Nanobiophotonics and Laser Microspectroscopy Center, Interdisciplinary Research Institute in Bio-Nano-Sciences, Babes-Bolyai University, 42 Treboniu Laurian Strada, Cluj-Napoca 400271, Romania.
Nanostructured Materials and Bio-Nano-Interfaces Center, Interdisciplinary Research Institute in Bio-Nano-Sciences, Babes-Bolyai University, 42 Treboniu Laurian Strada, Cluj-Napoca 400271, Romania.
ACS Appl Mater Interfaces. 2023 Dec 6;15(48):55925-55937. doi: 10.1021/acsami.3c08658. Epub 2023 Nov 20.
The implementation of metal enhanced fluorescence (MEF) as an efficient detection tool, especially in the near-infrared region of the electromagnetic spectrum, is a rather new direction for diagnostic analytical technologies. In this context, we propose a novel microfluidic plasmonic design based on paper for efficient MEF detection of the "proof-of-concept" biotin-streptavidin recognition interaction. Our design made use of the benefits of gold nanobipyramids (AuBPs), considering the strong enhanced electromagnetic field present at their sharp tips, and filter paper to operate as a natural microfluidic channel due to excellent wicking abilities. The calligraphed plasmonic paper, obtained using a commercial pen filled with AuBPs, was integrated in a robust sandwich optically transparent polydimethylsiloxane chip, exhibiting portability and flexibility while preserving the chip's properties. To place the Alexa 680 fluorophore at an optimal distance from the nanobipyramid substrate, the human IgG-anti-IgG-conjugated biotin sandwich reaction was employed. Thus, upon the capture of Alexa 680-conjugated streptavidin by the biotinylated system, a 1.3-fold average enhancement of the fluorophore's emission was determined by bulk fluorescence measurements. However, the local enhancement factor was considerably higher with values spanning from 5 to 6.3, as proven by mapping the fluorescence emission under both re-scan microscopy and fluorescence lifetime imaging, endorsing the proposed chip's feasibility for bulk MEF biosensing as well as high-resolution MEF bioimaging. Finally, the versatility of our chip was demonstrated by adapting the biosensing protocol for cardiac troponin I biomarker detection, validated using 10 plasma samples collected from pediatric patients and corroborated with a conventional ELISA assay.
金属增强荧光（MEF）作为一种有效的检测工具的应用，尤其是在电磁光谱的近红外区域，是诊断分析技术的一个相当新的方向。在这种情况下，我们提出了一种基于纸张的新型微流控等离子体设计，用于有效检测“生物素-链霉亲和素识别相互作用”的 MEF。我们的设计利用了金纳米双锥（AuBPs）的优势，考虑到其尖锐尖端存在强电磁场增强，而滤纸则由于出色的吸液能力而用作天然微流控通道。使用填充 AuBPs 的商用笔在纸上进行书法处理，获得了等离子体纸，并将其集成到坚固的三明治光学透明聚二甲基硅氧烷芯片中，在保留芯片性能的同时，具有便携性和灵活性。为了使 Alexa 680 荧光团与纳米双锥基底保持最佳距离，采用了人 IgG-抗 IgG 偶联生物素三明治反应。因此，通过 bulk 荧光测量确定，当 Alexa 680 缀合的链霉亲和素被生物素化系统捕获时，荧光团的发射增强了 1.3 倍。然而，通过重新扫描显微镜和荧光寿命成像下的荧光发射映射证明，局部增强因子要高得多，范围从 5 到 6.3，证明了所提出的芯片在 bulk MEF 生物传感以及高分辨率 MEF 生物成像方面的可行性。最后，通过适应心脏肌钙蛋白 I 生物标志物检测的生物传感方案，证明了我们芯片的多功能性，该方案使用从儿科患者收集的 10 个血浆样本进行了验证，并与传统的 ELISA 检测相吻合。
