Biology subjects

Moir, M.

Publications and source records attributed to Moir, M..

2 recordsLinked to original sources

bioRxiv2026

Post-loading ribonucleic acid into lipid nanoparticle carriers

Lipid nanoparticles (LNPs) are effective carriers for messenger ribonucleic acid (mRNA) delivery in vaccines; however, their reliance on extreme cold-chain storage limits global manufacturing and distribution. Conventional LNPs are formed by rapidly mixing four lipids with mRNA through electrostatic interactions between cationic ionizable lipids and negatively charged nucleic acids, facilitating nucleation and precipitation of mRNA-loaded LNPs. However, this binding also accelerates mRNA degradation, requiring stringent cold storage which limits widespread vaccine deployment. To overcome this limitation, we introduce a post-loading strategy in which empty LNPs (eLNPs) are first fabricated and RNA is subsequently loaded at a later stage. Using scalable confined impinging jet (CIJ) mixers, we optimized pH, buffer composition, lipid concentration, and ethanol content to produce colloidally stable eLNPs. Controlled adjustment of ethanol content and pH enabled efficient incorporation of four distinct RNA payloads while maintaining loaded LNP diameters below 100 nm. Post-loaded LNPs demonstrated mRNA delivery efficiencies in HeLa cells comparable to those of conventionally co-precipitated LNPs. Consistent size distributions and zeta potentials further confirmed comparable surface properties. Structural characterization by x-ray and neutron scattering revealed similar internal architectures for post-loaded and co-precipitated LNPs without compromising RNA loading efficiency. Together, these results demonstrate equivalent cellular delivery performance between the two formulations. This post-loading approach enables decentralized assembly of mRNA LNPs at the point of administration, with both eLNPs and mRNA stored under mild refrigeration, thereby improving vaccine accessibility. Moreover, eLNPs function as modular laboratory reagents, facilitating the translation of mRNA research toward clinical applications.

bioengineering↗

bioRxiv2025

Identifying genomic surveillance gaps in Africa for the global public health response to West Nile Virus

BackgroundWest Nile Virus (WNV) is a zoonotic flavivirus of significant One Health relevance and is classified as a priority pathogen with a high-risk of causing public health emergencies of global concern. WNV is endemic to Africa; however, the availability of genomic sequences from the continent remains limited. MethodsWe review the extent of polymerase chain reaction testing and genomic sequencing of WNV conducted across Africa. Using phylogeographic methods, we map the spatiotemporal spread of the virus across the continent and globally. FindingsOur study shows that WNV has been detected in 39 African countries (including Comoros, Seychelles, and Mauritius), the Canary Islands, and Reunion Island. Publications including molecular data originate from 24 countries; however, genomic sequences are publicly available for only 16 countries. We identify regions with detected viral circulation but lacking molecular surveillance. Further, we list such regions that overlap with Key Biodiversity Areas (sites harbouring significant bird diversity) as they may host high viral circulation, and high human population density that may be susceptible to spillover. InterpretationWe recognise significant knowledge gaps on the true disease burden, molecular epidemiology, and distribution of WNV in Africa. Addressing these gaps requires an integrated One Health surveillance approach which is challenging to establish. We propose three key surveillance needs as potential starting points to improve our understanding of the virus in Africa to strengthen the global public health response to this disease. FundingRockefeller Foundation, the National Institute of Health USA, Institute of Human Virology Nigeria, Global Health EDCTP3 Joint Undertaking, the Health Emergency Preparedness and Response Umbrella Program, managed by the World Bank Group, the Medical Research Foundation, and the Wellcome Trust.

molecular biology↗