Chlorogenic acid carbon dots inhibit NDV proliferation by suppressing virus-induced mitochondrial autophagy and MAVS degradation in host cells

Chlorogenic acid (CGA) is widely used to inhibit virus replication and transmission. However, it lacks targeting capabilities and sustained-release properties. In contrast, carbon quantum dots can not only inhibit virus replication directly but can also serve as drug carriers to enhance the targeting capacity and efficacy of antiviral drugs. In this study, CGA carbon dots (CGA-CDs) were prepared using a microwave-assisted synthesis method. The physicochemical characteristics and antiviral activities of CGA-CDs against Newcastle disease virus (NDV) were explored through a series of experiments. The average particle size of CGA-CDs was 5.675 ± 0.15 nm. The CGA-CDs were non-ordered carbon structures composed of C and O, with uniform size, good dispersion properties, and a surface rich in -COOH, -OH, and other hydrophilic groups. The optimal excitation wavelength of CGA-CDs was 390 nm, the emission wavelength was 450 nm, and the CGA-CDs thus emitted blue fluorescence. Notably, CGA-CDs produced significantly stronger antiviral effects than equivalent concentrations of CGA and could successfully inhibit virus adsorption and replication. Furthermore, CGA-CDs significantly inhibited virus-induced mitochondrial dysfunction, mitochondrial autophagy, and mitochondrial antiviral signaling protein (MAVS) degradation, providing superior antiviral efficacy. <i>In vivo</i> experiments further demonstrated the good biocompatibility of CGA-CDs. Moreover, in NDV-infected chickens, CGA-CDs significantly reduced the viral load in the spleen and proventriculus, alleviated pathological damage to major organs, enhanced antibody responses, and markedly lowered the mortality rate. In summary, CGA-CDs showed significant anti-NDV activity by inhibiting NDV adsorption and replication, likely through the inhibition of virus-induced mitophagy and MAVS degradation. These findings highlight the potential of CGA-CDs as potent antiviral agents.