Photoelectrochemical detection of circulating tumor cells based on aptamer conjugated Cu2O as signal probe

Application of electrochemical biosensors in tumor cell detection

“…In this study, a PEC biosensor was proposed based on hexagonal carbon nitride tubes (HCNT) as photosensitive material, and magnetic Fe3O4 nanospheres were used for efficient magnetic capture of CTCs, and Cu2O nanoparticles were used for signal amplification, making the detection range of this sensor range from 3 to 3000 cells/mL, with a detection limit down to 1 cell/mL. 18 With the development of science and technology, the basic operating units such as sample preparation, reaction, separation and detection of biological, chemical, and medical analysis processes are integrated into microscale chips, which automatically completes the entire analysis process and combines with electrochemical sensing for the detection of CTCs. In 2007, Nagrath and coworkers used a microfluidic chip modified with an epithelial-specific adhesion molecule (EpCAM) antibody to successfully separate untreated peripheral blood CTCs for the first time.…”

“…In addition, researchers have cleverly combined photoexcitation and electrochemical detection processes to construct photoelectrochemical (PEC) biosensors with higher detection sensitivity for the detection of circulating tumor cells. In this study, a PEC biosensor was proposed based on hexagonal carbon nitride tubes (HCNT) as photosensitive material, and magnetic Fe3O4 nanospheres were used for efficient magnetic capture of CTCs, and Cu2O nanoparticles were used for signal amplification, making the detection range of this sensor range from 3 to 3000 cells/mL, with a detection limit down to 1 cell/mL …”

Electrochemical Detection and Point-of-Care Testing for Circulating Tumor Cells: Current Techniques and Future Potentials

“…The sandwich assays add a signal probe on the basis of direct assays, that is, after CTC is bound to the capture probe on the electrode, a signal probe (another kind of nanomaterials-aptamer) is added. After the signal probe is combined with CTC, it can significantly amplify the signal, thereby increasing the sensitivity and reducing the detection limit ( Figure 2) [30,98,99]. We summarized the electrochemical-based CTC detection methods in Table 3, including the direct assay and the sandwich assay, and we listed the assay time, linear range, limit of detection, capture probe, and signal probe.…”

“…After spreading the capture cells on the electrode, the photocurrent intensity of hexagonal carbon nitride tubes (HCNT) is reduced due to the steric hindrance derived from MCF-7. After adding a signal probe Cu 2 O NPs, the photocurrent intensity of was further decreased because Cu 2 O NPs competitively absorbed the excitation light, and the aptamer molecules further increased the steric hindrance, the linear range is 3-3000 cell mL −1 , and the detection limit is 1 cell mL −1 (Figure 4D) [30]. Similarly, Zhang et al also used antibody-magnetic nanospheres to capture MCF-7 cells, and after coating the cells on the electrode, used gold nanoparticle-modified LiFePO 4 coupled with the aptamer as a signal probe, due to the reaction of phosphate group in LiFePO 4 with molybdate that formed redox molybdophosphate (PMo 12 O 40 ) precipitates and caused current change.…”

“…(D) Photoelectrochemical (PEC) cytosensor for detection of MCF-7 cells, Magnetic Fe3O4 nanospheres (MNs) as capture probe and Cu2O nanoparticles as signal probe. Reprinted with permission from ref[30], Copyright 2020, Elsevier. (E) Cyclic voltammetry (CV) cytosensor for MCF-7 cell detection, via rolling circle amplification (RCA) extension of the electrode-immobilized primer/circular DNA complexes as the capture probe, and anti-EpCAM/HRP-AuNP as signal probe.…”