posted on 2012-01-09, 00:00authored byRitu Goyal, Sushil
K. Tripathi, Esther Vazquez, Pradeep Kumar, Kailash C. Gupta
Use of cationic polymers as nonviral gene vectors has
several limitations
such as low transfection efficiency, high toxicity, and inactivation
by serum. In this study, varying amounts of low molecular weight branched
polyethylenimine 1.8 kDa (bPEI 1.8) were introduced on to a neutral
polymer, poly(vinyl alcohol) (PVA), to bring in cationic charge on
the resulting PVA-PEI (PP) nanocomposites. We rationalized that by
introducing bPEI 1.8, buffering and condensation properties of the
proposed nanocomposites would result in improved gene transfer capability.
A series of PVA-PEI (PP) nanocomposites was synthesized using well-established
epoxide chemistry and characterized by IR and NMR. Particle size of
the PP/DNA complexes ranged between 120 to 135 nm, as determined by
dynamic light scattering (DLS), and DNA retardation assay revealed
efficient binding capability of PP nanocomposites to negatively charged
nucleic acids. In vitro transfection of PP/DNA complexes in HEK293,
HeLa, and CHO cells revealed that the best working formulation in
the synthesized series, PP-3/DNA complex, displayed ∼2–50-fold
higher transfection efficiency than bPEIs (1.8 and 25 kDa) and commercial
transfection reagents. More importantly, the PP/DNA complexes were
stable over a period of time, along with their superior transfection
efficiency in the presence of serum compared to serum-free conditions,
retaining the nontoxic property of low molecular weight bPEI. The
in vivo administration of
PP-3/DNA complex in Balb/c mice showed maximum gene expression in
their spleen. The study demonstrates the potential of PP nanocomposites
as promising nonviral gene vectors for in vivo applications.