Preparation, identification, and application of PEG/ZIF-8@ Dendrobium huoshanense polysaccharide as an adjuvant to enhance immune responses

Zeolitic imidazolate framework-8 (ZIF-8) nanoparticles loaded with polysaccharides are excellent drug-delivery carriers with high loading capacity and pH sensitivity. This study describes the one-step encapsulation of Dendrobium huoshanense polysaccharides (DHP) in ZIF-8. The resultant PEG6000/ZIF-8@DHP complex exhibited drug release properties in acidic microenvironments, possessed water solubility, demonstrated high drug loading capacity, and displayed effective encapsulation. The effects of PEG6000/ZIF-8@ DHP administration on immunoregulation, antioxidant activities, and resistance against Aeromonas veronii in channel catfish were assessed. The study revealed that the PEG6000/ZIF-8@DHP complex stimulated cellular proliferation and phagocytosis, while also inducing the production of cytokines and nitric oxide. Additionally, the complex exhibited improved antioxidant properties and increased serum lysozyme and alkaline phosphatase activities. PEG6000/ZIF-8@DHP exhibited efficacy in vivo against Aeromonas veronii infection. These results indicate that PEG6000/ZIF-8@DHP is an efficient immunostimulant and vaccine adjuvant for enhancing immunity in channel catfish.