State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, PR China.
Anal Chem. 2009 Dec 15;81(24):9993-10001. doi: 10.1021/ac9018445.
In this paper, we unveil a novel naphthalimide-porphyrin hybrid based fluorescence probe (1) for ratiometric detection of Hg(2+) in aqueous solution and living cells. The ratiometric signal change of the probe is based on a carefully predesigned molecule containing two independent Hg(2+)-sensitive fluorophores with their maximal excitation wavelengths located at the same range, which shows reversibly specific ratiometric fluorescence responses induced by Hg(2+). In the new developed sensing system, the emissions of the two fluorophores are well-resolved with a 125 nm difference between two emission maxima, which can avoid the emission spectra overlap problem generally met by spectra-shift type probes and is especially favorable for ratiometric imaging intracellular Hg(2+). It also benefits from a large range of emission ratios and thereby a high sensitivity for Hg(2+) detection. Under optimized experimental conditions, the probe exhibits a stable response for Hg(2+) over a concentration range from 1.0 x 10(-7) to 5.0 x 10(-5) M, with a detection limit of 2.0 x 10(-8) M. The response of the probe toward Hg(2+) is reversible and fast (response time less than 2 min). Most importantly, the ratiometric fluorescence changes of the probe are remarkably specific for Hg(2+) in the presence of other abundant cellular metal ions (i.e., Na(+), K(+), Mg(2+), and Ca(2+)), essential transition metal ions in cells (such as Zn(2+), Fe(3+), Fe(2+), Cu(2+), Mn(2+), Co(2+), and Ni(2+)), and environmentally relevant heavy metal ions (Ag(+), Pb(2+), Cr(3+), and Cd(2+)), which meets the selective requirements for biomedical and environmental monitoring application. The recovery test of Hg(2+) in real water samples demonstrates the feasibility of the designed sensing system for Hg(2+) assay in practical samples. It has also been used for ratiometric imaging of Hg(2+) in living cells with satisfying resolution, which indicates that our novel designed probe has effectively avoided the general emission spectra overlap problem of other ratiometric probes.
在本文中，我们揭示了一种基于萘二甲酰亚胺-卟啉杂化的新型荧光探针（1），用于在水溶液和活细胞中对 Hg(2+)进行比率检测。探针的比率信号变化基于精心设计的分子，其中包含两个独立的对 Hg(2+)敏感的荧光团，其最大激发波长位于同一范围内，这表现出由 Hg(2+)诱导的可逆特异性比率荧光响应。在新开发的传感系统中，两个荧光团的发射很好地分离，两个发射峰之间有 125nm 的差异，这可以避免光谱位移型探针通常遇到的发射光谱重叠问题，特别有利于细胞内 Hg(2+)的比率成像。它还得益于发射比的大范围，从而具有对 Hg(2+)检测的高灵敏度。在优化的实验条件下，探针在 1.0 x 10(-7)至 5.0 x 10(-5) M 的浓度范围内对 Hg(2+)表现出稳定的响应，检测限为 2.0 x 10(-8) M。探针对 Hg(2+)的响应是可逆的，且快速（响应时间小于 2 分钟）。最重要的是，在存在其他丰富的细胞金属离子（即 Na(+)、K(+)、Mg(2+)和 Ca(2+)）、细胞中必需的过渡金属离子（如 Zn(2+)、Fe(3+)、Fe(2+)、Cu(2+)、Mn(2+)、Co(2+)和 Ni(2+)）以及环境相关重金属离子（Ag(+)、Pb(2+)、Cr(3+)和 Cd(2+)）的情况下，比率荧光变化对 Hg(2+)具有显著的特异性，这满足了生物医学和环境监测应用的选择性要求。实际水样中 Hg(2+)的回收测试证明了设计的传感系统在实际样品中测定 Hg(2+)的可行性。它还被用于活细胞中 Hg(2+)的比率成像，具有令人满意的分辨率，这表明我们的新型设计探针有效地避免了其他比率探针的一般发射光谱重叠问题。
