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摘要
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Chitosan nanoparticles (CSNs) were produced via spray drying to evaluate the effects of the molecular weight, concentration of chitosan, and nozzle size of a nanospray dryer on its physicochemical properties and adjuvant potential. Three molecular weights (465, 618, and 732 kDa) were tested. CSNs from 465 kDa chitosan had the smallest (95.4 nm) and the highest zeta potential (+45.7 mV), whereas 732 kDa chitosan yielded larger particles (335.9 nm, +29.6 mV). Reducing the chitosan concentration from 0.1% to 0.025% decreased the particle size (358.3 → 95.4 nm) and increased the surface charge (+39.3 → +45.7 mV). CSNs of five different sizes ranging from <100 to 3000 nm were loaded with the A/H5N1 antigen, with 95.3–97.7% loading efficiency and 4881–5035 HAU/mg capacity. Compared with antigen alone or Al(OH)₃ controls, vaccination with CSN formulations elicited significantly stronger immune responses. After booster immunization, serum IgG titers reached 1536–1843, nearly double those induced by Al(OH)₃ (768), while hemagglutination inhibition titers increased to 160–230 HIU (p < 0.05). Biocompatibility and toxicity tests confirmed the safety and good tolerance of CSN-based vaccine formulations. These results demonstrate that CSNs are effective and safe adjuvants for enhancing the immunogenicity of H5N1 vaccines. |
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