| Antibiotic pollution is growing in intensity,which interferes with the aquatic and soil ecosystem,causing environment destruction and threatening the human health.The low bioavailability and non-targeted behavior of antibiotics lead to the unpleasant side effects on normal cell.In addition,most of the unused antibiotics will be discharged into the environment with body fluids,causing environmental pollution.Therefore,how to improve the efficacy of antibiotics in the body,and reduce the usage and emission of antibiotics simultaneously is an urgent problem.In recent years,magnetic targeted drug delivery has become a promising technology.It can not only achieve targeted drug delivery,but also achieve efficient drug utilization in the body,and reduce side effects.However,it is difficult to develop superparamagnetic,stable,and controllable drug delivery vehicle.Previous studies have shown that Fe3O4 nanoparticles synthesized from plant extracts have good biocompatibility and supermagnetism.Hence,Fe3O4 by green synthesis method have potential as drug delivery carriers.However,the application of green synthesized Fe3O4 in biomedical field is rarely reported.In this paper,magnetic Fe3O4 nanoparticles and its composites were prepared by green synthesis method with the most commonly used fluoroquinolone antibiotics and anticancer antibiotics as model drugs.Their behaviors in drug loading and release were measured,and the corresponding mechanisms were proposed based on the kinetic studies and various characterization results.The main research contents and results are as follows:(1)Fe3O4,which was green synthesized by Euphorbia cochinchinensis and calcined were successfully used as magnetic targeted drug delivery vehicle.Two representative fluoroquinolone antibiotics,ofloxacin and pefloxacin were used as drug models and applied for drug loading and release performance testing.The Fe3O4 were highly magnetic with a saturation magnetization of 58.5 emu g-1.Peaks at 288.5 and 286.5 e V in the C 1s X-ray photoelectron spectra of Fe3O4 were attributed to O-C=O,C-Oand C=O groups,confirming the existence of a substantial organic capping agent on the nanoparticles surface,which facilitated fluoroquinolone loading and release.The results of experiment,characterization,kinetics and thermodynamics analysis show that the loading of ofloxacin and pefloxacin on Fe3O4 is mainly through the chemical adsorption of electrostatic interaction.At the condition of p H 10.5(T=37?),the release efficiency of ofloxacin and pefloxacin from Fe3O4 were reached 99.6%and 57.0%after 120 h,respectively.The results of p H control experiment and characterization demonstrated that Fe3O4 nanoparticles was a potential as a targeted drug delivery system.(2)Doxorubicin hydrochloride(DOX)was used as drug model to measure the optimization condition for adsorption of DOX onto the Fe3O4@Si O2-Glu and its potential mechanism.And the result showed that the adsorption efficiency of DOX reached 92.2%at a concentration of 20 mg L-1 employing 10 mg of Fe3O4@Si O2-Glu at 30?in p H 7.4.However,the adsorption efficiency of DOX was decreased to 18.7%at p H value down to3.0,implicating that the drug releasing process was controlled by p H.Adsorption kinetics were fitting to pseudo-second-order,and the isothermal adsorption conformed to Freundlich isotherm.Drug release experiments indicated that the release of DOX is p H controlled and the cumulative release efficiency reach 63.9%,within 72 h at p H 3.5.The morphology and surface composition of the synthesized Fe3O4@Si O2-Glu were characterized,revealing that the specific surface area being 79.9 m2 g-1 and the size ranging from 30 to 50 nm.The Zeta potential results indicated that Fe3O4@Si O2-Glu were negatively charged in various p H from 3.0 to 8.5.Fe3O4@Si O2-Glu still have the superparamagnetic propoty with a magnetization saturation of 25.9 emu g-1.The DOX was loaded and released by Fe3O4@Si O2-Glu,which was attributed to electrostatic interaction between-COO–on the surface of Fe3O4@Si O2-Glu and-NH3+of DOX.This system has important potential implications for the design of more effective and stable magnetic Fe3O4@Si O2-Glu materials as drug carriers for targeted and controlled drug release.(3)Metal organic frameworks(MOFs)have a high specific surface area and biodegradability due to their unique structure and composition.Besides,owing to the properties of nanomaterials and especially their magnetic properties,Fe3O4 nanoparticles and MOFs composite materials have great potential in the design and application of target drug release.Norfloxacin was used to study the drug release behavior at various p H levels,and antibacterial activity on the Fe3O4@ZIF-8.Results showed the release efficiencies reached 97.5%at 37?after 84 h(p H 7.4).Furthermore,the release model calculation illustrated that the release process fitted well to the Bhaskar model.The transmission electron microscope images show that Fe3O4@ZIF-8 particles'size ranged from 30 to 40nm.Overall,the batch experiments,magnetic property and model analysis of Fe3O4@ZIF-8 confirmed that the composite has potential application for targeted drug delivery system.As well,the antibacterial activities of Fe3O4@ZIF-8 and NOR-Fe3O4@ZIF-8 were tested against Escherichia coli.The results showed that Fe3O4@ZIF-8 had good biocompatibility while NOR-Fe3O4@ZIF-8 can inhibit the grouth of Escherichia coli. |
PDF Full Text Request