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High-stability spherical lanthanide nanoclusters for magnetic resonance imaging

National Science Review 2023年第4期10卷 123-132页

作者： Hai-Ling Wang Donglin Liu Jian-Hua Jia Jun-Liang Liu Ze-Yu Ruan Wei Deng Shiping Yang Si-Guo Wu Ming-Liang Tong Key Laboratory of Bioinorganic and Synthetic Chemistry of Ministry of Education School of Chemistry Sun Yat-sen University College of Chemistry and Materials Science Shanghai Normal University

High-nuclear lanthanide clusters have shown great potential for the administration of high-dose mononuclear gadolinium chelates in magnetic resonance imaging(MRI). The development of high-nuclear lanthanide clusters with excellent solubility and high stability in water or solution has been challenging and is very important for expanding the performance of MRI. We used N-methylbenzimidazole-2-methanol(HL) and LnCl3·6H2O to synthesize two spherical lanthanide clusters, Ln32(Ln = Ho, Ho32; and Ln =Gd, Gd32), which are highly stable in solution. The 24 ligands L-are all distributed on the periphery of Ln32and tightly wrap the cluster core, ensuring that the cluster is stable. Notably, Ho32can remain highly stable when bombarded with different ion source energies in HRESI-MS or immersed in an aqueous solution of different pH values for 24 h. The possible formation mechanism of Ho32was proposed to be Ho(Ⅲ),(L)-and H2O → Ho3(L)3/Ho3(L)4→ Ho4(L)4/Ho4(L)5→ Ho6(L)6/Ho6(L)7→ Ho16(L)19→Ho28(L)15→ Ho32(L)24/Ho32(L)21/Ho32(L)23. To the best of our knowledge, this is the first study of the assembly mechanism of spherical high-nuclear lanthanide clusters. Spherical cluster Gd32, a form of highly aggregated Gd(Ⅲ), exhibits a high longitudinal relaxation rate(1 T, r1= 265.87 mM-1·s-1). More notably, compared with the clinically used commercial material Gd-DTPA, Gd32has a clearer and higher-contrast T1-weighted MRI effect in mice bearing 4T1 tumors. This is the first time that high-nuclear lanthanide clusters with high water stability have been utilized for MRI. High-nuclear Gd clusters containing highly aggregated Gd(Ⅲ) at the molecular level have higher imaging contrast than traditional Gd chelates; thus, using large doses of traditional gadolinium contrast agents can be avoided.

关键词： T1-weighted MRI lanthanide clusters high stability low toxicity assembly mechanism

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Spherical lanthanide nanoclusters toward white-light emission and cell membrane imaging

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Nano Research 2023年第8期16卷 11495-11502页

作者： Hai-Ling Wang Zhiqiang Ni Ze-Yu Ruan Zhong-Hong Zhu Pei-Yu Liao Guangxue Feng Jian-Hua Jia Ming-Liang Tong Key Laboratory of Bioinorganic and Synthetic Chemistry of Ministry of Education School of ChemistrySun Yat-Sen UniversityGuangzhou 510006China State Key Laboratory of Luminescent Materials and Devices Guangdong Provincial Key Laboratory of Luminescence from Molecular AggregatesSchool of Materials Science and EngineeringSouth China University of TechnologyGuangzhou 510640China

Lanthanide doping is an effective strategy for modulating the emission of emitters.Herein,by changing the cluster composition to control the energy transfer pathway,the application potential of high-nuclearity lanthanide cluster(HLC)as white-light emitter has been confirmed for the first time.Specifically,by precisely controlling the proportion of GdIII,TbIII,and EuIII ions in reactants,we obtained a spherical heterotrimetallic nanocluster Gd_(10)Tb_(12)Eu_(10),a white-light emitter with quantum yield(QY)of 12.58%and lifetime of 327.14μs.High-resolution electrospray ionization mass spectrometry(HRESI-MS)demonstrates that homometallic nanoclusters Ln_(32)(Ln=Gd,Tb,and Eu)are tetracationic clusters and are highly stable in solution.The peripheral dense organic ligands provide a protective layer for the cluster core,which improves the stability of Ln_(32) in aqueous solution,avoids the contact between metal centers and bioactive molecules,and greatly reduces the biological toxicity.In cell imaging experiments,cationic clusters Ln_(32) are mainly localized on the cell membrane with negative charge distribution.As far as we know,this is the first time that spherical lanthanide nanoclusters have been used for membrane imaging of living cell,opening the door for the application of HLCs in biological imaging.

