Nanostructural and Morphological Control of Biological Molecules Arranged by Using Langmuir–Blodgett Films of Organo-modified Aluminosilicate as Templates

Abstract

Clay LangmuirBlodgett (LB) films play the role of a template in the formation of lysozyme thin layers. Chemisorption of biological molecules onto the anionic montmorillonite surface is confirmed by comparing the IR spectra of organoclay multilayers and the chemisorbed lysozyme. The difference between the height of the monolayers for the organo-modified aluminosilicates and that for their adsorbed lysozyme is about 9 nm. This value is almost twice the length of the lysozyme along the long axis.Layered silicates, clay minerals, have played important roles in modern technology.1 These materials have received considerable attention because of their potential use in numerous applications, ranging from nanocomposite materials to biomedical and personal care products.2 Clays are unique in the sense that they consist of negatively charged aluminosilicate layers held together by exchangeable interlayer cations. Hence, a large number of alkylammonium-modified layered silicates (organomodified clays) have been developed, which are now widely used to form a large variety of nanocomposite materials with enhanced material properties. Organo-modified montmorillonites are post-petroleum resources; it may be possible to form next-generation eco-materials from them. In addition, thin films of clay minerals have been studied for application to modified electrodes, (bio)sensors, photochromic devices, nonlinear optical devices, and so on. 4 The LangmuirBlodgett (LB) method is one of the most useful techniques to prepare ultrathin films.5 In this method, floating molecular monolayers formed at an air/water interface are deposited on a solid substrate in a layer-by-layer manner. Recently, clay LB films have been hybridized with alkylammonium cations. Previously, the authors have developed organomodified montmorillonite (MMT) with extremely high surface coverage and localized negative charges in the bottom, by modification at an oil/water interface. 610In this study, floating monolayers and multilayered films on the solid of preformed organo-modified MMTs with high coverage and localized negative charges in the bottom were constructed by the Langmuir and LB method. In this case, buffer solution containing a lysozyme as the cationic biomolecule was used as the subphase. The organo-modified aluminosilicate LB films play the role of a template in the formation of the adsorbed lysozyme array. These LB multilayers of organo-modified MMTs on which an enzyme was adsorbed were characterized by the ³A isotherm method, infrared (IR) spectroscopy, and atomic force microscopy (AFM) observation.Natural Na + montmorillonite with a cation-exchange capacity of 108.6 mequiv/100 g was supplied by Kunimine Co. The organophilic clay was prepared by cation-exchange reactions of natural clay (aqueous dispersion) with a 0.1% aqueous solution of dimethyldioctadecylammonium chloride. Four kinds of quaternary ammonium cations based on long alkyl chains were used for the hydrophobic parts of the clays. In order to estimate the hydrophobicity and the ability of f...

Extreme Physical Property of the Enzyme Layered Organization-The Functional Innovation by Using a Template of Layered Organization of Heat-Resistant and Low-Defect Organic / Inorganic Two-Dimensional Nano-Hybrid-

“…9 By using the LB method for the fabrication of films, regular, two-dimensional arrays of proteins, such as enzymes, can be controlled. 10 In recent years, attempts have been made to immobilize functional groups, and functional element immobilization in biomolecules has generated growing interest as a powerful tool in bioelectronics research. Improved stability and heat resistance of the enzyme as a result of enzyme immobilization has been confirmed.…”