Abstract
In this work, carbon dots (CDs) and black phosphorus quantum dots (BPQDs) were used to decorate titanium dioxide to enhance the photoelectrochemical (PEC) properties of the nanocomposites (TiO2@CDs@BPQDs), and the modified nanocomposites were used to sensitively detect DNA. We used the hydrothermal method and citric acid as a raw material to prepare CDs with good dispersion and strong fluorescence properties. BPQDs with a uniform particle size were prepared from black phosphorus crystals. The nanocomposites were characterized by fluorescence spectroscopy, UV-Vis absorption spectroscopy, Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). The preparation method of the working electrode was explored, the detection conditions were optimized, and the sensitive detection of target DNA was achieved. The results demonstrate that CDs and BPQDs with good optical properties were successfully prepared, and they were successfully combined with TiO2 to improve the PEC performance of TiO2@CDs@BPQDs. The TiO2-based PEC DNA detection method was constructed with a detection limit of 8.39 nM. The constructed detection method has many advantages, including good sensitivity, a wide detection range, and good specificity. This work provides a promising PEC strategy for the detection of other biomolecules.
Highlights
Photoelectrochemical (PEC) detection technology has been used in biomolecule detection for a long time and has good application prospects in environmental monitoring and biomedical diagnosis
In order to ensure the low toxicity of the material after modification, two kinds of narrow-gap semiconductors, carbon dots (CDs) and black phosphorous quantum dots (BPQDs), were used to decorate TiO2 in this work
Performance of the nanocomposites (TiO2 @CDs@BPQDs), and the PEC biosensors based on TiO2 @CDs@BPQDs were constructed for the detection of DNA with high detection sensitivity while maintaining the low toxicity and environmental protection in the process of detection
Summary
Photoelectrochemical (PEC) detection technology has been used in biomolecule detection for a long time and has good application prospects in environmental monitoring and biomedical diagnosis. As TiO2 belongs to n-type wide bandgap semiconductors, the photogenerated electrons and holes are easy to recombine It only absorbs ultraviolet light in sunlight, which only accounts for 5% of the energy in sunlight [4,5]. CDs are a kind of carbon-based zero-dimensional nanometer material that is composed of a carbonaceous framework and surface groups with a particle size of less than 10 nm It has good fluorescence performance, low toxicity, good biocompatibility, a tunable emission wavelength, easy functionalization and up-conversion photoluminescence [11], etc. Due to the quantum confinement effect and the existence of the edge effect [15], the PEC performance is superior to other related materials of black phosphorus, for example, phosphorene and so on It has a very good application prospects in the modification of the PEC properties of TiO2. CDs and BPQDs were used to decorate TiO2 and improve the PEC performance of the nanocomposites (TiO2 @CDs@BPQDs), and the PEC biosensors based on TiO2 @CDs@BPQDs were constructed for the detection of DNA with high detection sensitivity while maintaining the low toxicity and environmental protection in the process of detection
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