Plasma Membrane Dynamics And The Transmembrane Release Of Nanodrug By Fluorescence Correlation Spectroscopy

The nanodrug with adjustable physical and chemical properties and controllable release capability is an effective method for precise tumor diagnosis and treatment.The efficacy of nanomedicine depends on the transmembrane and release efficiency of the drug.In order to improve the efficacy of nanodrug,it is urgent to improve the understanding of the physicochemical properties and kinetic characteristics of the plasma membrane,and then provide a reliable plasma membrane model for the study of nanomedicine transmembrane.Secondly,the single-molecule detection and optical microscopy imaging provide a real-time optical high-temporal-resolution detection for the nano-drug transmembrane and release process.In response to the above requirements,this thesis studied the dynamic characteristics and physical and chemical properties of the plasma membrane through one-photon and two-photon fluorescence correlation spectroscopy,and established a model for the self-assembly lipid raft of plasma membrane.The transmembrane and release of gold nanorods and nano-photosensitive were further studied based on the above model.The results would provide important references for research on lipid raft transport of nanomedicine across membranes.The main work of the thesis includes:Constructed a one-photon and two-photon fluorescence correlation spectroscopy.Based on the realization of one-photon fluorescence correlation spectroscopy,the one-photon fluorescence correlation spectroscopy was extended to the two-photon fluorescence correlation spectroscopy.Proposed a self-assembly model of plasma membrane lipid rafts.Two-photon fluorescence microscopy and fluorescence correlation spectroscopy were used to quantify the liquid phase and molecular dynamics of plasma membranes.And the relationship between ordered membrane phase and slow sub-diffusion with the lipid raft structure of the plasma membrane were further analyzed.And it is verified that the liquid phase and molecular dynamics of the plasma membrane change correspondingly with the depolymerization of lipid rafts through drugs and cytokine.On this basis,a model of cell lipid raft self-assembly is established.The model can provide a theoretical basis for further understanding of the physicochemical properties of plasma membrane and drug transmembrane.Optical detecting the transmembrane and light-controlled release of gold nanorods.A light-controlled nanodrug model assembled with gold nanorods and rhodamine B was constructed.Fluorescence correlation spectroscopy was used to quantify the drug-carrying capacity of gold nanorods and monitor the photofragmentation process of gold nanorods.Gold nanorods were coated with lipid amphiphilic molecules to reduce drug toxicity.The transmembrane of gold nanorods depend on the microstructure of lipid rafts was monitored.The process of photofragmentation of gold nanorods to release loaded drugs was monitored in living MCF-7 cells.Finally,the damage to cells caused by the photothermal of gold nanoparticles was quantitative evaluated with microscopy and MTT.Optically characterizing the transmembrane of nano-photosensitizers.Two-photon fluorescence microscopy was used to study the kinetic characteristics of peptidecyanine photosensitizer and its assembly with amphiphilic molecules,and optically quantitatively analyzed the drug release of lipophilic nano-drug carrier in the plasma membrane of the cell.The results show that the transmembrane transport of nano-drugs is related to the liquid phase of the plasma membrane,and reveals the correlation between the intracellular localization and diffusion behavior of lipophilic drugs and the intracellular liquid phase.