Construction Of Liposomal Nanocarriers With SERS Activity And Their Interactions With Tumor Cells

The drug delivery systems based on liposome-nanoparticle hybrids enable tumor localization through imaging and simultaneously drug delivery,which makes liposome-nanoparticle hybrids new trends for the investigation of multifunctional drug carriers.Here,the liposome-metal nanohybrid has been proposed to develop a novel liposomal nanocarrier with surface-enhanced Raman scattering(SERS)activity.The SERS signals generated from metal nanoparticles are utilized to track the locations of nanohybrids in tumor cells,which is further employed to study the interactions between liposomal nanocarriers and tumor cells.The experimental results are fundamental for the realization of tumor theranostics based on liposome-metal nanohybrids.The main innovations of this thesis are listed as follows:(1)A liposome-gold nanoparticle hybrids with SERS activity was designed and fabricated.First,functionalized gold nanoparticles were achieved by coating the surfaces of the nanoparticles with Raman reporters and polymers,sequentially.Then,the liposome-gold nanoparticle hybrids were constructed by adsorbing the functionalized gold nanoparticles onto the liposomes,and the SERS activity of the nanohybrids was also studied.Finally,the liposome-gold nanoparticle hybrids were incubated with SKBR3 cells,in which the intracellular SERS performance was evaluated.The experimental results showed that SERS signals could be used to monitor the intracellular locations of nanohybrids.(2)SERS technique was employed to investigate the interactions between the pH-sensitive liposome-silver nanoparticle hybrids and tumor cells.In the experiment,the nanohybrids were achieved by anchoring the Raman reporter molecules tagged silver nanoparticles onto the surfaces of pH-sensitive liposomes.The SERS-active nanohybrids were incubated with HeLa cells,in which the interactions between nanohybrids and HeLa cells were investigated.The experimental results showed that the liposome-silver nanoparticle hybrids were located in the acidic lysosomes,where drug was released.Then the drug molecules diffused across the lysosomes and spread over the whole cytoplasm.The intracellular locations of nanohybrids and drugs were tracked simultaneously using SERS-fluorescence dual modal spectroscopy,which avoided the spectral overlap and provided experimental basis for the carrier-cell interactions and intracellular drug release.(3)The intracellular behaviors of liposome-metal nanohybrids were investigated by SERS technique in order to make insights into the influences of metal nanoparticles.First,MMTAA,a Raman reporter molecule,was employed to conjugate the thermo-sensitive liposomes and gold/silver core-shell nanoparticles.Then,the endocytosis pathway and intracellular fate of the nanohybrids were monitored by SERS signals.Finally,it was revealed that the nanohybrids entered SKBR3 cells through clathrin-mediated endocysotis and remained in lysosomes,which was quite consistent with that of pure liposomes.In addition,liposomes would not affect the SERS activity and photothermal effect of metal nanoparticles,neither.The experimental results suggested a universal rule in the modular design of multifunctional nanohybrids,which was expected to provide a new route for tumor theranostics.