Development And Application Of Nucleic Acid-based New Multifunctional Nanosystems

With the development of nanotechnology and life sciences,nucleic acid molecules have been widely applied in the fields of nanostructures,biosensors and biomedicine due to their unique features of easy synthesis,programmability and self-assembly ability,resulting in rapidly development of nucleic acid nanotechnology.Nucleic acid nanotechnology has obvious advantages over other carriers and treatment methods,which make it popular in the researches of nanomedicine,biosensors and nanorobot.Currently,nucleic acid nanotechnology has become the most progressive part in nanoscience.In the field of nucleic acid nanotechnology,nucleic acids have lots of fundamental properties,such as gene regulation,Watson-Crick base pairing,programmability,self-assembly,automatic modular synthesis and molecular recognition.Based on the properties of gene regulation and molecular recognition,nucleic acids can be designed as drugs with the functions of therapy and target,to participate in the treatment of various diseases.It can also be planed and self-assembled into specific structures for life science applications.However,many challenges of the traditional nucleic acid nanocarrier,such as short half-life in blood,limited residence time within cells and tumors,the tedious and time-consuming design,and costly services,significantly limit the practical application of nucleic acid nanotechnology.Meanwhile,nucleic acid drugs are overwhelming because of a series of defects such as restricted cell internalization,immunoreactivity,short half-life time,and serious side effects.Moreover,combining the functions of drugs and nanocarriers,the construction and application of the multifunctional nucleic acid nanomaterial with an integrated functions functions of target,therapy,delivery or otherwise,have attracted a lot of attention.Based on the advantages and challenges of nucleic acid nanocentrials and nucleic acid drugs,a series of new multifunctional nanocentrials have been developed for therapeutic research.The specific contents are as follows:(1)To improve the loading capacity of ModRNA,a biomineralized nanocarrier for ModRNA(ModRNA@ZIF-8@AS1411)was developed for targeting treatment of cell senescence.p H-sensitive and biomineralized nanoparticle ZIF-8 was formed by Zn²⁺and 2-methylimidazole through a"one-pot"process,where ModRNA could be encapsulated through N1-Zn²⁺-O(P)interaction,to form biocompatible ModRNA@ZIF-8.In order to improve the dispersion and cell internalization of ModRNA@ZIF-8,AS1411 was modified on the surface of ModRNA@ZIF-8 through PO₄^3--Zn²⁺interaction to form the targeting nanocarrier ModRNA@ZIF-8@AS1411.Once ModRNA@ZIF-8@AS1411 specificly recognize and entry into the cells,it will disintegrate in the acid microenvironment of lysosomes,leading to the imbalance of the microenvironment of lysosomes and a lysosome fracture.Meanwhile,the disintegration of ModRNA@ZIF-8@AS1411 will release the ModRNA inside into the cytoplasm,thus realizing the translation of ModRNA and expression of protein.Furthermore,the catalase ModRNA can efficiently express catalase protein in the cytoplasm,so as to relieve the oxidative pressure brought by cell senescence for the treatment of cell senescence.(2)Compared with traditional DNA nanostructure,DNA nanoflower has attracted our attention due to its simple design and synthesis method,high drug loading capacity resulting from dense and stable porous structure,resistance to enzymatic degradation,long blood half-life and long retention ability in disease regions.However,many challenges of DNA nanoflowers have to overcome.For example,the complexity of rolling circle replication technology makes it difficult to control the size of DNA nanoflowers,and its dense and stable structure also leads to low bioavailability of drugs in the treatment of diseases.Based on this,we developed a size adjustable and near infrared light-activated DNA nanoflower-inorganic nanoparticle composite drug delivery system(NFs-Pd)for photothermal therapy/chemotherapy synergistic treatment of tumors.With the participation of Pd nanosheets,the long DNA strand resulting from RCR could be adsorbed on the surface of Pd nanosheets through hydrogen bond,so as to endue NFs-Pd with photothermal activity.Meanwhile,the DNA nanoflower frames also greatly increased their drug loading capacity without any complex modification of Pd nanoparticles.Importantly,the photothermal effect of Pd nanosheets could greatly enhance the drug release of NFs-Pd/Dox.NFs-Pd with controllable size,near-infrared light activation and enhanced drug release capability,shew great potential in the photothermal therapy/chemotherapy synergistic treatment of tumors.