Institute of Analytical Chemistry, Chemo- and Biosensors , University of Regensburg , 93040 Regensburg , Germany.
Anal Chem. 2018 Dec 18;90(24):14247-14254. doi: 10.1021/acs.analchem.8b03279. Epub 2018 Nov 28.
A nanoengineered interface fabricated by self-assembly enables the online determination of vitamin B12 via a simple luminescence readout in serum without any pretreatment. The interplay of Tm-doped NaYF nanoparticles (UCNPs) and a gold nanotriangle array prepared by nanosphere lithography on a glass slide is responsible for an efficient NIR to UV upconversion. Hot spots of the gold assembly generate local electromagnetic-field enhancement, favoring the four-photon upconversion process at the low-power excitation of approximately 13 W·cm. An improvement by about 6 times of the intensity for the emission peaking at 345 nm is achieved. The nanoengineered interface has been applied in a proof-of-concept sensor for vitamin B12 in serum, which is known as a marker for the risk of cancer; Alzheimer disease; or, during pregnancy, neurological abnormalities in newborn babies. Vitamin B12 can be detected in serum down to 3.0 nmol·L by a simple intensity-based optical readout, consuming only 200 μL of a sample, which qualifies as easy miniaturization for point-of-care diagnostics. Additionally, this label-free approach can be used for long-term monitoring because of the high photostability of the upconversion nanoparticles.
通过自组装制造的纳米工程界面能够实现维生素 B12 的在线测定，通过血清中的简单发光读出，无需任何预处理。掺铥的 NaYF 纳米粒子 (UCNP) 和通过纳米球光刻在玻璃载玻片上制备的金纳米三角阵列之间的相互作用负责有效的近红外到紫外上转换。金组装体的热点产生局部电磁场增强，有利于在约 13 W·cm 的低功率激发下进行四光子上转换过程。发射峰在 345nm 处的强度提高了约 6 倍。该纳米工程界面已应用于血清中维生素 B12 的概念验证传感器中，维生素 B12 是癌症风险的标志物；老年痴呆症；或者在怀孕期间，新生儿神经系统异常。通过简单的基于强度的光学读出，可以在血清中检测到低至 3.0 nmol·L 的维生素 B12，仅消耗 200μL 的样本，这为即时诊断的小型化提供了便利。此外，由于上转换纳米粒子的高光稳定性，这种无标记方法可用于长期监测。
