SERS-active Liposome@Ag Au Nanocomposites For Controllable Drug Release

Now,it is important to control the drug release and detect the distribution of drug molecules before and after release.In this work,an innovative nanomaterials,liposome@AgAu nanocomposites is presented for drug delivery,which can not only control the release of drug but also target drug molecules by surface enhanced Raman scattering?SERS?during the release process.And the liposome@AgAu nanocomposites have tunable surface plasmon resonance band from the visible to near infrared.Doxorubicin?DOX?as anti-cancer drug,which has Raman and fluorescence signal molecules,was loaded into liposome@AgAu nanocomposites.After DOX was loaded into nanoposites,the Raman signal was enhanced because of the resonant coupling between the laser and the plasma of the bimetallic nanoshell.Meanwhile,the fluorescence signal was quenched by plasmon resonance energy transfer?PRET?between bimetallic nanoshells and DOX molecules.At the same time,when the laser irradiation,the photons of incident light can motivate the electron of metal nanoshell,stimulated electronic radiates energy outwards,when the temperature reaches phase transition temperature of the liposomes,doxorubicin will be released.The liposomes has a phase transition temperature and the metal nanoshell can trasfer light to thermal,so the the drug can be released by controlled release.Main contents of this paper are as follows:?1?The liposome@AgAu core/shell nanocomposites were prepared.Firstly,the liposome was prepared by the film drying method and ultrasonic dispersion method.The hydrodynamic diameter of liposome is determined as 79 nm.The Ag nanoparticles were prepared by the reduction of silver nitrate?AgNO3?by sodium borohydride?NaBH4?with the protection of the trisodium citrate?Na3C6H5O7?.The diameter of Ag nanoparticle was 4 nm.Secondly,Ag nanoparticles deposited on the surface of liposomes by electrostatic interaction to form the liposome@Ag nanocomposites.Finally,liposome@AgAu core/shell nanocomposites are obtained bythe galvanic replacement reaction?GRR?.The scanning electron microscope?SEM?,transmission electron microscope?TEM?,particle size analyzer and UV-Vis absorption spectroscopy was used to research and analysis these nanomaterials.The influence of the ratio of Ag nanoparticles and acide chloraurique?HAuCl₄?was discussed too.The MTT experiments was used to demonstrate the good biocompatibility of nanomaterials.?2?After loading doxorubicin?DOX?molecules,liposome@AgAu nanocomposites exit lower cytotoxicity by MTT assay.The fluorescence signal from DOX is quenched and SERS signal of DOX is obviously enhanced in liposome@AgAu nanocomposites.The mechanism for fluorescence quench is discussed here,which is due to the plasmon resonance energytransfer?PRET?between bimetallic nanoshells and DOX molecules.For the SERS enhancement,the resonant coupling between light and plasmons is mainly reason.Furthermore,the liposome@AgAu nanocomposites show higher photothermal conversion ability under resonance light irradiation.Under 633 nm laser irradiation,the liposome@AgAu nanocomposites loading DOX can release drug molecules for killing cancer cell.Meanwhile,the SERS and fluoresecence signals from DOX may be observed during drug release.Therefore,this nanocomposite can provide a platform for photothermal controllable drug release and SERS targeting for drug molecules.