dissociated nanogels will further react with the water soluble pdpa b pama polymer chains because the reaction between amino and epoxy groups can take place easily in weakly acidic solutions consequently the zeta potential of the system keeps on increasing after the complete dissociation of the composite nanocontainers given that more and more positively charged pdpa b pama chains are linked on the surface of nanogels a promising application for these composite nanocontainers is in the field of targeted drug delivery vehicles along with high target specificity and selectivity these vehicles need to possess excellent encapsulation stability during circulation fret was used to evaluate the encapsulation stability of the composite nanocontainers jiwpanich et al 2010 j am chem soc 132 10683 10685 a lipophilic fret pair 3 3 u2032 dioctadecyloxacarbocyanine perchlorate dio donor and 1 1 u2032 dioctadecyl 3 3 3 u2032 3 u2032 tetramethylindocarbocyanine perchlorate dii acceptor was chosen for this measurement the composite nanocontainers were formed from the dio encapsulated micelles and dii loaded nanogels fig2 a and b show the fret behavior of the composite nanocontainers composed of pdpa 30 b pama 15 micelles and nanogels with different crosslinking percentages u03bb ex 450 nm after mixing the nanogels with the micelles to prepare composite nanocontainers the intensity of the dio emission peak at around 480 nm decreased slowly with a gradual yet.