A novel “signal-on” photoelectrochemical sensor for ultrasensitive detection of alkaline phosphatase activity based on a TiO₂/g-C₃N₄heterojunction

Abstract

The use of alkaline phosphatase (ALP) as a biomarker in some diseases including hepatitis, obstructive jaundice, osteoblastic bone cancer, and osteomalacia is important in clinical diagnosis. Furthermore, ALP activity detection is an essential hot topic in environmental monitoring, biomedical research, and other research fields. In this study, a novel "signal-on" photoelectrochemical (PEC) biosensor based on the ALP-catalyzed phosphorylation reaction was designed to sensitively detect ALP activity. In this design, ascorbic acid-an electron donor-was catalytically produced by ALP from l-ascorbic acid 2-phosphate trisodium salt in situ, which results in an increased photocurrent response signal. For immobilizing the ALP on the electrode surface, poly diallyl dimethyl ammonium chloride was used for the conjugation of ALP, and titanium dioxide (TiO)-a photoactive material-and graphite-like carbon nitride (g-CN) nanocomposites were prepared and characterized. TiO attached on g-CN plays an important role for the biosensing purpose due to their good biocompatibility and chemical/thermal stability, while g-CN provides the PEC response signal. Furthermore, the prepared TiO/g-CN nanocomposites can effectively suppress electron-hole recombinations, improve the excitation conversion efficiency, and make the best use of solar energy. The PEC biosensor for ALP activity detection displays a detection limit of 0.03 U L (S/N = 3), which offers a new route for the ALP activity assay in human serum samples.

Host–Guest Recognition on 2D Graphitic Carbon Nitride for Nanosensing

“…The g-C 3 N 4 /metal-based materials (metal or metal oxide) can be synthesized by different methods for use as biosensors. The application of g-C 3 N 4 /metal oxide composites, including g-C 3 N 4 /ZnO, [103] g-C 3 N 4 /ZnO nanotubes, [104] ZnO nanodisks/g-C 3 N 4 quantum dots, [105] g-C 3 N 4 /TiO 2 nanotubes, [106] g-C 3 N 4 /TiO 2 NPs, [107] g-C 3 N 4 /TiO 2 nanosheets [108] and g-C 3 N 4 /WO 3 NPs, have been studied for the detection of biological substances by incorporaiton into PEC biosensors. [109] Xi et al reported hierarchically structured ZnO hybridized with g-C 3 N 4 as a new material for the nonenzymatic PEC sensing of hydrogen peroxide (H 2 O 2 ).…”

“…[106] Copyright 2016, Elsevier B.V.; (d, g) Reproduced with permission. [108] Copyright 2018, Royal Society of Chemistry; (e) Reproduced with permission. [103] Copyright 2015, Springer; (f) Reproduced with permission.…”

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

“…[16,45] Based on the observed photocurrent intensities, the functionalization of GO with NiTAPc reduced the rate of electron-hole recombination and resulted in steady photocurrent.…”

“…[6] Currently, RIF quantitation is performed using fluorescence spectroscopy, [7,8] ultraviolet-visible (UV-vis) spectroscopy, [9] high-performance liquid chromatography (HPLC)-ultraviolet spectroscopy, [10] and HPLCmass spectrometry, [11] which required much time and incurred high equipment and routine maintenance costs. [12][13][14][15] Photosensitive materials such as nanosemiconductors, Ru(II) complexes, organic compounds, composite photoelectric materials, and biological macromolecules [16][17][18][19] have been extensively used in the fields of bioanalysis and drug/contaminant quantitation. Photoelectrochemical (PEC) methods have particularly wide application prospects due to the above inherent advantages as well as their accuracy.…”

A photoelectrochemical sensor for glutathione based on Bi2S3-modified TiO2 nanotube arrays

“…Currently, a series of photosensitive materials have been applied to the construction of PEC sensors, such as CdS, 19 MoS 2 –ZnO, 20 CdSeTe, 21 MgIn 2 S 4 , 22 g -C 3 N 4 , 23 TiO 2 , 24 polythiophene, 25 polyaniline, 26 etc. Among these photoactive materials, titanium dioxide (TiO 2 ) is the most popular photoactive material due to its excellent stability, innocuity and low price.…”