Mphages and the Blood-Brain Barrier: A Review

The blood-brain barrier (BBB) is a protective barrier that prevents most substances from entering the brain from the bloodstream, including bacteria and viruses. Unfortunately, this restriction also applies to 99.9 % of therapeutics, posing significant challenges in the treatment of brain diseases. Overcoming this barrier is critical for effective treatment of neurological disorders. Several drug delivery systems are being developed to improve transport of therapeutic agent across the BBB. For example, nanoparticles (liposomes, polymeric nanoparticles, dendrimers), nanocarriers (micelles, nanogels), protein-based delivery (penetrating peptides, exosomes), focused ultrasound, and most recently, a filamentous phage based nanocarriers. Filamentous bacteriophages are viruses that infect bacteria and are not designed to infect eukaryotic cells. Recent evidence suggests that filamentous bacteriophages, such as M13, can cross BBB and enter the central nervous system (CNS). Researchers have been investigating the potential use of M13 as drug carriers, including the delivery of therapeutic agents to the brain. This entails modifying the bacteriophages to carry payloads such as drugs and using them as a delivery system. The BBB’s complexity and the potential risks associated with changing it necessitate careful consideration in the development of such strategies. M13 nanocarrier development is ongoing, and advancements may lead to new therapeutic options for treating infections in the CNS. However, it is important to note that this field is still in its infancy, and more research is needed to assess the feasibility and safety of using modified bacteriophages to cross the BBB. This brief review attempts to compile current research on the potential use of bacteriophages for drug transport across the BBB.