Personal Particulars

Research Assistant

Education

M. Eng., Chemical Engineering, University of Chinese Academy of Sciences, China, 2012.

B. Eng., Chemical Engineering and Technology, Qingdao University of Science & Technology, China, 2009.

Work expeiences

2012.7-2014.1, Research Assistant, Institute of Process Engineering, Chinese Academy of Sciences. Group: Advanced Energy Technology

2014.2-present, Research Assistant, NUS Environmental Research Institute, National University of Singapore. Topic: Energy and Environment Sustainability Solutions for Megacities (E2S2).

Research Interests

Thermal conversion of coal and biomass

Feng Fang

Personal Particulars

Visiting Scholar

Education

Ph.D. , 2002-2006, Materials Science, Shanghai Jiao Tong University, China

M. Sc., 1997-2000, Polymer Chemistry and Physics, Soochow University, China

B. Eng., 1993-1997, Chemical Engineering, Soochow University, China

Work experiences

2000-Present: Associate Professor (2009-), Suzhou University of Science and Technology

2014-Present: Visiting Scholar, Department of Chemical & Biomolecular Engineering, National University of Singapore

Research Interests

My research interests concentrate on: (i) design and synthesis of biodegradable microparticles/nanovehicles for therapeutic pathway in cancer; (ii) development of effective polymeric anti-cancer drugs and protein and peptide delivery systems; (iii) ecomaterials and reuse of solid waste.

During recent years, I has been the key member of one National Natural Science Foundation of China (NSFC 50878136) and five provincial research projects and participated in several municipal research projects. I am a PI of one Suzhou environmental research project, two research projects of Suzhou University of Science and Technology and two corporations’ cooperation projects.

Publication

P. Davoodi, F. Feng, Q. Xu, W.C. Yan, Y.W. Tong, M.P. Srinivasan, V. K. Sharma, C.H. Wang, “Coaxial Electrohydrodynamic Atomization: Microparticles for Drug Delivery Applications”, Jouirnal of Controlled Release, 205, 70-82 (2015).

Qiao Jian

Personal Particulars

Ph.D. Student

Education

B.Eng. (Chemical Engineering), Tsinghua University, China, 2008.

Research Interests

Supercritical anti-solvent (SAS) precipitation

SAS is a method of fabricating microparticles. In this process, a solution of drug, polymer and organic solvent enters a chamber filled with anti-solvent (in the experiment, CO2 is the most commonly used anti-solvent). The solution is sprayed and the liquid jet breaks up into small droplets. At the same time, the anti-solvent (CO2) diffuses into the droplets, leading to a sharp decrease in solubility of drug and polymer. As a result, precipitation of drug and polymer occurs in the form of particles.

Fig. 1: SAS equipment.

Supercritical anti-solvent precipitation with enhanced mass transfer (SAS-EM)

SAS-EM is an improvement to the existing SAS precipitati

on technique. CO₂ is also used as an anti-solvent. In this process, the solution jet is deflected by a surface vibrating at an ultrasonic frequency that atomizes the jet into even smaller microdroplets. On top of that, the ultrasonic field generated by the vibrating surface inside the supercritical medium enhances mass transfer and prevents agglomeration due to increased mixing.

Fig. 2: Fabrication of cell culture scaffold by supercritical CO2 gas foaming method.

Particle-liquid Flow in a Taylor-Couette Device in the Presence of Mobile Porous Particle

Taylor vortices can be formed by subjecting a viscous liquid to a shear stress in an annular space between two rotating cylinders and a stationary bottom surface. In this study, the light porous particle was introduced into a Taylor-Couette device with an aspect ratio (G) of 6 and a radius ratio (?) of 0.67. The interaction of floating light particles and Taylor vortices inside a Taylor-Couette system was investigated using a high speed camera and a laser-based non-invasive technique known as Particle Image Velocimetry (PIV). Moreover, FLUENT software was used to simulate the flow pattern of the fluid and analyze the particle motion. Our results show that the particle behavior in the Taylor-Couette device is strongly influenced by the Reynolds number, four types of particle behaviors were observed, which are the particle moved on a circular trajectory on the surface of the inner cylinder, an oval orbit, randomly motion between the circular trajectory and oval orbit, and trapped in the vortex center. In addition, the study of PIV shows that the trapped particle has local influence to the flow pattern and reduced the axial and radials velocity around the particle. The simulation from FLUENT helped to analyze the force exerted on the particle and expl

ain the particle behavior.

