Recognition of M2 type tumor-associated macrophages with ultrasensitive and biocompatible photoelectrochemical cytosensor based on Ce doped SnO2/SnS2 nano heterostructure

A competitive-type photoelectrochemical aptasensor for 17 beta-estradiol detection in microfluidic devices based on a novel Au@Cd:SnO2/SnS2 nanocomposite

A competitive-type photoelectrochemical (PEC) aptasensor coupled with a novel Au@Cd:SnO2/SnS2 nanocomposite was designed for the detection of 17β-estradiol (E2) in microfluidic devices. The designed Au@Cd:SnO2/SnS2 nanocomposites exhibit high photoelectrochemical activity owing to the good matching of cascade band-edge and the efficient separation of photo-generated e-/h+ pairs derived from the Cd-doped defects in the energy level. The Au@Cd:SnO2/SnS2 nanocomposites were loaded into carbon paste electrodes (CPEs) to immobilize complementary DNA (cDNA) and estradiol aptamer probe DNA (E2-Apt), forming a double-strand DNA structure on the CPE surface. As the target E2 interacts with the double-strand DNA, E2-Apt is sensitively released from the CPE, subsequently increasing the photocurrent intensity due to the reduced steric hindrance of the electrode surface. The competitive-type sensing mechanism, combined with high PEC activity of the Au@Cd:SnO2/SnS2 nanocomposites, contributed to the rapid and sensitive detection of E2 in a "signal on" manner. Under the optimized conditions, the PEC aptasensor exhibited a linear range from 1.0 × 10-13 mol L-1 to 3.2 × 10-6 mol L-1 and a detection limit of 1.2 × 10-14 mol L-1 (S/N = 3). Moreover, the integration of microfluidic device with smartphone controlled portable electrochemical workstation enables the on-site detection of E2. The small sample volume (10 µL) and short analysis time (40 min) demonstrated the great potential of this strategy for E2 detection in rat serum and river water. With these advantages, the PEC aptasensor can be utilized for point-of-care testing (POCT) in both clinical and environmental applications.

Magnetic photoelectrochemical sensor array utilizing addressing sensing strategy for simultaneous detection of amyloid-β 42 and microtubule-associated protein tau

The accurate diagnosis of diseases can be improved by detecting multiple biomarkers simultaneously. This study presents the development of a magnetic photoelectrochemical (PEC) immunosensor array for the simultaneous detection of amyloid-β 42 (Aβ) and microtubule-associated protein (Tau), which are markers for neurodegenerative disorders. A metal-organic framework (MOF) derivative, Fe2O3@FeS2 magnetic composites with exceptional photoelectric and ferromagnetic properties was synthesized while preserving the original structure and advantages. Thus, the immunoassembly process of the sensor can be carried out in homogeneous solution and recovered by magnetic separation. For simultaneous detection, a chip is divided into multiple independent sensing sites, which have the same preparation and detection environment, allowing for the implementation of a self-calibration method. The sensor array demonstrates considerable detection ranges of 0.01-100 ng mL-1 for Aβ and 0.05-100 ng mL-1 for Tau, with low detection limits of 2.1 pg mL-1 for Aβ and 7.9 pg mL-1 for Tau. The PEC sensor array proposed in this study exhibits exceptional stability, selectivity, and reproducibility, providing a new method for detecting multiple markers.

Novel Ultrasensitive Photoelectrochemical Cytosensor Based on Hollow CdIn2S4/In2S3 Heterostructured Microspheres for HepG2 Cells Detection and Inhibitor Screening

Hepatocellular carcinoma is a life-threatening malignant tumor found around the world for its high morbidity and mortality. Therefore, it is of great importance for sensitive analysis of liver cancer cells (HepG2 cells) in clinical diagnosis and biomedical research. To fulfill this demand, hollow CdIn₂S₄/In₂S₃ heterostructured microspheres (termed CdIn₂S₄/In₂S₃ for clarity) were prepared by a two-step hydrothermal strategy and applied for building a novel photoelectrochemical (PEC) cytosensor for ultrasensitive and accurate detection of HepG2 cells through specific recognition of CD133 protein on the cell surface with the respective aptamer. The optical properties of CdIn₂S₄/In₂S₃ were investigated by UV-vis diffuse reflectance spectroscopy (DRS) and PEC technology. By virtue of their appealing PEC characteristics, the resultant PEC sensor exhibited a wider dynamic linear range from 1 × 10² to 2 × 10⁵ cells mL^-1 with a lower limit of detection (LOD, 23 cells mL^-1), combined by evaluating the expression level of CD133 protein stimulated by metformin as a benchmarked inhibitor. This work opens a valuable and feasible avenue for sensitive detection of diverse tumor cells, holding great potential in early clinical diagnosis and treatment coupled by screening inhibitors.

2D SnS2 Nanostructure-Derived Photocatalytic Degradation of Organic Pollutants Under Visible Light

Wastewater produced by the textile industry contains various dyes and organic compounds that directly or indirectly affect surface water or groundwater pollution. Visible-light-driven semiconductor photocatalysis is the leading pathway for the degradation of environmental pollutants. Herein we report the bottom-up hydrothermal growth of 2D tin disulfide nanostructures (SnS2 NSs) for the efficient photodegradation of organic pollutants such as Rhodamine B (Rh.B) and Methyl Violet (M.V) in an aqueous medium under visible light (λ > 400 nm) irradiation. The as-synthesized SnS2 NSs were characterized by various structural, morphological, and optical techniques such as XRD, RAMAN, TEM, UV–Vis, Brunauer–Emmett–Teller, etc. Furthermore, the low bandgap (∼1.6 eV), the high surface area (56 m2/g), and the anionic nature of SnS2 NSs attribute to it as an efficient photocatalyst for photocatalytic applications. The photocatalytic properties of SnS2 NSs showed good degradation efficiency of 94 and 99.6% for Rh. B and M.V, respectively, in 25 min. The kinetic rate constant of these dyes was estimated by using the Langmuir–Hinshelwood model. Here we also performed the recyclability test of the photocatalyst and discussed the plausible mechanism for the photocatalytic degradation of organic pollutants. The XPS spectra of SnS2 NSs were studied before and after the photodegradation of Rh.B and M.V, indicating the high stability of the photocatalyst. Moreover, in vitro cytotoxicity was also evaluated against human cervical cancer cell lines (HeLa cells) with different concentrations (0–1,000 μg/ml) of as-synthesized SnS2 NSs. This intended work provides a possible treatment for the degradation of organic pollutants under visible light to balance the aquatic ecosystems.