Cytosolic delivery of CRISPR/Cas9 ribonucleoproteins for genome editing using chitosan-coated red fluorescent protein

Though plenty of viral and non-viral methods have been rapidly developed for the delivery of the CRISPR/Cas9 system, the direct delivery of Cas9 ribonucleoproteins (RNPs) into the nucleus for genome editing via the non-homologous end joining (NHEJ) or homology-directed repair (HDR) pathway, especially the latter one, remains a challenge. Here we report a delivery vehicle achieved by encapsulating red fluorescent protein (RFP) within chitosan (CS), which can simultaneously deliver engineered Cas9 RNPs with a poly-glutamate peptide tag (E-tag) and DNA donors into a range of cell types with high genome editing efficacy and non-cytotoxicity.