Fig. 3: Fabrication of cell culture scaffold by supercritical CO2 gas foaming method.

Study of Oxygen Transport in a Taylor-Couette Bioreactor

Taylor vortices can be formed by subjecting a viscous liquid to a shear stress within an annular space between two rotating cylinders and a stationary bottom surface. Taylor vortex flow is found in many practical applications such as reaction, filtration and extraction. In this study, Taylor vortex flow is applied in a bioreactor to culture cells that are seeded in degradable porous scaffolds. This choice is with reference to its advantages of low shear stress, high mass transfer rate and easy scaling-up characteristics. It is important to understand the transport phenomenon inside the bioreactor system for optimization on the performance. To avoid the shear stress caused by sparging, air bubbles are injected to form bubble rings inside the system. A high-speed camera is used to measure the bubble behavior, in conjunction with an oxygen sensor for in-situ measu

rements of the oxygen concentration in the flow field. The effect of flow pattern of bubbles on the oxygen consumption rate in the bioreactor is investigated for designing the optimal bubble size and bubble number for cell culture and tissue engineering applications.

Fig. 4. Typical trajectory of mobile particles at different Reynolds number regime; A: Trajectory at low Reynolds number regime, the particle the particle moved on the surface of inner cylinder; B: Trajectory at transition Reynolds number regime, the particle moved on the unstable orbit-moves along the circle and oval orbit alternately; C: Trajectory at moderate Reynolds number regime, the particle always sails along the oval orbit; D: Trajectory at high Reynolds number regime, the particle escapes from the oval orbit and moves to the center of vortex, thus its orbit evolves into a circle again.

Study of cell proliferation in porous scaffold in a TaylorCouette bioreactor

Taylor vortices can be formed by subjecting a viscous liquid to a shear stress in an annular space between two rotating cylinders and a stationary bottom surface. In recent years, Taylor vortex flow is found in many practical applications such as reaction, filtration and extraction. In this study, Taylor vortex flow is applied in a bioreactor to culture cells that are seeded in a degradable porous scaffold due to its advantages of low shear stress, high mass transfer rate and easy scaling up. The biodegradable porous scaffold is fabricated from solvent-free supercritical gas foaming technique. Cell seeding into the scaffold and proliferation inside the bioreactor is studied and compared with conventional bioreactor, and the optimal operation conditions are explored.

Journal Publications

J. Qiao, R, Deng, C.H. Wang, “Droplet Behavior in a Taylor Vortex”, International Journal of Multiphase Flow, 67, 132-139 (2014).

J.Qiao, C.M.J. Lew, A. Karthikeyan, C.H. Wang, ”Production of PEX protein from QM7 cells cultured in polymer scaffolds in a Taylor–Couette bioreactor”, Biochemical Engineering, 88, 179-187 (2014).

J. Qiao, R.S. Deng, C.H. Wang, “Particle Behavior in a Taylor Vortex”, International Journal of Multiphase Flow, in press (2015)

Conference Presentations

Eldin Wee Chuan Lim, Yu Xuan Tan, Jian Qiao, Chi-Hwa Wang, Particle Image Velocimetry Studies of a Taylor Vortex System with Immobilized Porous Scaffolds, APPCHE annual meeting, Taipei, 2010.

Jian Qiao, Eldin Wee Chuan Lim and Chi-Hwa Wang, Bubble Behavior and Oxygen Transport In a Taylor-Couette Bioreactor, AICHE annual meeting, Minneapolis, 2011.

Jian Qiao, Chi-Hwa Wang, Flow Characterization In a Taylor-Couette Bioreactor In the Presence of Mobile Scaffolds, AICHE annual meeting, Minneapolis, 2011.

Personal Particulars

Exchange Ph.D student

Education

Ph. D student. School of Material Science and Technology, Tongji University, No.4800, Caoan Road, Jiading District, Shanghai, China, 201804.

Research Interests

My research is mainly about magnetic PLGA hybrid nanoparticles for attaching target and moleculars in the biomedical application. Uniform and small particle size of these nanoparticles is an important factor for cellular uptake and tissue targeting. Another aspect of the research is to design and fabricate mechanized organic/inorganic hybrid mesoporous nanoparticles. The gatekeeper on the outlet of mesoporous silica nanoparticles can be cleaved under some certain stimulus conditions.

