Cancer antigen 125 (CA125) is the gold standard biomarker for clinical diagnosis of ovarian cancer, with a threshold value of 35 U/mL in serum. In this paper, a disposable ultrasensitive immunosensor based on Ti 3 C 2 T x -MXene/amino-functionalized carbon nanotube (NH 2 -CNT) modified screen-printed carbon electrode (SPCE) was constructed for the detection of the ovarian cancer antigen CA125. By optimizing the mass ratio of Ti 3 C 2 T x to NH 2 -CNT, Ti 3 C 2 T x /NH 2 -CNT composite with excellent electrochemical properties was prepared, which is beneficial for amplifying the initial electrochemical signal. The positively charged NH 2 -CNT effectively alleviated the stacking problem of Ti 3 C 2 T x , and its amino group also facilitated the covalent immobilization of the capture antibody. Meanwhile, chitosan (CS) with excellent film-forming ability was also used to successfully enhance the adsorption of electrode material, thus improving the stability of the sensor. In addition, CS could further enhance the current signal. The prepared immunosensor exhibited excellent performance in CA125 detection with a wide linear range from 1 mU/mL to 500 U/mL, and good selectivity, reproducibility and lomg-term stability. Furthermore, the immunosensor showed satisfactory results for the detection of CA125 in clinical serum samples, which is promising for the clinical screening, early diagnosis and prognostic examination of ovarian cancer.
Chulei Zhao,Kaihang Cao,Chaoyun Ma,Wenjun Li,Yiju Song,Xiuwen Qiao,Chenglin Hong
In this experiment, a Cu 2 O spherical nanoparticle was reduced by hydrothermal reaction to prepare a label-free electrochemical immunosensor based on a novel signal amplification strategy. Multi-walled carbon nanotubes are a platform that combines cuprous oxide with carbon nanotubes. Nanogold was modified on the surface of cuprous oxide nanospheres by electrostatic adsorption to further amplify the electrochemical signal and link-supported anti-alpha-fetoprotein (AFP). Under optimal conditions, the proposed immunosensor has a wide linear range from 0.001 to 40 ng/ml, with a detection limit as low as 0.33 pg/ml ( S / N = 3). Furthermore, the proposed label-free immunosensor has been used to determine AFP in human serum with satisfactory results. At the same time, it has good reproducibility, acceptable selectivity and long-term stability, and has broad application prospects in biometric analysis.
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