Impedimetric evaluation of hybrid cationic porphyrin/quantum dot multilayer assemblies: a biocompatible interface for calf thymus DNA immobilization

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• 作者：Camilo García ; Freddy Navarro ; Domingo Ruíz-León…
• 关键词：Cationic porphyrins ; Quantum dots ; DNA ; porphyrin interactions ; Layer by layer assemblies ; Calf thymus DNA determination
• 刊名：Journal of Solid State Electrochemistry
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：21
• 期：1
• 页码：243-253
• 全文大小：
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Physical Chemistry; Electrochemistry; Energy Storage; Characterization and Evaluation of Materials; Analytical Chemistry; Condensed Matter Physics;
• 出版者：Springer Berlin Heidelberg
• ISSN：1433-0768
• 卷排序：21

文摘

In this work, a cationic porphyrin, ascribed as [Ttolyl(P-(C₆H₅)₃)₄]4+, where Ttolyl = 5,10,15,20 tetrakistolylporphyrin, was electrostatically assembled with CdTe quantum dots capped with glutathione (GSH) of diameter ~3.28 nm via a layer-by-layer methodology. This multilayer assembly was evaluated as a biocompatible interface with synergic effects for calf thymus double-stranded DNA (CT DNA) immobilization, considering that the hybrid assembly contains a cationic porphyrin with a high binding constant for CT DNA, and quantum dots with polypeptide as a capping agent. The multilayer assembly, ascribed as ITO/{[Ttolyl(P-(C₆H₅)₃)₄]4+/CdTe}_n (n = 1–5), was characterized by UV-Vis spectroscopy, cyclic voltammetry, and electrochemical impedance spectroscopy (EIS). The last technique was explored in order to check the adsorption of CT DNA onto the multilayer porphyrin/quantum dot assembly. The difference in electron transfer resistance (ΔR_ct) obtained after CT DNA incubations showed the best result for a specific multilayer assembly, n = 3. {[Ttolyl(P-(C₆H₅)₃)₄]4+/CdTe}₃ showed a good correlation of ΔR_ct with the logarithmic concentration of CT DNA, in the range 1.0 × 10−10 to 1.0 × 10−6 M with a limit of detection (LOD) of 1.5 × 10−12 M. Conversely, when the {[Ttolyl(P-(C₆H₅)₃)₄]4+/CdTe}₃ system was incubated with calf thymus single-stranded DNA and salmon testes DNA, no significant difference in ΔR_ct was observed. We conclude that the newly described {[Ttolyl(P-(C₆H₅)₃)₄]4+/CdTe}_n system is a choice method for the impedimetric determination of CT DNA.