When you were in elementary school, do you remember learning about the three main states of matter? There are solids that have a defined shape and volume, gases have neither of these, and you probably learned that liquids have a set volume but can flow and take the shape of their container. I want to challenge this conventional thinking about liquids, and show that defining the shape of water can be harnessed with powerful results. This is an idea that’s found everywhere in nature – take the cells in your body, which are basically tiny liquid compartments that are supported by membranes that give them shape and protection.

What if we could design new materials to make membranes that were able to replicate the function of our cells? Imagine an artificial cell containing carefully shaped internal liquid compartments. The cell could move through your body and deliver a number of different therapies just by rearranging its membrane structure: releasing a drug or synthesizing a protein on demand.  It’s really exciting to think about the future of medicine this way, but one of the biggest challenges to achieving this is that current membrane technologies don’t effectively adapt in dynamic environments like your body. 

What we need is a better understanding of how responsive materials can be used to give shapes to water that changes over time. This is where my research comes in. In my work, I design thin layers of molecules called surfactants that form barriers between fluid phases. It’s similar to how a water balloon is able to separate water from its surroundings, except my membranes can be 1000 times thinner than a human hair, and can lock water into whatever shape I design it to be. In order to achieve those life-like properties that are so important for artificial cells, I design my molecular barriers to have a specific lifetime. I use high-energy molecules as a chemical fuel, and when the fuel is present, those balloon-like membranes are in place. When the fuel tank runs empty, the balloon pops, allowing the liquid inside to reshape and react with its surroundings. By carefully controlling the chemistry, strength, and lifetime of these nanoscale membranes, I am able to engineer larger scale liquid systems that evolve over time.  So, by reshaping the way that we think about liquids we’re paving the way for future advances in artificial cells and more effective and versatile medical technologies. I think we can agree that this is one idea that really holds water.