Nucleic acid delivery by ionizable nanocarriers for brain disease treatment

The successful application of messenger RNA vaccines in the market has demonstrated the potential of gene therapy in treating various diseases, including infectious diseases, autoimmune disorders, brain diseases, and other cancers. However, gene therapy faces great challenges in treating brain diseases such as brain tumors, infections, and strokes because the limitations of the blood-brain barrier make it difficult for nucleic acid drugs to be delivered safely and effectively into the brain. Therefore, there is a high demand for carriers delivering nucleic acid drugs to the brain. Ionizable nanocarriers (INs) have great advantages in gene therapy due to their pH-responsive properties, which facilitate the safe and efficient delivery of targets, responsive release in the disease microenvironment, and the protection of nucleic acids from degradation. To better understand INs and their potential as therapeutic vectors for brain diseases, the present review describes their biological properties, recent progress in the field, and promising applications. In particular, the related prospects and challenges are discussed to promote the further development of INs.