Coloured scanning electron micrograph of red blood cells

Red blood cells contain the iron-based molecule haemoglobin, which has now been harnessed to synthesize plastic. Credit: David Gregory & Debbie Marshall/CC BY 4.0

Chemistry

To make plastic, just add blood

Red blood cells harbour key ingredients for polymerization.

Red blood cells normally spend their time ferrying oxygen throughout the body. But now they’ve proved useful in a drastically different role — producing plastics.

Plastics are made by creating long chains of small molecules in a process called polymerization. In earlier research, Greg Qiao at the University of Melbourne in Australia and his colleagues developed a technique that uses hydroxyl radicals, a type of chemical group made up of oxygen and hydrogen, to kick off an advanced form of polymerization. Seeking a way to use a cell's resources to produce hydroxyl radicals, the researchers mixed sheep’s blood with an enzyme and the molecular subunits of one type of plastic, among other ingredients.

The enzyme converted oxygen in the blood into hydrogen peroxide. The hydrogen peroxide reacted with iron in the red blood cells to form hydroxyl radicals, which then triggered polymerization to form a plastic. The authors say that the technique opens the door for non-invasive manipulation of tissues and cells.