基于共振能量转移的上转换发光纳米体系的设计、合成及生物检测应用

Lanthanide-doped upconversion nanomaterials that convert low energy excitation wavelength to high energy emission, have attracted considerable attention due to the advantages of high penetration depth and high resistance to autofluorescence interference capability. Combined with optical active molecular probe by using resonance energy transfer technique, upconversion nanoprobes show high specificity, rapid response and high sensitivity to analytes. However, the distance between emitter ions and molecular probe is too long and the energy of upconversion nanoparticle cannot be effectively transferred to molecular probe, thus the detection ability of upconversion nanoprobe could be largely influenced. Herein, this proposal, based on long distance energy migration in lanthanide superlattices, provide a rational nanostructure design to enhance the energy transfer efficiency by shortening the distance between emitter ions and molecular probe. To develop ultrahigh sensitive bioprobes, we will establish a general method for the synthesis of upconversion nanoparticles with long distance (up to dozens of nanometers) energy migration capability to enhance the energy transfer efficiency between upconversion energy donor to molecular energy acceptor.

稀土离子掺杂的上转换发光纳米材料能将低能量的激发光子转换成更高能量的光子，具有检测深度大、无背景荧光干扰等优势。与光活性小分子探针相结合并利用发光共振能量转移技术，构筑的上转换发光纳米探针具有化学反应特异性识别、反应速度快、灵敏度高的特点。然而由于传统的上转换发光纳米粒子中掺杂的稀土离子发光中心与探针分子之间的距离较远，能量转移效率不高，因此影响了上转换发光探针的检测效果，并极大的限制了上转换发光材料在生物医药检测领域的进一步发展。本项目提出基于稀土离子间长距离能量迁移的机理，缩短发光中心与探针分子之间的距离，提高上转换纳米体系内能量转移效率来进行生物检测的概念。拟通过上转化发光纳米粒子的多层结构设计、合成和优化，实现纳米粒子内部几十纳米的长距离能量迁移，进而提高复合纳米结构中上转化发光纳米粒子（能量供体）和化学反应剂量计（能量受体）之间能量转移效率，达到降低检测限、提高探针灵敏度的目的。

稀土离子掺杂的上转换发光纳米材料能将低能量的激发光子转换成更高能量的光子，具有检测深度大、无背景荧光干扰等优势。与光活性小分子探针相结合并利用发光共振能量转移技术，构筑的上转换发光纳米探针具有化学反应特异性识别、反应速度快、灵敏度高的特点。然而由于传统的上转换发光纳米粒子中掺杂的稀土离子发光中心与探针分子之间，能量转移效率不高，因此影响了上转换发光探针的检测效果，并极大的限制了上转换发光材料在生物医药检测领域的进一步发展。本项目尝试不同方法，比如核壳结构设计、合成方法优化、浓度调控、基质材料组合等，利用稀土离子间长距离能量迁移的特点，提高上转换发光效率，并研究新的上转换发光机理。本项目还发展了不同方法，实现灵敏的生物检测。