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. Author manuscript; available in PMC: 2024 Sep 1.
Published in final edited form as: Nat Biotechnol. 2023 Apr 24;42(3):510–517. doi: 10.1038/s41587-023-01774-z

Fig. 3 |. SARS-CoV-2 vaccination using thermostable MNPs.

Fig. 3 |

a,b, Pyramid MNPs made from PVP:PVA are stiffer (a) and stronger (b) than similarly sized conical MNPs (n = 10 independent samples). Unpaired two-tailed t-tests. c, Both conical and pyramid MNPs are capable of penetrating (black arrows) the epidermis (e) and accessing the dermis (d) for ID delivery. d,e, Pyramid MNPs dissolve significantly faster than conical MNPs using optical imaging e before and after application (n = 3 independent samples). Unpaired two-tailed t-tests. f, GMTs are similar between IM and MNP for SARS-CoV-2 RBD mRNA (n = 5 biologically independent samples). Ordinary two-way ANOVA (Sidak’s multiple comparisons test). g, Anti-RBD protein IgG titers through week 11, showing the different kinetics of humoral responses between MNP and IM administration and similar responses for SARS-CoV-2 RBD mRNA (n = 5 biologically independent samples). h, Electrochemiluminescence serum anti-RBD binding assay responses for SARS-CoV-2 variants showing similar responses for IM and MNP with SARS-CoV-2 RBD mRNA (n = 5 biologically independent samples). Ordinary two-way ANOVA (Sidak’s multiple comparisons test). i, PVP:PVA stabilizes mRNA-LNPs in MNPs for high protein expression after 6 months of storage at room temperature (n = 5 biologically independent samples). Each dataset is plotted with a linear fit, and the 95% confidence interval is shaded. j, Design relationship for meeting dosing requirements in humans for common mRNA vaccines, illustrating the relationship among single microneedle volume, microneedles per MNP and dose delivered in a single MNP. Black arrows indicate the size (in microneedles per MNP) where a human dose of mRNA is satisfied for the constant single microneedle volume used in these studies. Data represent mean ± s.d. (a,b,d) or mean ± s.e.m. (f–i). P values are represented by: *P ≤ 0.05; **P ≤ 0.01; ***P ≤ 0.001; ****P ≤ 0.0001. MPa, megapascal; N, Newton; NS, not significant.