Coletta Giuliano, Amendola Vincenzo
Department of Chemical Sciences, University of Padova, Via Marzolo 1, 35131 Padova, Italy.
Nanomaterials (Basel). 2021 Apr 28;11(5):1147. doi: 10.3390/nano11051147.
Turbidimetric assays with latex nanoparticles are widely applied for the detection of biological analytes, because of their rapidity, low cost, reproducibility, and automatization. However, the detection limit can be lowered only at the price of a reduced dynamic range, due to the rapid saturation of the light scattering signal at high analyte concentration. Here, we use numerical calculations to investigate the possibility of increasing the performance of immuno-turbidimetric assays without compromising the measurement dynamic range, by combining plasmonic (gold, silver) and latex nanoparticles. Our modelling results show that plasmonic nanoparticles are compatible with a large signal change even when small aggregates are formed, i.e., at low analyte concentration. The working principle relies on the remarkable modification of the surface plasmon band when noble metal nanoparticles form oligomers, and also when latex particles are included in the aggregate. At high analyte concentration, when larger aggregates form, the latex particles can provide the required linear response of standard immuno-turbidimetric assays. Thus, the combination of the two components can be a successful strategy to improve the detection limit and the dynamic range, while maintaining all the advantages of the homogeneous immuno-turbidimetric assays.
基于乳胶纳米颗粒的比浊法由于其快速、低成本、可重复性和自动化等特点，被广泛应用于生物分析物的检测。然而，由于在高分析物浓度下光散射信号会迅速饱和，检测限只能以减小动态范围为代价来降低。在此，我们通过数值计算研究了结合等离子体（金、银）纳米颗粒和乳胶纳米颗粒来提高免疫比浊法性能而不影响测量动态范围的可能性。我们的建模结果表明，即使在形成小聚集体时，即低分析物浓度下，等离子体纳米颗粒也能与大的信号变化兼容。其工作原理依赖于当贵金属纳米颗粒形成低聚物时，以及当乳胶颗粒包含在聚集体中时，表面等离子体带的显著变化。在高分析物浓度下，当形成更大的聚集体时，乳胶颗粒可以提供标准免疫比浊法所需的线性响应。因此，这两种成分的组合可以成为一种成功的策略，既能提高检测限和动态范围，又能保持均相免疫比浊法的所有优点。
