基于关节液CD64核酸适配体构建关节假体周围感染精准诊断新方法

关节假体周围感染（PJI）是关节置换术后严重的灾难性并发症，也是早期失败最常见的原因，如何快速精准诊断PJI一直都是研究的热点和难点。PJI常表现为低毒性感染，微生物培养阳性率不高；血清学指标检测虽然简单易行，但是容易受到关节外感染及全身免疫系统疾病的影响；近来关节液生物标记物检测是研究的热点，但是受限于检测方法或者易受关节液中其他杂质影响结果。因此，目前针对PJI诊断仍缺乏早期精准标记物以及相应的快速检测手段。在前期研究工作中，申请人发现静脉血和关节液中性粒细胞CD64表达量增高可以作为PJI诊断新指标。然而，CD64流式细胞仪法具有样本处理复杂、仪器昂贵、试剂重复性差等局限性。本项目拟在前期研究基础上，进行CD64特异性核酸适配体的SELEX筛选，将所获核酸适配体进行生物信息学、亲和力和特异性分析，建立基于关节液中性粒细胞CD64荧光标记适配体直接检测法的PJI诊断新方法。

Periprosthetic joint infection (PJI) is the severely catastrophic complication and the most common cause of early failure after total joint arthroplasty. The rapid and accurate diagnosis of PJI has always been a hot and difficult issue for orthopedic surgeons. As PJI is often low-toxicity, the positive rate of microbial culture is not high and its sensitivity is only 0.72. Serum markers are easily affected by extra-articular infections and systemic immune system diseases. Nowadays, the synovial biomarkers (leucocyte esterase, α-defensins) have been a hot area of research. But they are subject to the detection method and the impurity in the synovial fluid. Therefore, early accurate markers and corresponding rapid detection technologies for PJI diagnosis are still scarce. In the preliminary research work, the proposer found that upregulation of CD64 expression in blood and synovial fluid neutrophils could be a new marker for PJI diagnosis. Given the limitations of CD64 flow cytometry (complex sample processing, expensive equipment, poor reagent repeatability) and based on the previous studies, this project is aimed to perform SELEX screening of CD64-specific aptamers. Then the binding force, specificity and bioinformatics analysis of the obtained aptamers are examined. The final purpose is to establish a new method of PJI diagnosis based on FLADA CD64 of in joint fluid neutrophils.