Near-infrared Responsive Photoelectrochemical Biosensors

Near-infrared (NIR) light-driven photoelectrochemical (PEC) sensing is a highly promising analytical technique, especially for in situ bioanalysis, due to the deep penetration capability and minimal invasiveness of NIR light. In this mini review, we provide a brief overview of recently developed NIR PEC sensors, focusing on NIR light-responsive materials and the representative applications of this type of PEC sensor. Future perspectives for NIR PEC sensors are also described.     

A Photoelectrochemical Sensor for Firstly the Detection of Amlodipine Besylate Based on an MnC4Pc Coated ZnO Composite Materials

In this study, tetracarboxylic manganese phthalocyanine coated nano-zinc oxide (MnC₄Pc-ZnO) composite material was prepared by in-situ growth method and modified with indium tin oxide (ITO) glass electrode to construct a photoelectrochemical (PEC) sensor. A PEC sensor for the determination of amlodipine besylate (AB) was developed for the first time based on the principle of precipitation reaction between heavy metal ions and dihydropyridine and the recombination suppression effect of the material. The morphology and optical properties of the MnC₄Pc-ZnO composites were characterized by scanning electron microscopy (SEM) and ultraviolet-visible diffuse reflectance spectroscopy (UV-vis DRS). Chronoamperometry (i-t) and electrochemical impedance spectroscopy (EIS) were used to study the PEC behavior of ITO electrodes modified by MnC₄Pc-ZnO composite material. The study found that the MnC₄Pc-ZnO composite material has a good photocurrent response to AB, and there was a good linear relationship between the concentration range of 75 nM-250 μM, the linear equation was I(μA)=−5.2×10⁻⁸×lgC+3.2×10⁻⁸ (r=0.9947), a limit of detection (LOD) of 20 nM. In addition, MnC₄Pc-ZnO/ITO also has good selectivity and stability. The PEC sensor detects amlodipine besylate tablets, amlodipine besylate dispersible tablets, and biological samples, with standard addition recovery rates of 96.11 % and 103.96 %, respectively. The determination result has good accuracy, and the PEC sensor provides a new method for detecting AB.     

碘氧铋/二氧化钛纳米棒复合材料的制备及其对双酚A的光电化学检测

采用简易的两步水热法在FTO导电玻璃表面合成碘氧铋/二氧化钛纳米棒(BiOI/TiO₂ NRAs)复合材料。通过扫描电子显微镜、X射线单晶衍射仪对该复合材料进行了表征,基于电流-时间法考察了其光电化学行为。 BiOI的负载不仅成功地将TiO₂的光吸收范围拓展到可见光区,同时二者结合形成的p-n异质结构有效地促进光生电子空穴分离,增强了光催化能力。 基于该复合材料对双酚A的光催化氧化作用,建立了一种新型检测双酚A的方法。 结果表明,420 nm可见光激发下,利用电流-时间法,在外加偏压为0.0 V时,光电流密度与双酚A浓度在0.0047~14.7 μmol/L范围内呈线性关系,检测限为0.93 nmol/L(S/N=3)。 该传感器具有高的灵敏度、良好的稳定性及重现性,将其应用于塑料制品和牛奶中的双酚A检测,获得令人满意的结果,回收率为98.0%~107.1%。     

A ratiometric photoelectrochemical microsensor based on a small-molecule organic semiconductor for reliable in vivo analysis

