Thrilled to share our latest work on lipid nanoparticle (LNP) delivery of a stable CRISPR-Cas9 ribonucleoprotein (RNP) for in vivo genome editing, now published @NatureBiotech! 🧬 nature.com/articles/s41587-0… In this paper, we first engineered robust, efficient, and stable CRISPR-Cas9 genome-editing enzymes, iGeoCas9s, through #directedevolution of Cas9 from Geobacillus stearothermophilus (GeoCas9). We then developed an LNP-based delivery platform that successfully encapsulates and delivers iGeoCas9 RNP to various cell lines, achieving high-efficiency genome editing in vitro, including homology-directed repair (HDR) via codelivery of RNP and ssDNA templates. In the end, we demonstrated that different LNP formulations enabled tissue-specific genome editing in the liver and lungs after single intravenous injections of iGeoCas9 RNP–LNP complexes without triggering detectable immune responses. Overall, our results show that stable Cas9 RNP–LNP complexes can be a robust alternative to mRNA–LNP delivery and expand the therapeutic potential of CRISPR genome editing. Our previous study @CellCellPress illustrated why our engineered iGeoCas9 exhibits dramatic improvements in its genome editing function. The high protein stability and desired negative charge density are the key to the successful development of the LNP delivery strategy for iGeoCas9 RNPs, which outperforms mRNA+sgRNA codelivery by LNPs for genome editing. We believe this LNP delivery platform can be further extended to other editing tools, such as base editors and prime editors. Huge thanks to my collaborators @doudna_lab and in the Murthy lab for making this possible! @igisci @berkeleyMCB