Fluorescence labelling strategies for nucleic acids and current applications in studying RNA delivery

Recent advances in nucleic acid delivery technologies have accelerated research in RNA therapeutics and vaccines across many areas of pre-clinical study. As the main limitation for RNA as a therapeutic remains its functional delivery to the cytosol, much current literature is focused on optimising the endosomal escape of internalised RNA molecules. Fluorescence labelling of RNA molecules offers an effective way to measure this experimentally, allowing researchers to develop assays which distinguish RNA location from protein production. In recent years, advances in fluorescent nucleic acid chemistry have produced a variety of novel labelling strategies. This work provides an overview of RNA labelling strategies, with an accompanying selection guide for researchers who design assays to measure RNA delivery. It also reviews recent applications of fluorescently labelled RNA in delivery studies and concludes with a perspective on how novel fluorescent label chemistries could be applied in future delivery-focused RNA research.