Fig. 3. PGC–PTX NP storage stability and release kinetics. PGC–PTX NPs were stored in solution at 4 °C or lyophilized, stored at –20 °C, and resuspended at given time-points. (a) NP diameter and (b) free/unconjugated PTX content were evaluated over the course of 6 months of storage. SEM micrographs of NPs stored as (c, e) a solution or as (d, f) a lyophilized powder after (c, d) 90 and (e, f) 180 days of storage. PTX release kinetics from 34% and 43% PGC–PTX NPs at 37 °C in 0.3% SDS pH 7.4 phosphate buffer at (g) early time-points (<10 days) and over (h) 70 days. All experiments were performed in triplicate, with data presented as mean ± standard deviation.