Achyuthan Komandoor E, Achyuthan Ann M, Brozik Susan M, Dirk Shawn M, Lujan Tracy R, Romero Janet M, Harper Jason C
Biosensors and Nanomaterials Department, Sandia National Laboratories, Albuquerque, NM 87185, USA.
Anal Sci. 2012;28(5):433-8. doi: 10.2116/analsci.28.433.
Plasmonic fluorescent nanocomposites are difficult to prepare due to strong quenching effects on fluorophores in the vicinity of noble metal nanoparticles such as gold (AuNPs). We successfully prepared plasmonic fluorescent nanocomposites of two cyanines (1 and 2) aggregating upon 2 - 40 nm AuNPs or streptavidin-conjugated 10 nm AuNPs. We used high throughput screening (HTS) for the first time to characterize the spectral properties, aggregation kinetics, aggregation density and photostability of the nanocomposites. Fluorescence from nanocomposites declined inversely with AuNPs size: 40 nm ≥ 20 nm > 10 nm > 5 nm > 2 nm. Sensitivity (limit of detection, LOD, 10(5) - 10(11) AuNPs/mL), brightness of the nanocomposites and surface coverage of AuNPs by cyanine aggregates were all influenced by five factors: 1) AuNPs size; 2) cyanine type (1 or 2); 3) aggregate density; 4) distance between aggregates and AuNPs surface; and 5) streptavidin protein conjugation to AuNPs. We propose a model for plasmonic fluorescent nanocomposites based on these observations. Our plasmonic fluorescent nanocomposites have applications in chemical and biological assays.
由于贵金属纳米颗粒（如金纳米颗粒，AuNPs）对附近荧光团有很强的猝灭作用，因此制备等离子体荧光纳米复合材料很困难。我们成功制备了两种菁染料（1和2）聚集在2 - 40 nm金纳米颗粒或链霉亲和素偶联的10 nm金纳米颗粒上的等离子体荧光纳米复合材料。我们首次使用高通量筛选（HTS）来表征纳米复合材料的光谱特性、聚集动力学、聚集密度和光稳定性。纳米复合材料的荧光与金纳米颗粒大小成反比：40 nm≥20 nm>10 nm>5 nm>2 nm。纳米复合材料的灵敏度（检测限，LOD，10(5) - 10(11) AuNPs/mL）、亮度以及菁染料聚集体对金纳米颗粒的表面覆盖率均受五个因素影响：1）金纳米颗粒大小；2）菁染料类型（1或2）；3）聚集体密度；4）聚集体与金纳米颗粒表面之间的距离；5）链霉亲和素蛋白与金纳米颗粒偶联。基于这些观察结果，我们提出了一种等离子体荧光纳米复合材料模型。我们的等离子体荧光纳米复合材料在化学和生物分析中具有应用价值。