Photoelectrochemical (PEC) sensing has been developing quickly in recent years, while its in vivo application is still in the infancy. The complexity of biological environments poses a high challenge to the specificity and reliability of PEC sensing. We herein proposed the concept of small-molecule organic semiconductor (SMOS)-based ratiometric PEC sensing making use of the structural flexibility as well as readily tunable energy band of SMOS. Xanthene skeleton-based CyOH was prepared as a photoactive molecule, and its absorption band and corresponding PEC output can be modulated by an intramolecular charge transfer process. As such, the target mediated shift of absorption offered the opportunity to construct a ratiometric PEC sensor. A proof-of-concept probe CyOThiols was synthesized and assembled on a Ti wire electrode (TiWE) to prepare a highly selective microsensor for thiols. Under two monochromatic laser excitation (808 nm and 750 nm), CyOThiols/TiWE offered a ratiometric signal (j₈₀₈/j₇₅₀), which exhibited pronounced capacity to offset the disturbance of environmental factors, guaranteeing its reliability for application in vivo. The ratiometric PEC sensor achieved the observation of bio-thiol release induced by cytotoxic edema and fluctuations of thiols in drug-induced epilepsy in living rat brains.

The first small-molecule organic semiconductor-based ratiometric photoelectrochemical sensor was proposed, which exhibited pronounced selectivity and capacity to offset environmental disturbance, guaranteeing its reliability for in vivo analysis.     

The synthesis of graphene oxide covalently linked with nickel tetraamino phthalocyanine: A photoelectrochemical sensor for the analysis of rifampicin irradiated with blue light

In this article, the fabrication and characterization of a photoelectrochemical (PEC) rifampicin sensor based on graphene oxide grafted with Ni tetraamino phthalocyanine was described, which presents an excellent PEC activity, sensitivity, and material stability. The synthesized graphene oxide grafted with Ni tetraamino phthalocyanine was characterized using ultraviolet–visible (UV–vis), Fourier transform infrared (FTIR), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) analyses. Specifically, detection for rifampicin was based on the reduction of photocurrent caused by binding of the analyte to the sensing electrode surface. The fabricated sensor was characterized in a broad linear response range (0.025–71.3 μM) and with a low detection limit (2.5 nM), outperforming the previously reported sensors and thus being well suited for quality control and other applications, as confirmed by successful real‐life sample testing.     

Label-free photoelectrochemical sensor based on 2D/2D ZnIn2S4/g-C3N4 heterojunction for the efficient and sensitive detection of bisphenol A

Photoelectrochemical （PEC） sensor is an emerging technology in analysis as the advantage of fast response,high sensitivity and uncomplicated operation.In this study,an effective label-free PEC sensor for bisphenol A （BPA） detecting is constructed,in which Zn In₂S₄/g-C₃N₄heterojunction is prepared via a simple hydrothermal method.The characterization outcomes display that the formation of p-n heterojunction helps for promoting the separation efficiency ...     

A Label-free Photoelectrochemical Sensor Based on Bi2S3@Nitrogen Doped Graphene Quantum Dots for Ascorbic Acid Determination

We report a photoelectrochemical(PEC) sensor for selective detection of ascorbic(AA) by introducing Z-scheme Bi₂S₃@nitrogen doped graphene quantum dots(Bi₂S₃@NGQDs) heterojunctions as efficient photoactive species. The Bi₂S₃@NGQDs were successfully prepared by a simple hydrothermal process, and the microstructures and components were investigated by various characterized techniques. The photocurrent of the Bi₂S₃@NGQDs-based sensor increased significantly in the presence of AA and showed excellent selectivity and stability for AA detection in the presence of some other antioxidants and small molecules. A wide linear range of 0.1-5 μmol/L and 5-1380 μmol/L was achieved for the AA detection with a detection limit of 36 nmol/L(S/N=3). Moreover, the proposed PEC sensor achieved the determination of AA in real red peppers and commercially available vitamin C tablets samples.     

Component reconstitution-driven photoelectrochemical sensor for sensitive detection of Cu2+ based on advanced CuS/CdS p-n junction

Science China Chemistry - The rational design of robust photoactive material and artful sensing strategy are vital for the construction of an ultrasensitive photoelectrochemical (PEC) sensor....     

