Preparation of chitosan self-aggregates as a gene delivery system.
Hydrophobically modified chitosan containing 5.1 deoxycholic acid groups per 100 anhydroglucose units was synthesized by an EDC-mediated coupling reaction. Formation and characteristics of self-aggregates of hydrophobically modified chitosan were studied by fluorescence spectroscopy and dynamic light scattering method. The critical aggregation concentration (cac) of the self-aggregate was determined by measuring the fluorescence intensity of pyrene as a fluorescent probe. The cac value in PBS solution (pH 7.2) was 1.7x10(-2) mg/ml. Mean diameter of self-aggregates in PBS solution (pH 7.2) was 162 +/- 18 nm with an unimodal size distribution. Charge complex formation between self-aggregates and plasmid DNA was confirmed by electrophoresis on an agarose gel. Migration of DNA on an agarose gel was completely retarded above a charge ratio ( +/-) of 4/1 at pH 7.2. The free DNA dissociated from the complexes was observed by electrophoresis above pH 8.0 at a fixed charge ratio of 4/1. An efficient of COS-1 cells was achieved by self-aggregates/DNA complexes.
Biomedical Research Centre, Korea Institute of Science and Technology, Seoul, South Korea.
K Y
KY
Lee
I C
IC
Kwon
Y H
YH
Kim
W H
WH
Jo
S Y
SY
Jeong
D001672:Biocompatible Materials / Q000737:chemistry*; D002460:Cell Line; D002686:Chitin / Q000031:analogs & derivatives* / Q000737:chemistry; D048271:Chitosan; D015500:Chloramphenicol O-Acetyltransferase / Q000032:analysis; D004269:DNA, Bacterial / Q000737:chemistry*; D003840:Deoxycholic Acid; D004926:Escherichia coli / Q000201:enzymology; D005456:Fluorescent Dyes / Q000032:analysis; D018014:Gene Transfer Techniques; D005947:Glucose; D006863:Hydrogen-Ion Concentration; D010957:Plasmids; D013050:Spectrometry, Fluorescence; D014162:Transfection
D001672:Biocompatible Materials; D004269:DNA, Bacterial; D005456:Fluorescent Dyes; D003840:Deoxycholic Acid; D002686:Chitin; D048271:Chitosan; D015500:Chloramphenicol O-Acetyltransferase; D005947:Glucose