title: A photoelectrochemical sensor based on CdS-polyamidoamine nano-composite film for cell capture and detection.
abstract: We demonstrated herein a newly developed photoelectrochemical cell-sensor for the determination of SMMC-7721 human hepatoma carcinoma cells (SMMC-7721 cells) by using a photosensitive CdS-polyamidoamine (G4) nano-composite film (CdS-PAMAM). The film was generated by electrodeposition method. The presence of PAMAM in the film eliminated the surface defects of CdS nanoparticles and therefore resulted in a greatly enhanced photocurrent and a reduced dark current. In the presence of the electron donor ascorbic acid (AA), the photoexcitation of this modified electrode potentiostated at 0 V versus Ag/AgCl led to an anodic photocurrent. As a result of the covalent coupling reactions, a layer of concanavalin A (ConA) was firmly bound to the functionalized CdS-PAMAM film via glutaraldehyde bridges. The resulting modified electrodes were tested as sensors for SMMC-7721 cell capture and detection via affinity interactions between ConA and mannosyl groups on cell surface. The cell concentration was measured from 5.0 x 10(3) to 1.0 x 10(7) cells mL(-1) through the decrease in photocurrent intensity resulting from its specific binding onto the photosensitive film, the detection limit being 5.0 x 10(3) cells mL(-1).
authors.affiliation: Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, China.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Qian
authors.forename: Hai-Jing
authors.initials: HJ
authors.lastname: Bai
authors.forename: Guang-Li
authors.initials: GL
authors.lastname: Wang
authors.forename: Jing-Juan
authors.initials: JJ
authors.lastname: Xu
authors.forename: Hong-Yuan
authors.initials: HY
authors.lastname: Chen
mesh_terms: D015374:Biosensing Techniques; D019187:Cadmium Compounds; D045744:Cell Line, Tumor; D003584:Cytological Techniques; D050091:Dendrimers; D055664:Electrochemical Techniques; D006801:Humans; D053761:Nanocomposites; D055668:Photochemical Processes; D045663:Quantum Dots; D013440:Sulfides
chemical_list: D019187:Cadmium Compounds; D050091:Dendrimers; C104700:PAMAM Starburst; D013440:Sulfides; C034939:cadmium sulfide