Lipid nanoparticle (LNP) delivery systems have become an established platform for clinical nucleic acid delivery, beginning with the approval of gene silencing therapy Patisiran (Onpattro) in 2018, and followed by mRNA vaccines against Covid19 and RSV. We will present a novel LNP platform, focussing on ionisable lipid optimisation and LNP performance in an in vivo vaccination setting.