title: Electrochemiluminescent determination of cancer cells based on aptamers, nanoparticles, and magnetic beads.
abstract: Herein we report a polymerase chain reaction (PCR)-free electrochemiluminescence (ECL) approach that uses ECL nanoprobes for the determination of cancer cells with high sensitivity. The ECL nanoprobe consists of gold nanoparticles (AuNPs), linker DNA, and tris(2,2'-bipyridyl)ruthenium (TBR)-labeled signal DNA. The linker DNA and signal DNA were modified on the surface of the AuNPs through Au-S bonds. The linker DNA can partly hybridize with the aptamers of cancer cells loaded onto the magnetic beads (MB1) to construct the magnetic biocomplexes. In the presence of the cancer cells, the aptamers conjugated with the cancer cells with higher affinity. The ECL nanoprobe was released from the biocomplexes and subsequently hybridized with the capture DNA loaded onto another magnetic bead (MB2) to form the magnetic nanocomposite. The nanocomposites can be easily separated and firmly attached to an electrode on account of their excellent magnetic properties. The ECL intensity of the TBR loaded onto the nanocomposites directly reflected the amount of cancer cells. By using cell lines of Burkitt's lymphoma (Ramos cells) as a model, the ECL response was proportional to the cell concentration in the range from 5 to 100 cells ml(-1); a limit of detection as low as 5 cells ml(-1) of Ramos cells could be achieved. The proposed method described here is ideal for the diagnosis of cancers due to its high sensitivity, simplicity, and low cost.
authors.affiliation: State Key Laboratory Base of Eco-chemical Engineering, Ministry of Education, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042, PR China. dingcaifeng2003@163.com
authors.forename: Caifeng
authors.initials: C
authors.lastname: Ding
authors.forename: Shuang
authors.initials: S
authors.lastname: Wei
authors.forename: Haitao
authors.initials: H
authors.lastname: Liu
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry*; D004247:DNA / Q000737:chemistry*; D006046:Gold / Q000737:chemistry*; D006801:Humans; D008163:Luminescent Measurements / Q000379:methods*; D053768:Metal Nanoparticles / Q000737:chemistry*; D008954:Models, Biological; D016133:Polymerase Chain Reaction; D014407:Tumor Cells, Cultured
chemical_list: D052157:Aptamers, Nucleotide; D006046:Gold; D004247:DNA