| Plasma-polymerized films (PPFs) usually refer a kind of films which are obtained by the deposition of ionizing organic monomer under glow discharge condition in gas phase, which are considered as polymers between oganic polymers and inorganic polymers. Such films are quite homogenous, hole-free and chemically stable and their thickness is controllable. Moreover, the plasma-polymerized films have strong adhesion to various substrates and many organic compounds with active groups can be used as precursors to conduct plasma polymerization. Due to their outstanding properties, PPFs as a potential sensing coating have attracted increasing attention. Some pioneering studies have demonstrated the chemical and biological sensing applications of the plasma-polymerized films, and the role of dry-process-based PPFs in biosensor design has become increasingly important. This research mainly covers the developments of PPFs in sensing interface design of emzymatic biosensors and immunosensors. The detail contents list as follows:1. A new urease biosensor based on the plasma modified PVC membrane has been developed. Using microwave plasma technique, an ethylene diamine plasma- polymerized layer with amine groups was first deposited on the pH-sensitive PVC membrane. The abundant amide groups make the plasma-modified pH sensitive membrane easier to bind H+, and thus the response range of the pH sensitive membrane has some shift toward high pH value and the response slope of 45.73 mV/pH is over that of common pH sensitive membrane, 42.81 mV/pH, showing an enhancing pH response. After activated with 2.5 % glutaraldehyde solution, urease molecules were covalently immobilized onto the plasma polymerized pH-sensitive PVC membrane surface and the urease biosensor was then obtained. The urease biosensor has a response time of less than 200 s and a detection limit of 5. 0×10-5 mol/L, and there is a good linear relationship between the potential response and the logarithm value of the urea concentration in the range of 6.0×10-4 - 8.4×10-3 mol/L with a correlation coefficient of 0.9978.2. A new renewable immobilization method for transferrin antibodies has been proposed, which is based on polyelectrolyte self-assembly. An ethylene diamine plasma- polymerized layer with amine groups was deposited on the surface of quartz crystal microbalance (QCM) with a microwave plasma method. The transfenrin antibodies were then or orientally immobilized through a protein A-alginic acid (PA-AA) compound self-assenbled layer,and the PA-AA layer can be easly removed by shiffing the solution pH value,making the immuosensor regenerable.This QCM immuosensor can quantifatively determine the transferrin.in the range of 0.15 and 78.9μg/mL and the detection limit is 0.15μg/mL. The immunosensors have been used to determine several transferrin samples, and the detection results are perfectly commensurate with that of ELISA.3. A new immunosensor based on PPFs has been proposed for the Schistosoma-Japonicum antibody (SjAb). The surfaces of quartz crystal microbalance (QCM) were modified with plasma polymerized films of ethylenediamine. The schistosoma-Japonicum antigen (SiAg) was first covalently coupled with alginic acid to obtain a SjAg-AA complex, and then the SjAg-AA complex was immobilized on the QCM surfaces through a self-anembly method. The proposed immunosensor can quantitatively determine the SjAb concentration in the range of 0.13μg/mL-20μg/mL with a correlation coefficient of 0.9945, showing good sensitivity. |
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