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TONG Yen Wah

Associate Professor

- PhD (Chem. Eng.) Toronto, 2000
- BSc ( Eng. Chem.) Queen's 1995

-Contact information:
- Blk E5, 4 Engineering Drive 4, #03-15, Singapore 117576
- Tel: (65) 6516 8467 Fax: (65) 6779 1936
- Email: chetyw@nus.edu.sg

Welcome to the Biomimetic Materials and Systems Lab

1. Pre-2009 Research
As far as I can remember since I was a teenager or younger, I have always been keenly interested in polymers as a very versatile and promising material for many possible uses. Together with strong influence from my father, himself a professor in chemistry, I had ambitions to complete a PhD and carry on academic research in studying polymers, making new polymers and how to use them. My undergraduate training in Engineering Chemistry at Queens’ University has given me detailed insight into the basics of polymer chemistry while my PhD at the University of Toronto has driven my interest towards biomedical and tissue engineering. Therefore, when I joined NUS in 2001, I have combined these interests by setting up my research programme in the Department of Chemical and Biomolecular Engineering (ChBE) to focus research on synthesizing, modifying, and using polymers for applications mainly in the biomolecular and biomedical areas.

fig1
Figure 1. Early research interest in my group.

I then called my laboratory at ChBE to be the Polymers for BioApplications Laboratory. In this laboratory, we have built up strengths in synthesizing polymers that are biocompatible, biodegradable and have tailored properties for tissue engineering. We also have established many techniques to control the surface, chemical and physical properties of the polymers by modifications with chemical functional groups, peptides, proteins, carbohydrates and etc. Finally, we have the knowledge to fabricate various polymers into nano- and micro-particles, thin films, and foams for use as drug delivery devices or tissue engineering scaffolds. As shown in Figure 1, all of these basic skills and tools are our core capabilities in which we have applied, as engineers, to the major research areas of (i) liver tissue engineering using microspheres, (ii) protein separation with molecularly imprinted polymers, and (iii) targeted and controlled drug and gene delivery. Although these fields might be seen as disparate and not related to each other, I have focused mainly on the polymer aspects as described above and below, while finding collaborators with the required expertise for the specific niches.

From 2001 until 2009, I believe that polymers were the foundation for multi-disciplinary research that characterizes the biomedical field thus polymers have been used as a tool for my intended end goals. Our unique strengths are in the making of polymers into spherical nano- or microparticles, together with our strategies of synthesizing biomimetic polymers in combination with polymer modification. Over this period as part of the main applications for the polymers, I have learnt more and more on biology and the environment, taking my interests and research into a broader area in the subsequent years.

2. Current Research Strategies
My research interest following promotion to Associate Professor has evolved from the applications of polymers for biological and biomedical purposes. This is due to many reasons, among them the biggest lies in finding that we have a lot to learn from nature and biology. The research work done before 2009 has given me a wide variety of exposure to how nature works, such as in healing the human body, in the development of cells into organized tissues, in the microbiology of DNA and genes in cancer development, in proteins and peptides properties and structure that can transform cells and control stem cell differentiation, and etc. Even with all of the knowledge out there, it appears that we have barely touched the surface of the wonders of biology, and thus I sought to learn even more in an effort to copy what nature is doing. As the saying goes, mimicry is the highest form of flattery, and thus what would be a better way to praise nature than to mimic biology in our engineering systems?

Therefore, from 2009 onwards, my research focus has evolved from using polymers and materials for biological applications, to mimicking biology in our materials and systems. This shift actually started even in 2007 as we were looking for materials that can mimic collagen for liver tissue engineering. The significant interest to make a synthetic material that looks and behaves exactly like collagen lead us to one of my current core research interests of collagen-mimetic peptide amphiphiles. This area will be further explained below, and our success with this material has expanded my interest to find other areas of nature to mimic. This was similarly supported by another core research area of molecular imprinting that began in 2006, which is really the mimicry of molecules and antibodies at the molecular level. In this work, we have successfully developed polymer nanoparticles that behaves like nature, mimicking antibodies to capture proteins, viruses and even small organic compounds.

fig3
Figure 2. Current research areas and focus.

Figure 2 shows the expansion of our biomimetic research from just the biomimetic materials to other works in biomimetic membranes, devices and systems. In all of these works, our group expertise in combining proteins and polymers enables us to learn from nature to mimic it for applications in water purification, waste treatment, and biomedical devices. Funding from large grants between 2009 and 2017 that we were awarded have been crucial in leading our efforts to understand more about nature to successfully tackle novel challenges in these areas.

In the following sections, more details will be given in how my research in the four areas outlined in Figure 2 can be seen with respect to my publications, funding and collaboration. Outcomes of these research will be highlighted to show what we have learnt and solutions offered.