Nam Jwa-Min, Jang Kyung-Jin, Groves Jay T
Department of Chemistry, Seoul National University, San 56-1, Sillim-dong, Gwanak-gu, Seoul 151-747, South Korea.
Nat Protoc. 2007;2(6):1438-44. doi: 10.1038/nprot.2007.201.
The colorimetric bio-barcode assay is a red-to-blue color change-based protein detection method with ultrahigh sensitivity. This assay is based on both the bio-barcode amplification method that allows for detecting miniscule amount of targets with attomolar sensitivity and gold nanoparticle-based colorimetric DNA detection method that allows for a simple and straightforward detection of biomolecules of interest (here we detect interleukin-2, an important biomarker (cytokine) for many immunodeficiency-related diseases and cancers). The protocol is composed of the following steps: (i) conjugation of target capture molecules and barcode DNA strands onto silica microparticles, (ii) target capture with probes, (iii) separation and release of barcode DNA strands from the separated probes, (iv) detection of released barcode DNA using DNA-modified gold nanoparticle probes and (v) red-to-blue color change analysis with a graphic software. Actual target detection and quantification steps with premade probes take approximately 3 h (whole protocol including probe preparations takes approximately 3 days).
比色生物条形码分析是一种基于红到蓝颜色变化的具有超高灵敏度的蛋白质检测方法。该分析基于生物条形码扩增方法（可实现以阿托摩尔灵敏度检测微量目标）和基于金纳米颗粒的比色DNA检测方法（可实现对感兴趣的生物分子进行简单直接的检测，在此我们检测白细胞介素-2，它是许多免疫缺陷相关疾病和癌症的重要生物标志物（细胞因子））。该方案由以下步骤组成：（i）将目标捕获分子和条形码DNA链偶联到二氧化硅微粒上，（ii）用探针捕获目标，（iii）从分离的探针中分离并释放条形码DNA链，（iv）使用DNA修饰的金纳米颗粒探针检测释放的条形码DNA，以及（v）用图形软件进行红到蓝颜色变化分析。使用预制探针进行实际目标检测和定量步骤大约需要3小时（包括探针制备的整个方案大约需要3天）。
