Preparation Of Fullerene-based Nanomaterials And Their Applications In Photodynamic Therapy And Bioimaging

The unique molecular size,three-dimensional cage structure and a huge non-localized conjugated electronic structure of fullerenes endow them with unique physical and chemical properties,so they have broad application prospects in the fields of energy,environment and biomedicine.The facile modification of carbon cages could introduce abundant functional molecules,thereby improving the biocompatibility of the pristine fullerenes and expanding their applications in the field of biomedicine.In this thesis,two kind of fullerene-based nanomaterials were designed and synthesized,and their applications in bioimaging,detection and photodynamic therapy are studied respectively.The details are as follows:1.Rational design and construction of fullerene derivatives play significant roles in the development of their applications for sensing,marking and imaging in the biomeidical fields.In the present work,a novel type of C60 fluorescent nanoparticles(C60 FNPs)were synthesized by the combination of thiol-ene chemistry and modification with folic acid(FA).The as-prepared C60 FNPs exhibited intense blue luminescence with a relatively high quantum yield(QY)of 26%,which is higher than any other reported fluorescent fullerene-based nanomaterials.Moreover,they revealed superior photobleaching resistance under constant UV lamp illumination for 5 h and excellent photostablity after 9 months of storage in water.Due to the mutual electron transfer,the obtained C60 FNPs were capable of a sensitive and specific probe for FA detection and quantization,with a liner range of 0.24 to 80 ?M and a detection limit of 0.24 ?M.Satisfactory recoveries(95.4-105.2%)were obtained from a series of actual samples,further confirming the feasibility of this nanoprobe.Additionally,taking advantage of the FA moiety of C60 FNPs,they had easy access to penetrate into particular cancer cells with higher expression levels of folate receptors(FRs),thereby achieving the function of targeted cellular imaging.C60 FNPs can be used as an efficient FA detection and bioimaging probe in the field of biomedicine.2.Herein,the water-soluble C60-COOH derivative was first obtained through the Bingel cyclopropanation of C60,and then MnO2 nanoparticles were loaded on it by the hydrothermal reaction.Finally,the tumor targeting molecule folic acid was conjugated with the aminated polyethylene glycol to synthesize the multifunctional nanocomposite C60-Mn-PEG-FA.The structural composition and water dispersion were characterized by FTIR,UV-Vis,XPS and DLS.The results show that the material has nanometer size,and has good water dispersibility and stability.In vitro and cell experiments show,the characterization results demonstrated that C60-Mn-PEG-FA not only achieved magnetic resonance imaging(MRI)at low pH,but also improved the O2 production.At a low concentration of 40 mg/L,when exposed to natural light(100 mW/cm2)for 5 minutes,it targeted and killed 82%of tumor cells without damaging normal cells.The prepared multifunctional C60-Mn-PEG-FA nanocomposite exhibits a significant light-induced damage effect of targeting cancer cells in vitro and at cell level,and is expected to become a potential integrated diagnosis and treatment preparation for clinical medicine.