Search

In this work, flower-like ZnO nanoparticles (ZnONPs) were synthesized using zinc nitrate (Zn(NO 3 ) 2 6H 2 O) as a precursor with KOH. The morphology of the ZnONPs was controlled by varying the synthesis temperature at 50, 75 and 95 °C. The morphology and structure of ZnONPs were characterized using Scanning Electron Microscopy, and X-Ray Diffraction and Brunauer-Emmett Teller analysis. ZnONPs were successfully synthesized by a simple chemical precipitation method. A synthesis temperature of 75 °C produced the most suitable flower-like ZnONPs, which were combined with graphene nanoplatelets to develop a label-free electrochemical immunosensor for the detection of the colon cancer biomarker carcinoembryonic antigen in human serum. Under optimum conditions, the developed immunosensor showed a linear range of 0.5-10.0 ng mL -1 with a limit of detection of 0.44 ng mL -1 . The label-free electrochemical immunosensor exhibited good selectivity, reproducibility, and repeatability, and recoveries were excellent. The immunosensor is used with a Near-Field Communication potentiostat connected to a smartphone to facilitate point-of-care cancer detection in low-resource locations., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

A novel label-free electrochemical immunosensor was prepared for the detection of carbohydrate antigen 19-9 (CA19-9) and carcinoembryonic antigen (CEA) as biomarkers of cholangiocarcinoma (CCA). A nanocomposite of gold nanoparticles, molybdenum trioxide, and chitosan (Au–MoO 3 -Chi) was layer-by-layer assembled on the porous graphene (PG) modified a dual screen-printed electrode using a self-assembling technique, which increased surface area and conductivity and enhanced the adsorption of immobilized antibodies. The stepwise self-assembling procedure of the modified electrode was further characterized morphologically and functionally. The electroanalytical detection of biomarkers was based on the interaction between the antibody and antigen of each marker via linear sweep voltammetry using ferrocyanide/ferricyanide as an electrochemical redox indicator. Under optimized conditions, the fabricated immunosensor showed linear relationships between current change (ΔI) and antigen concentrations in two ranges: 0.0025–0.1 U mL−1 and 0.1–1.0 U mL−1 for CA19-9, and 0.001–0.01 ng mL−1 and 0.01–1.0 ng mL−1 for CEA. The limits of detection (LOD) were 1.0 mU mL−1 for CA19-9 and 0.5 pg mL−1 for CEA. Limits of quantitation (LOQ) were 3.3 mU mL−1 for CA19-9 and 1.6 pg mL−1 for CEA. The selectivity of the developed immunosensor was tested on mixtures of antigens and was then successfully applied to determine CA19-9 and CEA in human serum samples, producing satisfactory results consistent with the clinical method. [Display omitted] • An Au–MoO 3 -chitosan/porous graphene nanocomposite was prepared in situ. • An electrochemical immunosensor for cholangiocarcinoma was based on the nanocomposite. • The immunosensor simultaneously detected CA19-9 and CEA in blood serum. • Good performances were obtained for the detection of cholangiocarcinoma. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel fluidic platform simultaneously detected two ovarian cancer biomarkers. • A dual carbon electrode was stencil-printed on flexible PVC sheet. • The proposed label-free immunosensor showed promise for onsite serum analysis. • The dual-electrode microfluidic device shows potential for point-of-care use. Carcinoembryonic antigen (CEA) and cancer antigen 125 (CA125) are important tumor markers for the diagnosis of ovarian cancer at the metastasis stage. Here, CEA and CA125 were simultaneously detected by a label-free electrochemical immunosensor. Using a stencil and carbon ink, a dual carbon electrode (DCE) was fabricated on a poly(vinyl chloride) substrate. Gold particles (AuPs) were electrodeposited on the electrode as a signal amplifier and support for immobilized antibodies. Linear sweep voltammetry was utilized to detect the tumor markers based on the specific binding of antigens to antibodies. Scanning electron microscopy and atomic force microscopy were used to characterize the fabricated DCE. The results were compared to those of a commercial DCE. Using the developed DCE immunosensor, we achieved a linear range of CEA from 0.5 to 25 ng mL−1 and a linear range of CA125 from 2 to 50 U mL−1. The limits of detection of CEA and CA125 were 0.15 ng mL−1 and 0.6 U mL−1, respectively. The reliability of the immunosensor was evaluated using human serum. The results were consistent with those obtained from the reference enzyme-linked fluorescence assay. The immunosensor was integrated with a small plasma membrane to form a fluidic cell (Flu-iDCE) based on acrylic sheet. The membrane had no effect on the detection of the tumor markers with the proposed Flu-iDCE. This first report of a fluidic device integrated with a DCE demonstrates the potential of the device for point-of-care detection of CEA and CA125. [ABSTRACT FROM AUTHOR]