α‐Fe2O3 Film with Highly Photoactivity for Non‐enzymatic Photoelectrochemical Detection of Glucose

A non‐enzyme photoelectrochemical (PEC) glucose sensor based on α‐Fe₂O₃ film is investigated. The α‐Fe₂O₃ film was fabricated via a simple spin coating method. The proposed glucose sensor exhibits good selectivity, a fast response time of <5 s, a linear range of 0.05 to 6.0 mM, sensitivity of 17.23 μA mM^?1 cm^?2 and a detection limit of 0.05 μM. Meanwhile, the excellent performances of the α‐Fe₂O₃ sensor were obtained in reproducibility and the long‐term stability under ambient condition. The linear amperometric response of the sensor covers the glucose levels in physiological and clinical for diabetic patients. Therefore, this non‐enzyme PEC sensor based on α‐Fe₂O₃ film has a great potential application in the development of glucose sensors.     

Photoelectrochemical dopamine sensor based on a gold electrode modified with SnSe nanosheets

Microchimica Acta - The authors have prepared SnSe nanosheets by a solvothermal method and used them to modify a gold electrode to obtain a photoelectrochemical (PEC) sensor for dopamine (DA) which...     

A novel photoelectrochemical hydrogen peroxide sensor based on nickel(II)-potassium hexacyanoferrate-graphene hybrid materials modified n-silicon electrode

A platinum (Pt) film coated n-silicon (Pt/n-n⁺-Si) was modified with nickel(II)-potassium hexacyanoferrate (NiHCF)-graphene sheets (GS) hybrid and used as a photo-electrochemical (PEC) sensor for non-enzyme hydrogen peroxide (H₂O₂) detection. A NiHCF film was deposited on the surface of GS/Pt/n-n⁺-Si electrode by chemical method. The structure and composition of the NiHCF film was characterized by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). PEC behavior of the NiHCF-GS/Pt/n-n⁺-Si electrode was investigated using cyclic voltammetry (CV) under illumination. The modified electrode has been used as PEC sensor for H₂O₂ detection with a linear range of 2.0 × 10^?6–2.9 × 10^?3 M and a detection limit of 1.0 × 10^?6 M at a signal-to-noise ratio of 3 in a two-electrode cell with a Pt plate as counter electrode. The characteristics of GS layer have been discussed in both the improvement of sensibility and selectivity.     

A Solution-Processable Porphyrin-Based Hydrogen-Bonded Organic Framework for Photoelectrochemical Sensing of Carbon Dioxide

Detecting CO₂ in complex gas mixtures is challenging due to the presence of competitive gases in the ambient atmosphere. Photoelectrochemical (PEC) techniques offer a solution, but material selection and specificity remain limiting. Here, we constructed a hydrogen-bonded organic framework material based on a porphyrin tecton decorated with diaminotriazine (DAT) moieties. The DAT moieties on the porphyrin molecules not only facilitate the formation of complementary hydrogen bonds between the tectons but also function as recognition sites in the resulting porous HOF materials for the selective adsorption of CO₂. In addition, the in-plane growth of FDU-HOF-2 into anisotropic molecular sheets with large areas of up to 23000 μm² and controllable thickness between 0.298 and 2.407 μm were realized in yields of over 89 % by a simple solution-processing method. The FDU-HOF-2 can be directly grown and deposited onto different substrates including silica, carbon, and metal oxides by self-assembly in situ in formic acid. As a proof of concept, a screen-printing electrode deposited with FDU-HOF-2 was fabricate as a label-free photoelectrochemical (PEC) sensor for CO₂ detection. Such a signal-off PEC sensor exhibits low detection limit for CO₂ (2.3 ppm), reusability (at least 30 cycles), and long-term working stability (at least 30 days).     

