The Fabrication Of Biocompatible Nanoprobes For Tumor Imaging And Therapy

Background and Objective: High-performance magnetic resonance?MR?imaging contrast agents are the key to reliable and accurate diagnosis of diseases using MR imaging technique.Especially,dual-modal MR imaging nanoprobes that integrated the advantages of high contrast effect and impressive sensitivity of T1-and T2-weighted MR imaging respectively have attracted more and more attention in recent years.However,the current methods for the fabrication of dual-modal MR imaging nanoprobes suffer from tedious synthesis procedure,harsh synthesis condition and ambiguous toxicity,strongly hindering their clinic transformation.Herein,we proposed a biomineralization approach for the fabrication of bovine serum albumin?BSA?-Fe₃O₄ nanoparticles with undoubted biosafety and robust T1 and T2 MR imaging ability.Methods and Materials: BSA-Fe₃O₄ nanoparticles were prepared via one-pot procedure at room temperature.Typically,FeCl₃·6H2O,Fe Cl2·4H2O and BSA were dissolved in deionized water in a three-necked flask with vigorous stirring at room temperature and purged with nitrogen to get rid of oxygen.Thereafter,Na OH was quickly added to above mixture and reaction for 20 min.BSA not only served as template to control the growth of nanocrystal,but also enabled the favorable water solubility of the nanoprobe.The alkaline environment plays in crucial role in the formation of BSA-Fe₃O₄ nanoparticles,as it not only unfolded tertiary configuration of BSA and enhance its encapsulation capacity towards nanostructure,but also triggered the formation of Fe₃O₄ nanocrystal.The prepared nanoparticles were characterized with TEM,FT-IR,XPS and DLS.Before the application of the BSA-Fe₃O₄ nanoparticles for organism,the 0.5 T MR scanner was used to determinate the performance of MR imaging andrelaxivity.Then,the performance of MR imaging on organism was carried out with kunming mouse via subcutaneous and tail vein injection on 3.0 T MR scanner.In order to investigate the biocompatibility of the BSA-Fe₃O₄ nanoparticles,the MTT assay in vitro and in vivo by monitoring body weight change and histological change of major organs of mice were implemented.Results: The results of characterizations indicated that the BSA-Fe₃O₄ nanoparticles were uniform spherical morphology with an average diameter of 3.2 nm.And the composition of BSA,the oxidation state of Fe element and the appropriate hydrodynamic size for in vivo application were all proved.MR imaging in vitro and in vivo showed that BSA-Fe₃O₄ nanoparticles have excellent performance on imaging and relaxivity.The r1 value of the nanoprobe was determined to be 6.98 m M-1 s-1,which is much higher than that of clinic Gd-DTPA?5.02 m M-1 s-1?.The darkening liver of T2-weighted MR imaging of mouse could be observed as long as 1 h after administration of the nanoprobe.The MTT assay and metabolic investigation revealed the neglectable adverse effect of BSA-Fe₃O₄ nanoparticles.Conclusion: In summary,we showed a simple biomineralization approach for the fabrication of BSA-Fe₃O₄ nanoparticles with convincing biosafety and dual-contrast MR imaging capability.The proposed biomineralization strategy lays down a new way for the fabrication of dua l-modal MR imaging BSA-Fe₃O₄ nanoparticles,and other function protein shows great potential to be employed as template for the fabrication of dual-contrast MR imaging nanoprobe with specific function using the proposed strategy.Background and Objective: Photothermal therapy as an invasive technique has attracted tremendously increasing interest on account of its easy operation and significantly reduced system toxicity,but suffers the potential side effects resulted from the risk of low accumulation in tumors and potential penetration into bloodstream of photothermal therapy agents.However,tumor microenvironment-responsive photothermal therapy agents with favorable biocompatibility and enhanced accumulation efficiency in tumors are still lacking.Herein,we present GSH triggered precipitation of polydopamine nanoparticles containing cystamine?cystamine-PDA NPs?,which shows great potential in improving the amount of photothermal therapy nanoparticles accumulated in tumors,enhancing the photothermal ablation efficacy and minimizing the side effects resulted from potential penetration into bloodstream of the nanoagents.Methods and Materials: Cystamine-PDA NPs were prepared via a simple one-pot method.Dopamine hydrochloride and cystamine dihydrochloride were dissolved in deionized water in a flask.Then,Na OH solution was added into aforementioned solution at 70 °C with water bath heating.After reacted for 5 h,cystamine-PDA NPs were collected via centrifugation and washed with absolute alcohol for several times.In alkaline aqueous solution,dopamine hydrochloride was oxidized and self-assembly,meanwhile,cystamine dihydrochloride with disulfide bond was introduced into polymers.The prepared cystamine-PDA NPs were characterized with TEM,DLS,FT-IR and ultravioblet spectrophotometer.The cystamine-PDA NPs were incubated with GSH environment in vitro to investigate the sensitivity of GSH-triggerd precipitation compared with PDA NPs fabricated by traditional method.In order to determinate the ability of NIR absorption and photothermal conversion efficiency and photothermal stability of cystamine-PDA NPs,the temperature change of the nanoprobe after irradiation by near-infrared laser and repeated irradiation by NIR laser were monitored and compared with ICG,which is a photothermal agent approved by FDA.The photothermal therapies in vivo and in vitro were further carried out using the cystamine-PDA NPs.The cytotoxicity and the in vivo toxicity of cystamine-PDA NPs were also evaluated by MTT assay,the change of body weight,biochemical indicator analysis and histological staining analysis of vital organs of mice.Results: The results of characterizations showed that the cystamine-PDA NPs were uniform spherical morphology with an average diameter of 120 nm,and exhibited strong NIR absorption and excellent colloidal stability.The assessment of in vitro responsiveness of the nanoprobe towards GSH revealed the high sensibility of cystamine-PDA NPs to tumor microenvironment.The photothermal performance evaluation in vitro and phototherapy in vitro and in vivo confirmed cystamine-PDA NPs could be employed as a high-performance photothermal therapy agent for tumor therapy.The negligible cytotoxicity and low toxicity in vivo of cystamine-PDA NPs were demonstrated by comprehensive toxicity assessmentse.Conclusions: In brief,we present smart cystamine-PDA NPs which were sensitive to tumor microenvironment for tumor photothermal therapy.The high-efficiency photothermal therapy and excellent biocompatibility were proved through a series of experiments.Therefore,cystamine-PDA NPs could act as a GSH-responsive photothermal therapy agent and show a promising prospect for future biological application.