Antibacterial and conductive injectable hydrogels based on quaternized chitosan-graft-polyaniline/oxidized dextran for tissue engineering

Cellulose is the most abundant polysaccharide on Earth. It can be obtained from a vast number of sources, e.g. cell walls of wood and plants, some species of bacteria, and algae, as well as tunicates, which are the only known cellulose-containing animals. This inherent abundance naturally paves the way for discovering new applications for this versatile material. This review provides an extensive survey on cellulose and its derivatives, their structural and biochemical properties, with an overview of applications in tissue engineering, wound dressing, and drug delivery systems. Based on the available means of selecting the physical features, dimensions, and shapes, cellulose exists in the morphological forms of fiber, microfibril/nanofibril, and micro/nanocrystalline cellulose. These different cellulosic particle types arise due to the inherent diversity among the source of organic materials or due to the specific conditions of biosynthesis and processing that determine the consequent geometry and dimension of cellulosic particles. These different cellulosic particles, as building blocks, produce materials of different microstructures and properties, which are needed for numerous biomedical applications. Despite having great potential for applications in various fields, the extensive use of cellulose has been mainly limited to industrial use, with less early interest towards the biomedical field. Therefore, this review highlights recent developments in the preparation methods of cellulose and its derivatives that create novel properties benefiting appropriate biomedical applications.

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Cellulose and its derivatives: towards biomedical applications

Antimicrobial activity and cytotoxicity of cotton fabric coated with conducting polymers, polyaniline or polypyrrole, and with deposited silver nanoparticles

Background: The post-myocardial infarction (MI) scar interrupts electrical impulse propagation and delays regional contraction, which contributes to ventricular dysfunction. We investigated the potential of an injectable conductive biomaterial to restore scar tissue conductivity and re-establish synchronous ventricular contraction. Methods: A conductive biomaterial was generated by conjugating conductive polypyrrole (PPY) onto chitosan (CHI) backbones. Trypan blue staining of neonatal rat cardiomyocytes (CMs) cultured on biomaterials was used to evaluate the biocompatibility of the conductive biomaterials. Ca2+ imaging was used to visualize beating CMs. A cryoablation injury rat model was used to investigate the ability of PPY:CHI to improve cardiac electrical propagation in the injured heart in vivo. Electromyography was used to evaluate conductivity of scar tissue ex vivo. Results: Cell survival and morphology were similar between cells cultured on biomaterials-coated and uncoated-control dishes. PPY:CHI established synchronous contraction of two distinct clusters of spontaneously-beating CMs. Intramyocardial PPY:CHI injection into the cryoablation-induced injured region improved electrical impulse propagation across the scarred tissue and decreased the QRS interval, whereas saline- or CHI-injected hearts continued to have delayed propagation patterns and significantly reduced conduction velocity compared to healthy controls. Ex vivo evaluation found that scar tissue from PPY:CHI-treated rat hearts had higher signal amplitude compared to those from saline- or CHI-treated rat heart tissue. Conclusions: The PPY:CHI biomaterial is electrically conductive, biocompatible and injectable. It improved synchronous contraction between physically separated beating CM clusters in vitro. Intra-myocardial injection of PPY:CHI following cardiac injury improved electrical impulse propagation of scar tissue in vivo.

Polypyrrole-chitosan conductive biomaterial synchronizes cardiomyocyte contraction and improves myocardial electrical impulse propagation

Impact of chain length on antibacterial activity and hemocompatibility of quaternary N-alkyl and n,n-dialkyl chitosan derivatives.

Synthesis, characterization and antimicrobial activity of biodegradable conducting polypyrrole-graft-chitosan copolymer

Electrokinetic properties of biodegradable conducting polyaniline-graft-chitosan copolymer in aqueous and non-aqueous media

Controlling the optical properties of polyaniline doped by boric acid particles by changing their doping agent and initiator concentration

In this study, synthesis, characterization, and antibacterial activity of chitosan-based biodegradable conducting graft copolymers namely polyaniline-g-chitosan, polypyrrole-g-chitosan, and polythiophene-g-chitosan with chemical oxidation method using (NH4)2S2O8 and FeCl3 as initiators were investigated. Characterizations of the materials were carried out by means of Fourier transform infrared spectroscopy, proton nuclear magnetic resonance, UV–vis, thermogravimetric analysis, scanning electron microscope, transmission electron microscope, and temperature-dependent electrical conductivity measurements. The grafting yield, grafting efficiency, particle sizes, dielectric constants, and densities of the conducting graft copolymers were determined. Grafting process improved the conductivities and thermal stabilities of the copolymers. The conducting polymer-g-chitosan copolymers were also tested against Klebsiella pneumoniae, Escherichia coli, Bacillus megaterium, Enterococcus faecalis, Staphylococcus aureus microorganisms and relatively higher or equipotent antibacterial activities were determined against the microorganisms compared with Penicillin, Amikacin, Erythromycin, Rifampicin, and Trimethoprim antibiotics. POLYM. COMPOS. 36:497–509, 2015. © 2014 Society of Plastics Engineers

Mehmet Cabuk

Papers

Synthesis, characterization and antimicrobial activity of biodegradable conducting polypyrrole-graft-chitosan copolymer

Electrokinetic properties of biodegradable conducting polyaniline-graft-chitosan copolymer in aqueous and non-aqueous media

Controlling the optical properties of polyaniline doped by boric acid particles by changing their doping agent and initiator concentration

Synthesis, characterization, and enhanced antibacterial activity of chitosan‐based biodegradable conducting graft copolymers

Electrokinetic, electrorheological and viscoelastic properties of Polythiophene-graft-Chitosan copolymer particles