC bioanalytical components.