Aptamer Guided Liposomes Loaded Upconversion Nanoparticles For Targeted Imaging

During tumor treatment, effective imaging diagnosis can monitor the biological distribution of nanomaterials in vivo, so as to reveal the therapeutic effect of nanomaterials and provide comprehensive information of tumor tissue. In conventional cancer therapy, nanomaterials that fail to distinguish between tumor cells and normal cells often lead to adverse side effects and higher systemic toxicity. Therefore, more and more attention has been paid to the development of multifunctional nano-platform for a variety of biomedical applications. Aptamers are single-stranded oligonucleotide that can specifically recognize their substrates, such as metal ions, small molecule, proteins and even cells. Owing to their high specificity, aptamers can endow the delivery system with robust targeting ability and enhance the enrichment of drugs and imaging agents in tumor tissues, holding great promise in molecular diagnosis and cancer therapy.Here, we designed a NIR-activated optical imaging and target-recognition multifunctional nanoplatforms by the capsulation of poly(acrylic acid) (PAA) coated NaYF4:Yb/Er/Nd@NaYF4:Nd upconversion nanoparticles (UCNPs-PAA) within aptamer-guided liposome (Apt-Lip) to form UCNPs@Apt-Lip. Transmission electron microscopy (TEM) images showed that the composite nanomaterials had a uniform spherical structure, and the UCNPs nanoparticles were successfully loaded into the liposome modified by AS1411 aptamer, and the monodispersity of nanoparticles was good. The Dynamic light scattering (DLS) detected that the hydrated particle size of UCNPs@Apt-Lip modified by AS1411 aptamer changed from 165.6 nm to 209.5 nm, and the zeta potential (-22.7 mV) was lower than UCNPs@Lip (-20.5 mV), which further confirmed that the AS1411 aptamer was successfully connected to the surface of UCNPs@lip. Flow cytometry and targeted cell fluorescence imaging experiments show that UCNPs@Apt-Lip nanostructure has strong ability of target recognition and fluorescence imaging to MCF-7 cells. With the unique properties of movable cores, interstitial hollow spaces, and the functionality of shells, we believe that multifunctional nanoplatforms will have great potential for application in various fields, such as photocatalysis, nanoreactors, drug delivery and tumor treatment.