Non-invasive nanoparticle barcoding in nonhuman primates.

The clinical relevance of a lipid nanoparticle (LNP)-mRNA drug candidate is often dictated by its behavior in nonhuman primates. Yet, evaluating how chemically distinct LNPs behave in nonhuman primates remains difficult, in part because nanoparticle barcoding assays require euthanasia and difficult downstream tissue processing. Here we report non-invasive nanoparticle barcoding, which quantifies functional mRNA delivery mediated by several LNPs in a single nonhuman primate using 30 µl of serum. This method is enabled by snapCodes, benzylguanine-modified DNA barcodes that covalently bind an mRNA-encoded nanoluciferase-SNAP-tag fusion protein in vivo. The resulting DNA-fusion protein complexes are exported from cells, isolated from serum and sequenced. After validating snapCode and fusion protein activity, we intravenously administer six snapCoded LNPs to mice and nonhuman primates, thereby comparing LNP delivery across species. Measuring mRNA delivery from multiple LNPs using a low-volume blood draw reduces animal use and may help identify promising nanoparticle formulations.