关键词： spherical lanthanide clusters white-light emission high stability low toxicity cell membrane imaging

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low toxic nitromethane based monopropellant for gas generator cycle air turbo ramjet engine

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Propulsion and Power Research 2022年第3期11卷 311-324页

作者： Ryojiro Minato Department of Engineering Muroran Institute of TechnologyMuroranHokkaido050-8585Japan

The present study proposes ethanol-nitromethane mixture as a safe, storable, andlow toxic monopropellant for a gas generator cycle air turbo ramjet engine and evaluates itspropulsion performance. The present study proposes that nitromethane is mixed with ethanolto adjust gas generator combustion temperature. The author developed the computational codefor the present analysis and verified its accuracy. The specific thrust of ethanol-nitromethane isnearly identical to that of ethanol-liquified oxygen and is higher than methanol-hydroxylammonium nitrate aqueous solution and hydrazine. Hydrazine has the highest Ispamong the propellants in the present analysis. However, Isp of ethanol-nitromethane is nearlyequal to that of ethanol-liquified oxygen and higher than those of methanol-hydroxylammonium nitrate aqueous solution, and hydroxyl terminated polybutadiene-ammonium perchlorate. With the propellant-to-air ratio range in the present study, ethanol-nitromethane has the stoichiometric condition at the ram combustor around the propellant-to-air ratio range from 0.2 to 0.25 and can obtain high ram combustion temperature. This resultis favorable for ethanol-nitromethane because it improves the specific thrust and the specificimpulse. Therefore, ethanol-nitromethane can be a promising low-toxic liquid monopropellantfor the air turbo ramjet engine.

关键词： Air turbo ramjet Monopropellant Nitromethane low toxicity Ethanol

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Healing Effect and Underlying Mechanism of Silver Nanoparticles Prepared Using Carboxymethyl Chitosan under Solar Irradiation

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Journal of Renewable Materials 2021年第6期9卷 1075-1085页

作者： Yi Long Chunling Zhang Lan Chen Tietao Di Lu Chen Lisha Tang Kaizhong Luo Yu Yan Pingzhen Tong Jie Xiang College of Pharmacy Guizhou University of Traditional Chinese MedicineGuiyang550025China Second Affiliated Hospital Guizhou University of Traditional Chinese MedicineGuiyang550002China Department of Environmental Monitoring Changsha Environmental Protection CollegeChangsha410004China Guizhou Provincial Center for Disease Control and Prevention Guiyang550004China

In our previous study,silver nanoparticles were prepared using AgNO_(3) and carboxymethyl chitosan(CMCS)which is commercially available with solar irradiation.In this study,the efficacy and safety of silver nanoparticles prepared by this method were evaluated for healing wounds in rats with diabetes.We also attempted to determine the underlying mechanism and influencing factors of the silver nanomaterial preparation method.Compared with growth factors,silver nanoparticles exhibit better healing effects for rats with diabetes.No remnant silver ions were detected in the major organs of these rats after the application of silver nanoparticles.Silver nanoparticles prepared using CMCS are less toxic than those prepared from the conventional method,promote the proliferation of skin fibroblasts,and are promising as a topical medication for infected wounds.An obvious breakage process of the particles is observed during the growth of nanocrystalline silver in CMCS.In this study,we also attempted to determine whether this method is suitable for synthesizing silver nanoparticles using N-trimethyl chitosan chloride and sodium alginate were used in this particular experiment.The characteristic UV-vis absorbance peak of silver nanoparticles was found only in the reaction mixture containing N-trimethyl chitosan chloride.Our study demonstrates that free radicals are the key factor in this silver nanoparticle preparation method.

关键词： Silver nanoparticle carboxymethyl chitosan low toxicity healing free radical

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基于亚甲基蓝制备的抗还原、抗聚集和抗DNA干扰的光动力治疗碳点

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Science China Materials 2021年第9期64卷 2325-2336页

作者：徐宁谷泉泳杜健军葛浩英龙飒然孙文樊江莉彭孝军 State Key Laboratory of Fine Chemicals Dalian University of TechnologyDalian 116024China Ningbo Institute of Dalian University of Technology Ningbo 315016China

光动力疗法(PDT)是一种重要的癌症治疗手段,亚甲基蓝(MB)作为一种有效的光敏剂被广泛应用于光动力治疗.然而,MB在体内由于聚集以及与DNA结合而导致减色效应.同时,MB在实体瘤的低氧环境中容易被还原为无色的还原态leucoMB,从而丧失光动... 详细信息

光动力疗法(PDT)是一种重要的癌症治疗手段,亚甲基蓝(MB)作为一种有效的光敏剂被广泛应用于光动力治疗.然而,MB在体内由于聚集以及与DNA结合而导致减色效应.同时,MB在实体瘤的低氧环境中容易被还原为无色的还原态leucoMB,从而丧失光动力能力.因此,我们以MB作为碳源,制备碳点MB-CDs.MBCDs不仅继承了MB的PDT能力,而且表现出良好的生物相容性和低毒性.重要的是,MB-CDs具有出色的抗还原、抗聚集和抗DNA干扰的能力,并且MB-CDs在体外和体内均表现出良好的PDT活性,仅用590 nm LED光源照射一次,即可使肿瘤体积减小到原始体积的20%以下.

关键词： carbon dots photodynamic therapy methylene blue low toxicity resistance to interference

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