Sensitive molecular detection using fluorescence-enhancing core-shell nanoparticles

荧光纳米粒子探针如量子点和染料掺杂的二氧化硅纳米颗粒(NPs)由于具有更高的发光强度和更高的化学和光物理稳定性，在生物分析化学中的应用越来越多。特别是染料掺杂二氧化硅纳米颗粒，可以在水介质中使用简单的溶胶-凝胶化学方法非常容易地制备出来。然后，这些发光的NPs可以用寡核苷酸、抗体等功能化，并用作各种分析物的光学标记。然而，这些纳米粒子中使用的荧光团的量子效率由于自猝灭(即相邻荧光团之间发生的信号损失)而大大降低，这一现象限制了染料掺杂纳米粒子中的有效荧光团浓度和可实现的检测灵敏度。

Fluorescent nanoparticle probes such as quantum dots and dye-doped silica nanoparticles (NPs) are used increasingly in bioanalytical chemistry, due to their higher luminescence and enhanced chemical and photophysical stability. Dye-doped silica NPs, in particular, can be prepared very easily in aqueous media using straightforward sol-gel chemistry. These luminescent NPs can then be functionalized with oligonucleotides, antibodies, etc. and used as optical markers for various analytes. However, the quantum efficiency of the fluorophores used in these NPs is strongly diminished by self-quenching (i.e. signal losses occurring between neighboring fluorophores) and this phenomenon limits the effective fluorophore concentration in dye-doped NPs and the achievable detection sensitivity.