Figure 1.
Representative 1H NMR spectra of chitosan (CS) and CS-g-PEI (CP) in a mixture solution (D2O/CD3COOD (VD2O: VCD3COOD = 1∶1) at 40°C.
Figure 2.
GPC Curves of chitosan (CS) and CS-g-PEI (CP).
Table 1.
Characteristic of prepared CS-g-PEI (CP).
Figure 3.
Gel retarding analysis of CP/DNA nanoparticles.
Lane 1: DNA marker. Lane 2: naked DNA control. Lane 3–8: CP/DNA nanoparticles prepared at CP:DNA weight ratios of 1∶2, 1∶1, 2∶1, 3∶1, 4∶1, and 5∶1 (a); electrophoresis photo of CP/DNA nanoparticles prepared with CP:DNA weight ratio = 3 at different pH levels (b); electrophoresis of CS/DNA nanoparticles prepared with the CS:DNA weight ratio = 3 at different pH levels (c).
Figure 4.
Physiochemical property of CP and CP/DNA nanoparticles.
(a) SEM images of CP/DNA nanoparticles at CP:DNA weight ratio = 3; (b) the effect of CP:DNA weight ratios on the particle size and the zeta potential of resulting nanoparticles (n = 3; error bars represent standard deviation); (c) size distribution of CP/DNA complexes prepared at the CP:DNA weight ratio = 3 measured by Mastersizer 2000 laser diffractometer; (d) buffering capacities of PEI (25 kDa), CS, and CP copolymers.
Figure 5.
Cell viabilities of CP/DNA nanoparticles, CS/DNA nanoparticles, PEI/DNA nanoparticles, and Lipofectamine™ 2000 in primary chondrocytes (a) and synoviocytes (b).
*P<0.01 compared to PEI/DNA nanoparticles; **P<0.01 compared to Lipofectamine™ 2000.
Figure 6.
Images of chondrocytes (a) or synoviocytes (b) transfected with CP/DNA nanoparticles, naked pDNA, CS/DNA nanoparticles, PEI (25 kDa)/DNA nanoparticles, and Lipofectamine™ 2000 as observed under fluorescence microscope or inverted phase contrast microscope.
(40× magnification for upper panel under inverted phase contrast microscope, and 40× magnification for lower panel under fluorescence microscope).
Figure 7.
In vitro transfection efficiency of CP/DNA nanoparticles.
(a) In vitro transfection efficiency of CP/DNA nanoparticles in both chondrocytes and synoviocytes compared to that of naked pDNA, CS/DNA nanoparticles, PEI (25 kDa)/DNA nanoparticles, and Lipofectamine™ 2000 (n = 3; 48 h post-transfection; error bars represent standard deviation). *P<0.01 when CP/DNA nanoparticles compared to CS/DNA nanoparticles transfected towards chondrocytes (n = 3); **P<0.01 when CP/DNA nanoparticles compared to PEI (25 kDa)/DNA nanoparticles transfected towards synoviocytes (n = 3); # or ## P>0.05 when CP/DNA nanoparticles compared to Lipofectamine™ 2000 transfected towards chondrocytes or synoviocytes (n = 3). (b) Percentage of chondrocytes or synoviocytes transfected in vitro using CP/DNA nanoparticles as measured by flow cytometry 48 h post-transfection. The influence of CP:DNA weight ratios on the transfection efficiency was assessed 48 h post-transfection (n = 3; error bars represent standard deviation).
Figure 8.
Intracellular distribution of Cy3-labeled pDNA/CP complexes was observed with a confocal fluorescence microscope in chondrocytes (a) and synoviocytes (b).
(Panel 1) 0.5 h post-incubation; (Panel 2) 1 h post-incubation; (Panel 3) 2 h post-incubation; and (Panel 4) 4 h post-incubation. Row A shows the Cy3-labeled pDNA (red); row B shows the lysosomal (green); row C shows the nucleus (blue); and row D shows the overlap of A, B, and C rows content.