Synthesis And Application Of "Green" Fluorescent Nanoprobes Based On FRET Principle

Nanomaterials have many excellent optical and chemical properties,which can be used as fluorescent probes for biomedical detection.The development and optimization of the nano-probe has greatly promoted the development of biology,it has been widely used in many fields.The combination of fluorescence resonance energy transfer（FRET）detection technology and functional nano probes has particularly prominent in the fields of living cells testing and photodynamic therapy.The nano probe based on the FRET principle has become a routine method for material detection and dynamic monitoring of biological molecules.The optical non-radiation process provides a valuable research tool for biomedical detection,including early detection and treatment of tumors.In this paper,we discusses the multi-photon excited FRET systems of nano materials in detail.The experimental results show that the FRET systems have good stability and low toxicity.The photodynamic therapy of multi-photon excited FRET systems on MCF-7 cancer cells and in mice tumor were also realized.The main contents of this paper are as follows:1.Detection of silver ions in FITC-CdTe system based on FRET principleCdTe quantum dots were prepared by the synthesis of aqueous phase,and CdTe quantu m dots in different sizes were obtained by adjusting the reaction time.The FRET system was constructed by using fluorescein isothiocyanate and CdTe quantum dots.The method of the rapid detection of metal ions was realized,and the detection limit was 4.2nmol/L.2.The theoretical research on multi-photon excited FRETWe give brief introduction of the process of multi-photon excited FRET systems,based on the nonlinear optical properties of quantum dots,improving the biological application of FRET system.3.Multi-photon-excited fluorescence resonance energy transfer in an aqueous system from ZnSe:Mn/ZnS quantum dots to Hypocrellin AWe achieved FRET system with ZnSe:Mn/ZnS QDs and HA solutions.Four-photon excitation properties of the FRET systems was studied by using ⁵0fs laser pulses at wavelengths of 1300 nm.We apply this system in the treatment of MCF-7 breast cancer cells.When the HA concentration reach to 1mM.The cell killing rate of cancer cells can reach to 84.8%.This study shows that there is a bright future for these materials in biomedical applications.4.The photodynamic therapy study of multi-photon excited CIS/ZnS-ALA systemCuInS₂/ZnS（CIS/ZnS）quantum dots and 5-aminolevulinic acid（ALA）were used to construct a new type of photodynamic medicine“CIS/ZnS-ALA conjugate”.Two-photon and three-photon excited fluorescence resonance energy were achieved.The experimental results show that under 800 nm and 1300 nm femtosecond laser radiation,extremely low concentrations of ALA still can kill more than 60% of MCF-7 breast cancer cell,the treatment of tumors in mice was further achieved.The system has almost no damage on the normal cells without light,which is more suitable for clinical application.