Department of Applied Chemistry, Graduate School of Engineering, Nagoya University, Nagoya, Japan; MEXT Innovative Research Center for Preventive Medical Engineering, Nagoya University, Nagoya, Japan; Department of Chemical and Biological Engineering, Chalmers University of Technology, Göteborg, Sweden.
Biosens Bioelectron. 2014 Jan 15;51:280-5. doi: 10.1016/j.bios.2013.07.058. Epub 2013 Aug 6.
We reported an optical DNA/protein microfluidic sensor which consists of single stranded (ss) DNA-Cy3 probes on gold surface and simple line-shape microfluidic channel. These ssDNA-Cy3 probes with random sequence in bulk solution or on gold surface exhibits fluorescence enhancement after binding with complementary ssDNA (cssDNA) targets. Particularly it did not require complicated design or hairpin-like stem-loop conformation, which made it easier to be made and applied in analytes detection by fluorescence switching techniques. Using ssDNA-cy3 probes attached on gold surface in a microfluidic channel, strong fluorescence enhancement was measured by ssDNA with cssDNA binding or ssDNA with cssDNA-biotin binding. The following introduction of streptavidin resulted in fluorescence quenching (fluorescence decrease) because of the binding of hybridized DNA-biotin with streptavidin. This sensor showed strong affinity and high sensitivity toward the streptavidin, the minimum detectable concentration for streptavidin was 1 pM, equating to an absolute detection limit of 60 amol in this microfluidic channel. Microfluidic channel height and flow rate is optimized to increase surface reaction efficiency and fluorescence switching efficiency. In contrast to previously reported optical molecular beacon approach, this sensor can be used not only for the detection of cssDNA target, but also for the detection of streptavidin. This microfluidic sensor offers the promise of analyzing kinds of molecular targets or immunoreactions.
我们报道了一种光学 DNA/蛋白质微流控传感器，它由金表面上的单链 (ss) DNA-Cy3 探针和简单的线状微流道组成。这些在大量溶液或金表面上具有随机序列的 ssDNA-Cy3 探针在与互补 ssDNA (cssDNA) 靶标结合后表现出荧光增强。特别是它不需要复杂的设计或发夹样茎环构象，这使得它更容易通过荧光开关技术进行分析物检测。使用 ssDNA-cy3 探针在微流道中附着在金表面上，通过与 cssDNA 结合的 ssDNA 或与 cssDNA-生物素结合的 ssDNA 测量到强荧光增强。随后引入链霉亲和素会导致荧光猝灭（荧光减少），因为杂交 DNA-生物素与链霉亲和素结合。该传感器对链霉亲和素有很强的亲和力和高灵敏度，链霉亲和素的最小可检测浓度为 1 pM，相当于在这个微流道中绝对检测限为 60 amol。微流道高度和流速得到优化，以提高表面反应效率和荧光开关效率。与以前报道的光学分子信标方法相比，该传感器不仅可用于检测 cssDNA 靶标，还可用于检测链霉亲和素。这种微流控传感器有望分析各种分子靶标或免疫反应。
