title: Aptamer-quantum dots conjugates-based ultrasensitive competitive electrochemical cytosensor for the detection of tumor cell.
abstract: A novel competitive electrochemical cytosensor was reported by using aptamer (Apt)-quantum dots (Qdots) conjugates as a platform for tumor cell recognition and detection. The complementary DNA (cDNA), aptamer and Qdots could be assembled to the gold electrode surface. When the target cells existed, they could compete with cDNA to bind with Apt-Qdots conjugates based on the specific recognition of aptamer to MUC1 protein overexpressed on the cell surface, which resulted in the denaturation of double-stranded DNA structure and the release of the Apt-Qdots conjugates from the electrode. Electrochemical stripping measurement was then employed to determine the Cd(2+) concentration in Qdots left at the electrode. The peak current was inversely proportional to the logarithmic value of cell concentration ranging from 1.0 × 10(2) to 1.0×10(6) cells mL(-1) with a detection limit of 100 cells mL(-1). Meanwhile, the recognition of aptamer to the target cells could be clearly observed through the strong fluorescence from Qdots. This is an example of the combination of aptamer and nanoparticles for the application of cell analysis, which is essential to cancer diagnosis and therapy.
authors.affiliation: State Key Lab of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, People's Republic of China.
authors.forename: Jingjing
authors.initials: J
authors.lastname: Li
authors.forename: Mi
authors.initials: M
authors.lastname: Xu
authors.forename: Haiping
authors.initials: H
authors.lastname: Huang
authors.forename: Jinjun
authors.initials: J
authors.lastname: Zhou
authors.forename: E S
authors.initials: ES
authors.lastname: Abdel-Halimb
authors.forename: Jian-Rong
authors.initials: JR
authors.lastname: Zhang
authors.forename: Jun-Jie
authors.initials: JJ
authors.lastname: Zhu
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry* / Q000235:genetics; D001483:Base Sequence; D015374:Biosensing Techniques / Q000379:methods*; D019187:Cadmium Compounds / Q000737:chemistry; D045744:Cell Line, Tumor; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics; D004563:Electrochemistry / Q000379:methods*; D005022:Ethyldimethylaminopropyl Carbodiimide / Q000737:chemistry; D006801:Humans; D018613:Microscopy, Confocal; D057054:Molecular Imaging; D045663:Quantum Dots; D013388:Succinimides / Q000737:chemistry; D013691:Tellurium / Q000737:chemistry
chemical_list: D052157:Aptamers, Nucleotide; D019187:Cadmium Compounds; D018076:DNA, Complementary; D013388:Succinimides; C001426:N-hydroxysuccinimide; D013691:Tellurium; D005022:Ethyldimethylaminopropyl Carbodiimide; C028337:cadmium telluride