Retein stabilizes aquaporins in lipids and silica to desalinate and purify water.


  • Improved water treatment and re‑use
  • Reduced energy use


  • Industrial wastewater treatment

UN Sustainable Development Goals Addressed

  • Goal 3: Good Health & Wellbeing

  • Goal 6: Clean Water & Sanitation

  • Goal 14: Life Below Water

  • Goal 15: Life on Land

The Challenge

Water scarcity affects every continent, with more than 2 billion people lacking access to safe drinking water. Small, harmful pollutants, such as pharmaceutical residues, pathogens, and microplastics, are wreaking havoc in our oceans, lakes, and rivers. And although we have powerful water purification systems, forcing millions of gallons of water through the membrane of a filter takes a significant amount of energy. So, if we want a higher purity of water we must use a higher energy input, therefore pumping more carbon dioxide into the atmosphere, and creating a much greater cost for clean water.

Innovation Details

Retein is on the cusp of revolutionizing the water purification industry. The team is mimicking the way diatoms form their cell wall out of silica and utilizing aquaporins, proteins that transport pure water across cell membranes throughout nature. Their energy-efficient and selective technology produces high purity grade water in a single filter pass, desalination at any scale, and removes industrial pollutants and contaminants such as arsenic, microplastics, and pharmaceutical residues.


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Watch how the team at Retein (formerly Aquammodate) was inspired by diatoms and aquaporins to create a biomimetic method for water purification.

Biological Model

Water is an indispensable component of living cells—in a Goldilocks sort of way. Too much and the cell will burst; too little and it will dry out and die. How does a cell keep its water content just right? It makes aquaporin molecules that form hourglass-shaped tunnels through its otherwise water-repelling membranes. Electrical charges inside the tunnels ensure that only water (and sometimes a few select other molecules) can get through, and only in small amounts, maintaining the balance needed to maintain life.

To embed aquaporins in a stable, usable material for humans, Retein looked to single-celled organisms found in lakes, rivers, and oceans around the world. Diatoms use special proteins to draw the mineral silica from water into a sac inside their cell. There, other proteins link the silica atoms together to form the hard surfaces. Yet other proteins connect the hard parts to form a box around the cell and to make a pinch point that holds them together. Sugar and other organic materials add yet more stability and create different shapes for different species.

Ray of Hope Prize

Retein (formerly Aquammodate) was selected as the runner up for the 2021 Ray of Hope Prize, which celebrates nature-inspired solutions addressing the world’s biggest environmental and sustainability challenges. Created in honor of Ray C. Anderson, founder of Interface, Inc. and a business and sustainability leader, the $100,000 Ray of Hope Prize helps startups cross a critical threshold in becoming viable businesses by amplifying their stories and providing them with equity-free funding. The prize shines a light on the innovative, nature-inspired solutions that we need to build a sustainable and resilient world.