Mechanisms and challenges of nanocarriers as non-viral vectors of therapeutic genes for enhanced pulmonary delivery

With the rapid development of biopharmaceuticals and the outbreak of COVID-19, the world has ushered in a frenzy to develop gene therapy. Therefore, therapeutic genes have received enormous attention. However, due to the extreme instability and low intracellular gene expression of naked genes, specific vectors are required. Viral vectors are widely used attributed to their high transfection efficiency. However, due to the safety concerns of viral vectors, nanotechnology-based non-viral vectors have attracted extensive investigation. Still, issues of low transfection efficiency and poor tissue targeting of non-viral vectors need to be addressed. Especially, pulmonary gene delivery has obvious advantages for the treatment of inherited lung diseases, lung cancer, and viral pneumonia, which can not only enhance lung targeting and but also reduce enzymatic degradation. For systemic diseases therapy, pulmonary gene delivery can enhance vaccine efficacy via inducing not only cellular, humoral immunity but also mucosal immunity. This review provides a comprehensive overview of nanocarriers as non -viral vectors of therapeutic genes for enhanced pulmonary delivery. First of all, the characteristics and thera-peutic mechanism of DNA, mRNA, and siRNA are provided. Thereafter, the advantages and challenges of pul-monary gene delivery in exerting local and systemic effects are discussed. Then, the inhalation dosage forms for nanoparticle-based drug delivery systems are introduced. Moreover, a series of materials used as nanocarriers for pulmonary gene delivery are presented, and the endosomal escape mechanisms of nanocarriers based on different materials are explored. The application of various non-viral vectors for pulmonary gene delivery are summarized in detail, with the perspectives of nano-vectors for pulmonary gene delivery.

Automated summary

With the rapid development of biopharmaceuticals and the outbreak of COVID-19, there is a growing interest in the development of gene therapy. Gene therapy relies on specific vectors for stable and efficient gene delivery. While viral vectors have been widely used, there is a concern regarding their safety. Non-viral vectors based on nanotechnology have gained attention, but they still need improvement in terms of transfection efficiency and tissue targeting. Pulmonary gene delivery is particularly advantageous for treating lung diseases and enhancing vaccine efficacy. This review provides a comprehensive overview of nanocarriers as non-viral vectors for pulmonary gene delivery, discussing the characteristics of therapeutic genes, the advantages and challenges of pulmonary gene delivery, the inhalation dosage forms for nanoparticle-based drug delivery systems, and the materials used as nanocarriers.