Congratulations
to Brian Lewis, a senior biochemistry major at Columbia College,
who is the proud recipient of an Outstanding Poster Award at the
2011 Biomedical Research Conference for
Minority Students (ABRCMS), held November 11 and 12 in St. Louis. Brian
is currently a student researcher in Chemistry Professor Wei Min's lab. The research project for which he received
his award, "Combination of Chitosan and Dextran as a Novel
Gene Delivery System," was carried out under the direction of Professor Aliasger
Salem at the University of Iowa. The ABRCMS conference is organized
into twelve disciplines -- Brian's award was in the chemistry division.
There were over 3,000 student participants in the conference this year and, of
these, just 225 were selected for awards.
An abstract of Brian's research project follows below. More information about the ABRCMS conference can be found on the organization's website.
"Combination of Chitosan and Dextran as a Novel Gene Delivery System"
Chitosan is a naturally occurring cationic polymer that is an ideal candidate for drug/gene delivery. However, its transfection efficiency is poor. Our hypothesis is that chitosan binds too strongly to DNA thereby inhibiting its release. Thus, incorporation of an anionic polymer like dextran sulphate can improve its transfection efficiency. In this study we are evaluating if a chitosan and dextran combination is an efficient carrier for DNA. We have used pCpG Luciferase (pCpGLuc) as a model plasmid for testing the efficiency of this delivery system. The study was completed in two stages. The first stage involves preparation and characterization of nanocomplexes. Nanocomplexes were prepared using medium molecular weight chitosan (MM-HD) and low molecular weight chitosan (LM-HD) with pCpGLuc. N/P ratios of plasmid DNA: chitosan varying from 10 to 100 were studied to optimize the best delivery system. Size and charge of nanocomplexes were evaluated using a Nano ZS series zetasizer. In the second stage of this study, the transfection efficiency of nanocomplexes were tested in human embryonic kidney (HEK293) cells. Transfection efficiency was quantified using a luciferase assay. Our results show that an N/P ratio of 25 gave the best transfection. Low molecular weight chitosan was more efficient at delivery than high molecular weight chitosan.
