Rare earth upconversion nanomaterials have the advantages of near-infrared region excitation, almost zero interference background, large anti-Stokes shifts without broad emission peaks, which can overcome parts of the defects of organic fluorescent probes. In this work, core-shell rare earth upconversion nanoparticles NaYF₄:Yb,Tm:20 %Yb,0.35 %Tm@NaYF₄ (UCNPs) were synthesized, and then water-soluble nanoparticles DMSA-UCNPs and PAA-UCNPs were subsequently fabricated. Meanwhile a naphthalimide-based colormetric Hg²⁺-probe was synthesized, and assembled with DMSA-UCNPs and PAA-UCNPs to give composite nanoprobes A-DMSA-UCNPs and A-PAA-UCNPs toward mercury ions. Both nanoprobes use the upconversion luminescence ratio at 451 nm and 361 nm (UCL₄₅₁/UCL₃₆₁) as the detection signal, and can quickly respond to Hg²⁺ ions within 1–2 min. The detection limits of A-DMSA-UCNPs and A-PAA-UCNPs were calculated to be 2.47 μmol/L and 8.15 μmol/L respectively. A-DMSA-UCNPs and A-PAA-UCNPs both could be employed as ratiometric nanoprobes for Hg²⁺ imaging in living cell and lysosomal localization.

稀土上转换纳米材料具有近红外激发，几乎零干扰本底，大的反斯托克斯频移，发射峰不宽等优点，可以克服有机荧光探针的部分缺陷。本研究合成了核壳稀土上转换纳米颗粒NaYF ₄：Yb，Tm：20％Yb，0.35％Tm @ NaYF ₄（UCNPs），然后制备了水溶性纳米颗粒DMSA-UCNPs和PAA-UCNPs。 。同时合成了基于萘二甲酰亚胺的比色Hg ²⁺探针，并将其与DMSA-UCNPs和PAA-UCNPs组装在一起，从而形成了针对汞离子的复合纳米探针A-DMSA-UCNPs和A-PAA-UCNPs。两种纳米探针均使用451 nm和361 nm的上转换发光率（UCL ₄₅₁/ UCL ₃₆₁）作为检测信号，并且可以在1-2分钟内快速响应Hg ²⁺离子。计算得出A-DMSA-UCNPs和A-PAA-UCNPs的检出限分别为2.47μmol/ L和8.15μmol/ L。A-DMSA-UCNPs和A-PAA-UCNPs均可作为比率纳米探针用于活细胞中Hg ²⁺成像和溶酶体定位。