Preparation and Characterization of pH-Responsive Charge Reversal Nanocomposite for miRNA Delivery

pH-responsive charge reversal loaded miRNA nanocomposite was prepared by electrostatic self-assembly. The morphology, particle size and zeta potential of the nanocomposites were analyzed by transmission electron microscopy and dynamic light scattering. The synthesis of the polymer was analyzed by ¹H-NMR. The zeta-potential changes and cellular uptake effects of the nanocomplexes under different pH environments were investigated. The experimental results show that the surface morphology of the nanocomposite is spherical, and the average particle size is about 135 nm. As the pH value of the solution gradually decreases, the surface charge of the nanocomposite reverses from negative charge to positive charge (from −9.4 to +17.1 mV). Cellular uptake mediated by pH-responsive nanocomposite is selective for tumor cells, and the cellular uptake effect in tumor cells at pH 6.5 was approximately 3 times higher than that at pH 7.4. This pH responsive charge reversal nanocomposite has promising application prospects for gene delivery in the weak acid environment of tumors.