Synthesis, characterization, and immune efficacy of layered double hydroxide@SiO₂ nanoparticles with shell-core structure as a delivery carrier for Newcastle disease virus DNA vaccine

Abstract

Layered double hydroxide (LDH)@SiO₂ nanoparticles were developed as a delivery carrier for the plasmid DNA expressing the Newcastle disease virus F gene. The LDH was hydrotalcite-like materials. The plasmid DNA encapsulated in the LDH@SiO₂ nanoparticles (pFDNA-LDH@SiO₂-NPs) was prepared by the coprecipitation method, and the properties of pFDNA-LDH@SiO₂-NPs were characterized by transmission electron microscopy, zeta potential analyzer, Fourier transform infrared spectroscopy, and X-ray diffraction analysis. The results demonstrated that the pFDNA-LDH@SiO₂-NPs had a regular morphology and high stability with a mean diameter of 371.93 nm, loading capacity of 39.66%±0.45%, and a zeta potential of +31.63 mV. A release assay in vitro showed that up to 91.36% of the total plasmid DNA could be sustainably released from the pFDNA-LDH@SiO₂-NPs within 288 hours. The LDH@SiO₂ nanoparticles had very low toxicity. Additionally, their high transfection efficiency in vitro was detected by fluorescent microscopy. Intranasal immunization of specific pathogen-free chickens with pFDNA-LDH@SiO₂-NPs induced stronger cellular, humoral, and mucosal immune responses and achieved a greater sustained release effect than intramuscular naked plasmid DNA, and the protective efficacy after challenge with the strain F₄₈E₉ with highly virulent (mean death time of chicken embryos ≤60 hours, intracerebral pathogenicity index in 1 -day-old chickens >1.6) was 100%. Based on the results, LDH@SiO₂ nanoparticles can be used as a delivery carrier for mucosal immunity of Newcastle disease DNA vaccine, and have great application potential in the future.

Keywords:

• LDH@SiO₂ nanoparticles
• Newcastle disease
• mucosal immunity
• Cytotoxicity
• IgA

Supplementary material

Figure S1 Preparation of pFDNA-LDH@SiO2-NPs.

Abbreviations: APTES, 3-aminopropyl-triethoxysilane; LDH, layered double hydroxide; NPs, nanoparticles; pFDNA-LDH@SiO₂-NPs, Newcastle disease virus F gene encapsulated in LDH@SiO₂-NPs; pFDNA-SiO₂-NPs, Newcastle disease virus F gene encapsulated in SiO₂-NPs; TEOS, tetraethyl orthosilicate.

Acknowledgments

We gratefully acknowledge the Key Laboratory of Functional Inorganic Material Chemistry (Heilongjiang University), the Ministry of Education and Engineering Research Center of Agricultural Microbiology Technology, and the Ministry of Education for providing the facilities to carry out this work. This work was supported in part by the National Natural Science Foundation of China (31072119), the Key Project of the Chinese Ministry of Education (212048), the Key Program of Natural Science Foundation of Heilongjiang Province of China (ZD201515), the Innovative Research Team for Agricultural Microbiology Fermentation Technology at Heilongjiang Provincial University (2012td009), the Changjiang Scholar Candidates Program for Provincial Universities in Heilongjiang (2014CJHB005), the Scientific and Technological Key Project of Heilongjiang Province (GC13B403), the Early Research and Development Cultivation Project of Scientific and Technological Achievements Industrialization for Provincial Universities in Heilongjiang (1253CGZH10), and the Technological Innovation Talent Foundation of Harbin (2013RFQXJ030).

Disclosure

The authors report no conflicts of interest in this work.