Tiny Trojan horse 'stealth' liposomes deliver drugs direct to brain injury sites

The blood-brain barrier (BBB) allows what is needed to nourish the brain and keeps out potentially dangerous, neurotoxic cells. When a person experiences traumatic brain injury (TBI) the BBB opens for a brief period of up to six hours after injury. Monash researchers have discovered that a small lipid sphere called a liposome - normally excluded from the brain - accumulates in the injured side of the brain during this window.



Professor Rob Medcalf said, "Liposomes are harmless structures that can stay in the blood stream for up to a day. They are now being used to carry drugs for therapeutic needs to increase the effectiveness of drugs that otherwise are cleared very fast from the blood. We showed that liposomes can selectively enter the damaged brain within a 6 hour time window after trauma. This has now paved the way to introduce drugs to improve outcome after trauma. By acting as mini Trojan horses, these drug laden liposomes provide a targeted drug delivery system to direct drugs to the place in need".

Liposomal drug delivery is an established technology as the cells can encapsulate and carry drugs inside themselves, and bind to specific targets, releasing the drug at that point. The drug carriers are called stealth liposomes because of their ability to evade detection by the immune system. The technique is used in a number of existing medications, and is being investigated for different kinds of drugs for various conditions.

Reference:  Boyd BJ, Galle A, Daglas M, Rosenfeld JV, Medcalf R. Traumatic brain injury opens blood-brain barrier to stealth liposomes via an enhanced permeability and retention (EPR)-like effect. Journal of Drug Targeting: 23(9), 21 October 2015, pp. 847-853