Utilization of Interfacial Films of Organo‐Modified Carbon Nanotubes as Adsorption Templates for a Number of Biomolecules while Maintaining their Activity

Abstract

AbstractWe investigated the versatility of a monolayer of organo‐modified single‐walled carbon nanotubes (SWCNTs) on a water surface as a template to maintain activity by adsorbing various biomolecules from the subphase. Organo‐modified SWCNTs with amphiphilic properties formed a Langmuir film on the subphase containing biomolecules, and adsorbed and immobilized biomolecules via electrostatic interactions. In this study, the interactions of trypsin, lysozyme, cytochrome C protein, glucose oxidase sugar chain polymer, deoxyribonucleic acid, and chitosan with SWCNTs at the air/water interface were investigated. The uniqueness of this study is that it shows the possibility of wide‐ranging applications by utilizing an organo‐modified SWCNT interfacial film as an adsorption template for various biomolecules. The expansion behavior of the surface pressure‐area isotherms indicated the existence of interactions between the organo‐modified SWCNTs monolayer on the water surface and the biomolecules. The morphology and spectroscopic properties of the films transferred onto solid substrates clearly indicate the adsorption and immobilization of biomolecular groups. DNA and chitosan were not immobilized on the organo‐modified SWCNTs film template; however, the other four enzyme/protein molecules were adsorbed onto the solid substrate and maintained their fine second‐order structures, even under harsh conditions.