In this work, a new theranostic nanoplatform is developed to construct an anticancer drug carrier by integrating the distinct advantages of upconversion nanoparticles (UCNPs) and metal organic frameworks (MOFs) encapsulated with a targeting ligand. Here NaYF:Yb,Er is chosen as an upconversion nanoparticle for its high luminescence properties. Then, folic acid encapsulated Zeolitic Imidazolate Framework-8 (ZIF-8) is directly coated on UCNPs in one step to form a monodispersed core-shell structured nanocomposite (labeled as UCNPs@ZIF-8/FA). The synthesized upconversion nanoscale MOFs (NMOFs) are simultaneously used as a targeted anticancer drug carrier and in cellular imaging. The UCNP@ZIF-8/FA nanocomposites are found to be nontoxic towards the human cervix adenocarcinoma (HeLa) and mouse fibroblast (L929) cell lines via a cell viability assay. It is worthwhile noting that, the anticancer drug 5-fluorouracil (5-FU) is absorbed into UCNP@ZIF-8/FA nanocomposites (loading amount 685 mg g) and also pH responsive drug release is observed. The as-prepared 5-FU loaded UCNP@ZIF-8/FA nanocomposites exhibited greater cytotoxicity towards HeLa cells due to the folate receptor-mediated endocytosis. Our study highlights the potential of developing multifunctional upconversion NMOFs for simultaneous targeted cellular imaging with delivery of anticancer drugs.

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Herein, we report a centrifugal force-driven end-toend assembly of gold nanorods (Au NRs) via the H-bonded interaction of para-aminothiophenol (p-ATP) selectively bound to the longitudinal ends of the Au NRs. The plasmonic hot spots generated due to the Au NR assembly served as a catalytic center for carrying out the photochemical coupling reaction of p-ATP to dimercaptoazobenzene (DMAB). We also demonstrate the degradation of DMAB in the presence of hydrogen peroxide (H 2 O 2 ) at the plasmonic hot spot. The coupling reaction was carried out at the hot spot of the assembled Au NRs upon surface plasmon excitation using a 632.8 nm laser. Surface-enhanced Raman scattering (SERS) kinetic data indicated that the plasmonmediated coupling reaction was 1.6-fold faster at the plasmonic hot spot of the assembled Au NRs than that on the surface of the longitudinal end of the Au NRs. This, therefore, showed a new way of carrying out photocatalytic reactions at the plasmonic hot spot with a higher reaction rate.

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