Correlation Between Surface Property And In Vivo Fate Of Nano-Drug Delivery System

The in vivo fate of nanoparticle delivery system corelated closely with its surface properties.The surface properties of nanoparticles can be modified and optimized based on their effects on its in vivo fate.To improve therapeutic effectsof nanoparticles,positively charged nanoparticles can effectively enter tumor cells,increase nanoparticle penetration throughout the tumor site via the possibly intercellular transfer process,and increase the drug concentration in the tumor cells by its superior cellular uptake.Moreover,the proton sponge effect of positively charged nanoparticles could also achieve endosome escape.In addition,the surface hydrophobicity can be altered by adjusting the PEG density on the surface of nanoparticles,which has been proven to significantly regulate its interaction with macrophages.However,the surface of nanoparticles would rapidly adsorb a variety of proteins due to opsonization after entering the physiological micro-environment in vivo.These adsorbed proteins determine the complicated interactions occurring at the bio-interface between cells and nanoparticles,which could further affect their in vivo fate ultimately.Therefore,it is quite important to study the physicochemical properties and protein adsorption of nanoparticle at the same time.In this dissertation,we firstly studied the effect of cancer treatment by regulating the surface charge and PEG density of nanoparticles.In the later stage,further research was conducted by establishing the correlation between nanoparticle protein binding properties and in vivo fate.It was promising to predict complicated in vivo fate based on surface properties of nanoparticles.The main content of this dissertation is divided into three parts as below:1.We have synthesized cisplatin conjugated polylactic acid prodrugs,and a series of positively charge nanoparticles was obtained by using polyethylene glycol polylactide(mPEG-PLA)as main part,with the assistance of cationic lipid DOTAP.The cationic lipid assisted nanoparticle(CLAN)promoted cellular uptake and intracellular release of cisplatin due to the reduction environment of cancer cells,which resulted in the increased DNA binding with platinum drug and DNA damage,leading to enhanced apoptosis induction and proliferation inhibition in vitro.Cationic nanoparticles further enhanced the transvascular transportation and cellular internalization,without significantly reducing the blood circulation time.The CLANs exhibited pronounced cellular accumulation in tumor,and caused significant cytotoxicity by increasing intracellular drug concentration of tumor cells,suggesting cisplatin resistance to cancer cells was overcome.2.To further establish the correlation between in vivo fate of nanoparticle and protein binding property,we prepared a library of PEG-PLA nanoparticles with different PEG densities.The surface hydrophobicity and protein binding property were studied using ITC and MST,protein association constant Kd was chosen as the characteristics of biointerface between nanoparticle and cells.In vitro macrophage uptake was detected and it was correlated positively with Kd.There was a significant correlation between in vivo fate with protein association constant even for further research on in vivo blood clearance and Kupffer cells uptake.It was demonstrated that the in vivo fate of nanoparticle could be predicted by protein binding property.This is the first research trying to estract a more simplified parameter related with nanoparticle surface property to predict macrophage recognition and blood clearance of nanoparticles in vivo.3.The influence of the surface hydrophobicity was as important as surface charge.Therefore,we further studied the effect of surface hydrophobicity(PEG density)and positive charge on the knockout of disease gene of nanoparticle delivery system.We proved that the in vivo delivery efficiency into neutrophils of CLANs was dependent on their surface PEG density and surface charge.The CLAN with a lower surface PEG density and a higher surface charge was better internalized by neutrophils in vivo.Then,we utilized the optimized CLAN to deliver pCas9/gNE to disrupt the NE gene of the neutrophils in HFD-induced T2D mice.CLANpCas9/gNE was able to down-regulate NE expression both in the liver and eWAT,which subsequently improved the glucose tolerance and insulin sensitivity in T2D mice.We successfully achieved modulating the function of immune cells by regulating the properties of nanoparticles to deliver CRISPR/Cas9.