The Blackett Laboratory , Imperial College London , Prince Consort Road, London SW7 2AZ , United Kingdom.
Institute of High Performance Computing, A*STAR (Agency for Science, Technology and Research) , 1 Fusionopolis Way, #16-16 Connexis , Singapore 138632 , Singapore.
Nano Lett. 2019 Sep 11;19(9):5853-5861. doi: 10.1021/acs.nanolett.9b01137. Epub 2019 Aug 9.
Plasmon-polaritons are among the most promising candidates for next-generation optical sensors due to their ability to support extremely confined electromagnetic fields and empower strong coupling of light and matter. Here we propose quantum plasmonic immunoassay sensing as an innovative scheme, which embeds immunoassay sensing with recently demonstrated room-temperature strong coupling in nanoplasmonic cavities. In our protocol, the antibody-antigen-antibody complex is chemically linked with a quantum emitter label. Placing the quantum-emitter-enhanced antibody-antigen-antibody complexes inside or close to a nanoplasmonic (hemisphere dimer) cavity facilitates strong coupling between the plasmon-polaritons and the emitter label resulting in signature Rabi splitting. Through rigorous statistical analysis of multiple analytes randomly distributed on the substrate in extensive realistic computational experiments, we demonstrate a drastic enhancement of the sensitivity up to nearly 1500% compared to conventional shifting-type plasmonic sensors. Most importantly and in stark contrast to classical sensing, we achieve in the strong-coupling (quantum) sensing regime an enhanced sensitivity that is no longer dependent on the concentration of antibody-antigen-antibody complexes down to the single-analyte limit. The quantum plasmonic immunoassay scheme thus not only leads to the development of plasmonic biosensing for single molecules but also opens up new pathways toward room-temperature quantum sensing enabled by biomolecular inspired protocols linked with quantum nanoplasmonics.
等离子体激元是下一代光学传感器最有前途的候选者之一，因为它们能够支持极其受限的电磁场，并实现光与物质的强耦合。在这里，我们提出了量子等离子体免疫分析传感作为一种创新方案，将免疫分析传感与最近在纳米等离子体腔中展示的室温强耦合相结合。在我们的方案中，抗体-抗原-抗体复合物通过化学方法与量子发射器标签连接。将增强了量子发射器的抗体-抗原-抗体复合物放置在纳米等离子体（半球二聚体）腔体内或附近，有利于等离子体激元与发射器标签之间的强耦合，从而导致特征性的拉比分裂。通过在广泛的现实计算实验中对随机分布在基底上的多个分析物进行严格的统计分析，我们证明了灵敏度的大幅增强，与传统的移位型等离子体传感器相比，灵敏度提高了近 1500%。最重要的是，与经典传感形成鲜明对比的是，我们在强耦合（量子）传感范围内实现了灵敏度的增强，不再依赖于抗体-抗原-抗体复合物的浓度，甚至可以达到单分析物的极限。因此，量子等离子体免疫分析方案不仅为单分子的等离子体生物传感开辟了道路，而且还为基于生物分子启发的协议与量子纳米等离子体相结合的室温量子传感开辟了新途径。
