A novel QD-based immunoassay on a paper-based lateral flow system has been developed to quantitatively detect C-reactive protein (CRP). Different standard CRP antigens from 1 to 200 μg mL-1 were diluted 200-fold and only 60 μL diluted sample were needed to load onto the sample pad. The QD fluorescence signals on the test line and the control line were able to be observed within 3 min after the initiation of assay, and the limit of detection was as sensitive as 0.30 ng mL-1 by measuring the fluorescence intensity immediately afterwards with fluorescence immunoassay analyzer. The linearity on the detection of QD fluorescence signals has been established well in the range of 0.5 ng mL-1 and 1 μg mL-1 for CRP. The precision of the assay has been confirmed for low coefficient of variation (CV), satisfying less than 15% (intra-assay and inter-assay), and the accuracy of assay meets the requirements with the mean recovery of the control was 102.63%. These results indicated that such newly developed platform was reliable with high sensitivity, rapidness, and could cover a broad range of target concentrations. Furthermore, a total of 135 human serum clinical samples with inflammation or infection with the concentration of CRP from 0.2 to 200 μg mL-1 has been used to check the performance of this QD-based LFIA, it correlated very well with Roche Tina-quant CRP (Latex) (r = 0.966, n = 135).

中文翻译：

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基于量子点的侧流试纸定量快速检测C反应蛋白

已开发出一种基于纸基侧流系统的新型 QD 免疫测定法，以定量检测 C 反应蛋白 (CRP)。将 1 至 200 μg mL-1 的不同标准 CRP 抗原稀释 200 倍，只需将 60 μL 稀释样品加载到样品垫上。测定开始后3 min内可观察到检测线和对照线上的QD荧光信号，检测限灵敏至0.30 ng mL-1，随后立即用荧光免疫测定法测定荧光强度分析器。对于 CRP，在 0.5 ng mL-1 和 1 μg mL-1 范围内，QD 荧光信号的检测线性良好。测定的精密度已被确认为低变异系数（CV），满足小于 15%（批内和批间），测定准确度符合要求，对照的平均回收率为102.63%。这些结果表明，这种新开发的平台可靠、灵敏度高、速度快，并且可以覆盖广泛的目标浓度。此外，共有 135 份具有炎症或感染的 CRP 浓度为 0.2 至 200 μg mL-1 的人血清临床样本被用于检查这种基于 QD 的 LFIA 的性能，它与 Roche Tina-quant 非常相关CRP（乳胶）（r = 0.966，n = 135）。