  When elaborating the biosensor based on single-walled carbon nanotubes
(SWNTs), it is necessary to solve such an important problem as the
immobilization of a target biomolecule on the nanotube surface. In this work,
the enzyme (glucose oxidase (GOX)) was immobilized on the surface of a nanotube
network, which was created by the deposition of nanotubes from their solution
in 1,2-dichlorobenzene by the spray method. 1-Pyrenebutanoic acid succinimide
ester (PSE) was used to form the molecular interface, the bifunctional molecule
of which provides the covalent binding with the enzyme shell, and its other
part (pyrene) is adsorbed onto the nanotube surface. First, the usage of such a
molecular interface leaves out the direct adsorption of the enzyme (in this
case, its activity decreases) onto the nanotube surface, and, second, it
ensures the enzyme localization near the nanotube. The comparison of the
resonance Raman (RR) spectrum of pristine nanotubes with their spectrum in the
PSE environment evidences the creation of a nanohybrid formed by an SWNT with a
PSE molecule which provides the further enzyme immobilization. As the RR
spectrum of an SWNT:PSE:GOX film does not essentially differ from that of
SWNT:PSE ones, this indicates that the molecular interface (PSE) isolates the
enzyme from nanotubes strongly enough. The efficient immobilization of GOX
along the carbon nanotubes due to PSE is confirmed with atom-force microscopy
images. The method of molecular dynamics allowed us to establish the structures
of SWNT:PSE:GOX created in the aqueous environment and to determine the
interaction energy between hybrid components. In addition, the conductivity of
the SWNT network with adsorbed PSE and GOX molecules is studied.
