We report the development of a tuneable plasmonic nanochain immunoassay with increased sensitivity over traditional monodisperse nanoparticle lateral flow tests. Our approach takes advantage of the unique self-assembling properties of polyamidoamine dendrimers with gold nanoparticles in aqueous media to create one-dimensional nanochains, with a distinct red to blue colour change, attributable to a longitudinal plasmon resonance, which can be readily detected by eye and a digital camera. We optimise and characterise nanochain formation and stability using UV-visible spectroscopy, transmission electron microscopy and dynamic light scattering. As a proof-of-principle we focus on the application of nanochains for point-of-care diagnostics for p24, an important biomarker of early HIV infections and successfully detect p24 with a limit of detection of 5 ng ml⁻¹ in pseudo-serum, 4 fold more sensitive than comparable studies with gold nanoparticles. These findings and underlying concepts highlight the potential of advanced functional organic–inorganic composite nanomaterials to diagnose infections, with broad applicability to non-communicable diseases.

中文翻译：

---

可调谐的等离激元金树状大分子纳米链用于敏感疾病检测

我们报告了可调谐的等离激元纳米链免疫测定法的发展，其灵敏度高于传统的单分散纳米粒子侧向流动试验。我们的方法利用聚酰胺胺树枝状聚合物与金纳米颗粒在水性介质中的独特自组装特性来产生一维纳米链，具有明显的红色到蓝色变化，这归因于纵向等离振子共振，可以很容易地用眼睛检测到和一台数码相机。我们使用紫外可见光谱，透射电子显微镜和动态光散射来优化和表征纳米链的形成和稳定性。作为原理的证明，我们专注于纳米链在p24的即时诊断中的应用，伪血清中的^-1灵敏度比金纳米颗粒的可比研究高4倍。这些发现和基本概念突显了先进的功能性有机-无机复合纳米材料在诊断感染方面的潜力，对非传染性疾病具有广泛的适用性。