Role of Defects of Carbon Nanomaterials in the Detection of Ovarian Cancer Cells in Label-Free Electrochemical Immunosensors

Developing label-free immunosensors to detect ovarian cancer (OC) by cancer antigen (CA125) is essential to improving diagnosis and protecting women from life-threatening diseases. Four types of carbon nanomaterials, such as multi-wall carbon nanotubes (MWCNTs), vapor-grown carbon fiber (VGCFs), graphite KS4, and carbon black super P (SP), have been treated with acids to prepare a carbon nanomaterial/gold (Au) nanocomposite. The AuNPs@carbon nanocomposite was electrochemically deposited on a glassy carbon electrode (GCE) to serve as a substrate to fabricate a label-free immunosensor for the detection of CA125. Among the four AuNPs@carbon composite, the AuNPs@MWCNTs-based sensor exhibited a high sensitivity of 0.001 mu g/mL for the biomarker CA125 through the square wave voltammetry (SWV) technique. The high conductivity and surface area of MWCNTs supported the immobilization of AuNPs. Moreover, the carboxylic (COO-) functional groups in MWCNT improved to a higher quantity after the acid treatment, which served as an excellent support for the fabrication of electrochemical biosensors. The present method aims to explore an environmentally friendly synthesis of a layer-by-layer (LBL) assembly of AuNPs@carbon nanomaterials electrochemical immunoassay to CA125 in a clinical diagnosis at a low cost and proved feasible for point-of-care diagnosis.

Automated summary

Developing label-free immunosensors for the detection of ovarian cancer through cancer antigen (CA125) is crucial for enhancing diagnosis and women's protection against life-threatening diseases. In this study, carbon nanomaterials, including multi-wall carbon nanotubes (MWCNTs), vapor-grown carbon fiber (VGCFs), graphite KS4, and carbon black super P (SP), were treated with acids to create a carbon nanomaterial/gold (Au) nanocomposite. An AuNPs@carbon nanocomposite was then electrodeposited on a glassy carbon electrode (GCE) to construct a label-free immunosensor for CA125 detection. Among the four composite materials, the AuNPs@MWCNTs-based sensor demonstrated high sensitivity (0.001 μg/mL) for the biomarker CA125 using square wave voltammetry (SWV). The high conductivity and surface area of MWCNTs facilitated the immobilization of AuNPs, while the increased quantity of carboxylic (COO-) functional groups after acid treatment provided excellent support for the fabrication of electrochemical biosensors. This environmentally friendly method offers a cost-effective layer-by-layer (LBL) assembly of AuNPs@carbon nanomaterials for electrochemical immunoassay of CA125 in clinical diagnosis and proves to be feasible for point-of-care diagnosis.