Figure 3.

Biophysical Properties of Polymeric Gene Delivery Nanoparticles Were Not Affected by pH Nanosensor Labeling

(A and B) Polymeric gene delivery nanoparticles were formed by self-assembly of cationic polymers using the pH nanosensor or unlabeled plasmid DNA and assessed using dynamic light scattering for (A) hydrodynamic diameter and (B) zeta potential, where no statistical differences were observed. Values shown are mean ± SEM of three independently prepared samples. Differences between nanoparticles formulations were assessed using multiple t tests with multiple comparisons corrected for using the Holm-Sidak method. (C and D) Polymer binding strength with labeled pH nanosensor or unlabeled plasmid DNA was compared using a (C) Yo-Pro-1 binding assay (values shown are mean ± SEM of three wells) and (D) heparin binding assay, where only minor differences were observed in polymer-DNA interaction. Values on the heparin binding assay show the w/w ratio of heparin to the mass of polycation per well. A possible increase in binding interaction between pH nanosensor DNA and cationic polymer may be accountable by the presence of carboxylic acid groups in two of the fluorophores used.