A) Dynamic light scattering demonstrated that si-NP diameter was around 40-nm at N/P ratios of 2 or greater, and at N/P = 1, the charge neutrality caused the NPs to be less stable and larger. This is further represented by the ζ–potential, which was slightly negative at N/P of 1, 8.3 mV at N/P of 2, and approximately 20 mV at all N/P of 4 or greater. B) The TEM image confirmed the micellar architecture and size of fresh si-NPs. Releasate si-NPs had a larger diameter of approximately 100 nm as shown both by DLS and TEM (B, bottom), and PUR-release si-NPs also had significantly reduced ζ–potential that was approximately charge neutral.