Accelerating the clearance of mutant huntingtin protein aggregates through autophagy induction by europium hydroxide nanorods

Autophagy is one of the well-known pathways to accelerate the clearance of protein aggregates, which contributes to the therapy of neurodegenerative diseases. Although there are numerous reports that demonstrate the induction of autophagy with small molecules including rapamycin, trehalose and lithium, however, there are few reports mentioning the clearance of aggregate-prone proteins through autophagy induction by nanoparticles. In the present article, we have demonstrated that europium hydroxide [Eu^III(OH)₃] nanorods can reduce huntingtin protein aggregation (EGFP-tagged huntingtin protein with 74 polyQ repeats), responsible for neurodegenerative diseases. Again, we have found that these nanorods induce authentic autophagy flux in different cell lines (Neuro 2a, PC12 and HeLa cells) through the expression of higher levels of characteristic autophagy marker protein LC3-II and degradation of selective autophagy substrate/cargo receptor p62/SQSTM1. Furthermore, depression of protein aggregation clearance through the autophagy blockade has also been observed by using specific inhibitors (wortmannin and chloroquine), indicating that autophagy is involved in the degradation of huntingtin protein aggregation. Since [Eu^III(OH)₃] nanorods can enhance the degradation of huntingtin protein aggregation via autophagy induction, we strongly believe that these nanorods would be useful for the development of therapeutic treatment strategies for various neurodegenerative diseases in near future using nanomedicine approach.     

Visible-light-excited and europium-emissive nanoparticles for highly-luminescent bioimaging in vivo

Europium(III)-based material showing special milliseconds photoluminescence lifetime has been considered as an ideal time-gated luminescence probe for bioimaging, but is still limited in application in luminescent small-animal bioimaging in vivo. Here, a water-soluble, stable, highly-luminescent nanosystem, Ir–Eu–MSN (MSN = mesoporous silica nanoparticles, Ir–Eu = [Ir(dfppy)₂(pic–OH)]₃Eu·2H₂O, dfppy = 2-(2,4-difluorophenyl)pyridine, pic–OH = 3-hydroxy-2-carboxypyridine), was developed by an in situ coordination reaction to form an insoluble dinuclear iridium(III) complex-sensitized-europium(III) emissive complex within mesoporous silica nanoparticles (MSNs) which had high loading efficiency. Compared with the usual approach of physical adsorption, this in-situ reaction strategy provided 20-fold the loading efficiency (43.2%) of the insoluble Ir–Eu complex in MSNs. These nanoparticles in solid state showed bright red luminescence with high quantum yield of 55.2%, and the excitation window extended up to 470 nm. These Ir–Eu–MSN nanoparticles were used for luminescence imaging in living cells under excitation at 458 nm with confocal microscopy, which was confirmed by flow cytometry. Furthermore, the Ir–Eu–MSN nanoparticles were successfully applied into high-contrast luminescent lymphatic imaging in vivo under low power density excitation of 5 mW cm⁻². This synthetic method provides a universal strategy of combining hydrophobic complexes with hydrophilic MSNs for in vivo bioimaging.     

Ionic liquid as an emerging alternative for the separation and recovery of Nd,Sm and Eu using solvent extraction technique-A review

Rare earth metals (REMs), especially neodymium, samarium and europium are termed as critical metals since their supply is experiencing shortfall due to sudden rise in demand. Solvent extraction as an effective separation technique has been widely adopted for the recovery and recycling of these metals from a collection of several primary and secondary resources. Ionic liquids possessing negligible volatility have potential usefulness in rare earth extraction, either as the diluents or as extractants. The diversity in terms of structural properties, superior physico chemical characteristics and tunability to achieve higher selectivity have made these ionic liquids interesting and potential stakeholders for the application in liquid-liquid extraction and separation of Nd, Sm and Eu. The extractive separation of these elements by quaternary ammonium, phosphonium ionic liquids occurs mostly through ion exchange mechanism while it follows neutral complexation pathway when functionalized ionic liquids are in action. The present review comprehensively describes the separation and recovery of Nd, Sm and Eu employing different types of ionic liquids based on various operating conditions, extraction mechanism and efficiency. The process schemes for the recovery of these metals from post-cosumer products like magnets and phosphors using ionic liquids have also been summarized and discussed in detail.     

Enzyme-amplified lanthanide luminescence based on complexation reaction--a new technique for the determination of doxycycline

A new spectrofluorimetric method is described for the determination of doxycycline, based on modified enzyme-amplified lanthanide luminescence. Under the optimum conditions, Eu³⁺–doxycycline forms a ternary complex with lysozyme in close proximity and lysozyme can remarkably enhance the characteristic fluorescence intensity of Eu³⁺ at 612 nm in doxycycline–Eu³⁺ binary complex. The enhanced fluorescence intensity is in proportion to the concentration of doxycycline. The limit of detection is 1.28×10⁻⁸ mol l⁻¹, with a linear range from 1.7×10⁻⁷ to 1.7×10⁻⁶ mol l⁻¹. Interferences of other coexisting substances were studied. The developed method was successfully applied to the determination of doxycycline in serum, urine and real samples. The mechanism of fluorescence enhancement was also studied.     

