Functionalization of Magnetic Nanowires by Charged Biopolymers

Abstract

We report on a facile method for the preparation of biocompatible and bioactive magnetic nanowires. The method consists of the direct deposition of polysaccharides by layer-by-layer (LbL) assembly onto a brush of metallic nanowires obtained by electrodeposition of the metal within the nanopores of an alumina template supported on a silicon wafer. Carboxymethylpullulan (CMP) and chitosan (CHI) multilayers were grown on brushes of Ni nanowires; subsequent grafting of an enzyme was performed by conjugating free amine side groups of chitosan with carboxylic groups of the enzyme. The nanowires are finally released by a gentle ultrasonic treatment. Transmission electron microscopy, electron energy-dispersive loss spectroscopy, and x-ray photoelectron spectroscopy indicate the formation of an homogeneous coating onto the nickel nanowires when one, two, or three CMP/CHI bilayers are deposited. This easy and efficient route to the biochemical functionalization of magnetic nanowires could find widespread use for the preparation of a broad range of nanowires with tailored surface properties.

Urea potentiometric enzymatic biosensor based on charged biopolymers and electrodeposited polyaniline

“…LbL assembly was performed by immersing alternately the substrates for 5 min into aqueous solutions of CMP and CHI (1 mg mL −1 and pH 5.5 for each polyelectrolyte), each immersion in a polyelectrolyte solution being followed by two rinsing steps with milli-Q water for 2 min. The process was cycled to obtain an assembly composed of PANI-(CMP-CHI) 2 -CMP (PANI-LbL in the following sections) (Magnin et al, 2008).…”

“…In this work, enzyme immobilization is ensured by covalent binding of the enzyme on a LbL film (Magnin et al, 2008) deposited beforehand on the conducting polyaniline film. The LbL film is aimed at improving both the enzyme immobilization and stability, in order to increase the lifetime of the urea biosensor for biomedical applications.…”

“…The LbL film used in this work is composed of 2.5 bilayers of two biopolymers: negatively charged carboxymethylpullulan and positively charged chitosan. The enzyme is covalently attached to the outer layer of the LbL film (carboxymethylpullulan) through a carbodiimide coupling reaction as previously studied (Magnin et al, 2008). This reaction simultaneously crosslinks the polysaccharide film, by reacting the amine groups of chitosan with the carboxylic acid moieties of carboxymethylpullulan which contributes to the stabilization of the film.…”

Effect of carboxymethyl groups on degradation of modified pullulan by pullulanase from Klebsiella pneumoniae

“…CMPull can also be used with other polysaccharides to form magnetic nanowires structures using the layer by layer method. These nanostructures can be used for biological applications (Magnin et al, 2008).…”

Structural and magnetic characterization of batch-fabricated nickel encapsulated multi-walled carbon nanotubes

“…Due to the specific surface chemistry of each segment, several molecules can be selectively linked along the NW [4]. Another means of promoting the attachment of chemical species is by coating the NW body with a shell of a polymeric [5] or carbonaceous material. Carbon capsules, such as fullerenes or carbon nanotubes (CNTs), are particularly attractive for drug delivery purposes since there is a broad range of chemical methods available to exohedrally functionalize them [6][7][8].…”