Thermo/moisture responsive shape-memory polymer for possible surgery/operation inside living cells in future

The recoverable strain of shape-memory polymers (SMPs) is an order higher than their metal counterpart, i.e., shape-memory alloys. The recent finding of the influence of moisture on the glass transition temperature of a polyurethane SMP, which is traditionally known for its thermo-responsive nature, enables us to realize not only water-driven for shape recovery, but also recovery following a pre-determined sequence. Utilizing these features of this SMP, we propose the concept of delivering a tiny device which is made of this material into a pore through a very small hole. The feasibility of the concept is demonstrated experimentally. This concept could eventually be used to deliver a micro/nano device into living cells for surgery or operation inside of them. (C) 2009 Elsevier Ltd. All rights reserved.