Biocomposite Breakthrough: Self-digesting spore-filled polymers

This article caught my eye this morning - researchers based at the University of California San Diego have developed a new class of biocomposite material that has the potential to be used in a wide range of applications and also offers a “self-digest” function - offering one solution to the issue of plastic pollution in the environment.

The new material is a polyurethane that incorporates bacterial spores from a polymer-degrading bacteria. The bacterial spores have been engineered to improve their heat tolerance which has allowed them to be introduced as a filler to the polyurethane and then subjected to a melt extrusion process. It seems this has been a bit of a breakthrough as, previously, engineered living materials have incorporated living cells - which are fragile and vulnerable to heat, osmotic pressure, pH, etc. This has typically placed a constraint on the manufacturing conditions that can be used. In contrast, spores can preserve viability of a bacteria against extreme conditions and their germination can be triggered at a later stage.   Fortuitously the inventors have observed that not only do the spores facilitate the breakdown of the polymer material after germination, but they can also improve the tensile properties. Additional work has shown that when the spores have been genetically engineered to express green fluorescent protein (GFP), fluorescence could be detected in the final material after germination of the spores. This is significant as it indicates the embedded spores could be used to provide a variety of biological functionalities in the polymer material. 

I could not immediately find a patent application associated with this research but the group's paper has only recently published in Nature Communications and so I would not be surprised to see a corresponding patent application coming out within the next 18 months. It certainly would have been a nice one to draft - a neat solution to a well-known problem!