An immune sandwich electrochemical biosensor based on triple-modified zirconium derivatives for detection of CD146 in serum

CD146, also known as melanoma cell adhesion molecule (MCAM), is overexpressed in various cancer patients, making it a valuable predictor for early diagnosis. In this work, an immune sandwich electrochemical biosensor is proposed for sensitive and non-invasive quantitative detection of CD146 in serum. Zirconium-based MOF (UIO-66) was modified by simultaneous copper atom doping, in situ growth carbon-based support and physical embedding of platinum nanoparticles (PtNPs). Triple-modified Cu-UIO-66@SWCNT/PtNPs nanocomposites with high stability and excellent electrochemical properties, serve as surface modification materials for glassy carbon electrodes. Anti-CD146 antibody (Ab1) was grafted onto the electrode surface via Pt-S bond. Meanwhile, the secondary antibody (Ab2) was conjugated with silver nanoparticles (AgNPs) to cooperate for CD146 capture and achieve secondary electrical signal amplification. Under optimal conditions, square wave voltammetry was employed to determine CD146 in the concentration range of 10-9-10-4 mg/mL and a limit of detection of 12 fg/mL was obtained. Finally, it was successfully applied to the analysis of CD146 in lung and liver cancer patients' serum samples.

Current and Prospective of Breast Cancer Biomarkers

Biomarkers have shown great promise over the past decade the process of drug development more effective and have become an integral part of diagnosis of diseases. Biosensors were integrated with biomarker detection and point-of-care detection for signal amplification, high specificity and sensitivity, rapid response time, low cost, simplicity and multi-analytical testing. In order to detect more sensitively, these particular biomarkers have been explored with the possibility of real-time measurements in order to develop simple and compact systems which can analyze complex specimens. Various biosensors including electrochemical biosensors have recently been developed based on disease-specific biomarkers in the diagnosis of cancer disease. The main objective of the book chapter is to review research with new materials/methods in electrochemical biosensing techniques to detection of breast cancer biomarkers and evaluating latest techniques for detection of important analytes in real samples. In this book chapter, the recent development of electrochemical biosensors of breast cancer biomarkers will be reviewed. Furthermore, recent and future trend application of breast cancer biomarkers will be discussed.

An ultrasensitive electrochemical immunosensor based on the synergistic effect of quaternary Cu2SnZnS4 NCs and cyclodextrin-functionalized graphene

Cu₂ZnSnS₄ nanocrystals were first used as electrocatalysts for H₂O₂ reduction for the ultrasensitive detection of alpha-fetoprotein.

Enzymatically catalytic signal tracing by a glucose oxidase and ferrocene dually functionalized nanoporous gold nanoprobe for ultrasensitive electrochemical measurement of a tumor biomarker

A nanoporous gold nanosphere (pAu NS) was synthesized to load high-content glucose oxidase (GOx) and ferrocene (Fc) for the successful preparation of a new gold nanoprobe. After the specific recognition of the tumor biomarker of carcinoembryonic antigen (CEA) at a gold electrode based aptasensor, this GOx and Fc dually functionalized pAu NS nanoprobe was further used for sandwich immunoreaction and signal tracing. Based on the Fc-mediated GOx-catalytic reaction, the gold nanoprobes quantitatively captured onto the electrode surface produced a sensitive electrochemical signal corresponding to the protein recognition events, which led to the development of a new biosensing method for CEA measurement. Both the high loading of GOx and Fc on the pAu NS nanocarrier and the enzymatically catalytic reaction of the nanoprobe greatly amplify the electrochemical signal; meanwhile, the immobilization of the Fc mediator on this enzyme nanoprobe and the highly specific aptamer recognition drastically decrease the background current, resulting in the achievement of ultrahigh sensitivity of the method. Under optimum conditions, this method shows an excellent analytical performance including a wide linear relationship of five-order of magnitude and a low detection limit down to 0.45 pg mL(-1). Thus this pAu NS based gold nanoprobe and the proposed immunoassay method provide great potential for practical applications.

Ultrasensitive electrochemical aptasensor for the detection of thrombin based on dual signal amplification strategy of Au@GS and DNA-CoPd NPs conjugates

In this work, an ultrasensitive electrochemical aptasensor for the detection of thrombin was developed based on Au nanoparticles decorated graphene sheet (Au@GS) and CoPd binary nanoparticles (CoPd NPs). A sulfydryl-labeled thrombin capture probe (Apt1) and a biotin-labeled thrombin reporter probe (Apt2) were designed to achieve a sandwich-type strategy. Au@GS was used as a sensing platform for the facile immobilization of Apt1 through Au-S bond, forming a sensing interface for thrombin. The specific recognition of thrombin induced the attachment of Apt2-CoPd NPs to the electrode. The labeled CoPd NPs showed good catalytic properties toward the reduction of H2O2, resulting in an amperometric signal. The amperometric response was correlated to the thrombin concentration in sample solutions. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) confirmed the successful fabrication of the aptasensor. A linear response to thrombin in the range of 0.01-2.00 ng mL(-1) with a low detection limit (5 pg mL(-1)) was achieved. The proposed aptasensor showed good selectivity, good reproducibility and acceptable stability. This proposed strategy may find many potential applications in the detection of other biomolecules.