Aptamer‐Based Electrochemical Sensor for Label‐Free Recognition and Detection of Cancer Cells

Abstract

An electrochemical biosensor was developed for the label-free and selective detection of leukemia cells based on aptamer-modified gold electrode using electrochemical impedance spectroscopy (EIS) technique. The thiolterminated aptamer (sgc8c) selected for CCRF-CEM acute leukemia cells was self-assembled onto the gold electrode surface as recognition probe, which was characterized by cyclic voltammetry (CV) and EIS using Fe(CN) 6 3À/4À as a redox probe. The surface density of aptamers was determined by chronocoulometric method using a redox cation of Ru(NH 3 ) 6 3þ . Upon incubation of the aptamer-modified electrode with CCRF-CEM cells, the electron-transfer resistance (R et ) of Fe(CN) 6 3À/4À on the sensor surface increased substantially. Only a small R et change of the sensor to the control negative cell line RAJI was observed, indicating the excellent selectivity of the sensor. The selective capture of CCRF-CEM cells on the sensor surface was also confirmed by fluorescence microscopy. A linear relationship between R et and the logarithmic value of CCRF-CEM cells concentration was found in the range of 1 Â 10 4 to 1 Â 10 7 cells/mL, with a detection limit of 6 Â 10 3 cells/mL. This work provided a simple, convenient, lowcost and label-free method for early leukemia diagnosis.

Aptamer-based and DNAzyme-linked colorimetric detection of cancer cells

“…Meanwhile, the results of the control experiments revealed that this method also displayed a considerable selectivity. Furthermore, the detection limits of recent reports were in a level of 1 × 10 3 cells (He et al, 2009;Pan et al, 2009); benefiting from the DNAzyme-linked amplification, we were able to detect cancer cells in 1 × 10 2 level.…”

“…Recently, Herr et al (2006) made use of aptamer to target cancer cells. From then on, a variety of aptamer-based assays for cancer cells have been developed with different measuring techniques, including fluorescence , colorimetry (Herr et al, 2006;Smith et al, 2007;Medley et al, 2008) and electrochemistry (Pan et al, 2009). These efforts provide a novel concept for the early cancer diagnosis.…”

“…Though the previous reported aptamer-based biosensors for cancer cell detection have shown advantages of simplicity, rapidness and cost-efficiency over traditional methods (Herr et al, 2006;Smith et al, 2007;Medley et al, 2008;Pan et al, 2009), there is still huge potential for further improvement. Here, by combining aptamer and DNAzyme together, we developed an aptamer-based and DNAzyme-linked colorimetric biosensor for the detection of CCRF-CEM acute leukemia cells.…”

Aptamer-Based Hydrogels and Their Applications

“…Since their discovery in the 1990s [78], aptamers have been developed as specific, high-affinity probes for bioanalytical and cancer-related research. Aptamers can be chemically conjugated with various signal-generating components for acoustic [79][80][81], electrochemical [82][83][84][85], and optical [86][87][88] sensing. The high affinity, easy fabrication, low cost, and easy modification of aptamers have made them excellent components in DNA hydrogel engineering.…”

A new strategy for label-free detection of lymphoma cancer cells

“…Moreover, the existing antibodies are quite limited and their preparation is very complex. In order to overcome these limits, some ligand binding molecules, such as aptamers and lectins, were recently discovered, and more recently, oligonucleotides tethered with target-binding small molecules were considered because the small molecule moiety at the terminal of the oligonucleotides can exhibit reasonable affinity and selectivity towards target molecules [10][11][12][13][14][15].…”