Covalent Functionalization of Layered Double Hydroxides to Generate Peptide-Based SARS-CoV-2 Nanovaccine

Area of Science:

• Nanomaterials Science
• Vaccine Development
• Bioconjugation Chemistry

Background:

• Nanoclays, including Layered Double Hydroxides (LDHs), offer biocompatibility and cost-effectiveness for biological applications.
• LDHs have been utilized in nanovaccines as adjuvants and antigen carriers via passive bioconjugation.
• Active bioconjugation for covalent antigen binding to create subunit nanovaccines using LDHs is an underexplored area.

Purpose of the Study:

• To synthesize, functionalize, and actively conjugate LDH nanoparticles with SARS-CoV-2 peptides for subunit nanovaccine development.
• To optimize the functionalization and conjugation methods for creating stable and effective nanovaccine candidates.
• To evaluate the physicochemical properties, cytotoxicity, and immunogenicity of the developed nanovaccines.

Main Methods:

• Mg-Al LDH nanoparticles were synthesized using coprecipitation and hydrothermal treatment.
• Surface functionalization was achieved using (3-aminopropyl)triethoxysilane, followed by optimization of reductive amination with glutaraldehyde.
• Two SARS-CoV-2 spike protein peptides (P2 and P5) were covalently conjugated to the LDH surface.

Main Results:

• Monodisperse Mg-Al LDH nanoparticles (approx. 100 nm) were successfully synthesized and characterized.
• Optimized functionalization and conjugation methods yielded nanovaccine candidates with high peptide concentrations (125-270 µg/mL).
• The P2-conjugated LDH nanovaccine demonstrated non-toxicity up to 250 µg/mL and induced IgG titers comparable to aluminum hydroxide adjuvant.

Conclusions:

• Active bioconjugation of LDH nanoparticles with SARS-CoV-2 peptides is feasible for creating subunit nanovaccines.
• The developed LDH-based nanovaccines exhibit favorable safety and immunogenicity profiles.
• These findings highlight the potential of LDH nanoparticles as a platform for next-generation subunit vaccines.