Novel High-Viscosity Polyacrylamidated Chitosan for Neural Tissue Engineering: Fabrication of Anisotropic Neurodurable Scaffold via Molecular Disposition of Persulfate-Mediated Polymer Slicing and Complexation

Abstract

Macroporous polyacrylamide-grafted-chitosan scaffolds for neural tissue engineering were fabricated with varied synthetic and viscosity profiles. A novel approach and mechanism was utilized for polyacrylamide grafting onto chitosan using potassium persulfate (KPS) mediated degradation of both polymers under a thermally controlled environment. Commercially available high molecular mass polyacrylamide was used instead of the acrylamide monomer for graft copolymerization. This grafting strategy yielded an enhanced grafting efficiency (GE = 92%), grafting ratio (GR = 263%), intrinsic viscosity (IV = 5.231 dL/g) and viscometric average molecular mass (MW = 1.63 × 106 Da) compared with known acrylamide that has a GE = 83%, GR = 178%, IV = 3.901 dL/g and MW = 1.22 × 106 Da. Image processing analysis of SEM images of the newly grafted neurodurable scaffold was undertaken based on the polymer-pore threshold. Attenuated Total Reflectance-FTIR spectral analyses in conjugation with DSC were used for the characterization and comparison of the newly grafted copolymers. Static Lattice Atomistic Simulations were employed to investigate and elucidate the copolymeric assembly and reaction mechanism by exploring the spatial disposition of chitosan and polyacrylamide with respect to the reactional profile of potassium persulfate. Interestingly, potassium persulfate, a peroxide, was found to play a dual role initially degrading the polymers—“polymer slicing”—thereby initiating the formation of free radicals and subsequently leading to synthesis of the high molecular mass polyacrylamide-grafted-chitosan (PAAm-g-CHT)—“polymer complexation”. Furthermore, the applicability of the uniquely grafted scaffold for neural tissue engineering was evaluated via PC12 neuronal cell seeding. The novel PAAm-g-CHT exhibited superior neurocompatibility in terms of cell infiltration owing to the anisotropic porous architecture, high molecular mass mediated robustness, superior hydrophilicity as well as surface charge due to the acrylic chains. Additionally, these results suggested that the porous PAAm-g-CHT scaffold may act as a potential neural cell carrier.

Chitosan coated cotton cloth supported zero-valent nanoparticles: Simple but economically viable, efficient and easily retrievable catalysts

“…All the spectra exhibited a typical cellulose FTIR, which was widely described in previous literature 39 , 40 . Also, its peaks at are well assigned and discussed in previous reports 41 , 42 . FTIR analysis suggests that no interaction occur between oxygenated functional groups of CC, CH amino and oxygenated groups, and MNPs because in all spectra the peaks were located on the same position.…”

Chitosan-titanium oxide fibers supported zero-valent nanoparticles: Highly efficient and easily retrievable catalyst for the removal of organic pollutants

“…The sharp band at 1640 cm −1 correspond to N-H bending in amide group of chitosan. The characteristic bands of any polysaccharide such chitosan can be observed at 1030, 1085, and 1375 cm −1 was due to O-H bending vibration, C-O-C asymmetrical stretching vibration and C-N stretching vibration respectively 66 , 67 . These characteristic band of chitosan can be easily observed in all spectra of nanocomposite fibers of chitosan with different wt% of TiO 2 and templated with various MNPs (Fig.…”

A review of bioactive plant polysaccharides: Biological activities, functionalization, and biomedical applications

“…For example, Lu, Xu, Zhang, Cheng, and Zhuo (2008), prepared a chitosanbased copolymer, which had a good potential as efficient nonviral gene vectors, through grafting polyethylenimine (800 Da) to N-maleated chitosans. Kumar et al (2012) utilized polyacrylamide, instead of normal acrylamide monomer, for grafting onto chitosan with high grafting efficiency (GE¼92%) and grafting ratio (GR¼263%). The resulting macroporous polyacrylamide-grafted-chitosan exhibited superior neuronal B i o a c t i v e C a r b o h y d r a t e s a n d D i e t a r y F i b r e 5 ( 2 0 1 5 ) 3 1 -6 1 cell infiltration owing to the anisotropic porous architecture, high-molar-mass mediated robustness, and superior hydrophilicity, as well as surface charge due to the acrylic chains and the substrate could act as a potential neural cell carrier applied in scaffolds for neural tissue engineering.…”