Improvement of thermal stability of enzyme via immobilization on Langmuir–Blodgett films of organo-modified aluminosilicate with high coverage

Ultrathin films of regularly adsorbed biological molecules have been fabricated by means of the modified Langmuir–Blodgett (LB) method using an organo-modified aluminosilicate (montmorillonite). In this combined method, clay LB films play a template role in the formation of the lysozyme thin layer. Chemisorption of biological molecules to the anionic montmorillonite (MMT) surface was confirmed by a comparison between infrared spectra of multilayers of organo-clay and of chemisorbed lysozyme. The surface morphology of these monolayers was observed by atomic force microscopy. In the case of organo-modified aluminosilicate, it is also indicated that chemisorbed enzyme activity is possible to maintain until 160 °C at attempting to evaluation of the heat-resistance. The maintaining of enzyme activity at high temperature region is possible together with the maintaining of three-dimensional steric structure of enzyme. This maintaining of steric structure of enzyme is based on the formation of aggregate of adsorbed enzyme induced by epitaxial-growth from aluminosilicate surface and the construction of sandwiched structure of enzyme between organo-aluminosilicates.