Lee Lai Yeng

Personal Particulars:

Ms Lee Lai Yeng

Singapore MIT Alliance (MEBCS Programme) Ph.D student

National University of Singapore;

4 Engineering Drive 4,

Singapore 117576

Email: laiyeng.lee@nus.edu.sg

Fax: 65 6775 2920 (Attn Lai Yeng)

Education:

1998 - 2002:      National University of Singapore B. Eng (Chemical Engineering) 2002 (Hons)

2002 - 2003:      National University of Singapore (SMA) S.M (Molecular Engineering of Biological and Chemical Systems)

2003 - 2008:      National University of Singapore (SMA) Ph.D. (Molecular Engineering of Biological and Chemical Systems)

2008 - present:   Current Affiliation: FeyeCon, The Netherlands

Research Interests:

Supercritical fluid techniques for particle fabrication; controlled drug delivery systems; Flow visualization for high pressure systems; Process optimization and control for supercritical fluid systems

Research Projects:

I. Supercritical antisolvent (SAS) techique for microparticle fabrication

The research focuses on fabrication of controlled release devices for a model anticancer drug paclitaxel using supercritical fluid techniques. Currently, the Supercritical Antisolvent (SAS) method was employed to investigate the jet breakup and particle size control during SAS.  Several factors may affect the particle size and properties achieved from SAS process. This includes the phase behavior of the ternary mixture, the hydrodynamics of the solution injected into the supercritical phase, as well as the thermodynamic conditions of the supercritical fluid. Considerable literature suggests that the controlling parameter for particle size in the SAS process is the rate of mass transfer. This may be influenced by both the spray hydrodynamics and thermodynamic properties of the supercritical fluid phase as illustrated in the schematic above. In our studies, we have found that by varying the operating conditions for the same biomaterials used, we were able to obtain different types of controlled release particles such as micro- or nano-spheres, porous particles and even fibers. It is our interest to further develop the technique for more precise control of particle sizes obtained using the SAS process.

The jet disintegration process of organic solution (specifically dichloromethane) in Carbon dioxide is also investigated. Jet breakup regimes of dripping, Rayleigh disintegration, Wavy disintegration and turbulent jets could be achieved by varying flowrate and pressure of the carbon dioxide phase. Microparticle fabrication in various operating regimes were explored for fine tuning and better control on final particle size and morphology.

II. Supercritical gas foaming technique for microporous PLGA foams

The fabrication of microporous foams from biodegradable polymers using supercritical CO2 gas foaming technique have been applied for scaffold material in tissue regeneration studies, tissue engineering as well as protein encapsulation and delivery. In our research, PLGA foams were fabricated for encapsulation and sustained delivery of paclitaxel. This type of drug-releasing foams have potential applications as implants in post-surgical treatment of tumors. Pore size of the foams could be controlled by altering the saturation pressure and contact time used in the gas foaming process.

 

Publications:

L.Y. Lee, C.H. Wang, K.A. Smith, “Supercritical antisolvent production of biodegradable micro- and nanoparticles for controlled delivery of paclitaxel”, Journal of Controlled Release, 125, 96-106 (2008).

L. Y. Lee, L.Y. Lee, L.K. Lim, J. Hua, C.H. Wang Jet breakup and droplet formation in near-critical regime of carbon dioxide-dichloromethane system”, Chem Eng. Sci. 63, 3366 – 3378 (2008).

H. Nie, L. Y. Lee, H. Tong, C.H. Wang,”PLGA/Chitosan Composites from a Combination of Spay Drying and Supercritical Fluid Foaming Techniques: New Carriers for DNA Delivery”, Journal of Controlled Release, 129, 207–214 (2008).

L. Y. Lee, S.H. Ranganath, Y. Fu, J.L. Zheng, H.S. Lee, C.H. Wang, K.A. Smith , “Paclitaxel Release from Micro-Porous PLGA Discs”, Chem. Eng. Sci. in press (2009).

H. Nie, S.T. Khew,L. Y. Lee, K.L. Poh, Y.W. Tong, C.H. Wang, "Arial">Functionalized PLGA foams for controlled gene delivery: Influence of surface modification on matrix-DNA interaction”, Journal of Controlled Release, in press (2009).

D. Y. Arifin, L. Y. Lee, C H Wang, "Mathematical modeling and simulation of drug release from microspheres:
implications to drug delivery systems". Advanced Drug Delivery Reviews 58, 1274-1325 (2006).

L. Y. Lee, T. Y. Quek, R Deng, M B. Ray, C H Wang. "Pneumatic transport of granular materials through a 90 degree bend." Chemical Engineering Science. 59, 4637 – 4651 (2004)

Conference presentations:

B. Y. S. Ong, L. Y. Lee,  J. Xie, H. S. Lee, N. V. Sahinidis, K. A. Smith, C. H. Wang. Controlled delivery of paclitaxel from micro-porous foams for the post surgical treatment of Glioblastoma Multiforme. AICHE Annual Meeting, San Francisco, United States, November 2006

L Y Lee, KA Smith, C H Wang. Paclitaxel-loaded Poly L Lactide (PLA) prepared by Supercritical Antisolvent (SAS) methods. Singapore-MIT Alliance Annual Symposium, Singapore, 17 January 2006

L Y Lee, K A Smith, C H Wang. Nanoparticle fabrication of biodegradable polymers using supercritical antisolvent: Effects of mixing and thermodynamic properties. AICHE Annual Meeting, Ohio, United States, 30 October – 04 November 2005 

L Y Lee, K A Smith, C H Wang. Fabrication of controlled release devices for anticancer agents using supercritical antisolvent method. . AICHE Annual Meeting, Ohio, United States, 30 October – 04 November 2005

Other publications:

LY Lee, KA Smith, C H Wang. Fabrication of controlled release devices using supercritical antisolvent methods. Singapore-MIT Alliance Annual Symposium, Singapore, 19 – 20 January 2005

L.Y. Lee, T.Y. Quek, R. Deng, M. B. Ray, and C.H. Wang. Pneumatic transport of granular materials through a 90 degree bend. Fluidization XI: Present and Future for Fluidization Engineering, Naples, Italy, 9 – 14  May 2004

L. Y. Lee, T. Y. Quek, M. B. Ray, and C.H. Wang. Pneumatic transport of granular materials through a bend. The 9th Asian Conference on Fluidized-Bed and Three-Phase Reactors, Taipei, Taiwan, 21 – 24 November 2004.

 

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