A Photoelectrochemical Immunosensor for Prostate Specific Antigen Detection Based on Graphdiyne Oxide Conjugated with Horseradish Peroxidase

Graphdiyne (GDY) was a novel flat material with sp and sp² hybridized carbon atoms. It exhibited good biocompatibility. The application of GDY in PEC immunosensor was very limited. Thus, a novel photoelectrochemical sensor for the sensitive detection of prostate specific antigen (PSA) was proposed by using GDY oxide (GDYO) conjugated with horseradish peroxidase (HRP) and secondary antibody for photocurrent signal inhibition. GDYO was prepared by oxidation of honeycomb-like nanotubes composed of numerous GDY nanosheets. It showed high loading capacity for HRP and the catalytic activity of HRP could be remained. With reduced graphene oxide-CdS (rGO-CdS) as photoelectrochemical sensing platform, a sandwich-type photoelectrochemical (PEC) immunosensor was thus fabricated. The immunosensor presented a wide linear concentration range of 10 fg mL⁻¹–20.0 ng mL⁻¹ with a detection limit (LOD) of 3.5 fg mL⁻¹. Moreover, the PEC immunosensor displayed ideal reproducibility, stability, and selectivity, which was a promising platform for the detection of other important tumor targets.     

Novel photoelectrochemical immunosensor for MCF-7 cell detection based on n-p organic semiconductor heterojunction

In this work, we developed a novel photoelectrochemical（PEC） sensor based on n-p organic semiconductor heterojunction for sensitive detecting MCF-7 cancer cells. BTA-C4 Ph and PM6 were designed as photoactive materials to form n-p heterojunction, which greatly enhanced the photoelectric conversion efficiency. Antibody-modified magnetic nanoparticles were utilized to capture and separate MCF-7 cells from samples. Detection of MCF-7 is ascribed to the loading of MCF-7 onto BTA-C4 Ph-PM6 modified e...     

Novel visible-light-responsive photoelectrochemical sensor of 2,4-dichlorophenoxyacetic acid using molecularly imprinted polymer/BiOI nanoflake arrays

A novel and highly sensitive visible-light photoelectrochemical (PEC) sensor for the detection of 2,4-D has been developed using a nanocomposite of molecularly imprinted gold nanoparticles-polypyrrole polymer (MIP) modified BiOI nanoflake arrays (BiOINFs) as a photoactive electrode (labeled as MIP@BiOINFs). Our results demonstrate that the smart combination of BiOINFs with MIP offers a high-performance photoactive sensing platform. It features the intrinsically excellent visible-light responsive properties of BiOI and prominent recognition ability from MIP. The designed MIP@BiOINF composite dramatically facilitates the PEC determination of 2,4-D. The detection limit for 2,4-D is found to be as low as about 0.04 ng mL^− 1 (S/N = 3). Moreover, the resulting sensor could be used to detect 2,4-D in spiked soil samples.     

基于Zr-MOFs光电化学传感用于同型半胱氨酸的检测

以4-羧基苯基卟啉（TCPP）作为配体,金属锆（Zr）作为配位金属,通过水热法合成Zr-MOFs。以Zr-MOFs材料作为光电活性材料构建了阴极光电化学传感器用于检测同型半胱氨酸（Hcy）。当λ > 420 nm的氙灯光源照射Zr-MOFs时,处于价带（VB）上的电子（e^-）跃迁至导带（CB）,并在价带上产生空穴（h⁺）,从而产生光电流。同型半胱氨酸的加入会阻碍电子的传递,从而造成阴极光电流降低。当目标物浓度为10 ~ 100 nmol·L^-1和100 ~ 1000 nmol·L^-1时,光电流信号变化值与目标物浓度呈线性关系,且检出限为2.17 nmol·L^-1,制备的传感器具有良好的稳定性和选择性。     

Non-noble metal Bi/BiVO4 photoanode for surface plasmon resonance-induced photoelectrochemical biosensor of hydrogen peroxide detection

