Construction And Anticancer Research Of Nano-drug Delivery System Based On MnO₂ Nanosheets And DNA Vesicles

At present,although people’s living standards have improved,the incidence of cancer is increasing rapidly,which has drawn the attention of people all over the world.Researchers are trying to cure cancer by using various strategies.Conventional chemotherapy,as one of the most commonly used cancer treatments,is still unsatisfactory due to significant side effects and poor targeting ability of anticancer drugs.To overcome these problems,targeted drug delivery systems（TDDS）,especially nanocarrier-based TDDS,have been intensively researched and developed.Nanocarriers have the advantages of good modification ability,large drug loading,and tunable physicochemical properties,making them ideal for encapsulating anticancer drugs and changing their stability,solubility,and in vivo behavior.Meanwhile,the surface properties of nanocarriers can enhance their blood circulation residence time and enable more precise targeting.However,nanocarriers also have many shortcomings,such as the toxic and side effects of the material itself,poor repeatability,etc.,which make it difficult to meet the standards for clinical use,thus prompting researchers to develop more safe,non-toxic and efficient drug delivery systems.Using human endogenous,safe and non-toxic substances as raw materials to assemble nanocarriers that can not only be used to load anticancer drugs,but also directly enter cells is the current research trend.In this paper,manganese dioxide nanosheets and DNA vesicles are used as drug-carrying units to construct a composite nanoprobe drug-carrying system based on the synergistic effect of multiple therapies for anti-cancer research.The specific research contents are as follows:1.MnO₂nanosheet-based nanomedicines induce ferroptosis through multiple pathways for cancer therapyWe used manganese dioxide nanosheets（MnO₂-NS_S）as a carrier to modify transferrin（Tf）,dihydroartemisinin（DHA）and down-regulate glutathione peroxidase 4（GPX4）on its surface.A multifunctional nanosystem（Tf-DHA-ASO-MnO₂）for tumor therapy was constructed by using a sense oligonucleotide sequence（ASO）.After Tf-DHA-ASO-MnO₂is targeted and transported to tumor cells,it can promote cell ferroptosis through synergistic effects such as glutathione（GSH）depletion,reactive oxygen species（ROS）generation,and down-regulation of GPX4 expression,effectively inhibiting tumor growth..At the cellular level,the Tf-DHA-ASO-MnO₂nanosystem exhibited high cytotoxic activity against different cancer cells.In vivo,the nanosystem significantly inhibited tumor growth in 4T1 tumor-bearing mice.Therefore,the results of this study demonstrate that our designed composite nanosystem can induce ferroptosis in cells through multiple pathways,thus providing a very promising platform for tumor therapy.2.Aptamer-functionalized 2F-DNAsomes（DNA vesicles）for targeted drug delivery to cancer cellsDue to the unique hydrophobic and oleophobic physicochemical properties of perfluorocarbons（PFs）,here we prepared a conjugate of bifluorinated lipids and oligonucleotides that can self-assemble into liposomes with The surface of the structure is modified with DNA sequence DNA vesicles（2F-DNAsome）.As a self-assembled nanocarrier for DNA amphiphiles,2F-DNAsome has good biocompatibility,high drug encapsulation ability,enhanced stability and DNA surface modification ability.After the nucleic acid aptamer was integrated into the surface of 2F-DNAsome by sequence-specific hybridization,the aptamer-functionalized 2F-DNAsome could selectively deliver chemotherapeutic drugs to targeted cancer cell lines.The study shows that the2F-DNAsome structure combined with the unique physicochemical properties of PFs not only enhances its stability,but also shows the potential for targeted therapy of cancer,making it a promising candidate nanocarrier for targeted drug delivery.3.Construction of 3F-DNAsome（DNA vesicle）and anticancer researchThis project constructed a new multifunctional DNA vesicle:3F-DNAsome.The methyl trisperfluorobenzoate synthesized by organic reaction is hydrolyzed and acidified to finally generate trisperfluoro-benzoic acid,which can be esterified with NH2-DNA under certain conditions to prepare DNA-trisperfluorododecane It is a base amphiphilic compound,which can self-assemble in buffer to form a surface modified with a DNA sequence 3F-DNAsome with a liposome structure.Compared with the synthesis conditions and process of 2F-DNAsome,3F-DNAsome can synthesize amphiphilic molecules in a very short time by chemical one-step synthesis.The synthesis method does not require the use of a DNA solid-phase synthesizer,and saves time and effort under the premise of low cost.Further studies have shown that the assembled 3F-DNAsome has better stability because the hydrophobic part of the DNA amphiphilic molecule is composed of three perfluorododecyl groups,the DOX-loaded nano-drug loading system 3F-DOX/DNAsome can be obtained.Cytotoxicity tests show that the drug-loading system can enter cancer cells in the form of endocytosis,and effectively release drugs to induce apoptosis of cancer cells,which shows a very promising potential value in the field of anti-cancer research.