Journal Publications

Y. Cui, Q. Xu, P K.H. Chow,D. Wang, C.H. Wang, “Transferrin-conjugated magnetic silica PLGA nanoparticles loaded with doxorubicin and paclitaxel for brain glioma treatment”, Biomaterial, 34, 8511-8520 (2013).

C. Lei, Y. Cui , L. Zheng, P.K.H. Chow, C.H. Wang, “Development of a gene/drug dual delivery system for brain tumor therapy: Potent inhibition via RNA interference and synergistic effects”, Biomaterial, 34(30), 7483-7494 (2013).

Cui Yanna, Wang Deping, Huang Wenhai, Yao Aihua, “Synthesis and Magnetic Properties of M?Fe2O4 (M=Fe, Ni) Hollow Nanospheres? Journal of Material Science and Technology(Chinese), 2011, 29 (4): 496-501.

Cui Yanna, Haiqing Dong, Xiaojun Cai, Deping Wang, Yongyong Li, “Mesoporous silica nanoparticles capped with disulfide-linked PEG gatekeepers for glutathione-mediated controlled release?(Submitted).

PhD Candidate

Personal Particulars:

M. Eng. (Env. Eng.), TsingHua University, P.R. China, 2003.

B. Eng. (Env. Eng.), TsingHua University, P.R. China, 2000.

Research Interests:

Current work focuses on constructing an engineered liver tissue using a three-dimensional microsphere scaffold to reduce the cost of implantation and to solve the shortage of liver donors due to the high incidence of liver diseases and failure. Poly(3-hydroxybutyrate-co-3-hydroxyvalerate), a type of microbial polyester, is chosen as the cell attachment substrate due to its biodegradability, biocompatibility and non-toxicity. Bio-conjugation of extracellular matrix (ECM) proteins to the microsphere surface can further improve its biocompatibility, and the encapsulation of bioactive factors into the microsphere will make it possible to engineer a complete functional liver.

Publication:

X.H. Zhu, D.Y. Arifin, B.H. Khoo, J. Hua, C.H. Wang, “Study of Cell Seeding on Porous Poly(D,L-lactic-co-glycolic acid) Sponge and Growth in a Couette-Taylor Bioreactor, Chem. Eng. Sci., 65 2108-2117 (2010).

X.H. Zhu, X.H. Zhu, C.H. Wang, Y.W. Tong, “In vitro characterization of hepatocyte growth factor release from PHBV/PLGA microsphere scaffold”, J. Biomed. Mat. Res. Part A, 89A, 411-423 (2009).

X.H. Zhu, X.H. Zhu, L. Y. Lee, J.S. Hong, Y.W. Tong, C.H. Wang, , “Characterization of Porous Poly(D,L-lactic-co-glycolic) Acid Sponges Fabricated by Supercritical CO2 Gas- foaming Method as a Scaffold for Three-dimensional Growth of Hep3B cells”, Biotechnology and Bioengineering, 100, 998-1009 (2008).

X.H. Zhu, X.H. Zhu, Y. Tabata, C.H. Wang, Y.W. Tong , “Delivery of basic fibroblast growth factor from gelatin microsphere scaffold for the growth of human umbilical vein endothelial cells”, Tissue Engineering, 14(12) 1-9 (2008).

X.H. Zhu, C.H. Wang, Y.W. Tong, “Growing Tissue-Like Constructs with Hep3B/Hepg2 Liver Cells on PHBV Microspheres of Different Sizes” Journal of Biomedical Materials Research: Part B: Applied Biomaterials, 82B, 7-16 (2007).

X.H. Zhu,, C.H. Wang, Y.W. Tong, “Proteins Combination on PHBV Microsphere Scaffold to Regulate Hep3B Cells Activity and Functionality: A Model of Liver Tissue Engineering System” Journal of Biomedical Materials Research: Part A, 83A, 606-616 (2007).

Y.Q. Lu, J.M. Hao, X. H. Zhu. ‘Control techniques for gaseous pollution’, in Point sources of pollution: local effects and it’s control, edited by Qian Yi and Sklespc. (2003)

X. H. Zhu, