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

RESEARCH

Designing of Polymer Surfaces for Controlling Cell-Material Interaction

Surfaces play an important role in the development of a suitable scaffold for tissue engineering. Surface chemical and physical properties have been known to affect cell attachment, differentiation and function. Grafting of low-molecular weight poly(ethylene glycol) onto a polymer can effectively prevent cell and protein adhesion, while attaching peptides and extracellular matrix molecules can enhance cell adhesion. The effects of these factors on in vitro cultured liver cells will be studied.

Tissue Engineering Scaffold via Microspheres

The current concept of tissue engineering uses a three-dimensional construct or scaffold as support for cell attachment in growing an organ in vitro. Porous polymeric cubes, layered interwovenfibers, rolled-up films, and hollow tubes are among the scaffolds being studied. However, there are limitations to current designs such as cell seeding, necrosis and vascularization. The maximum thickness of tissue obtained has been no larger than 10 mm. The research work will use a novel system of drug encapsulated microspheres as a support scaffold to tissue engineer a complete functional liver.

Synthesis of Novel Biodegradable Polymers as Biomaterials

The majority of polymers that are in use today for biomedical applications are based on polylactide and polyglyoclide. While these have the necessary degradation and physical properties for use as sutures and drug delivery, they invoke a slight inflammatory response by the immune system. The synthesis of a new polymers derived from the extracellular matrix of the body can eliminate the negative immune response and increase the host acceptance.

Molecularly Imprinted Polymeric Nanoparticles for Bioseparations

The use of molecular imprinting, where specific recognition of molecules based on shape, has been successfully used for the separation of small molecules. However for biological molecules such as proteins, separation is still a major issue. Using nanoparticles together with molecular imprinting can solve diffusion and rebinding problems. Polymeric nanospheres with surface imprinting has been shown to have specific protein recognition.

SELECTED PUBLICATIONS

S.Q. Liu, Y. W. Tong and Y.Y. Yang, "Incorporation and in vitro release of doxorubicin in thermally sensitive micelles made from poly(N-isopropylacrylamide-co-N,N-dimethylacrylamide)-b-poly(D,L-lactide-co-glycolide) with varying compositions", Biomaterials, 26, 5064 (2005)

S.Q. Liu, Y.Y. Yang, X.M. Liu and Y.W. Tong, "Preparation and Characterization of temperature-sensitive poly(N-isopropylacrylamide)-b-poly(D,L-lactide) microspheres for protein delivery", Biomacromolecules, 4, 1784 (2003).

Y. W. Tong and M. S. Shoichet, "Enhancing the Neuronal Interaction on Fluoropolymer Surfaces with Mixed Peptides or Spacer Group Linkers", Biomaterials, 22, 1029 (2001).

Y. W. Tong and M. S. Shoichet, "Defining the Surface Chemistry of Ammonia-Modified Poly(tetrafluoroethylene-co-hexafluoropropylene) Films", Macromolecules, 32, 3464 (1999).