Non-noble metal for surface plasmon resonance (SPR)-induced nano-enzymatic photoelectrochemical (PEC) biosensors is a promising method for broad applications. Non-noble metal bismuth (Bi) is gradually being valued for their properties such as non-toxicity, abundant reserves, and good catalysis. Meanwhile, metallic Bi nanoparticles (NPs) have superior SPR properties similar to that of noble metal. Therefore, a non-noble metal Bi/BiVO₄ photoanode based on SPR was designed for the PEC detection of H₂O₂ in this work. The synergistic effect of BiVO₄ with suitable band gap (2.5 eV) and Bi NPs with superior SPR effectively reduces the recombination of photogenerated electrons and holes, which significantly improves the PEC activity of Bi/BiVO₄ electrode at low voltage. The in situ Bi/BiVO₄/FTO photoelectrode not only exhibits a more comprehensive linear range of 0.005–2.6 mM with a lower detection limit of 2.0 μM but also possesses excellent selectivity for the determination of H₂O₂ because the coexisting substances are difficult to be oxidized at 0 V bias voltage. The investigation of Bi/BiVO₄-based sensor has contributed to the development of non-noble metal for SPR-induced PEC biosensors.

     

Label-free photoelectric sensor for lactic acid determination in human sweat

A label-free lactic acid sensor has been successfully developed by using a Dysprosium single crystal-based photoelectric potential technique via Dy-SCN/FTO electrode. Interestingly, the proposed sensor demonstrated excellent performance for l-lactic acid analysis with a wide linear range of 0.0196～16.31 mmol/L, the detection limit of as low as 3.20 µmol/L as well as an advisable stability. The feasibility of this strategy was also verified by practical application towards human sweat samples. The mechanism studies indicated that lactic acid molecules specifically bind to the surface of semiconductor materials, which alters the charge distribution of the electrode surface and subsequently results in band bending/photoelectric potential changes. The theoretical formula for this photoelectric chemistry (PEC) strategy was then derived according to charge balance theory. We believe that the proposed Dy-SCN/FTO sensor would open a new way for rapid, non-invasive l-lactic acid level evaluation during human physical condition monitoring.     

Implantable optical fiber microelectrode with anti-biofouling ability for in vivo photoelectrochemical analysis

In-situ monitoring of neurochemicals is of vital importance for the understanding of brain functions. Microelectrode-based photoelectrochemical (PEC) sensing has emerged as a promising tool for in vivo analysis since it inherits the merits of both optical and electrochemical methods. However, the in-situ excitation of photoactive materials on the photoelectrode in living body is still a challenge because of limited tissue penetration depth of light. To circumvent this problem, we herein developed an implantable optical fiber (OF)-based microelectrode for in vivo PEC analysis. The working electrode was constructed by coating Au film as conducting layer and CdS@ZnO as photoactive material on a micron-sized OF, which was free of the limitation of light penetration in biological tissues. Further decoration of an anti-biofouling layer on the surface made the sensor robust in biosamples. It was successfully applied for monitoring Cu²⁺ level in three different brain regions in the rat model of cerebral ischemia/reperfusion.     

A Visible‐Light Driven Photoelectrochemical Aptasensor for Endocrine Disrupting Chemicals Bisphenol A with High Sensitivity and Specificity

A visible‐light driven photoelectrochemical (PEC) sensor based on aptamer immobilized TiO₂‐Fe₂O₃ nanotubes was proposed for the first time and highly sensitive and selective bisphenol A determination was realized. Taking advantage of the alloy oxide nanotube structure, high surface area, good biocompatibility, superior photoelectrocatalytic performance, a limit of detection toward BPA as low as 1.8×10^?11 M with linearity in the range from 1.8×10^?11 to 3.2×10^?9 M could be achieved. Specificity was greatly exhibited for this aptasensor under 100‐fold excess concentration of estriol, resorcinol, nonylphenol, 2,4‐D, acetamiprid, chlorpyrifos and omethoate. Simultaneously, satisfactory results were obtained in real water sample investigation from industrial plastics and drinking water. A novel visible‐light driven PEC method for highly sensitive and selective detection of BPA was thus established.