Preparation And Bio-application Studies Of Nanodiamond/Rare-earth-complex Nanocomposites

Nanodiamond is one of the most important carbon nanomaterials,which have high chemical stability,low toxicity,good biocompatibility and versatile surface chemistry.And nanodiamond have attracted much attention in bio-medical area recently.In view of the advantages of nanodiamond and the ongoing prevail of multifunctional nanoparticles in diagnostic-therapy area,we come up with the idea to construct a rareearth hybridized multifunctional platform based on nanodiamond,which is expected to simultaneously enable targeted drug delivery and bio-imaging.In this article,we focus on the preparation,characterization and bio-medical experiments of the rareearth-nanodiamond nanocomposites.The main points of this essay are as follows:1.Preparation and bio-application study of nanodiamond-based/ rare-earth(Eu,Gd)hybridized multifunctional nanocompositesThe nanocomposites is fabricated by binding the Eu,Gd complexes onto the surface of functionalized nanodiamond through a chemical route.The characterization results shows that the as-synthesized nanoparticles is in a size ranging from 100 to 200 nm,and have excellent fluorescence and paramagnetic properties.In-vitro and in-vivo fluorescence imaging were carried out to examine the utility of ND-TTA:RE in bioimaging.The results shows that the cancer cells could be effectively labeled by the ND-TTA:RE nanoparticles and the red emission under the skin of unhaired rats could be observed by naked eyes after subcutaneous administration.In addition,the MRI experiment shows the ND-TTA:RE could effectively reduce the relaxivity of H nucleus,which lead to a concentration-dependent T1-weighted image and thus could be potentially used as contrast agent in MRI.The drug loading and in vitro release experiments shows that the ND-TTA:RE drug loading rate reach 37.5% and exhibit an p H-responsive drug-release property.The MTT assays were carried out to examine the toxicity of ND-TTA:RE nanoparticles.The result shows there is no obvious toxicity observed during the experiment.And the ND-TTA:RE-Dox shows enhanced therapy in the cell cytotoxicity experiment,which could be could be attributed to the enhanced uptake by cancer cells induced by the interaction between the positive-charged surface of nanodiaond and the cytomembrane.The results above indicate that the ND-TTA:RE could be potentially used as a multifunctional nanoplatform for simultaneous bio-imaging and targeted drug delivery.2.NDs-Na Gd F4:Yb,Er nanocomposites for simultaneous UCL/MR imaging and drug deliveryNa Gd F4:Yb,Er Upconversion nanoparticle(UCNP)is well-known for its excellent NIR excited Upconversion luminescence(UCL),which make it a promising candidate for bio-medical imaging.In addition,the nanodiamonds have been widely used as nanoplatform for drug delivery for its superior physical-chemistry properties.To combine the advantages of both NDs and UCNP,we com up with the idea to couple the NDs with UCNP to a multifunctional nanocomposites.Firstly,we fabricated UCNPs through solvothermal method,which was characterized to have a uniform size of 200 nm and show good upconversion luminescence under 980 nm laser excitation.And then the ND-UCNP nonocomposites was synthesized through amido bond formed between functionalized NDs and UCNP.The toxicity of UCNP,NDs,ND-UCNP were carried out toward Hela cells,and the result shows that the viability and morphology of Hela cells were not significantly influenced in the concentration ranging from 0 to 500 ug/m L for all experiments,which make it possible for NDUCNP to be used in bio-medical applications.In all,these results suggest that the synthesized ND-UCNP nanocomposites have good biocompatibility,special surface structure which facilitate the loading of drugs,and the excellent UCL/MR imaging potential,making it a promising multifunctional nanoplarform for simultaneous diagnosis and therapy.