CRISPR-Cas9 genome editing: technological advances, delivery strategies and precision engineering of primary cells for therapeutic application in genetic disorders and diabetes mellitus.

The CRISPR-Cas9 system has revolutionized modern life sciences, driving a paradigm shift in biomedical research and becoming an indispensable tool in molecular biology due to its remarkable precision, efficiency, and simplicity. Originating from a bacterial adaptive immune mechanism, CRISPR-Cas9 has evolved rapidly, providing a versatile framework for manipulating genetic material and addressing a wide spectrum of human diseases. Recent progress includes the discovery of novel Cas orthologs and the rational engineering of Cas9 variants to enhance editing fidelity, broaden target range, and minimize off-target effects. Structural and functional optimization of single-guide RNAs (sgRNAs) has further improved target binding affinity, stability, and Cas9-sgRNA complex formation, thereby increasing overall editing performance. The development of high-fidelity Cas9 derivatives and next-generation platforms such as base editors and prime editors has enabled precise single-nucleotide substitutions and small insertions or deletions without generating double-stranded DNA breaks. Advanced delivery systems-including viral vectors, lipid nanoparticles, and ribonucleoprotein electroporation-have facilitated efficient CRISPR-mediated editing across in vitro, ex vivo, and in vivo models. Remarkable therapeutic milestones have been achieved in treating monogenic disorders such as sickle cell disease, β-thalassemia, and cystic fibrosis, where long-term clinical benefits have been documented. Furthermore, CRISPR-Cas9 technology is redefining diabetes research by enabling precise modeling of disease mechanisms, uncovering molecular pathways involved in glucose homeostasis, and opening new avenues for cellular and gene-based therapies. This review highlights recent advances in CRISPR-Cas9-mediated genome editing, emphasizing breakthroughs in primary cell editing and the development of translational models for genetic diseases and diabetes mellitus.