Dang Hien Nguyen

Vietnam Academy of Science and Technology, Kanh-Hoa, Khánh Hòa, Vietnam

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Publications (2)3.62 Total impact

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    [Show abstract] [Hide abstract] ABSTRACT: We report for the first time the preparation of luminescent lanthanide nanomaterial (LLN) linked bioconjugates and their application as a label tool for recognizing virus in the processing line of vaccine industrial fabrication. Several LLNs with the nanostructure forms of particles or rods/wires with europium (III) and terbium (III) ions in lattices of vanadate, phosphate and metal organic complex were prepared to develop novel fluorescent conjugates able to be applied as labels in fluorescence immunoassay analysis of virus/vaccine.With regard to the LLNs, we have successfully synthesized nanoparticles around 10 nm of YVO4:Eu(III), with high emission in the red spectral region, nanorod and nanowire of TbPO4·H2O and Eu1-xTbxPO4·H2O, width 5–7 nm and length 300 nm, showing very bright luminescence in green, and core/shell nanosized Eu(III) and Tb(III)/Eu(III) complexes with naphthoyl trifluoroacetone and tri-n-octylphosphineoxide (Eu.NTA.TOPO@PVP, EuXTb1-X.NTA.TOPO). The appropriated core/shell structures can play a double role, one for enhancing luminescence efficiency and another for providing nanophosphors with better stability in water media for facilitating the penetration of nanophosphor core into a biomedical environment.The organic functionalizations of the obtained LLNs were done through their surface encapsulation with a functional polysiloxane including active groups such as amine (NH2), thiocyanate (SCN) or mecarpto (SH). The properties of functional sol-gel matrix have great influence on the luminescence properties, especially luminescence intensity of YVO4:Eu(III), Eu.NTA.TOPO@PVP, TbPO4·H2O and EuxTb1-xPO4·H2O. Bioconjugation processes of the functionalized LLNs have been studied with some bioactive molecules such as biotin, protein immunoglobulin G (IgG) or bovine serum albumin (BSA).The results of LLN-bioconjugate linking with IgG for recognizing virus (vaccine) will be presented in brief. It is consistent to state that the LLN bioconjugates prepared from YVO4:Eu(III)–nanoparticles, TbPO4·H2O nanorod or wire and EuNTA.TOPO@PVP nanosized core/shell complex could be used as labels for recognizing virus in diagnosis or in vaccine production by use of the fluorescence immunoassay (FIA) method. The fluorescence images of the incubated specimens consisting of LLN bioconjugate and vaccine fabricate could be obtained well in terms of sharpness, reproductivity and stability.However, much work still needs to be done to develop an ordinary LLN-conjugate using the FIA method for analysis of virus and, moreover, to extend the study of biomedical cell processes at nano/microscale in practical application.
    Full-text · Article · Sep 2012 · Advances in Natural Sciences: Nanoscience and Nanotechnology
  • [Show abstract] [Hide abstract] ABSTRACT: We tested a candidate live, oral, rotavirus vaccine (Rotavin-M1™) derived from an attenuated G1P [8] strain (KH0118-2003) isolated from a child in Vietnam. The vaccine was tested first for safety in 29 healthy adults. When deemed safe, it was further tested for safety and immunogenicity in 160 infants (4 groups) aged 6-12 weeks in a dose and schedule ranging study. The vaccine was administered in low titer (10(6.0)FFU/dose) on a 2-dose schedule given 2 months apart (Group 2L) and on a 3-dose schedule given 1 month apart (Group 3L) and in high titer (10(6.3)FFU/dose) in 2 doses 2 months apart (Group 2H) and in 3 doses 1 month apart (Group 3H). For comparison, 40 children (group Rotarix™) were given 2 doses of the lyophilized Rotarix™ vaccine (10(6.5)CCID(50)/dose) 1 month apart. All infants were followed for 30 days after each dose for clinical adverse events including diarrhea, vomiting, fever, abdominal pain, irritability and intussusception. Immunogenicity was assessed by IgA seroconversion and viral shedding was monitored for 7 days after administration of each dose. Two doses of Rotavin-M1 (10(6.3)FFU/dose) were well tolerated in adults. Among infants (average 8 weeks of age at enrollment), administration of Rotavin-M1 was safe and did not lead to an increased rate of fever, diarrhea, vomiting or irritability compared to Rotarix™, indicating that the candidate vaccine virus had been fully attenuated by serial passages. No elevation of levels of serum transaminase, blood urea, or blood cell counts were observed. The highest rotavirus IgA seroconversion rate (73%, 95%CI (58-88%)) was achieved in group 2H (2 doses--10(6.3)FFU/dose, 2 months apart). The 2 dose schedules performed slightly better than the 3 dose schedules and the higher titer doses performed slightly better than the lower titer doses. These rates of seroconversion were similar to that of the Rotarix™ group (58%, 95%CI (42-73%)). However more infants who received Rotarix™ (65%) shed virus in their stool after the first dose than those who received Rotavin-M1 (44-48%) (p<0.05) and the percent shedding decreased after subsequent doses of either vaccine. Rotavin-M1 vaccine is safe and immunogenic in Vietnamese infants. A trial in progress will assess the safety, immunogenicity and efficacy of Rotavin-M1 (2 doses at 10(6.3)FFU/dose) in a larger number of infants. The trial registration numbers are NCT01375907 and NCT01377571.
    No preview · Article · Apr 2012 · Vaccine