Different Mechanisms for Nanoparticle Formation between pDNA and siRNA Using Polyrotaxane as the Polycation

Abstract

Ratios that matter: Investigations of nanoparticle formation using polyrotaxane as a polycation reveal that the formations of pDNA and siRNA nanoparticles with polycations are dependent on the nitrogen/phosphate ratio and the molar ratio, respectively.

Post-nuclear gene delivery events for transgene expression by biocleavable polyrotaxanes

“…[23,24]. We previously confirmed that pDNA particles condensed with DMAE-SS-PRX efficiently released DNA and showed a high transfection activity, when the positive particles were formed at a nitrogen/phosphate (N/P) ratio of 5 [11]. In this study, we prepared condensed pDNA nanoparticles at an N/P ratio of 5, and their diameters and ζ potentials were measured (Table 2).…”

“…Figure 3 shows the relationship between efficiency of DNA release (x-axis) and transfection activity (y-axis). Based on previous report that there would be a positive correlation between the efficiency of DNA release and transfection activity [11], it was expected that DMAE-SS-PRX with a high efficiency for DNA release would result in the production of a strong gene expression. The results in Figure 3 showed that the transfection activity was proportional to the efficiency of the DNA release to some extent.…”

“…It is particularly noteworthy that, from the standpoint of transfection, our integration system, which is comprised of the R8-MEND with DMAE-SS-PRX, was 5-fold greater than that for a conventional R8-MEND with protamine, which is a natural DNA condenser that shows a high transfection activity [18][19][20]. In vitro DNA release experiments showed that pDNA was efficiently released from the condensed pDNA particles, when DMAE-SS-PRX with a high cationic density was used [11]. Moreover, we provide evidence to show that cationic density in DMAE-SS-PRX clearly has a positive influence on the efficiency of DNA release in the nucleus in living cells, resulting in high gene expression, as evidenced by imaging the nuclear condensation/decondensation status of pDNA using a new technology [10] Based on the previous results, we hypothesized that a high cationic density in DMAE-SS-PRX would aid nuclear DNA release, resulting in strong transgene expression.…”

“…We previously demonstrated the existence of a close relationship between the efficiency of DNA release and the transfection activity, using an integrated system of R8-MEND and DMAE-SS-PRX [10,11]. It is particularly noteworthy that, from the standpoint of transfection, our integration system, which is comprised of the R8-MEND with DMAE-SS-PRX, was 5-fold greater than that for a conventional R8-MEND with protamine, which is a natural DNA condenser that shows a high transfection activity [18][19][20].…”

“…To date, we reported on the development of an innovative gene delivery system [10,11], prepared by integrating a multifunctional envelope-type nano device (MEND) [5,[12][13][14] and a biocleavable polyrotaxane (DMAE-SS-PRX) [15][16][17] (Fig. 1B).…”