Detection of catechol using mixed Langmuir-Blodgett films of a phospholipid and phthalocyanines as voltammetric sensors.
Detection of catechol using mixed Langmuir-Blodgett films of a phospholipid and phthalocyanines as voltammetric sensors.
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DOI：
10.1039/c0an00159g
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发表时间：
2010-10-01
期刊：
影响因子：
--
通讯作者：
Rodriguez-Mendez, Maria Luz
中科院分区：
文献类型：
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作者：
Alessio, Priscila;Pavinatto, Felippe J;Rodriguez-Mendez, Maria Luz
金属酞菁（MPcs）和生物分子的组合已经在文献中被探索作为研究分子相互作用的模拟系统或作为支撑层来固定生物分子。在此，含有磷脂二肉豆蔻酰磷脂酸（DMPA）与铁酞菁（FePc）或与镥双酞菁（LuPc（2））混合的LB膜被用作ITO修饰电极，使用循环伏安法检测邻苯二酚。FePc + DMPA和LuPc（2）+ DMPA的混合膜显示出表面压等温线，没有证据表明分子水平的相互作用。多层LB膜的傅里叶变换红外（FTIR）光谱证实了组分之间缺乏相互作用。发现DMPA和FePc分子垂直于衬底取向，而LuPc（2）分子随机排列。结果表明，该复合LB膜可用于邻苯二酚的检测，FePc + DMPA和LuPc（2）+ DMPA的检测限分别为4.30 × 10（-7）M和3.34 × 10（-7）M。动力学实验结果表明，离子扩散控制的修饰电极的响应。灵敏度与其他非酶传感器相当，足以检测食品工业中的邻苯二酚。LB膜的电化学响应的更高的稳定性和控制分子结构的能力是有希望的进一步研究与掺入生物分子。
The combination of metallic phthalocyanines (MPcs) and biomolecules has been explored in the literature either as mimetic systems to investigate molecular interactions or as supporting layers to immobilize biomolecules. Here, Langmuir-Blodgett (LB) films containing the phospholipid dimyristoyl phosphatidic acid (DMPA) mixed either with iron phthalocyanine (FePc) or with lutetium bisphthalocyanine (LuPc(2)) were applied as ITO modified-electrodes in the detection of catechol using cyclic voltammetry. The mixed Langmuir films of FePc + DMPA and LuPc(2) + DMPA displayed surface-pressure isotherms with no evidence of molecular-level interactions. The Fourier Transform Infrared (FTIR) spectra of the multilayer LB films confirmed the lack of interaction between the components. The DMPA and the FePc molecules were found to be oriented perpendicularly to the substrate, while LuPc(2) molecules were randomly organized. The phospholipid matrix induced a remarkable electrocatalytic effect on the phthalocyanines; as a result the mixed LB films deposited on ITO could be used to detect catechol with detection limits of 4.30 * 10(-7) and 3.34 * 10(-7) M for FePc + DMPA and LuPc(2) + DMPA, respectively. Results from kinetics experiments revealed that ion diffusion dominated the response of the modified electrodes. The sensitivity was comparable to that of other non-enzymatic sensors, which is sufficient to detect catechol in the food industry. The higher stability of the electrochemical response of the LB films and the ability to control the molecular architecture are promising for further studies with incorporation of biomolecules.