Preparation and hydrophilicity of copolymerization of chitosan selectively grafted by polyethylene glycol

Abstract

Copolymerization of chitosan selectively grafted by polyethylene glycol was prepared. Chitosan was selectively grafted by monomethoxy polyethylene glycol(mPEG-OH), which contained a hydroxyl group combining with hexamethylene diisocyanate(HDI) to form a novel macromonomer namely monomethoxy polyethylene glycol isocyanate(mPEG-NCO) containing a isocyanate group with higher chemical activity in ethyl glyoxalate solution absolutely without water. The selective grafted copolymerization of Chitosan with mPEG-NCO was conducted under heterogeneous conditions as suspension in dimethylformamide. The hydrophilic copolymers of chitosan were prepared by condensation reaction of isocyanate group on mPEGNCO with hydroxy groups on chitosan chains because amino groups on chitosan chains were protected by complexion formation with copper ions. The effect of reaction condition on the grafting extents was discussed. Swelling properties of mPEG-g-CS were researched. The graft copolymer mPEG-g-CS was characterized by the infrared spectra. The experimental result showed that the copper ions were very effective to protect amino groups from condensation reaction. The swelling degree in water increases with adding of grafting ratio. The maximum swelling degree was up to above 132% when the grafting ratio was about 270%. The graft copolymer can be soluble partially in pure water.

Keywords

chitosan / polyethylene glycol / selectively graft / grafting ratio / hydrophilicity / swelling properties

References

[1] Abdou ES, Nagy KSA, Elsabee MZ Extraction and Characterization of Chitin and Chitosan from Local Sources[J]. Bioresour. Technol., 2008, 99: 1359

[2] Yang Y, Qiang H, Li D, . Assembled Alginate/chitosan Nanotubes for Biological Application[J]. Biomaterials, 2007, 28: 3 083-3 090.

[3] Said S, Elkholy Khalid D, . Grafting of Acryloyl Cyanoacetohydrazide onto Chitosan[J]. J. Polym. Res., 2011, 18: 459-467.

[4] Fanny Lebouc. Different Ways for Grafting Ester Derivatives of Poly(ethylene glycol) onto Chitosan: Related Characteristics and Potential Properties[J]. Polymer, 2005, 46: 639-651.

[5] Chen Y, Lu M, Wang H, . Study on the Preparation of the Chitosan Graft Poly(acrylic acid) Superabsorbent Polymer[J]. Polymer Materials Science and Engineering, 2005, 21(5): 266-269.

[6] Zhang W, Pan S, Zhang X, . In Vitrostudy on Polyethylene Glycol-chitosan Copolymer as a Gene Delivery Vector[J]. Acta Pharmaceutica Sinica, 2008, 43(8): 848-854.

[7] Erbacher P, Zou S, Bettinger T, . Chitosan-based Vector/DNA Complexes for Gene Delivery: Biophysical Characteristics and Transfection Ability[J]. Pharm. Res., 1998, 15: 1 332-1 339.

[8] Richardson S C, Kolbe H V, Duncan R Potential of Low Molecular Mass Vhitosan as a DNA Delivery System: Biocompatibility, Body Distribution and Ability to Complexand Protect DNA[J]. Int. J. Pharm., 1999, 178: 231-243.

[9] Kping-Hggard M, Tubulekas I, Guan H, . Chitosan as a Non Viral Gene Delivery System. Structure-property Relationships and Characteristics Compared with Polyethylenimine in vitro and after Lung Administration in vivo[J]. Gene Ther., 2001, 8: 1 108-1 121.

[10] Bozkir A, Saka O M Chitosan Nanoparticles for Plasmid DNA Delivery: Effect of Chitosan Molecular Structure on Formulation and Release Characteristics[J]. Drug Deliv., 2004, 11: 107-112.

[11] Bozkir A, Saka O M Chitosan-DNA Nanoparticles: Effect on DNA Integrity, Bacterial Transformation and Transfection Effi ciency[J]. J. Drug Target, 2004, 12: 281-288.

[12] Jiang X, Dai H, Leong KW, . Chitosan-g-PEG/DNA Complexes Deliver Gene to the Rat Liver Via Intrabiliary and Intraportal Infusions[J]. J. Gene Med., 2006, 8: 477-487.

[13] Natalija G, Ricardas Makuska Synthesis and Study of Water-soluble Chitosan-O-poly(ethylene glycol) Graft Copolymers[J]. European Polymer Journal, 2004, 40: 685-691.

[14] Huh K M, Cho Y W, . Supramolecular Hydrogel Formation Based on Inclusion Complexation between Poly(ethyleneglycol)-modified Chitosan and α-cyclodextrin [J]. Macromolecular Bioscience, 2004, 4: 92-99.