背景:C反应蛋白(CRP)代表早期临床生物标志物,表明人体内存在炎症或感染性疾病。如今,食品和药物管理局(FDA)批准的程序意味着昂贵的设备和训练有素的人员来执行测试。因此,迫切需要一种检测效率高且成本较低的新诊断方法,以便在现场护理(POC)服务中提供快速及时的结果.
结果:这里,我们提出了一个新的,无设备,和便携式传感办法,用于将来基于Tyndall效应(TE)的POC检测。在我们的研究中,利用适体缀合的柠檬酸盐稳定的金纳米颗粒(apta-AuNP)作为传感平台。apta-AuNPs在盐水环境中与CRP的相互作用导致它们的聚集,因此,当溶液暴露于640nm指针激光线时,增强光的散射。首先,使用典型的90度角荧光分光光度计通过光谱测量散射光随溶液中CRP浓度增加的增强,然后将测量结果与使用UV-Vis分光光度计的经典比色检测进行比较。最后,为了实现高便携性和可访问性,我们证明,CRP浓度的测量可以以相似的精度进行,但更直接,更便宜的方式,通过使用激光笔作为激发源,使用低预算智能手机的相机作为定量阅读器,而不是最昂贵的荧光分光光度计.
结论:基于便携式TE的测定法显示出用于检测CRP的宽线性动态范围(1-60μg/mL),检出限(LOD)为92ng/mL。所提出的方法能够在单个程序中整合标准和高灵敏度的CRP分析,同时增加灵敏度并迅速提供分析结果。此外,传感程序明显快于FDA批准的,检测时间仅为10分钟。最后,作为一个概念证明,我们的研究结果表明,在加标和稀释的尿液样本中,CRP检测的回收率很好,突出了这种传感方法在POC应用中的强大潜力。
BACKGROUND: C-reactive protein (CRP) represents an early clinical biomarker that indicates the presence of inflammatory or infectious conditions in the human body. Today\'s procedures approved by the Food and Drug Administration (FDA) imply expensive equipment and highly trained personnel to perform the test. Therefore, a new diagnostic method with high detection efficiency and less cost is urgently needed for delivering rapid and timely results in point-of-care (POC) service.
RESULTS: Herein, we propose a new, equipment-free, and portable sensing method for the future POC detection of CRP based on the Tyndall effect (TE). In our study, aptamer-conjugated citrate-stabilized gold nanoparticles (apta-AuNPs) are exploited as the sensing platform. The apta-AuNPs\' interaction with CRP in a saline environment leads to their aggregation, thus enhancing the scattering of light when the solution is exposed to a 640 nm pointer laser line. Firstly, the enhancement of the scattering light as a function of increasing concentration of CRP in solution is measured spectroscopically using a typical 90-degree angle spectrofluorometer and then the measurements are compared to the classic colorimetric detection using an UV-Vis spectrophotometer. Finally, to achieve high portability and accessibility, we demonstrate that the measurement of CRP concentration can be performed with similar accuracy but in a more direct and inexpensive way by using a laser pointer pen as the excitation source and a camera of a low-budget smartphone as a quantitative reader instead of most expensive spectrofluorometer.
CONCLUSIONS: The portable TE-based assay exhibits a wide linear dynamic range (1-60 μg/mL) for the detection of CRP with a limit of detection (LOD) of 92 ng/mL The proposed method is capable to integrate both standard and high-sensitivity CRP analysis in a single procedure with increased sensitivity and prompt delivery of analysis results. Moreover, the sensing procedure is significantly faster than the FDA approved ones with a detection time of only 10 min. Finally, as a proof-of-concept, our findings demonstrate excellent recovery for CRP detection in spiked and diluted urine samples, highlighting the strong potential of this sensing method for POC applications.