Hariharan P S, Sivasubramanian Arvind, Anthony Savarimuthu Philip
School of chemical & Biotechnology, SASTRA University, Thanjavur, 613 403, Tamil Nadu, India.
J Fluoresc. 2014 Mar;24(2):319-27. doi: 10.1007/s10895-013-1333-4. Epub 2013 Nov 28.
Turn-off fluorescence of organic fluorophore, 2-{[4-(2H-Naphtho[1,2-d][1,2,3]triazol-2-yl)-phenyl]carboxylic acid (NTPC), with metal ions (Fe(3+), Cu(2+), Pb(2+)) was converted into turn-on fluorescent sensor for biologically important Zn(2+), Cu(2+) and Fe(3+) metal ions in aqueous solution at ppb level by exploiting strong fluorescence quenching phenomena of metal nanoparticles when organic fluorophores assembled in the vicinity of metallic surface. Amino acid attached phenolic ligands (L) were used as reducing as well as functional capping agents in the synthesis of silver nanoparticles (AgNPs). The hydrogen bonding functionality of L facilitated the assembling of NTPC in the vicinity of metallic surfaces that leads to complete quenching of NTPC fluorescence. The strong and selective coordination of L with metal ions (Zn(2+), Cu(2+) and Fe(3+)) separates the NTPC from the AgNPs surface that turn-on the NTPC fluorescence. HR-TEM and absorption studies confirm the metal coordination with L and separation of NTPC from the AgNPs surface. Mn(2+) showed selective red shifting of NTPC fluorescence after 12 h with all sample. Effects of different amino acid attached phenolic ligands were explored in the metal ion sensitivity and selectivity. This approach demonstrates the multifunctional utility of metal NPs in the development of turn-on fluorescence sensor for paramagnetic heavy metal ions in aqueous solution. ᅟ
通过利用有机荧光团在金属表面附近组装时金属纳米颗粒的强荧光猝灭现象，将有机荧光团2-{[4-(2H-萘并[1,2-d][1,2,3]三唑-2-基)-苯基]羧酸(NTPC)与金属离子(Fe(3+)、Cu(2+)、Pb(2+))之间的荧光猝灭转化为用于水溶液中生物重要的Zn(2+)、Cu(2+)和Fe(3+)金属离子的ppb级开启式荧光传感器。在银纳米颗粒(AgNPs)的合成中，氨基酸连接的酚类配体(L)用作还原剂和功能性封端剂。L的氢键功能促进了NTPC在金属表面附近的组装，导致NTPC荧光完全猝灭。L与金属离子(Zn(2+)、Cu(2+)和Fe(3+))的强选择性配位将NTPC与AgNPs表面分离，从而开启NTPC荧光。高分辨透射电子显微镜(HR-TEM)和吸收研究证实了金属与L的配位以及NTPC从AgNPs表面的分离。Mn(2+)在12小时后对所有样品均显示出NTPC荧光的选择性红移。研究了不同氨基酸连接的酚类配体对金属离子灵敏度和选择性的影响。该方法证明了金属纳米颗粒在开发水溶液中顺磁性重金属离子的开启式荧光传感器中的多功能用途。
