In this work, we report on the development of a bio-sensing film for the detection of organophosphorous compounds using sol-gel technology. A novel sol-gel immobilization method employing tetraethoxysilane/3- glycidoxypropyltrimethoxysilane/water hybrid material was developed and used to immobilize the hexahistidinetagged organophosphorous hydrolase enzyme (His6-OPH). Bio-sensing layers with encapsulated His6-OPH of various structures (water/silane, precursor ratios) have been prepared. The optimal (P=5:1, R=188) bio-sensing layers retained 90% of the initial enzyme activity. Furthermore, the bio-sensing layer prepared by this method was able to maintain its activity at or above 80% of its initial activity for 2 weeks. The bio-hybrid film also showed excellent reusability and improved activity atneutral pH in comparison to the same enzyme in solution.
COBISS.SI-ID: 15269398
The book chapter reviews the most important parameters that contribute to the sensor's design and its final characteristics. The survey of selected applications of nanosensors is based on polymer nanoparticles (prepared from e.g. polyacrylates, polystyrene) and on sol-gel based nanoparticles, namely for the determination of pH, oxygen, ions and some other molecules.
COBISS.SI-ID: 15769366
Hydrolysis and polycondensation reactions of tetraethoxysilane (TEOS) with 3,3,3-trifluoropropyl-trimethoxysilane (TFMS) or 1H,1H,2H,2H-perfluorooctyltriethoxysilane (PFES) were used to synthesize xerogels functionalized with fluorine-containing groups. According to transmission electron microscopy, the skeletons of synthesized polysiloxane xerogels have globular structures and consist of agglomerates of particles with fluorinated groups on their surfaces. FTIR spectroscopy showed that primary xerogel particles possess spatial polysiloxane networks, with fluorinated groups along with silanol groups and water in the surface layer. According to thermal analyses, the water content was 3-8 wt.%, and it decreased with increasing length of the fluorinated chain. Thermal destruction of the surface layer starts above 300 °C. The sorbents that were obtained were predominantly mesoporous materials with well-developed porous structures (SBET = 400-960 m2 g-1, Vs = 0.66-0.93 cm3 g-1). The influence of the TEOS/functional silane ratio and the natures of the functional groups on the structural and adsorptive properties were shown. The samples synthesized are organophilic. The affinity for n-hexane increases with increasing length of the fluorine-containing chain (PFES) and the content of fluorinated groups in the surface layer. The hybrid organic-inorganic materials that were obtained can be used for adsorption of hydrocarbons, including oil, from water.
COBISS.SI-ID: 15405334