The detection of Hg²⁺ in biological systems and its imaging is of highly importance. In this work, a novel ratiometric fluorescence probe is developed based on through-bond energy transfer (TBET) with a 2-(2-hydroxyphenyl)benzoxazole (HBO) as donor and a Rhodamine derivative-Hg conjugate (RDM-Hg) as acceptor. Hg²⁺ weakens the fluorescence of HBO at 430 nm and meanwhile interacts with Rhodamine B derivative to form a fluorescent conjugate (RDM-Hg) giving rise to emission at 597 nm with a 167 nm red-shift. Further, the difference 282 nm between the donor absorption (315 nm) and the accepter emission (597 nm) for 1+Hg²⁺ is comparable to the highest value of the Stokes shift (282 nm) reported earlier for other reported TBET-based cassette. Through-bond energy transfer from HBO to RDM-Hg is triggered by Hg²⁺ resulting in concentration-dependent variation of fluorescence ratio I₅₉₇/I₄₃₀. A linear calibration of I₅₉₇/I₄₃₀ versus Hg²⁺ concentration is obtained within 0–5 μM, along with the lowest detection limit being found to be as low as 1.31 × 10⁻⁹ mol·L⁻¹ (~ 0.26 ppb) for Hg²⁺. This feature is further demonstrated by colorimetric imaging of test strip and intracellular Hg²⁺. On the other hand, the HBO/RDM TBET sensing system is characterized by a combination of high sensitivity and selectivity. The present study provides an approach for further development of ratiometric probes dedicated to selective in vitro or in vivo sensing some species of biologically interest.

在生物系统中检测Hg ²⁺及其成像非常重要。在这项工作中，基于2-（2-羟苯基）苯并恶唑（HBO）作为供体和若丹明衍生物-Hg共轭物（RDM-Hg）的穿透键能量转移（TBET），开发了一种新型比例荧光探针。 。Hg ²⁺减弱430 nm处HBO的荧光，同时与若丹明B衍生物相互作用形成荧光共轭物（RDM-Hg），从而在597 nm处发出167 nm红移。此外，对于1 + Hg ²⁺，施主吸收（315 nm）与受主发射（597 nm）之间的差282 nm与先前报道的其他基于TBET的盒式磁带的斯托克斯位移（282 nm）的最大值相当。Hg ²⁺触发从HBO到RDM-Hg的键间能量转移，导致荧光比I ₅₉₇ / I _430的浓度依赖性变化。的线性校准我₅₉₇ /我₄₃₀ 对汞²⁺浓度为0-5μM内获得，具有最低检测限是沿发现低至1.31×10 ^-9莫尔^-1（〜0.26 ppb）的汞²⁺。试纸和细胞内Hg ^2+的比色成像进一步证明了这一特征。另一方面，HBO / RDM TBET传感系统的特点是具有高灵敏度和选择性。本研究提供了一种进一步开发比例探针的方法，该探针专门用于选择性地在体外或体内感测某些生物学上感兴趣的物种。