Working at the interface of polymers and biomaterials, Dr Kazuaki Matsumura who is based at the Japan Advanced Institute of Science and Technology (JAIST), develops synthetic cryopreservant biopolymers such as polyampholytes and zwitterionic materials. In addition to their use in the long-term preservation of cells and tissues, the Matsumura laboratory team investigate the application of freezing technologies to the improvement of drug delivery systems. Biomaterials are materials that interact with biological systems. Cryopreservant biomaterials such as polyampholyte protect cells from freezing damages. The exact mechanism remains unclear, but those polymers that interact with the cell membrane most strongly are known to provide the highest protection during freezing. "That is why we chose to add some hydrophobicity into the polymer," Matsumura points out. In his laboratory, an important line of investigation is the synthesis of novel cryoprotectant polymers. "This work involves the development of synthetic polymers similar to naturally derived polyampholytes by making copolymers of positively and negatively charged monomers," Rajan explains. The use of reversible addition fragmentation chain transfer (RAFT) polymerisation allows to control the molecular weight of the polymers, as well as essential properties such as hydrophobicity. Another major research area is the use of freeze concentration, a physicochemical phenomenon wherein the formation of ice crystals during freezing leads to the concentration of solutes in the unfrozen water phase, to increase the delivery rate of nanocarriers and therapeutic proteins into cells. "The low toxicity and higher internalisation obtained through this method is very promising in therapeutic applications," claims Ahmed. The most immediate application of cryoprotectant polymers is the industrialisation and long-term preservation of tissue constructs produced by regenerative medicine. "If exchangeable tissues or organ can be cryopreserved with our materials for a long time through the establishment of a regenerative tissue bank, clinical applications can be performed more easily," says Matsumura. Additionally, freeze concentration-mediated delivery can be a novel strategy for gene therapy and immunotherapy. "Once our cells are taken out from the body, genes or antigens can be delivered very efficiently by using our technology," he continues. "Because our nanocarrier has endosome-escaping ability, the location of substrates on the target site to perform their activity is facilitated.