Department of Chemistry and Environmental Engineering, Wuhan Bioengineering Institute, Wuhan 430415, China.
Anal Chim Acta. 2010 Mar 17;663(1):19-26. doi: 10.1016/j.aca.2010.01.015. Epub 2010 Jan 18.
A novel biocompatible composite film based on a water-insoluble surfactant, didodecyldimethylammonium bromide (DDAB), and a hydrophobic room-temperature ionic liquid (RTIL), 1-hexyl-3-methyl-imidazolium hexafluorophosphate (HIMIMPF(6)), for the immobilization of biocatalytical proteins was reported. Differential scanning calorimetry (DSC) showed that the DDAB-HIMIMPF(6) composite film has higher thermal stability than the DDAB film alone. SEM images indicated that different microstructures existed between the DDAB film and the composite film, indicating the interaction between DDAB and RTILs. This composite can be used as the immobilization matrix of proteins and other biomacromolecules. Heme-proteins, including hemoglobin (Hb), myoglobin (Mb) and horseradish peroxidase (HRP), were used as model proteins for studying the electrochemical behaviors of the resulting biocatalytical composite films. In the case of Hb, a pair of well-defined quasi-reversible redox peaks was obtained when the composite film containing Hb was modified on a glassy carbon electrode. The formal potential (E degrees '), the surface coverage (Gamma(*)) and the electron transfer rate constant (k(s)) were calculated as -0.308V, 1.32x10(-11)molcm(-2) and 11.642s(-1), respectively. While, these parameters for Hb on DDAB films alone were -0.309V, 7.20x10(-12)molcm(-2) and 2.748s(-1), respectively. Therefore, the composite are more suitable for the direct electron transfer between Hb than DDAB alone. The native conformation and bioactivity of Hb adsorbed on the composite film was proved to be maintained, reflected by the unchanged ultraviolet-visible (UV-vis) as well as the catalytic activity toward hydrogen peroxide (H(2)O(2)) and nitric oxide (NO) compared with the free Hb molecules. Furthermore, Hb on the composite film are more sensitive for the detection of hydrogen peroxide (H(2)O(2)) and nitric oxide (NO) than that on DDAB film alone. The linear range of H(2)O(2) on Hb/DDAB-RTILs/GC electrode is from 0.5 to 57.5microM with linear regression equations I(microA)=0.149+0.00904C(microM), while, the linear range of H(2)O(2) on Hb/DDAB/GC electrode is from 0.5 to 57.5microM with linear regression equations I(microA)=0.0938+0.00553C(microM). For NO, its linear range on Hb/DDAB-RTILs/GC electrode is from 1.8 to 21.6microM with linear regression equations I(microA)=0.0937+0.0232C(microM). But its linear range on Hb/DDAB/GC electrode is from 1.8 to 21.6microM with linear regression equations I(microA)=0.0285+0.0167C(microM). Similar results were observed for Mb and HRP in the DDAB-HIMIMPF(6) composite film.
一种新型的基于水不溶性表面活性剂双十二烷基二甲基溴化铵（DDAB）和疏水性室温离子液体（RTIL）1-己基-3-甲基-咪唑六氟磷酸盐（HIMIMPF(6)）的生物相容性复合膜，用于固定生物催化蛋白。差示扫描量热法（DSC）表明，DDAB-HIMIMPF(6)复合膜比单独的 DDAB 膜具有更高的热稳定性。SEM 图像表明 DDAB 膜和复合膜之间存在不同的微观结构，表明 DDAB 与 RTILs 之间存在相互作用。这种复合材料可用作蛋白质和其他生物大分子的固定化基质。血红素蛋白，包括血红蛋白（Hb）、肌红蛋白（Mb）和辣根过氧化物酶（HRP），被用作研究所得生物催化复合膜电化学行为的模型蛋白。在 Hb 的情况下，当含有 Hb 的复合膜修饰在玻碳电极上时，获得了一对定义良好的准可逆氧化还原峰。计算得到的形式电位（E 度 '）、表面覆盖率（Gamma(*))和电子转移速率常数（k(s))分别为-0.308V、1.32x10(-11)molcm(-2)和 11.642s(-1)。而，在单独的 DDAB 膜上的 Hb 的这些参数分别为-0.309V、7.20x10(-12)molcm(-2)和 2.748s(-1)。因此，与单独的 DDAB 相比，复合膜更适合 Hb 之间的直接电子转移。吸附在复合膜上的 Hb 的天然构象和生物活性被证明得以保持，这反映在与游离 Hb 分子相比，紫外-可见（UV-vis）以及对过氧化氢（H(2)O(2))和一氧化氮（NO）的催化活性没有变化。此外，与单独的 DDAB 膜相比，Hb 在复合膜上对过氧化氢（H(2)O(2))和一氧化氮（NO）的检测更敏感。Hb/DDAB-RTILs/GC 电极上 H(2)O(2)的线性范围为 0.5 至 57.5μM，线性回归方程为 I(microA)=0.149+0.00904C(microM)，而 Hb/DDAB/GC 电极上 H(2)O(2)的线性范围为 0.5 至 57.5μM，线性回归方程为 I(microA)=0.0938+0.00553C(microM)。对于 NO，其在 Hb/DDAB-RTILs/GC 电极上的线性范围为 1.8 至 21.6μM，线性回归方程为 I(microA)=0.0937+0.0232C(microM)。但在 Hb/DDAB/GC 电极上的线性范围为 1.8 至 21.6μM，线性回归方程为 I(microA)=0.0285+0.0167C(microM)。在 DDAB-HIMIMPF(6)复合膜中也观察到类似的结果。
