Abstract
One of the major challenges in the design of biosensors for cancer diagnosis is to introduce a low-cost and selective probe that can recognize cancer cells. In this paper, we combined the phage display technology and electrochemical impedance spectroscopy (EIS) to develop a label-free cytosensor for the detection of cancer cells, without complicated purification of recognition elements. Fabrication steps of the cytosensing interface were monitored by EIS. Due to the high specificity of the displayed octapeptides and avidity effect of their multicopy display on the phage scaffold, good biocompatibility of recombinant phage, the fibrous nanostructure of phage, and the inherent merits of EIS technology, the proposed cytosensor demonstrated a wide linear range (2.0 × 102 − 2.0 × 108 cells mL−1), a low limit of detection (79 cells mL−1, S/N = 3), high specificity, good inter-and intra-assay reproducibility and satisfactory storage stability. This novel cytosensor designing strategy will open a new prospect for rapid and label-free electrochemical platform for tumor diagnosis.
Highlights
Antigen antibody as recognition element[23]
To study the phage-based cytosensor, the SW620 colorectal carcinoma cells were used as the model targets, which were derived from metastatic lesions of colon cancer[44]
The purified phage solution was diluted with phosphate-buffered saline (PBS) for the required concentration
Summary
Antigen antibody as recognition element[23]. Li et al explored indium tin oxide electrode covered with a monoclonal antibody for EIS sensing of E. coli without enzymatic signal amplification[17]. Wan et al fabricated an impedimetric cytosensor for label-free and rapid detection of Desulforibrio caledoiensis by immobilizing lectin (Concanavalin A, Con A) onto the surface of AuE20. Gamella et al fabricated label-free screen-printed AuE for EIS detection of bacteria by the selective interaction of lectin (Con A) with carbohydrate component from E. coli cell surface[25]. Protein recognition elements (antibody, lectin and receptor protein) and DNA aptamer, are complicated in preparation and purification, and lack the stability under a variety of monitoring conditions or long-term storage[27]. A label-free EIS cytosensor for cancer cells was developed by immobilizing the above-mentioned specific octapeptide-fused phages on the electrode surface. The as-fabricated cytosensor was sensitive, selective, reliable and stable, which was benefitted from the inherent merits of phage-displayed specific octapeptides and the superiority of EIS. This work will provide a new avenue to fabricate the phage-based sensors for detection of cancer cells
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