ADVANCED materials best thought of as microsponges could be used to soak up oil spills and to decontaminate land polluted by toxic heavy metals. Research at Greenwich University's school of chemical and life sciences is looking at how "smart" nano-particles contract with heating and expand with cooling. This means they can "soak up" other materials and then be "squeezed out" when necessary. Researcher Martin Snowden is also working with microsponges that expand and contract with changes in acidity.