Construction Of Efficient Cationic Gene Delivery Vector With Traceability And Antibacterial Function

In recent years,gene therapy has been increasingly used to treat various diseases including cancer and viral infections.Viral vectors are very efficient in gene transfection,but their application in the human body is often frustrated due to the introduction or production of infectious viruses,the small packaging capacity,carcinogenesis,immunogenicity,and potential safety concerns.Nonviral vectors,such as some natural and synthesis polycations have attracted much attention because of the potential advantages in low immunogenicity and possibility for further facile modification and large-scale preparation in the practice of gene therapy.High transfection efficiency and superior cell imaging are required for cationic polymers-based gene delivery system to afford high therapeutic effect and traceability in basic research.However,the problems of low transfection efficiency caused by the high cytotoxicity and unstable cell imaging of cationic gene carriers are still huge challenges in gene therapy.Based on this,the present study proposes the following three strategies to develop efficient gene delivery vectors with imaging and antibacterial functions,to overcome multiple obstacles such as the cellular uptake,nuclease degradation,endosomal escape,carrier dissociation,and intracellular transport during nano-drug delivery.Firstly,supramolecular strategy was applied to construct stimulus-responsive carriers.Supramolecular strategies are considered to be effective methods for improving gene transfection.Through simple and reversible host-guest interactions,stimulus-responsive intelligent supramolecular systems can be constructed.Inspired by the hierarchical structure of virus,a novel virus-mimicking PG/CB/TPE/DNA(system one)gene delivery system is developed via multistep noncovalent self-assembly process between p DNA and the preformed PG/CB/TPE complexes based on host-guest interaction between cucurbit[7]uril(CB[7])and protonated diamine group in poly(glycidyl methacrylate)s derivative(PG),as well as electrostatic interaction between para-carboxyl functionalized tetraphenylethylene(TPE)and cationic PG.The developed efficient multifunctional gene delivery system exhibits stimuli response characteristics and aggregation-induced emission phenomena,thereby enabling gene delivery p H responsiveness and traceability.Moreover,the introduction of TPE and CB[7] endows the self-assembled PG/CB/TPE/DNA complexes virus-mimicking architecture and properties with low cytotoxicity,highstability,excellent endosomal escape,and efficient transfection efficiency,which are expected to be used as a promising gene delivery system.Secondly,model protein was introduced to increase endosomal escape and reduce carrier toxicity.Amphiphilic bovine serum albumin(BSA),a biocompatible protein,can not only reduce the toxicity of the carrier,but also promote rapid endososomal escape by virtue of the protonation of BSA in the acidic endosome.Thus,BSA was introduced into the transfection system as a model protein.Firstly,TPE/BSA nanoparticles(TB NP)were prepared through hydrophobic interaction and hydrogen bonding interaction.Meanwhile,cationic PG was combined with p DNA through electrostatic interaction to form PG/p DNA nanocomposite.Then,PG/p DNA nanocomposite continues to compound with TB NP to obtain PG/p DNA-TPE/BSA(PDTB)(system two)quaternary nanocomposites(NPs).After inclusion of TB NPs,BSA promoted dissociation of the complexes upon being protonated,and the lipophilic TPE reduced endosomal membrane stability,which enhanced endosomal escape of p DNA payload,finally resulting in an excellent gene transfection.On the other hand,PDTB NPs exhibited less positive surface charge than the binary PD complexes.Meanwhile the addition of BSA furher enhanced biocompatibility,both factors contributed to the improved cell viability.Moreover,the AIE feature of TPE,compared to aggregation-caused quenching character of conventional fluorophores,enabled the complex with stably tracking the delivery of p DNA into cancer cells.Therefore,our newly developed PDTB complexes may be a promising candidate vector for traceable,safe,and effective gene delivery.Thirdly,targeting groups and antibacterial groups were introduced to increase cell uptake and reduce cell resistance.Most diseases(such as tumors)are usually accompanied by microbial infections.Symbiotic bacteria can control the cancer response by regulating the tumor microenvironment,especially after surgery,which hinders the successful treatment of cancer.Therefore,it is necessary to develop a multifunctional material with good antibacterial activity,biocompatibility,and drug/gene delivery capabilities for next-generation biomedical applications.In this study,by covalently linking 4-carboxyphenylboronic acid(PBA)and lauric acid(LA)to oligomeric polyethyleneimine(OEI,Mw: 1.8 k Da),the cationic carrier can effectively suppress p DNA to form multifunctional gene delivery vector(OEI-PBA-LA/DNA)(system three)with high antibacterial activity.PBA can specifically recognize over-expressed sialic acid groups on the surface of cancer cellmembranes to increase cell uptake.LA can inhibit the symbiotic bacteria Fusobacterium nucleatum(Fn)in colon cancer tissues and also increase the stability of the carrier through hydrophobic interaction.Therefore,this research is expected to develop a multifunctional polymer gene carrier with high-efficiency antibacterial properties and gene transfection properties.