UM establishes precise immunoassay platform for detecting cancer-related markers

A research team led by Kwok Hang Fai, associate professor in the Faculty of Health Sciences (FHS) at the University of Macau (UM), has made significant progress in establishing a robust photoelectrochemical (PEC) immunoassay platform to evaluate cancer-related markers with rapidity and accuracy. The research results have been published in the internationally renowned journal Biosensors and Bioelectronics and have received considerable attention.

Biomarkers are substances that can be used to distinguish cancer cells from normal cells. They can be measured in tissues, blood, or body fluids. In the clinic, biomarkers are often used to help cancer patients to choose the most appropriate treatment. Prof Kwok’s research team has successfully developed an ultra-sensitive and stable biosensing platform for the recovery of disease-related markers such as carcinoembryonic antigen (CEA) in low-abundance serum samples. This method reduces additional expensive instrumentation support through a rationally constructed biocatalytic precipitation scheme with a stable photoanode system.

The experimental results revealed that the outer carbon layer introduced on the inorganic photoactive materials could cause the amplifying photocurrent by improving light harvesting and separating photo-generated e-/h+ pairs. Under optimum conditions, the split-type PEC immunosensing platform displayed good photocurrent responses within the dynamic range of 0.01-80 ng mL-1 CEA. It allowed the detection of CEA as low as a concentration of 3.6 pg mL-1 at the 3Sblank level. The strong attachment of the antibodies onto the nano label and high-performing photoanode produced good repeatability and reduced the intermediate precision to 9.83%. No significant differences at the 0.05 significance level were encountered in analysing six human serum specimens between the developed PEC immunoassay and the commercially available CEA ELISA kits.

The PEC bioimmunosensing strategy developed by Prof Kwok’s research team has the following advantages: (1) The split immunoincubation and catalytic procedures reduce the interference to the electrode signal by reducing the confusion of the test environment; (2) the CdS@C photoanode system exhibits efficient photoelectric conversion efficiency and stability; and (3) the developed assay has clear stability and resistance to interference. According to the research team, the established robust PEC immunoassay method can address the appearance of false reports due to signal fluctuations and can be used to evaluate cancer-related markers in the field with rapidity and accuracy.

Prof Kwok is the primary corresponding author of the study. FHS postdoctoral fellow Guo Libin and PhD graduate Li Bin share the co-first authorship. PhD student Wong Sin Wa and former postdoctoral fellow Ge Lilin also made contributions to the study. The research project was supported by the Science and Technology Development Fund of the Macao SAR (File no: 0027/2022/A1). The full version of the research article can be viewed at: https://www.sciencedirect.com/science/article/pii/S0956566323003469.