In vivo engineering of CAR immune cells by nonviral nanoparticles.

Chimeric antigen receptor (CAR) immune cell therapy has revolutionized the treatment of hematologic malignancies, yet conventional ex vivo manufacturing remains costly, complex, and logistically demanding. Emerging in vivo engineering strategies, especially those based on nonviral nanoparticles (NPs), offer a transformative alternative by enabling direct programming of immune cells within the body. Recent advances in NPs-mediated delivery of CAR constructs, including mRNA, circular RNA (circRNA), self-amplifying RNA (saRNA), DNA and gene editing tools, have demonstrated promising potential for achieving transient, tunable and repeatable expression with reduced genotoxicity. Immune cell targeting has been achieved by multiple targeting strategies for T cells, NK cells and macrophages, allowing precise control of CAR expression and functional activation in disease-relevant contexts. For T cells specifically, antibody-functionalized NPs categorized by antibody types including CD3, CD4, CD5, CD7 and CD8, demonstrate differential engagement of T cell subsets and influence their activation profiles across various therapeutic contexts. This review highlights key advances in the development of immune cell targeting NPs, discusses evolving CAR architectures and quality control considerations, and outlines future directions for integrating in vivo CAR platforms into broader immunotherapeutic landscapes. Nonviral NPs are poised to redefine CAR therapy by enabling scalable, off-the-shelf immune interventions for cancer, autoimmune, and fibrotic diseases.