A label-free electrochemical immunosensor for CA125 detection based on CMK-3(Au/Fc@MgAl-LDH)n multilayer nanocomposites modification

A label-free electrochemical immunosensor was constructed for cancer antigen 125 (CA125) detection based on multiple-enlargement means of layer-by-layer (LBL) assembly of ordered mesoporous carbon (CMK-3), gold nanoparticles (Au NPs) and MgAl layered double hydroxides containing ferrocenecarboxylic acid (Fc@MgAl-LDH). A CMK-3(Au/Fc@MgAl-LDH)n multilaminate nanocomposites was designed using technology of LBL self-assembly among negatively charged Au NPs, positively charged CMK-3 and Fc@MgAl-LDH nanosheets. The CMK-3(Au/Fc@MgAl-LDH)n multilaminate nanocomposites was used as carriers to increase the immobilization of antibody and the number of loading Fc, conductors to strengthen conductivity and enhancers to amplify signal of Fc step-by-step. Besides, this special and excellent way of LBL assembly can immensely amplify the signal of immunosensor and more immobilize the biomolecules, and label-free method is a more simple the measuring way and the procedure. The immunosensor displayed a wider linear range of 0.01 U ml 1-1000 U ml(-1) and a lower detection limit of 0.004 U ml(-1). Therefore, the sensor can stablely and accurately be applied for CA125 detection in clinical cancer diagnosis.

Automated summary

In this study, a label-free electrochemical immunosensor was constructed for the detection of cancer antigen 125 (CA125). This immunosensor used a multiple-enlargement means of layer-by-layer (LBL) assembly, incorporating ordered mesoporous carbon (CMK-3), gold nanoparticles (Au NPs), and MgAl layered double hydroxides containing ferrocenecarboxylic acid (Fc@MgAl-LDH). The LBL assembly approach greatly amplified the signal of the immunosensor and improved the immobilization of biomolecules.