Construction Of Bacteria-driven Microtubule With Drug Loaded For Antithrombolytic Therapy

In addition to cancer,acute myocardial infarction,stroke,deep vein thrombosis,pulmonary embolism,atherosclerosis and other symptoms have gradually become the main cause of morbidity and mortality,and thrombosis is a key event inducing these diseases.Therefore,the development of antithrombotic drugs has received great attention.Antithrombotic drugs are conceptually classified into anticoagulants,antiplatelet agents,and fibrinolytic drugs.Antithrombotic drugs can be classified into anticoagulant drugs and thrombolytic drugs.Traditionally,anticoagulants have long been considered to prevent thrombosis because they only inhibit thrombus growth and are not thrombolytic.Thrombosis can be dissolved by thrombolytic agents,and thrombolytic agents have better thrombolytic effects than anticoagulants,but are also associated with greater bleeding side effects.Therefore,in the treatment of thrombosis,how to reduce side effects,which has important clinical significance.In this paper,styrene-maleic anhydride copolymer?PSMA?fibers with an average diameter of about 0.9?m were prepared by an electrospinning technique,and then a polydopamine?PDA?layer was deposited using a fiber as the template.Urokinase?uPA?and the salt algae polysaccharide?Fu?were mixed into the PDA layer to obtain ^FuPDA_uPA@PSMA fibers.Then,the short fiber with a length of about 2?m was prepared by cryosection,and the core layer was dissolved to obtain the drug-loaded microtube(^FuMT_uPA).Escherichia coli Nissle 1917?EcN?was loaded into ^FuMT_uPA to construct a self-operating targeted drug-loaded microtubule(EcN@^FuMT_uPA)containing the targeting group Fu with an average velocity of approximately 7.6?m/s.The release of uPA in vitro showed that EcN@MT_uPAPA and EcN@^FuMT_uPA had a slow release rate,with a cumulative release of 81.0%and 80.0%of the drug at 20 h.In vitro targeting results indicate that EcN@^FuMT_uPA has optimal targeting.In vitro simulated thrombus infiltration experiments showed that EcN@MT_uPA can diffuse into the interior of the thrombus,and the clot lysis is higher than the non-moving MT_uPA.In the in vitro thrombolysis experiment,EcN@^FuMT_uPA slowly releases uPA after targeting the blood clot,so that the concentration of uPA around the clot is continuously increased,and further moves to the inside to promote clot lysis.Pharmacokinetic analysis showed that the half-life of uPA can be extended after loading uPA into microtubules.The results of drug distribution in vivo showed that EcN@^FuMT_uPA had the highest retention at the thrombus.The bacterial distribution in vivo showed that the bacterial content of EcN@^FuMT_uPA in the thrombus site was more than three times that of the EcN@MT_uPA group,further indicating that EcN@^FuMT_uPA can effectively target thrombus.In vivo thrombolysis results show that EcN@^FuMT_uPA has the best thrombolytic effect.EcN@^FuMT_uPA?1/2?,which halved the dose of uPA,also had a higher thrombolytic effect than free uPA during 10 h of treatment.This further proves that the drug-loaded microtubule can effectively promote the dissolution of thrombus under the combined action of motility and targeting function.The results of in vivo bleeding experiments showed that free uPA increased bleeding time,while drug-loaded microtubules did not differ much from the normal group.In vivo toxicity was assessed by blood routine and blood biochemical tests.The results showed that the drug-loaded microtubules did not produce significant toxic effects.