Fig. 4. Representative degradation and release kinetics of bile salt microparticles.

(A) SEM images of the surface morphology of cholate particles after incubation at 37°C for various time points. Scale bars, 1 μm. (B) Quantified amount of released cholate after incubation of bile salt particles at 37°C for different time points. Fluorescence image of rhodamine-loaded (C) cholate and (D) deoxycholate particles. (E) Release profile of rhodamine from deoxycholate composite particles fabricated in the presence of different amounts of HAuCl₄. The concentration of the particles in phosphate-buffered saline (PBS) was set at 10 mg/ml. Each condition was repeated for n = 3 (error bars are smaller than 1% for all points). Two-way ANOVA was used to analyze (E), and significance for each point was calculated with respect to the corresponding condition fabricated in the presence of 25 mg of gold. ****P < 0.0001.