基于单个量子点荧光共定位光谱成像的“药物亲和响应靶点稳定性”技术研究

Drug Affinity Responsive Target Stability（DARTS）is a new method for identification of small-molecule target. Although in its infancy, DARTS has the potential to be a major player in drug identification and drug screening. However, a current disadvantage shared with DARTS is the need for identification of target relying on the traditional quantitative proteomics. Future improvements in DARTS are expected to increase its sensitivity and throughput and reduce the sample/reagents consumption for the high throughput screening of drug and targets. Here, we are going to develop a novel platform for DARTS method based on spectral imaging of fluorescence colocalization of single quantum dots (QD). Using the array single quantum dot modified with the target protein as sensors, we build a platform to detect 3 model proteins with wide range affinity interactions with small molecules. Fluorescence colocalization imaging of QDs can be achieved based on the nanoassemblies of between the two color antibody-functionalized QDs and target protein-functionalized QDs. Because free target protein competes with the QD-protein in binding with the antibody, the fluorescence colocalization spectral imaging changed with the increasing of free target protein concentration upon the addition of it into an appropriate QD-protein-antibody-QD system.Therefore, monitoring the changes of the fluorescence colocalization spectral imaging provides the opportunity to quantify the free target protein concentration. The plateform integrated with microarray chips has devised a strategy for DARTS at single-molecule level with great advantadges including easy operation, low detection limitation, high throughput and low consumption of samples and reagents.

“药物亲和响应靶点稳定性”（Drug Affinity Responsive Target Stability, DARTS）技术是一种小分子药物靶标的寻找方法。自提出后在靶蛋白发现和药物筛选中起到重要作用。然而，由于该技术强烈依赖于传统蛋白质定量技术，存在试剂及样品消耗量较大，分析通量及灵敏度低等问题，难以适应大规模靶蛋白或药物筛选的需求。因此，本项目拟发展一种基于单个量子点荧光共定位光谱成像方法的DARTS技术。选择亲和能力级别不同的三组药物和靶蛋白体系为研究模型，以修饰靶蛋白的单个量子点为传感器，构建芯片阵列，在药物和蛋白酶作用下，通过与另一种颜色量子点标记的靶蛋白抗体作用形成荧光共定位信号的光谱变化为检测参数，建立单分子层面上的DARTS技术平台。本项目的建立具有操作简便、灵敏度高、分析通量高、样品及试剂消耗量少等优点，为进一步实现高通量药物筛选、药靶筛选及药理活性研究打下基础。

"药物亲和响应靶点稳定性"（Drug Affinity Responsive Target Stability, DARTS）是一种小分子药物靶标的寻找方法。自提出后在靶蛋白的发现和药物筛选中起到重要作用。然而，由于该项技术强烈依赖于传统蛋白质定量技术，存在试剂及样品消耗量较大，分析通量及灵敏度低等问题，难以适应大规模靶蛋白或药物筛选的需求。因此，本研究以单分子荧光成像为手段，计数量子点诱导团聚体为检测依据，建立DARTS在微观体系下的研究方法模型，研究内容主要有:.（1）分析几种不同分子量的聚合物对量子点光学性质的影响。通过几种聚合物对量子点光学性质的影响，寻找一种最能凸显量子点优势的聚合物，以游离胆红素的检测为应用模型，计数聚合物诱导形成的同色量子点团聚体，将同色量子点团聚比率与目标物浓度进行关联，实现了对游离胆红素的准确定量，并进一步应用到了人体中全血和血清实际样品的检测。此外，所提出的简单单色量子点聚集方法对改性量子点传感器的设计用于DARTS体系研究具有潜在应用价值。.（2）抗原诱导形成异色量子点二聚体。因为团聚体中量子点的距离小于衍射极限，所以在荧光显微镜下异色量子点在空间上是“重叠”的，导致异色量子点团聚后呈现新颜色，而未结合抗原的单个量子点仍保持原有颜色。以此为依据，计数异色量子点的团聚体，将异色量子点的团聚比率与目标物浓度进行关联，从而测定出未知样品中目标物含量。