Hongmei Cao,Daixin Ye,Qianqian Zhao,Juan Luo,Song Zhang,Jilie Kong
A novel strategy for the quantitative determination of human colon cancer DLD-1 cells utilizing an electrochemical aptasensor was developed by effective surface recognition between Mucin 1 glycoprotein over-expressed on the cell membrane and MUC-1 aptamer (MUC-1) bound on carbon nanospheres (CNSs). An MTT assay revealed that the as-prepared CNSs by green route exhibited satisfactory biocompatibility for cell viability, providing a suitable platform for the cell adhesion study. Furthermore, using CNSs as a sensing layer accelerated electron transfer and provided a highly stable matrix for the convenient conjugation of target MUC-1 aptamer, considerably amplifying the electrochemical signals. Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) were applied to assess the optimal conditions and detection performance of the as-fabricated aptasensor. The attachment of colon cancer DLD-1 cells onto the MUC-1 aptamer immobilized CNSs led to increased EIS responses, which changed linearly in cell concentration ranging from 1.25 × 102 to 1.25 × 106 cells per mL with a lower detection limit of 40 cells per mL. With this method, colon cancer DLD-1 cells can be easily distinguished from normal cells, Human astrocytes 1800. The novel aptasensor revealed high specificity to DLD-1 cells. Furthermore, the aptasensor described here showed good reproducibility and high stability because of the CNSs of high stability and biocompatibility. The proposed protocols are a promising technique for the early monitoring of human colon cancer, and might have potential clinical applications such as cancer diagnosis, drug screening.
The article describes the use of a designed histidine (His)-tagged arginine-glycine-aspartic acid (RGD) peptide as a linker to bind integrin to captured cancer cells, and how to amplify the surface plasmon resonance (SPR) signal after binding of NiO nanoparticles (NiO-NPs) via the His-tag on the peptide. Specifically, breast cancer cells were captured via the interaction between human mucin (MUC-1) and a gold surface modified with a MUC-selective aptamer. The resulting cytosensor exhibits specificity and high sensitivity which is due to the enhancement of the SPR signal by NiO-NPs. The breast cancer cell line MCF-7 can be easily distinguished from normal islet beta cells by using this biosensor. Implementation of the His-tagged RGD peptide modified with NiO-NPs resulted in 20-fold enhancement of the SPR signal at the limit of detection. Hence, the actual limit of detection is lowered to 136 cells per mL. In our perception, this cytosensor has a large clinical potential in that it may also be used to detect various other kinds of tumor cells.
Histidine-tagged arginine-glycine-aspartic acid peptide carried by NiO interacts with the integrin of cancer cells and amplifies the SPR signal resulting from interaction between human mucin (MUC-1) and a gold surface modified with a MUC-selective aptamer. As little as 136 cells·mL −1 are detectable.
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