尽管纳米粒子镜腔的灵敏度很高,等离子体纳米材料的一个重要分支,复杂的制备和读出过程限制了其在生物传感中的广泛应用。或者,液态金属(LMs)结合了流动性和出色的等离子体特性,已成为构建等离子体纳米结构的潜在候选者。在这里,我们提出了一种微流控集成策略来构建基于LM的免疫分析平台,使基于LM的纳米等离子体传感器可用于即时护理(POC)临床生物标志物检测。将可流动的LM引入到蛋白质涂覆的Au纳米颗粒单层上,形成“镜面纳米颗粒”纳米结构,简化了在常规的纳米颗粒镜腔中的制造工艺。当抗体被包被在Au纳米颗粒单层上的抗原捕获时,器件响应生物分子层的厚度和折射率变化,输出肉眼可读信号,具有高灵敏度(检测限:~604fM)和宽动态范围(6阶)。这种新的检测方法,在30分钟内产生定量结果,允许高吞吐量,基于智能手机的SARS-CoV-2抗体检测针对临床血清或血液样本中的多种变体。这些结果为使用LM材料进行POC测试建立了先进的途径,并证明其促进诊断的潜力,各种传染病的监测和流行研究。
Despite high sensitivity of nanoparticle-on-mirror cavities, a crucial branch of plasmonic nanomaterials, complex preparation and readout processes limit their extensive application in biosensing. Alternatively, liquid metals (LMs) combining fluidity and excellent plasmonic characteristics have become potential candidates for constructing plasmonic nanostructures. Herein, we propose a microfluidic-integration strategy to construct LM-based immunoassay platform, enabling LM-based nanoplasmonic sensors to be used for point-of-care (POC) clinical biomarker detection. Flowable LM is introduced onto protein-coated Au nanoparticle monolayer to form a \"mirror-on-nanoparticle\" nanostructure, simplifying the fabrication process in the conventional nanoparticle-on-mirror cavities. When antibodies were captured by antigens coated on the Au nanoparticle monolayer, devices respond both thickness and refractive index change of biomolecular layers, outputting naked-eye readable signals with high sensitivity (limit of detection: ∼ 604 fM) and a broad dynamic range (6 orders). This new assay, which generates quantitative results in 30 min, allows for high-throughput, smartphone-based detection of SARS-CoV-2 antibodies against multiple variants in clinical serum or blood samples. These results establish an advanced avenue for POC testing with LM materials, and demonstrate its potential to facilitate diagnostics, surveillance and prevalence studies for various infectious diseases.