In the first 9 months of the project, we have reformulated and optimized the iTOP reagent to make it fully chemically defined, standardizing and optimizing experimental reproducibility, efficacy and compatibility with a large variety of (GMP) cell systems. We have developed a procedure for iTOP-mediated gene editing in various adherent cell lines, including HAP1 and HEK293 cells, and studied the introduction of CRISPR/Cas9 system into several “hard-to-transfect” cell types, such as hIPSCs and T-cells. In the second reporting period (Month 10 – 22), we have further optimized the iTOP procedure, and we have developed procedures for the transduction of CRISPR/Cas9 systems in different cell lines like ARPE-19, Jurkat and HeLa cells. Furthermore, we have performed comparison of iTOP to electroporation and Lipofectamine CRISPRMAX, and generated first experimental data that will be the basis of a publication. Focus of the ENTRANCE project has shifted towards the transduction of CRISPR/Cas9 systems, and NTrans is exploring avenues to get an exclusive license to develop and market a novel CRISPR/Cas9 system developed at a Dutch University. The ENTRANCE project has allowed us to establish several collaborations with pharmaceutical companies and suppliers of gene-editing tools who have interest in the iTOP technology, which will be enforced by the combination of the iTOP delivery tool and this novel CRISPR/Cas9 system.