The research group of Michael Best in Tennessee Chemistry, led by graduate student Jinchao Lou, recently published an article describing the development of ATP-responsive liposomes in the Journal of the American Chemical Society. The nanocarriers reported in this work show strong prospects for enhancing clinical drug delivery applications.
Liposomes are highly effective nanocarriers for therapeutics due to their ability to encapsulate drugs with wide-ranging properties and enhance their circulation and delivery to cells. However, their potential could be improved by achieving control over the release of cargo to maximize drug potency and diseased-cell selectivity. While liposome-triggered release represents a vibrant field of research due to this significance, the toolbox for controlling liposome release remains limited and prior strategies face many challenges that obstruct clinical application.
The Best Group has explored a new paradigm for triggered release in which cargo escape is triggered only when liposomes encounter specific small molecule metabolites that are overly abundant in disease states. This is achieved using synthetic stimuli-responsive lipid switches designed to undergo programmed conformational changes upon the binding of small molecule targets, events that compromise membrane packing and thereby drive release.
In this work, Lou and co-workers developed liposomes that selectively respond to ATP over eleven other structurally similar phosphorylated small molecules. ATP is a critical target for metabolite-mediated drug delivery since this molecule is a universal energy source that is known to be heavily upregulated in-and-around cancer cells. This opens up the potential for selective drug delivery and release driven by overly abundant ATP associated with diseased cells.
This project also entailed a collaboration with the group of Dr. Francisco Barrera in the Tennessee Biochemistry & Cellular and Molecular Biology (BCMB) Department. Through cellular delivery and fluorescence imaging experiments, graduate student Jennifer Schuster showed that modulation of cellular ATP levels using drugs led to direct control of cellular delivery of ATP-responsive liposomes. These results demonstrate the key advancement that liposome delivery can be modulated by the cellular abundance of ATP.
A provisional patent has been filed for this ATP-responsive liposome technology. Additionally, the Best Group is currently working on advancing this platform for clinical delivery applications and developing liposomes that respond to other disease-associated small molecule metabolites.