he Institute of Materials Research and Engineering (IMRE) began work on controlled drug release three years ago to develop fabrication technology for release devices built out of biocompatible and biodegradable polymers.

To support Singapore's aspiration to become a regional biotechnology hub, IMRE has been expanding its efforts beyond the field of tissue engineering and biomaterials. The new thrust will take place in microtechnology and nanotechnology to develop systems, machines, and devices that can be used in biomedicine. The devices can be implanted, ingested, or worn - to interact with the body in various ways.

The effectiveness of drugs, vaccines, and bioactive agents on the body depends on delivery-system performance. When subjected to multiple and sometimes hostile internal biological conditions, these agents may lose effectiveness, making it necessary that they be given again. Readministration of these agents could delay effective treatment and generate additional cost and effort. One way to counter this effect is to use controlled-release devices.

Scientists at the institute are developing such systems as polymeric microcapsules, composite tablets, transdermal drug-delivery systems, and stimuli-sensitive hydrogels to encapsulate various bioactive agents. Some of these systems act as diffusion barriers that allow only the desired agents into the selected environment. Modulated release of the agents can also be effected by means of the material's slow degradation within the body, thereby maintaining constant levels.

IMRE has designed polymeric microspheres that encapsulate low-molecular-weight drugs and peptides to deliver and to improve the bioavailability of certain drugs. Researchers have successfully developed systems containing Salmonella bacteria for vaccination of chickens and encapsulated drugs such as steroids for keloid treatment.

Another group in IMRE investigates transdermal delivery devices for different therapeutic purposes, using dense or asymmetric membranes to regulate the drug-release rate. Researchers are also conducting studies on a new class of injectable and bioabsorbable supramolecular hydrogels for delivery of delicate protein drugs. They base the design of the hydrogels on the formation of highly ordered macromolecules. Becoming less viscous under shear force, the hydrogel can be injected via ordinary medical syringes, thereby doing away with the need for implantation, the standard delivery system for most conventional hydrogels.

This platform hydrogel technology developed by IMRE has attracted investment from a US biomedical company, Omeros Medical Systems, which has signed an agreement to co-develop a protein-delivery system for treatment of such joint diseases as arthritis. The hydrogel is thought to be the best device to deliver such delicate bioactive agents to specific target areas, thus increasing the efficacy of the drug.

IMRE's director, Professor Albert Yee, was formerly the Chairman of the Materials Science and Engineering Department at the University of Michigan, Ann Arbor, as well as director of the university's multidisciplinary Center for Advanced Polymer Engineering Research. He believes collaboration is the key to building up a global presence and reputation for excellence in materials research, especially for a small research organization.

IMRE has forged close partnerships with the University of Michigan and the Max-Planck Institute in microelectronic materials and polymers. It has joint projects with the National University of Singapore, Nanyang Technological University, Peking University, and Imperial College, London. One group has been investigating polymer light-emitting displays with the Nobel laureate in Chemistry in 2000, Professor Alan Heeger of the University of California at Santa Barbara.

To maintain industry links, IMRE conducts cross-research projects with such multinational companies as Agilent Technologies, Infineon, Fujitsu Quantum Devices, British Gas, and Hitachi Chemical Asia Pacific.

Set up in 1996 on the grounds of the National University of Singapore, IMRE promotes resource and manpower development by means of strategic and innovative research on advanced materials and processes and their industry applications. The institute undertakes research in selected fields of materials science and engineering. It seeks partners among international organizations and industry in a synergistic, multidisciplinary, and collaborative approach to research and development.

To achieve its objectives, IMRE works to develop core competency and interdisciplinary teams, organized into clusters (bigger, systems-oriented groups) and laboratories (smaller, science-oriented groups), explains Yee. Each group has representatives with highly concentrated expertise in critical technological areas, enabling the institute to make fundamental new discoveries, to develop advanced materials that can lead to new commercial products, and to transform various existing technologies.

The groups currently comprise the Chemical Systems Cluster, the Opto- and Electronic Systems Cluster, the Molecular and Bio-Materials Laboratory, the Materials Science and Characterization Laboratory, the Materials Theory and Modeling Laboratory, and the Micro- and Nano-Systems Laboratory.

The institute's work, which covers the spectrum of science and engineering research, will have an impact on industry and technology, Yee points out. He foresees materials that will greatly influence future generations of technologists working in such areas as the life sciences, information technology, communications, and nanotechnology.

For more information contact Prof Albert Yee at afyee@imre.org.sg.