Chen Jian, Zeng Fang, Wu Shuizhu, Su Junhua, Zhao Jianqing, Tong Zhen
College of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, People's Republic of China.
Nanotechnology. 2009 Sep 9;20(36):365502. doi: 10.1088/0957-4484/20/36/365502. Epub 2009 Aug 18.
A facile approach was developed to produce a dye-doped core-shell nanoparticle chemosensor for detecting Cu(2+) in aqueous media. The core-shell nanoparticle sensor was prepared by a one-step emulsifier-free polymerization, followed by the doping of the fluorescent dye Nile red (9-diethylamino- 5H-benzo[alpha] phenoxazine-5-one, NR) into the particles. For the nanoparticles, the hydrophilic polyethyleneimine (PEI) chain segments serve as the shell and the hydrophobic polymethyl methacrylate (PMMA) constitutes the core of the nanoparticles. The non-toxic and biocompatible PEI chain segments on the nanoparticle surface exhibit a high affinity for Cu(2+) ions in aqueous media, and the quenching of the NR fluorescence is observed upon binding of Cu(2+) ions. This makes the core-shell nanoparticle system a water-dispersible chemosensor for Cu(2+) ion detection. The quenching of fluorescence arises through intraparticle energy transfer (FRET) from the dye in the hydrophobic PMMA core to the Cu(2+)/PEI complexes on the nanoparticle surface. The energy transfer efficiency for PEI/PMMA particles with different diameters was determined, and it is found that the smaller nanoparticle sample exhibits higher quenching efficiency, and the limit for Cu(2+) detection is 1 microM for a nanoparticle sample with a diameter of approximately 30 nm. The response of the fluorescent nanoparticle towards different metal ions was investigated and the nanoparticle chemosensor displays high selectivity and antidisturbance for the Cu(2+) ion among the metal ions examined (Na(+), K(+), Mg(2+), Ca(2+), Zn(2+), Hg(2+), Mn(2+), Fe(2+), Ni(2+), Co(2+) and Pb(2+)). This emulsifier-free, biocompatible and sensitive fluorescent nanoparticle sensor may find applications in cupric ion detection in the biological and environmental areas.
开发了一种简便的方法来制备用于检测水介质中Cu(2+)的染料掺杂核壳纳米颗粒化学传感器。核壳纳米颗粒传感器通过一步无乳化剂聚合制备，随后将荧光染料尼罗红（9-二乙氨基-5H-苯并[α]吩恶嗪-5-酮，NR）掺杂到颗粒中。对于纳米颗粒，亲水性聚乙烯亚胺（PEI）链段作为壳，疏水性聚甲基丙烯酸甲酯（PMMA）构成纳米颗粒的核。纳米颗粒表面无毒且具有生物相容性的PEI链段对水介质中的Cu(2+)离子表现出高亲和力，并且在Cu(2+)离子结合时观察到NR荧光猝灭。这使得核壳纳米颗粒系统成为用于Cu(2+)离子检测的水分散性化学传感器。荧光猝灭是通过颗粒内能量转移（FRET）从疏水性PMMA核中的染料转移到纳米颗粒表面的Cu(2+)/PEI络合物上产生的。测定了不同直径的PEI/PMMA颗粒的能量转移效率，发现较小的纳米颗粒样品表现出更高的猝灭效率，对于直径约为30nm的纳米颗粒样品，Cu(2+)检测限为1μM。研究了荧光纳米颗粒对不同金属离子的响应，并且在检测的金属离子（Na(+)、K(+)、Mg(2+)、Ca(2+)、Zn(2+)、Hg(2+)、Mn(2+)、Fe(2+)、Ni(2+)、Co(2+)和Pb(2+)）中，纳米颗粒化学传感器对Cu(2+)离子表现出高选择性和抗干扰性。这种无乳化剂、生物相容性好且灵敏的荧光纳米颗粒传感器可能在生物和环境领域的铜离子检测中找到应用。