新型铕络合物用于HBsAg的时间分辨荧光免疫检测

利用稳定的新型铕荧光络合物BHHCT与Eu3+标记羊抗人HBsAb和Eu3+标记BSA-SA,建立定量测定血清HBsAb的Eu3+-BHHCT-HBsAb-TRFIA法和Eu3+-BHHCT-BSA-SA-TRFIA法.结果表明,这两种方法最低检出值分别为0.2ng/mL和0.05ng/mL,标准曲线范围均为0-100ng/mL,批内变异系数CV均小于10%,后者回收率为85%-115%.用Eu3+-BHHCT-BSA-SA-TRFIA法与ELISA法同时检测118份血清样品,结果表明前者的检出率比后者高.     

Detection of rubella virus antigen by one-step time-resolved fluoroimmunoassay and by enzyme immunoassay

A one-step time-resolved fluoroimmunoassay (TR-FIA) and a conventional two-step enzyme immunoassay (EIA) for the detection of rubella virus antigen were developed. Two noncompetitive mouse monoclonal antibodies reactive with epitopes on the E1 polypeptide of rubella virus served as immunoreagents. One of the monoclones (7A6) was used for coating the solid phase, and the other (2C3) was labeled with either Europium chelate or with horseradish peroxidase. For TR-FIA, the specimen was incubated simultaneously with the label at 4 degrees C overnight. EIA required an overnight incubation with the specimen and after washing another 1 hr of incubation at 37 degrees C with the conjugate. The sensitivity of TR-FIA was 10 pg in an assay volume of 100 microliters, and the sensitivity of EIA was between 50 and 100 pg. Antigens could be detected by TR-FIA in supernatant of cultures of Vero cells 48 hr after inoculation with approximately 1 TCID50, while cytopathogenic effect (CPE) at that time was detected only in cultures inoculated with 10(5) TCID50 or more. Virus mixed with human amniotic fluid containing antirubella-specific IgG was detectable after an incubation at 37 degrees C for 5 days. The assays may find applications in prenatal diagnosis of intrauterine rubella infection, in early identification of viral antigens in cell culture and in monitoring production, concentration, and purification of rubella antigen for antibody assays.     

铕标记基因探针半定量检测丙型肝炎病毒RNA

目的 利用自行设计的引物、探针和新型铕螯合物BHHCT,建立一种半定量丙型肝炎病毒(HCV)RNA的检测方法。方法 收集44份丙型肝炎病人血清,20份正常人血清。利用中山大学达安基因有限公司RNA提取试剂提取HCV RNA,用自行设计的引物进行逆转录聚合酶链反应(RT-PCR)。扩增产物cDNA与微孔板上的捕捉探针杂交后,借助于其上游引物5′端带有的生物素,与标记有铕的链霉亲合素特异性结合,将铕连接到微孔板上,在特定波长激发光激发下,发出荧光,进行检测。结果 铕标记HCV RNA检测法的线性范围为102-106cDNA拷贝,敏感性、特异性均为100％。结论 铕标记RT-PCR检测HCV RNA法的线性范围宽,敏感性、特异性好,检测时间短,无放射性污染,有推广应用的价值。     

荧光光度法测定血清中卵磷脂的含量

目的:建立测定卵磷脂(PC)含量的荧光光度法。方法:以多西环素(DC)-铕(Eu3+)为荧光探针,在pH7.1条件下,扫描不同浓度的PC与DC-Eu3+的荧光光谱,优化测定PC含量的最佳试验条件。结果:主要试验条件最佳值为DC浓度3.0×10-6mol.L-1,Eu3+浓度1.0×10-5mol.L-1,PC检测浓度线性范围为4.0×10-7～2.4×10-5mol.L-1,检测限为3.1×10-7mol.L-1。结论:该方法能成功地应用于实际样品的含量测定。     

Sensitive time-resolved fluorimetric immune-complex-transfer immunoassay for antithyroglobulin IgG in serum

A sensitive time-resolved fluorimetric immune-complex-transfer immunoassay for antithyroglobulin IgG in serum is described. Antithyroglobulin IgG in test serum was reacted with dinitrophenyl europium ion-labeled thyroglobulin. The complex formed of antithyroglobulin IgG and dinitrophenyl europium ion-labeled thyroglobulin was trapped onto two polystyrene balls coated with affinity-purified rabbit antidinitrophenyl bovine serum albumin IgG. The polystyrene balls were washed to eliminate nonspecific IgG in the test serum, and the complex was eluted from the polystyrene balls with dinitrophenyl-L-lysine and transferred to two polystyrene balls coated with affinity-purified rabbit antihuman IgG gamma-chain IgG. Europium ion bound to the polystyrene balls was measured by time-resolved fluorimetry. Antithyroglobulin IgG was demonstrated in all patients with Graves' disease and all patients with chronic thyroiditis. This immunoassay was more sensitive than the conventional enzyme immunoassay and less time-consuming than the previously described immune-complex-transfer enzyme immunoassays, although there were larger assay variations.