Singapore Scientists Develop Drug Delivery Microbe That Travels Up the Nose

The Blood-brain barrier(BBB) is layer of protective cells which line the circulatory system connected to the central nervous system which regulates what can and cannot enter. This functions to ensure that dangerous microbes and other dangers do not pose a threat to the brain and central nerves which are imperative to life. Despite this robust security system, it has one flaw... the nasal cavity. Microbes which are capable of navigating to the central nervous system nasally via the olfactory nerve are able to bypass the blood brain barrier and cause havoc to human health. However, scientists had realised this pathway could be critical to drug delivery bypassing the liver and BBB and began to experiment with intranasal drug delivery. Researchers at the National University of Singapore have taken this concept a step further and have developed microbes to deliver drugs directly into the nervous system via olfactory nerves.

The binding of the microbe to olfactory sites and

the movement of drugs(+) to the CNS via the olfactory nerve.

        

The BBB and liver are major obstacles in drug effectiveness, where their protective and selective nature prevents many drugs from being absorbed to their fullest potential. The researchers identified a myriad of nasal bacteria as candidates for this experiment, and ultimately decided upon Lactobacillus plantarum due to it's affinity for olfactory binding sites. The microbes were dyed to create fluorene for easier tracking, and then deployed into rats for live testing. The microbes remained in the nasal cavity while their drug payloads were diffused across the olfactory pathway into the central nervous system. The microbe underwent numerous edits via transformation in order to maximise olfactory binding and drug delivery, and the result was that the microbe administered drugs remained longer than those administered simply intranasally. While future studies and testing are needed to ensure that this method is safe, it is nonetheless a fascinating method of drug delivery and medical science. 

Sources:

https://phys.org/news/2025-02-bloodbrain-barrier-payload-bacteria.html

https://www.cell.com/cell/fulltext/S0092-8674(25)00046-7?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS0092867425000467%3Fshowall%3Dtrue        

https://pubmed.ncbi.nlm.nih.gov/22465159/