(3)Based on the advantages of DNA nanostructures and nucleic acid drugs,we engineered bioinspired,size-controllable,self-degradable cancertargeting DNA nanoflowers(Sgc8-NFs-Fc)via the incorporation of an artificial sandwich base.More specifically,the introduction of a ferrocene base not only resulted in the size controllability of Sgc8-NFs-Fc from 1000 to 50 nm but also endowed Sgc8-NFs-Fc with self-degradability in the presence of H₂O₂ via Fenton's reaction.Here,Sgc8-NFs-Fc was a nanocarrier with high loading capacity and one kind of nucleotide drugs to improve oxidative stress in cells and drug release of Sgc8-NFs-Fc/Dox.In vitro experiments confirmed that Sgc8-NFs-Fc/Dox could be selectively taken up by protein tyrosine kinase 7(PTK7)-positive cancer cells and subsequently cleaved via Fenton's reaction,resulting in rapid release kinetics,nuclear accumulation,and enhanced cytotoxicity of their cargo.In vivo experiments further confirmed that Sgc8-NFs-Fc has good tumor-targeting ability and could significantly improve the therapeutic efficacy of doxorubicin in a xenograft tumor model.On the basis of their tunable size and on-demand drug release kinetics upon H₂O₂ stimulation,the Sgc8-NFs-Fc nanocarriers possess promising potential in drug delivery.(4)Inspired by versatility of DNA and the compact and stable porous structure of the nanocarrier,we herein reported a customizable and adipocyte-targeted antioxidative nanostructure(TADN)using DNA nanoengineering for the treatment of obesity.TADN could be used as an antioxidant drug based on the antioxidant property of DNA,and a nanocarrier to encapsulate a large number of antioxidant TA,for the synergistic antioxidant effect of DNA and TA.The antioxidant tannic acid(TA)could be interacted with DNA strand resulting from RCR through hydrogen bond,to shrink the micron meter TDM from?1000 nm to?100 nm and form the multifunctional and extensively antioxidant TADN.Exhaustive molecular,cellular and in vivo studies are provided to better understand the molecular and physiological basis of the engineered DNA nanostructures,showing adipocyte-targeted delivery and robust scavenging effects towards various RONS generated during adipogenesis.More impressively,they are also capable of suppressing multiple sources of inflammatory activation for minimized crosstalk between adipocytes and inflammatory cells.Systematic in vivo evaluation in a mouse model of high fat diet-induced obesity clearly demonstrates that DNA nanostructures can be a robust antioxidant for controlling weight and effectively protecting liver against steatosis.In addition,the completely natural ingredients of the engineered nanostructure,along with the adipocyte-specific property,could minimize toxicities and off-target influence on redox and cytokine balance elsewhere in the body,thus offering safety advantages for potential long-term administration and patient compliance.DNA nanotechnology consists of DNA dynamic nanotechnology that focuses on dynamic strand displacement and DNA structural nanotechnology that focuses on creating various DNA structures.DNA nanoengineering can be defined as a project that building dynamic and static nanodevices by taking advantage of DNA nanotechnology.DNA engineers don't pay too much attention to the natural function of DNA as the carrier of genetic information,but use DNA strands as molecular materials.With reasonable design,DNA strands can hybridize or displace in a certain way so that some molecular signal can be transmited and some fancy structures can be formed.The rigid principle of Watson-Crick base pairing,the programmability and the ease of DNA modification allow the creation of series of DNA dynamic/structural nanotechnology-based reaction network or nanodevices.