Novel Lipid Nanoparticle Formulations Co-encapsulating DNA and Polyamines for Global Health Applications

Abstract

Lipid nanoparticles (LNPs) have revolutionized drug delivery by effectively delivering therapeutic molecules and nucleic acids to target cells, as demonstrated by the success of mRNA COVID-19 vaccines. However, mRNA-based therapies are limited in treating diseases that require prolonged expression of target proteins, which DNA delivery can provide. Additionally, the cold chain handling requirement remains a significant limitation of current LNP-mRNA therapeutics, resulting in barriers to access in global health. While DNA is relatively more thermostable than mRNA, similar challenges will likely apply to DNA. Despite its potential, LNPs for DNA delivery are still in their infancy and remain challenging due to low delivery efficiency, high immunogenicity, and a lack of targeted delivery. Previous research demonstrates that polyamines–spermine and spermidine–have immune-regulatory and DNA-condensing properties that could be harnessed to overcome these barriers. This study proposes a new approach that incorporates a polyamine-complexing agent to make DNA LNPs, aiming to optimize formulations for improved efficacy. Here, we demonstrate the successful production of 100-200 nm sized LNPs that co-encapsulate spermine or spermidine and plasmid-DNA using Flash NanoPrecipitation. Characterization of these novel formulations revealed impressive in vitro stability in plasma and stable physicochemical properties. At the standard Onpattro® and Comirnaty® mRNA vaccine style formulations, spermine and spermidine notably enhanced transfection in HeLa and HepG2 cell types. We also assessed the long-term particle stability at room temperature, 4°C, -20 °C, -80 °C, and lyophilized conditions. Integrated with a qualitative analysis of challenges encountered during the COVID-19 pandemic, explicitly focusing on cold chain handling of LNPs within the context of Bangladesh alongside the emerging threat of dengue, this research lays the groundwork for novel LNP formulations geared for global health applications. By addressing cold chain storage issues and confronting emerging public health threats, this study paves the way for innovative solutions to enhance the efficacy and accessibility of LNP-based therapies