A Label-Free Electrochemical Immunosensor for CEA Detection on a Novel Signal Amplification Platform of Cu2S/Pd/CuO Nanocomposites.

Linlin Cao,Wen Zhang,Dantong Zhang,Wanshan Ma,Sumei Lu,Chengjie Guo,Peijun Wang

doi:10.3389/fbioe.2021.767717

Abstract

Carcinoembryonic antigen (CEA) is regarded as one of the crucial tumor markers for colorectal cancer. In this study, we developed the snowflake Cu2S/Pd/CuO nanocomposite to construct an original label-free electrochemical immunosensor for the ultrasensitive detection of CEA levels. The nanocomposite of cuprous sulfide (Cu2S) with Pd nanoparticles (Pd NPs) was synthesized through an in situ formation of Pd NPs on the Cu2S. Cuprous sulfide (Cu2S) and CuO can not only be used as a carrier to increase the reaction area but also catalyze the substrate to generate current signal. Palladium nanoparticles (Pd NPs) have excellent catalytic properties and good biocompatibility, as well as the ability of excellent electron transfer. The immunosensor was designed using 5 mmol/L H2O2 as the active substrate by optimizing the conditions with a detection range from 100 fg/ml to 100 ng/ml and a minimum detection limit of 33.11 fg/ml. The human serum was detected by electrochemical immunoassay, and the results were consistent with those of the commercial electrochemical immunosensor. Therefore, the electrochemical immunosensor can be used for the detection of human serum samples and have potential value for clinical application.

Highlights

Colorectal cancer (CRC) is one of the most frequent malignancies worldwide and is correlated with high mortality (Dekker et al, 2019)
Label-free immunosensors directly detect the signal changes of the antigen–antibody complex, which greatly simplifies the sensor preparation and operation and does not require secondary antibody markers (Filik and Avan, 2019; Tan et al, 2020; Rahmati et al, 2021). Nanomaterials, such as graphene oxide, metal nanoparticles, and metal–organic frameworks (MOFs), are often used as a means of signal amplification to heighten the sensitivity of sensors because of their high specific surface area, prominent electron transfer ability, and excellent biocompatibility (Song et al, 2016; Farka et al, 2017)
After 60 min of incubation, the Bovine serum albumin (BSA)/anti-Carcinoembryonic antigen (CEA)/Cu2S/Pd/CuO/glass carbon electrode (GCE) was washed with Phosphate buffer solutions (PBS) and was added different concentration gradients of CEA for 60 min to optimize the reaction conditions between CEA and anti-CEA

Summary

INTRODUCTION

Colorectal cancer (CRC) is one of the most frequent malignancies worldwide and is correlated with high mortality (Dekker et al, 2019). Electrochemical immunosensors are biosensing devices that convert biochemical reactions into electrical signals based on the combination of highly sensitive sensing technology and specific immune reactions to study the reaction kinetics of antigens and corresponding antibodies They have the advantages of high specificity and sensitivity, rapidity, low cost, and simple operation (Cho et al, 2018; Felix and Angnes, 2018). Label-free immunosensors directly detect the signal changes of the antigen–antibody complex, which greatly simplifies the sensor preparation and operation and does not require secondary antibody markers (Filik and Avan, 2019; Tan et al, 2020; Rahmati et al, 2021) Nanomaterials, such as graphene oxide, metal nanoparticles, and metal–organic frameworks (MOFs), are often used as a means of signal amplification to heighten the sensitivity of sensors because of their high specific surface area, prominent electron transfer ability, and excellent biocompatibility (Song et al, 2016; Farka et al, 2017). The proposed immunosensor has great potential for clinical application

MATERIALS AND METHODS

RESULTS AND DISCUSSION

ETHICS STATEMENT