PUA/PSS/Nano Au Hybrid Hollow Microcapsules: Self-assembly Preparation And Smart Drug Delivery Property

The multi-responsive drug delivery systems made of near Infrared(NIR) responsive gold nanoparticles(Au NPs), positively charged p H-/thermal-responsive aliphatic poly(urethane-amine)(PUA) and hollow hydroxyapatite(HAP) were successfully fabricated at the first time by Layer by Layer(Lb L) self-assembly technique in the present research. The drug release poverties of the systems at different conditions have been studied. The present paper provides a facile and green route to fabricate smart hybrid hollow drug carriers by combining inorganic microparticles, metal nanoparticles and polyelectrolytes, which also endows the NIR-responsive microcapsules with multi-responsiveness and thus expands the application of NIR-responsive drug carriers. The research is highly attractive for drug delivery systems. There are two major sections in this paper:Firstly, PUA/PSS/Au hollow microcapsules based on Mn CO3 template were successfully fabricated via Lb L technique. TEM, FESEM characterization and the doxorubicin hydrochloride(DOX) release results demonstrated that the microcapsules exhibitied distinguished NIR/p H/temperature responsiveness and the morphology of microcapsules has changed after NIR laser irradiation, and the morphology exhibited different forms after laser irradiation at different p H conditions. At p H 7.4, microcapsules could maintain their intact structure after NIR laser irradiation and the drug release rate was relatively slow, while at p H 4.5 the microcapsules were destroyed after laser irradiation with a fast drug release rate, indicating that the microcapsule morphology and the corresponding NIR-responsive drug release are strongly dependent on the p H value and temperature of the media.Secondly, multi-responsive hybrid microparticles based on hydroxyapatite(HAP) were successfully fabricated. Briefly, calcium carbonate microparticles were converted to HAP via hydrothermal method, then PUA, PSS and Au NPs were absorbed onto HAP by Lb L technique, and finally HAP/PUA/PSS/Au hollow hybrid microparticles were easily abtained by removing the Ca CO3 core. TEM characterization confirmed the hollow structure of the microparticles and the successfully absorbed of Au NPs. FESEM, EDX and FT-IR characterization confirmed the HAP/PUA/PSS/Au hollow hybrid microparticles were achieved by HAP hollow microparticles as the core and the surface of polyelectrolyte multilayers. The ζ-potential results demonstrated that the electrostatic interaction and hydrogen bonding between aliphatic PUA and PSS contribute to the formation of the multilayer polyelectrolytes. The drug release results demonstrated that the hybrid microparticles with good p H/temperature/NIR multiple responsive property and the drug loading efficiency of HAP/PUA/PSS/Au hollow hybrid microparticles was higher than that of HAP microparticles, which was due to the the inner hollow space plays an important role in enhancing the drug loading efficiency of hybrids.