Synthesis And FRET Bioassay Application Of Near-infrared Quantum Dots

NIR quantum dots,as a new type of fluorescent nanomaterial with emission spectral distribution from 650 nm to 900 nm,have outstanding advantages in the field of biological imaging and biological detection.Comparing with the traditional quantum dots,the penetration depth of near-infrared quantum dots is large and the interference from the auto-fluorescence of the tissues is extremely small.These advantages determine that the near-infrared quantum dots have unique application value in the field of biomedical detection.Among them,the effectively combination of near-infrared quantum dots and fluorescence resonance energy transfer(FRET)detection technology has particularly prominent in the fields to reveal the weak changes in cancer cells.In this thesis,the preparation,characterization,surface modification and biological application in fluorescence resonance energy transfer of InP/ZnS QDs have been studied.Firstly,the InP/ZnS quantum dots with the emission peak at 720 nm were prepared by oily synthesis method.InP/ZnS QDs were surface modified by trimercaptopropionic acid(MPA)in order to apply it in the field of biological detection.A series of characterization(transmission electron microscopy,absorption spectroscopy,emission spectroscopy and dynamic light scattering particle size analysis)of InP/ZnS quantum dots were studied.After successfully preparing InP/ZnS quantum dots,we constructed a fluorescence resonance energy transfer(FRET)system using the prepared near-infrared InP/ZnS quantum dots and the near-infrared dye Cy7.Using this FRET system,we achieved a high sensitivity solution pH measurement,the detection accuracy can reach to 0.1.Finally,fluorescence imaging of MCF-7 breast cancer cells in vitro and pH detection of cancer cell liquid were studied.The research shows that the FRET system constructed by near-infrared InP/ZnS quantum dots has good stability,low toxicity and high sensitivity to pH.It can be used in the field of bio-fluorescence imaging and early diagnosis of cancer.