| At present,more than 40% of new synthetic chemical entities are lipophilic compounds that are difficult to dissolve in water,thus poor water solubility is one of the most challenging scientific and industrial problems in developing new drugs.There are many ways to improve the solubility of drugs.Among them,it is becoming more and more important to develop nanodrugs by reducing particle size to improve drug solubility.The construction of nanodrugs and release and uptake of drugs essentially are the processes of constructing the micro-nano interface and the mass transfer of the drug in the main phase and the micro-nano interface.In addition to improving the solubility of drugs through the construction of micro-nano interfaces,drug nanometerization can also achieve targeted drug delivery through enhanced permeability and retention(EPR)effects.In recent years,although significant progress has been made in the development of anti-cancer nanodrugs,the nanodrugs used clinically still have disadvantages,including of frequent drug resistance and poor passive targeted drug delivery.New developed nanomedicines also have the shortcomings of resource-consuming trial and error.The used carrier has the potential to induce cancer cell metastasis and is usually toxic to tissues and organs.This thesis used poorly soluble molecules such as paclitaxel,camptothecin,ferrocene,and indomethacin as model drugs.The superiority of building a micro-nano interface to improve the solubility of drugs,the mitochondria-targeting anti-cancer characteristic of berberine,the potential of combination therapy to overcome drug resistance,the advantage of computational simulation in predicting the complex interactions between nanomedicine molecules and the mass transfer behavior of molecules at the micro-nano interface were combined.The construction,mass transfer and mitochondrial targeting characteristics of multifunctional berberine nanomedicine were systematically studied in terms of the formation,targeted uptake,release,biological activity evaluation of nanodrugs and drug delivery at the micro-nano interface.The main research content as follows:(1)Molecular dynamics simulation was used to predict the self-assembly mechanism of the disulfide bond-coupled paclitaxel-berberine conjugate(PTX-ss-BBR),the micro-nano interface was built to form nanodrug PTX-ss-BBR NPs and its anti-cancer activity was studied.Molecular dynamics simulation results found that PTX-ss-BBR could form self-assembly through hydrophobic interaction and ?-? stacking.Experimental results showed that the prepared nanomedicine could target mitochondria to achieve drug delivery and control the release of drugs in the tumor microenvironment.The anti-cancer mechanism indicated that due to the up-regulation of ROS levels and the decrease of mitochondrial membrane potential,the ability of PTX-ss-BBR NPs to inhibit the growth of A549 cells in vitro was enhanced.More importantly,PTX-ss-BBR NPs had the same efficacy as berberine against bacteria closely related to the development of lung cancer.The synergistic effect of paclitaxel and berberine improved the therapeutic effect of conventional chemotherapy drugs on A549 cells.(2)Molecular dynamics simulation was used to predict the self-assembly mechanism of GSH-responsive disulfide bond-coupled camptothecin-berberine conjugate(CPT-ss-BBR)and indocyanine green(ICG),and the conjugate CPT-ss-BBR was synthesized,the micro-nano interface was constructed to form the nanodrug CPT-ss-BBR/ICG NPs and its anti-cancer activity was studied.Molecular dynamics simulation results showed that CPT-ss-BBR and ICG mainly formed self-assembly through electrostatic interaction.The experimental results showed that the prepared nanomedicine had good stability in a normal physiological environment,and had a suitable particle size and uniform monodispersity.The in vitro drug release results showed that p H,light,and GSH could trigger the rapid release of the prepared nanomedicine.CPT-ss-BBR/ICG NPs could specifically target the mitochondria of cancer cells due to their inherent cationic properties,and induce rapid photothermal conversion,high-level ROS production and a large amount of loss of mitochondrial membrane potential after near-infrared light radiation,therefore produced a stronger A549 cell inhibitory effect than camptothecin.(3)Computational simulation was used to predict the mechanism of the self-assembly of glucose oxidase(GOD)induced by ferrocene-berberine(FC-BBR)conjugate and indomethacin(IND),and the synthesized FC-BBR with IND induced GOD self-assembly,and then were wrapped by hyaluronic acid(HA)to construct micro-nano interface to form nanodrug FC-BBR/IND@GOD@HA NPs,and the anti-cancer activity of the nanodrugs was studied.Molecular docking found that FC-BBR and IND could spontaneously combine with17 possible binding sites of GOD;Molecular dynamics simulation results showed that IND could induce GOD self-assembly through van der Waals forces.Experimental results showed that the nanomedicine had the potential to achieve targeted chemodynamic therapy and starvation therapy.The prepared nanomedicine had suitable particle size,uniform monodispersity,and good effects of inhibiting and inducing Hep G2 cell growth and apoptosis.Mechanism studies showed that targeted FC-BBR/IND@GOD@HA NPs mainly blocked cancer cells in the S phase,reduced the mitochondrial membrane potential,and produced reactive oxygen species.More importantly,the nanomedicine could significantly inhibit the migration of cancer cells and potentially prevent the metastasis of cancer cells.(4)The mass transfer process of the drug at the micro-nano interface of the biological membrane was studied by the method of computational simulation.Berberine and its alkyl,hydroxyl and benzyl derivatives were used as model drugs.Through molecular dynamics simulations and density functional theory calculations,berberine was systematically explored in terms of structural properties,interaction energy,and electrostatic potential distribution.The interactions between drug molecules and the phospholipid bilayer and their effects on the interaction between the phospholipid bilayer and the solvent at the interface were researched.The simulation results showed that among the drug molecules modified by different lengths of alkyl chains,the molecules modified by the medium length alkyl chains had a greater probability when delivered to the biomembrane interface and disturbed the orderly arrangement of the phospholipid bilayer in the solvent.This might be account for the fact that a too long alkyl chain easily induced self-folding of the molecule and hindered the delivery of drug molecules into the membrane,while a too short alkyl chain would weaken the hydrophobicity of the drug and was not conducive to the directional mass transfer of the drug.The BBR-OH molecule had a relatively negative binding energy to the biological membrane,and it mainly moved on the polar surface of the membrane.This might be due to the presence of hydroxyl in the molecule,which enhanced the interaction between the drug molecule and the solvent or the polar head of the phospholipid molecule.The benzyl-modified berberine had the potential to enter the phospholipid bilayer for interaction,which might be caused by the rigid planar structure of the benzene ring,which caused it to penetrate into the interior of the membrane. |
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