Self-Powered Cathodic Photoelectrochemical Aptasensor Comprising a Photocathode and a Photoanode in Microfluidic Analysis Systems

Abstract

An intriguing self-powered cathodic photoelectrochemical (PEC) microfluidic aptasensor with enhanced cathodic photocurrent response is proposed for sensitive detection of prostate-specific antigen (PSA). The self-powered system is constructed by a cadmium sulfide-sensitized zinc oxide nanorod array (CdS/ZnO NA) as a photoanode with an iodide-doped bismuth oxychloride flower-array (I 0.2 :BiOCI 0.8 ) as a photocathode, which can generate the electrical output under visible light irradiation with no external power supply. In addition, the ptype semiconductor I 0.2 :BiOCI 0.8 with a special internal electric field between the iodide ion layer and the [Bi 2 O 2 ] 2+ layer could increase the cathodic photocurrent response by facilitating the separation of electron/hole pairs under visible light excitation. It is worth noting that dissolved oxygen as an electron acceptor can be reduced by the photogenerated electron to form a superoxide radical ( • O 2 − ) in the self-powered cathodic PEC system. The further enhanced cathodic photocurrent response can be achieved by eliminating • O 2 − that reacts with the luminol anion radical (L •− ) to produce chemiluminescence emission, which serves as an inner excitation light source. What is more exciting is that the integration of the photoanode and the photocathode into a microfluidic chip could realize automatic sample injection and detection. On this basis, the proposed aptasensor presents excellent reproducibility and high sensitivity for detecting PSA and exhibits a good linearity range (50 fg•mL −1 to 50 ng•mL −1 ) with a low detection limit (25.8 fg•mL −1 ), which opens up a new horizon of potential for sensitively detecting other kinds of disease markers.

Photoelectrochemical Assay Based on SnO2/BiOBr p–n Heterojunction for Ultrasensitive DNA Detection

“…Photoelectrochemical (PEC) analysis, as a thriving analytical technique, not only has the merits of simple operation and low cost but also possesses the advantages of low background noise and high sensitivity owing to the total separation of excitation light source and the detection signal, gathering tremendous attention in recent years. − As is well known, the photoelectric conversion efficiency of the photoactive material makes great difference on the performance of PEC biosensors. , Reducing the electron–hole pair recombination probability and enhancing the light absorption in the ultraviolet–visible (UV–vis) region are effective ways to promote the photoelectric conversion efficiency of photoelectric material . Unfortunately, single photoelectric materials usually have the disadvantage of low photoelectric conversion efficiency, which limits their practical applications. , In recent years, the construction of heterojunctions is considered to be a feasible and effective way to facilitate the electron–hole separation and restrain the recombination of electron–hole of optoelectronic materials. − For instance, Xiong’s group synthesized a ZnO/CeO 2 Z-scheme heterojunction for photodegradating rhodamine B .…”

Self-Powered Photoelectrochemical Aptasensor for Oxytetracycline Cathodic Detection Based on a Dual Z-Scheme WO3/g-C3N4/MnO2 Photoanode

“…As an emerging sensing technique, self-powered photoelectrochemical (PEC) sensors have attracted the widespread attention because they not only have the advantages of traditional PEC sensing systems like simple structure, fast response, high sensitivity, and low cost but can also work without an external voltage. − In the past few years, self-powered PEC sensors have mainly been constructed based on three-electrode systems, but regardless of anodic type or cathodic type, the three-electrode schemes employ the single work electrode as a signal source and as a specific recognition platform simultaneously, which inevitably causes the decline in PEC sensing performance resulting from interactions between photoelectrodes and reductive reagents or target molecules. , To overcome the side effects, some self-powered PEC sensors based on a two-electrode system have emerged recently. − The separation of light absorption and target recognition as well as the ability to generate electricity ensured detection performance. Sun and co-workers constructed a dual-mode PEC biosensor to explore the feasibility of this novel PEC mode.…”

MoSe2/CdSe Heterojunction Destruction by Cation Exchange for Photoelectrochemical Immunoassays with a Controlled-Release Strategy

“…15 An immunoassay affects the flow of carriers directly or indirectly so as to achieve the quantitative detection of disease markers. Recently, immunoassay strategies 16 have been constructed primarily to affect electrolyte solutions, and the analyte or compound acted as the intermediate substance in the interaction between the electrolyte solution and the working electrode. Here, we optimized a novel detection mode based on the structural destruction of the heterojunction through a cation exchange (CE).…”