Synthesis, characterization, and self-assembly with plasmid DNA of a quaternary ammonium derivative of pectic galactan and its fluorescent labeling for bioimaging applications

Quaternized derivatives of pectic galactan (QPG) were synthesized by a reaction of pectic galactan (PG) with 3-chloro-2-hydroxypropyl trimethyl ammonium chloride (CHPTAC) in the presence of aqueous sodium hydroxide solution under mild reaction conditions. The results showed that the concentration of CHPTAC and NaOH has great impact on the quaternization reaction. QPG was found to interact electrostatically with plasmid DNA in aqueous solution to form complexes in globular condensed morphology in a nanometer scale size ranging from 60 to 160 nm. Complexes formed with QPG fluorescently labeled with 5-DTAF (QPG-5-DTAF) were introduced to the C6 rat glioma cell line, and were found to be able to enter the cell and approach the nucleus within 24 h. The results suggest that this type of modified natural polysaccharide may have an advantage as a biocompatible and biodegradable gene delivery carrier and furthermore may serve as a cell specific carrier.

Highlights
• Synthesis, characterization of QPG and its fluorescent labeling with 5-DTAF was achieved.
• FT-IR, NMR, TGA and elemental analysis techniques were used to characterize the molecular structure of QPG and fluorescently labeled QPG.
• Concentration of NaOH and CHPTAC has great impact on quaternization of pectic galactan
• QPG was found to interact electrostatically with pDNA in aqueous solution to form complexes in globular condensed morphology in a nanometer scale size.
• QPG/pGFP labeled complexes were found to enter C6 rat glioma cells, and surround the nucleus within 24 h.Figure optionsDownload as PowerPoint slide