Abstract

Central nervous system (CNS) infections caused by pathogens such as HIV, 
Herpes simplex virus, Cryptococcus neoformans, and Toxoplasma gondii 
remain among the most difficult to treat due to the physiological barrier 
posed by the blood-brain barrier (BBB), pathogen latency, and systemic 
toxicity associated with conventional therapies. Exosome-based delivery 
systems are becoming a game-changing platform that can solve these 
therapeutic problems using their natural biocompatibility, minimal 
immunogenicity, and capacity to cross the BBB. This review current 
developments in exosome engineering that aim to make brain-targeted 
therapy for neuroinfectious illnesses more selective and effective. Much focus 
is on new molecular methods like pathogen-specific ligand display, aptamer 
conjugation, 
lipid 
modification, and click–chemistry–based surface 
functionalisation. These methods make it possible to target diseased areas of 
the brain precisely. Exosomes can also carry therapeutic payloads, such as 
anti-viral and antifungal drugs, gene editing tools like CRISPR/Cas9 and 
siRNA, and more. This makes them helpful in changing pathogens’ 
persistence and the host’s immunological responses. The paper tackle 
problems with translation, such as biodistribution, immunogenicity, GMP 
production, and regulatory issues. Future possibilities like synthetic exosomes, 
combinatory medicines, and delivery design that uses AI. The combination of 
nanotechnology, molecular biology, and infectious disease therapies shows 
that exosome engineering offers a new way to meet the clinical needs that 
are not satisfied in treating CNS infections.