Biodegradable polymers from plants used in tissue regeneration and
24 February 2010
A new type of biodegradable polymer made from non-food plant
material has applications as diverse as food packaging to tissue
regeneration, medical stitches and drug delivery.
The degradable polymer is made from plant sugars known as
lignocellulosic biomass, which come from non-food crops such as
fast-growing trees and grasses, or renewable biomass from
agricultural or food waste.
The material is being developed at Imperial College London by a
team of scientists from the Engineering and Physical Sciences
Research Council and Imperial College spin-out BioCeramic
The search for greener plastics, especially for single-use items
such as food packaging, is the subject of significant research
worldwide. “It’s spurred on not only from an environmental
perspective, but also for economic and supply reasons,” explains
team leader Dr Charlotte Williams.
Around 7% of worldwide oil and gas resources are consumed in
plastics manufacture, with worldwide production exceeding 150
million tonnes per year. Almost 99% of plastics are formed from
“Our key breakthrough was in finding a way of using a non-food
crop to form a polymer, as there are ethical issues around using
food sources in this way,” said Williams.
Current biorenewable plastics use crops such as corn or sugar
beet. The leading example is poly(lactic acid) which derives from
lactic acid, produced by fermentation of corn or sugar beet. These
biorenewable plastics are different to biopolymers, which are
naturally occurring polymers such as starch or cellulose — which are
not plastic materials.
The chemical name for the compostable polymer is Poly(acetic
acid-5-acetoxy-6-oxo-tetrahydro-pyran-2-yl-methyl ester) and
acid-5-acetoxy-6-oxo-tetrahydro-pyran-2-yl-methyl ester). The
polymer was discovered and developed by Dr Min Tang and Dr Anita
Haider in their doctoral research.
“For the plastic to be useful it had to be manufactured in large
volumes, which was technically challenging. It took three-and-a-half
years for us to hit a yield of around 80% in a low energy, low water
use process,” explains Dr Williams.
This is significant as the leading biorenewable plastic,
polylactide, is formed in a high energy process requiring large
volumes of water. In addition, when it reaches the end of its life
polylactide must be degraded in a high-temperature industrial
In contrast, the oxygen-rich sugars in the new polymer allow it
to absorb water and degrade to harmless products — meaning it can be
tossed on the home compost heap and used to feed the garden.
Because the new polymer can be made from cheap materials or waste
products its production is also economic compared to
The polymer has a wide range of properties, making it suitable
for more than a replacement for plastic packaging. Its degradable
properties make it ideal for specialised medical applications. The
polymer has been shown to be non-toxic to cells and decomposes in
the body creating harmless by-products.
The research team — including commercial partner BioCeramic
Therapeutics, which was set up by Professor Molly Stevens and
colleagues at Imperial College — are investigating ways of using the
material as artificial scaffolds for tissue regeneration. They are
also focusing on exploiting the degradable properties of the
material to release drugs into the body in a controlled way.
“The development of the material is very promising and I’m
optimistic that the technology could be in use within two to five
years,” says Williams, who is already working with a number of
commercial partners and is keen to engage others interested in the