Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education of China), College of Chemistry and Chemical Engineering, Hunan Normal University , Changsha 410081, PR China.
Anal Chem. 2014 Jul 15;86(14):6940-7. doi: 10.1021/ac500753f. Epub 2014 Jun 26.
Poly-L-lysine (PLL), which has been employed as a conductive polymer in the construction of some electrochemical sensors, can be prepared using L-lysine by cyclic voltammetry (CV) with a wide potential range. However, the presented explanation and description about its polymerization mechanism seems oversimplified because the self-reaction of electrode and the electrolysis of solvent at high potential are ignored. This work presents an intensive investigation on the relevant reactions during the process of PLL-polymerization using CV, X-ray photoelectron spectroscopy, Fourier transform-infrared spectroscopy, and electrochemical impedance spectroscopy. At a higher positive potential, the transfer from lysine molecules to cation radicals and the polymerization reaction on the glassy carbon electrode (GCE) could be achieved, accompanied by the activation of GCE, the formation of oxygen-containing functional groups, and the generation of oxygen derived from the oxidation of water. The adsorbed oxygen had a seriously negative effect on the formation of PLL unless it suffered reduction at a lower negative potential. The charge transfer through the electrochemical polymerized PLL film was seriously hindered by the immobilization of suspension cells due to the electrostatic interaction. The charge-transfer resistance difference (ΔR(ct)) was increased with the enhancement of the cell number (N(cells)) and the 1/ΔR(ct) value displayed a linear response with 1/N(cells) in the range of 5.0 × 10(2)-1.0 × 10(5) cells with a detection limit of 180 cells estimated at a signal-to-noise ratio of 3. A sensitive electrochemical sensor for the quantitative detection of suspension cells was developed.
聚-L-赖氨酸（PLL）已被用作一些电化学传感器构建中的导电聚合物，可通过循环伏安法（CV）在宽电位范围内使用 L-赖氨酸进行制备。然而，关于其聚合机制的解释和描述似乎过于简单化，因为忽略了电极的自反应和高电位下溶剂的电解。本工作使用 CV、X 射线光电子能谱、傅里叶变换红外光谱和电化学阻抗谱对 PLL 聚合过程中的相关反应进行了深入研究。在较高的正电势下，赖氨酸分子向正离子自由基的转移和在玻碳电极（GCE）上的聚合反应可以实现，伴随着 GCE 的活化、含氧官能团的形成以及来自水氧化的氧的生成。吸附氧对 PLL 的形成有严重的负面影响，除非它在较低的负电势下还原。由于静电相互作用，悬浮细胞的固定严重阻碍了通过电化学聚合 PLL 膜的电荷转移。由于静电相互作用，悬浮细胞的固定严重阻碍了通过电化学聚合 PLL 膜的电荷转移。由于静电相互作用，悬浮细胞的固定严重阻碍了通过电化学聚合 PLL 膜的电荷转移。由于静电相互作用，悬浮细胞的固定严重阻碍了通过电化学聚合 PLL 膜的电荷转移。电荷转移电阻差（ΔR(ct)）随着细胞数量（N(cells))的增加而增加，并且 1/ΔR(ct)值在 5.0×10(2)-1.0×10(5)个细胞范围内与 1/N(cells)呈线性响应，检测限估计为 180 个细胞，信噪比为 3。开发了一种用于悬浮细胞定量检测的灵敏电化学传感器。
