His6-OPH enzyme-based bio-hybrid material for organophosphate detection

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 hexahistidine-tagged 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 at neutral pH in comparison to the same enzyme in solution.