Luo Yang, Chen Ming, Wen Qianjun, Zhao Meng, Zhang Bo, Li Xiaoyan, Wang Feng, Huang Qing, Yao Chunyan, Jiang Tianlun, Cai Guoru, Fu Weiling
Department of Laboratory Medicine, Southwest Hospital, The Third Military Medical University, Chongqing, People's Republic of China.
Clin Chem. 2006 Dec;52(12):2273-80. doi: 10.1373/clinchem.2006.073569. Epub 2006 Oct 19.
Urinary proteins are predictive and prognostic markers for diabetes nephropathy. Conventional methods for the quantification of urinary proteins, however, are time-consuming, and most require radioactive labeling. We designed a label-free piezoelectric quartz crystal microbalance (QCM) immunosensor array to simultaneously quantify 4 urinary proteins.
We constructed a 2 x 5 model piezoelectric immunosensor array fabricated with disposable quartz crystals for quantification of microalbumin, alpha1-microglobulin, beta2-microglobulin, and IgG in urine. We made calibration curves after immobilization of antibodies at an optimal concentration and then evaluated the performance characteristics of the immunosensor with a series of tests. In addition, we measured 124 urine samples with both QCM immunosensor array and immunonephelometry to assess the correlation between the 2 methods.
With the QCM immunosensor array, we were able to quantify 4 urinary proteins within 15 min. This method had an analytical interval of 0.01-60 mg/L. The intraassay and interassay imprecisions (CVs) were <10%, and the relative recovery rates were 90.3%-109.1%. Nonspecificity of the immunosensor was insignificant (frequency shifts <20 Hz). ROC analyses indicated sensitivities were > or =95.8% and, specificities were > or =76.3%. Bland-Altman difference plots showed the immunosensor array to be highly comparable to immunonephelometry.
The QCM system we designed has the advantages of being rapid, label free, and highly sensitive and thus can be a useful supplement to commercial assay methods in clinical chemistry.
尿蛋白是糖尿病肾病的预测和预后标志物。然而，传统的尿蛋白定量方法耗时，且大多需要放射性标记。我们设计了一种无标记的压电石英晶体微天平（QCM）免疫传感器阵列，用于同时定量4种尿蛋白。
我们构建了一个2×5模式的压电免疫传感器阵列，该阵列由一次性石英晶体制成，用于定量尿液中的微量白蛋白、α1-微球蛋白、β2-微球蛋白和IgG。在以最佳浓度固定抗体后制作校准曲线，然后通过一系列测试评估免疫传感器的性能特征。此外，我们使用QCM免疫传感器阵列和免疫比浊法测量了124份尿液样本，以评估这两种方法之间的相关性。
使用QCM免疫传感器阵列，我们能够在15分钟内定量4种尿蛋白。该方法的分析区间为0.01-60mg/L。批内和批间不精密度（CV）<10%，相对回收率为90.3%-109.1%。免疫传感器的非特异性不显著（频率偏移<20Hz）。ROC分析表明，灵敏度≥95.8%，特异性≥76.3%。Bland-Altman差异图显示免疫传感器阵列与免疫比浊法具有高度可比性。
我们设计的QCM系统具有快速、无标记和高灵敏度的优点，因此可作为临床化学中商业检测方法的有用补充。
