Authors: Raik S.V., Poshina D.N., Lyalina T.A., Polyakov D.S., Vasilyev V.B., Kritchenkov A.S., Skorik Y.A.
А novel cationic chitosan derivative, N-[4-(N,N,N-trimethylammonium)benzyl]chitosan chloride (TMAB-CS), with different degrees of substitution (DS) was synthesized by a chemoselective interaction of 4-formyl-N,N,N-trimethylanilinium iodide with chitosan amino groups using a reductive amination method. Several factors (pH, reactant ratio, reaction time, and chitosan structure) were studied for their effects on the DS of the resulting TMAB-CS. The obtained derivatives were characterized by 1H NMR and FTIR spectroscopy. Turbidimetric titration showed enhanced solubility over a wide pH range even for low-substituted TMAB-CS. TMAB-CS provided strong DS-dependent binding of plasmid DNA. Dynamic light scattering measurements revealed the formation of stable polyplexes with hydrodynamic diameters of 200–300 nm and ζ-potential of 20–30 mV. TMAB-CS with relatively low DS (25%) demonstrated more pronounced transfection efficiency (up to 2000 cell/cm2) of plasmid DNA into the HEK293 cell line promoted by free TMAB-CS. The positive effects of lower DS can be related to a better polyplex dissociation within the cell. The cytotoxicity of TMAB-CS was comparable to that of the initial chitosan at concentrations up to 300 ng/μL, even at high DS.
Keywords: cationic polymer; cell transfection; chitosan; gene delivery; polyplex.
DOI: 10.1016/j.carbpol.2017.11.093.
Read Full: https://www.ncbi.nlm.nih.gov/pubmed/29254024.