Aptamer-aided target capturing with biocatalytic metal deposition: an electrochemical platform for sensitive detection of cancer cells

Abstract

A novel aptamer biosensor for cancer cell assay has been reported on the basis of ultrasensitive electrochemical detection. Cancer cell capturing is first accomplished via aptamer-aided recognition, and the cell-aptamer binding events then mediate an alkaline phosphatase-catalyzed silver deposition reaction which can be probed by electrochemical detection. Following biocatalytic silver deposition, an efficient amplification approach for sensitive electrochemical measurements is demonstrated, for cell detection with high sensitivity. Ramos cell are used as a model case, a typical biomarker of the acute blood cell cancer, Burkitt's lymphoma. The results reveal that the developed technique displays desirable selectivity in Ramos cell discrimination, and linear response range from 10 to 10(6) cells with a detection limit as low as 10 cells. Due to the simple procedures, label-free and electrochemistry based detection format, this technique is simple and cost-effective, and exhibits excellent compatibility with miniaturization technologies. The electrochemical cell detection strategy may create an intrinsically specific and sensitive platform for cancer cell assay and associated studies.

Application of electrochemical biosensors in tumor cell detection

“…A nucleic acid adapter shows highly specific binding to tumor cell surface target molecules and is easy to use, which has been widely used in the construction of cell sensors in recent years, [62][63][64][65] greatly improving the target recognition ability of sensors and detection selectivity to tumor cells. [66][67][68][69] For example, Li et al used MUC1 to bind an aptamer for detecting MUC1 proteins on the surface of tumor cells while identifying their CEA proteins with nanometer CdS-labeled carcinoembryonic antigen (CEA), which effectively reduced the occurrence of false positives in the detection of tumor cells. 58 Studies have shown that ITO electrodes with good light transmittance and electrical conductivity were first modified by the AS1141 aptamer, which can selectively bind to the overexpressed nucleolins on the The strong red fluorescence of DNA-AgNCs shows the presence of cancer cells, the strong conductivity of DNA-AgNCs can improve the sensitivity of quantitative analysis, making the detection limit up to 3 cells/mL.…”

Detection and Characterization of Cancer Cells and Pathogenic Bacteria Using Aptamer-Based Nano-Conjugates

“…Yi et al developed a different electrochemical method for detecting Ramos cancer cells using Apt-AuNPs and enzyme-triggered silver enhancement [ 80 ]. They immobilized a thiol-modified aptamer onto the Au electrode to capture the Ramos cells.…”

“…As a detection probe, a biotinylated secondary aptamer was subsequently employed to amplify target cells with the addition of streptavidin-alkaline phosphatase (ALP); the presence of ALP on the surface promoted enzymatic silver ion reduction and deposition onto the Au-electrode, allowing for simple electrochemical detection. Through two aptamer-based sandwich assays and enzymatic reaction, the LOD of Ramos cells was determined to be as low as 10 cells [ 80 ].…”

Hydroquinone diphosphate/Ag + as an enzymatic substrate for alkaline phosphatase catalyzed silver deposition

“…The only reported possibility to get an AP catalyzed silver deposition not having any other insoluble reaction product is based on the substrate ascorbic acid-2-phosphate (AAP), where ascorbic acid is generated in the enzymatic reaction and used as reducing agent for silver ions [8,9]. However the high spontaneous hydrolysis of AAP in aqueous solution produces high background signals and low repeatability for quantitative detection purposes.…”