Mello Sarita V, Mabrouki Mustapha, Cao Xihui, Leblanc Roger M, Cheng Tu-Chen, DeFrank Joseph J
Department of Chemistry, University of Miami, Coral Gables, Florida 33146, USA.
Biomacromolecules. 2003 Jul-Aug;4(4):968-73. doi: 10.1021/bm025775+.
In this paper, we describe the preparation and characterization of Langmuir and Langmuir-Blodgett (LB) monolayers of the enzyme organophosphorus acid anhydrolase (OPAA). Langmuir films of OPAA were characterized on different subphases, such as phosphate, ammonium carbonate, and bis-tris-propane buffers. Monolayers at the air-water interface were characterized by measuring the surface pressure and surface potential-area isotherms. In situ UV-vis absorption spectra were also recorded from the Langmuir monolayers. The enzyme activity at the air-water interface was tested by the addition of diisopropylfluorophosphate (DFP) to the subphase. LB films of OPAA were transferred to mica substrates to be studied by atomic force microscopy. Finally, a one-layer LB film of OPAA labeled with a fluorescent probe, fluorescein isothiocyanate (FITC), was deposited onto a quartz slide to be tested as sensor for DFP. The clear, pronounced response and the stability of the LB film as a DFP sensor show the potential of this system as a biosensor.
在本文中，我们描述了有机磷酸酐酶（OPAA）的朗缪尔（Langmuir）和朗缪尔-布洛杰特（LB）单分子层的制备与表征。OPAA的朗缪尔膜在不同的亚相上进行了表征，如磷酸盐、碳酸铵和双三羟甲基氨基甲烷缓冲液。通过测量表面压力和表面电势-面积等温线对气-水界面的单分子层进行了表征。还从朗缪尔单分子层记录了原位紫外-可见吸收光谱。通过向亚相中添加二异丙基氟磷酸酯（DFP）来测试气-水界面处的酶活性。将OPAA的LB膜转移到云母基底上，以便通过原子力显微镜进行研究。最后，将用荧光探针异硫氰酸荧光素（FITC）标记的OPAA单层LB膜沉积在石英载玻片上，用作DFP传感器进行测试。LB膜作为DFP传感器具有清晰、明显的响应和稳定性，表明该系统作为生物传感器具有潜力。
