Particles were columned using size exclusion chromatography with sephadex G-50, and release efficiency was estimated by comparing the fluorescence intensity before and after treatment with Triton X-100 (2.5 µL; 5 % w/w) which led to full release of encapsulated cargo. Normalised end fluorescence intensities of LLC column fractions were then compared to a standard curve for CBF in the same buffer/pH environment (See SI Fig. ) to estimate % loading efficiencies (See SI Fig. ). The same fractions were also used to determine passive release of CBF dye at room temperature over 12 hours (Fig. ).