Polymer PH Sensor Film Based On Optical Signal

Microbioreactors, adapt to high-throughput screening, have obtained broad attention in the world, the application of optical sensing technology has paved the way for miniaturization of bioreactor. Successful operation of microbioreactors is critically dependent on the monitoring and control of pH of the culture fluids. Polymeric pH chemical probe can be easily fabricated into films and fixed onto microbioreactors, with good abilities of high-throughput screening, noninvasive and easy integration.The polymer, formed by HEMA and NI by covalent bond, has good hydrophilicity film-forming property and biological compatibility, along with avoiding phase separation of molecules in polymers. Polymerization condition, ways to making films, thickness of the film, monomer ration and metal ions were studied on effect of pH film sensing abilities. The pH film shows high sensitivity, high selectivity and good stability.In order to improve the response rate of pH polymer film, the third monomer was incorporated into the polymer matrix. The results showed that the pH response rate of films decreased with the incorporation of adamantine, while with the incorporation of hydrophilic PEG into the polymer, the response rate was significantly improved. These pH sensor films showed good pH on-line monitoring performance in yeast culture.Azo-H,Azo-CH3 and Azo-COOH were designed, their maximum absorption wavelength appeared red shift with increasing solvent polarity and electron-withdrawing group (-COOH) on the azobenzene. The polymer film shows good liner response at pH=-0.5-1.5 with its absorption wavelength changes, the film can not sense pH in alkaline condition because of hydrolysis of ester.