碳点是一种尺寸介于1-10 nm的碳纳米粒子，不仅具有良好的发光特性和生物相容性，而且其本身还能诱导干扰素产生，是制备高效抗病毒药物的良好材料。本项目拟采用对猪繁殖与呼吸综合征病毒(PRRSV)有抑制效果的甘草酸为原料，通过水热炭化技术制备甘草酸碳点，采用共价偶联方法将PRRSV特异性核酸适配体偶联到碳点表面，提高碳点抗病毒特异性；利用仿生矿化技术将磷酸钙进一步修饰在碳点表面，增强其进入细胞的能力，从而获得对PRRSV具有高效、特异性抑制作用的复合甘草酸碳点(简称复合碳点)。在细胞水平上比较复合碳点、甘草酸碳点及甘草酸对PRRSV的抑制效果，并从对病毒复制周期的影响以及诱导干扰素能力等方面揭示复合碳点抑制PRRSV的机制；在此基础上，以断奶仔猪为模型，评价复合碳点对猪繁殖与呼吸综合征(PRRS)的预防和治疗效果。本研究不仅为PRRS的防控提供新的思路，还可为其他中草药抗病毒研究提供借鉴。

Carbon dots are a kind of carbon nanoparticles in the range of 1-10 nm, which not only have excellent luminescent properties and good biocompatibility, but also induce the production of interferon, so they are good materials for the preparation of highly effective antiviral drugs. In this project, glycyrrhizic acid, which can inhibit proliferation of porcine reproductive and respiratory syndrome virus (PRRSV), is used as precursor to prepare glycyrrhizic acid-carbon dots by the hydrothermal carbonization technology. To improve the antiviral specificity of carbon dots, PRRSV specific aptamers are attached to the surface of the glycyrrhizic acid-carbon dots by covalent coupling method. To enhance the ability of carbon dots to enter cells, calcium phosphate is further coated in the surface of glycyrrhizic acid-carbon dots by using biomimetic technology. Based on above processes, composite glycyrrhizic acid-carbon dots (composite carbon dots) with high efficiency and specificity of inhibition for PRRSV are obtained. The inhibition effects of composite carbon dots, glycyrrhizic acid-carbon dots and glycyrrhizic acid on PRRSV are compared on the cellular level. The inhibition mechanism of composite carbon dots on PRRSV is revealed according to the influence of virus replication cycle and the ability of inducing interferon. On this basis, the effect of composite carbon dots on the prevention and treatment of porcine reproductive and respiratory syndrome (PRRS) is evaluated by using PRRSV artificial infection weaned piglets as models. The study not only provides a novel idea for the prevention and control of PRRS, but also is used for reference in antiviral investigation of other Chinese herbal medicines.