Synthesis And Properties Study On The Gene Delivery Materials And Photoresponsive Nanomaterials For Drug Delivery

Drug delivery system has attracted more and more attention in medical and pharmaceutical fields,since it can enhance the efficiency of various treatment methods.Compared with traditional treatment like chemotherapy,development of drug delivery system can prevent the drugs from degrading during its transporting to target,increase the efficiency of drugs,prolong the time of circulation in blood,increase the bioavailability of the drugs which are poor soluble in water,and deliver the drugs to the appropriate site with high efficiency.Photoresponsive materials have attracted much attention because among the stimuli factors light is the promising select.Light can be tuned by changing the light wavelength and irradiance,and it can also provide spatiotemporal control by adjusting the beam diameter,anatomic target,and timing of application and further to control the drug release.Gene therapy means inserting therapeutic genes to cells or tissues for the supplementation of defective genes.PEIs are cationic polymers.Because of its large number of amino groups,PEIs have positive surface charges,which make them easily to react with negatively charged molecules like DNA.PEIs have been successfully used for in vitro and in vivo gene delivery.However,some studies showed that with the increase of the molecular weight,the transfect efficiency will increase and the toxicity will also increase.So to increase the efficiency of transfect and decrease the toxicity,researchers have made some modification to the low molecular weight PEIs.Firstly,we designed a photoresponsive drug delivery system,we use two photo-cleaved groups(2-nitrophenylethylene glycol and 7-diethylamino-4-hydroxymethylcoumarin)to react with ethanol amine,and dimethyl allyl chloride to get polyester.Then we used emulsion polymerization to gain the photoresponsive nanoparticles,meantime we encapsulated the curcumin or lapachone into the particles.We characterized these two nanoparticles by DLS,UV-Vis absorbance spectra,and SEM.To evaluate the uptake efficacy of the ?-lapachone and lapachone entrapped nanoparticles,we studied cellular uptake and release of the nanoparticles in macrophages cells.The experiments suggested that the nanoparticles were photo-degradable and they can release encapsulates to achieve treatment of the cancers.This method may provide new strategies for the photoresponsive nanomaterials.Secondly,we used disulfide cross-linkers to react with low molecular weight PEIs to get large ones.When the large ones enter the cells the disulfide bonds will be cracked by GSH,then the molecular weight will decrease and the toxicity will also decrease.We designed a polymer PEI-CL,then characterized it by Infrared spectra,and tested the transfect efficiency of GFP,we found that the transfect efficiency was higher than PEI 1.8k.