Construction And Antitumor Activity Study On SPION Based Drug Delivery System

Nowadays,cancer remains a great threat to human health in worldwide.Due to the widespread metastasis with cancer,millions of patients die of cancer each year.Early detection,accurate diagnosis and effective treatment help increase cancer survival rates and reduce suffering.Despite the enormous advances in diagnostic technologies,a substantial number of cancer patients are still diagnosed with metastasis because of the poor selectivity and sensitivity of conventional diagnostic techniques.A variety of therapeutic strategies,such as surgery,chemotherapy and radiation therapy,are widely used in clinical cancer treatment.However,systemic toxicity,drug resistance and low selectivity often lead to an unsatisfactory outcome.Attacking these problems head on,we need developing innovative strategies to improve the cure rate and reducing the side-effects in cancer therapy that are all urgently needed.In recent decades,magnetic nanoparticles have attracted extensive interest for the multifunctions of magneticresonance imaging?MRI?,targeted drug delivery,magnetic enrichment and purification.Furthermore,magnetic nanoparticles can be used as core to construct core-shell structure,which allow the single nanocomposite to exert multifunctions including drug delivery,therapy and imaging.Among kinds of targeted magnetic nanodeliverers,the superparamagnetic iron oxide nanoparticles are particularly interesting since they are devoid of magnetic remanence due to their small size.The purpose of this paper is to adopt the technology of functional modification and assembly of nanocarriers,we used superparamagnetic nanoparticles as the carrier,modifying the surface of citric acid,titanium dioxide,silica and other coatings,and then mounting daunorubicin?DNM?.A drug system with multi-functional targeted delivery was constructed,and the binding mechanism between the targeting system and the protein molecule was studied using spectroscopic techniques and a molecular docking model to evaluate its biological toxicity.The specific research content is as follows:In the fist part,we prepare Fe₃O₄ nanoparticles by coprecipitation Fe³⁺and Fe²⁺in alkaline medium under nitrogen atmosphere,and combine DNM to nanoparticles using a pre-formed Fe²⁺-DNM complex.In addition,the characterization of the drug delivery is presented using Magnetic hysteresis loop,FTIR and TEM.modified superparamagnetic iron oxide nanoparticles were employed to load daunomycin and the drugloadednanospheres exhibited satisfactory size and smart pH-responsive release.The cellular uptake efficiency,targeted cell accumulation,and cell cytotoxicity experimental results proved that the superparamagnetic iron oxide nanoparticleloading process brings high drug targeting without decreasing the cytotoxicity of daunomycin.Moreove,we explored the interation mechanism between SPION-DNM and HSA depengding on the combination of spectroscopic and molecular modeling methods.The results indicate that the drug-loaded delivery could unfold the conformation of protein and increase the exposure of chromophore group in the internal hydrophobic region,leading to a microenvironment change of amino acid residues.protein's conformation is slightly changed?with a-helix decreases from69.30 to 66.75%?in the SPION-DNM delivery process and the biosafety of the drug was thus worthy of attention.The present work not only designed a new SPION drug with high magnetic targeting and cytotoxicity but also gave concerns for the biosafety evaluation of the nanomaterials.In the second part,The Fe₃O₄@TiO₂ core-shell nanocomposites were fabricated via sol-gel processof hydrolysis and condensation of TBOT.the particle size,dispersion and modification effect of magnetic composites were explored with the aid of SEM,TEM,FTIR and other testing methods.In the present study,TiO₂-coated Fe₃O₄nanoparticles?Fe₃O₄@TiO₂ NPs?were employed to load DNM and the drug-loaded Fe₃O₄@TiO₂-DNM Nps exhibited smart pH-controlled releasing and satisfactory cytotoxicity as well as photocytotocity.The combination of prussian blue staining and fluorescence methods evidenced the effortless cell internalization of the fabricated Fe₃O₄@TiO₂-DNM Nps for the cancer cells.The cell cycle status experiments indicated that the as-prepared nanospheres arrested the S and G2/M periods of the cancer cell proliferation in the dark,and further induced the apoptosis under the irradiation of ultraviolet light.The cell apoptotic results revealed that the apoptosis induced by the Fe₃O₄@TiO₂-DNM Nps was in the early stage.The constructed Fe₃O₄@TiO₂-DNM NPs have been endowed with multifunctions that allow them to selectively deliver combinatorial therapeutic payload and exhibit integrated therapeutic effectiveness to tumors.In the third part,Calcium carbonate was then employed as acid activated gatekeepers to cap the mesopores of the MMSN,namely,MMSN-FA-CaCO₃.The formation of the MMSN-FA-CaCO₃ was proved by several characterization techniques viz.transmission electron microscopy?TEM?,zeta potential measurement,Fourier transform infrared?FT-IR?spectroscopy,BET surface area measurement,and UV–Vis spectroscopy.Daunomycin?DNM?was successfully loaded in the MMSN-FA-CaCO₃ and the system exhibited sensitive pH stimuli-responsive release characteristics under blood or tumor microenvironment.Cellular uptake by folate receptor?FR?-overexpressing HeLa cells of the MMSN-FA-CaCO₃ was much higher than that by non-folated-conjugated ones.Intracellular-uptake studies revealed preferential uptake of these nanoparticles into FR-positive[FR?+?]HeLa than FR-negative[FR?-?]A549 cell lines.DAPI stain experiment showed high apoptotic rate of MMSN-FA-DNM-CaCO₃ to Hela cells.The present data suggests that the CaCO₃ coating and FA modification of MMSN are able to create a targeted,pH-sensitive template for drug delivery system with application in cancer therapy.