Supercooled nanoparticles offer targeted delivery approach

Supercooled water--Courtesy of YouTube

The ability to supercool drug-carrying vesicles inside the body and time the exact moment of crystallization could lead to a targeted approach to drug delivery, researchers at Tel Aviv University have found.

Supercooling is the process by which a liquid such as water is cooled so quickly that it remains in its liquid form even below its normal freezing temperature. The liquid is then so unstable that a simple jolt could inspire it to crystallize into ice. It's a process that is complex and not wholly understood, but the team of researchers has broken down the supercooling science and controlled it to the point where it can someday be used to freeze nanomembranes at a specific moment to keep drugs in a desired location.

"One key challenge in designing new nano-vesicles for drug delivery is their stability," lead researcher Roy Beck said in a statement. "On the one hand, you need a stable vesicle that will entrap your drug until it reaches the specific diseased cell. But on the other, if the vesicle is too stable, the payload may not be released upon arrival at its target."

For this fine line between too-stable and not-stable-enough, the scientists looked at the dynamics of crystallization in nano-sized drug vesicles, using an X-ray system to determine the timing.

The experiments demonstrated over and over again that the membranes could be stable for many hours before undergoing crystallization at a specific time.

"Supercooled material is a suitable candidate since the transition between liquid and crystal states is very drastic and the liquid membrane explodes to rearrange as crystals," Beck said. "Therefore this new physical insight can be used to release entrapped drugs at the target and not elsewhere in the body's microenvironment. This is a novel mechanism for timely drug release."

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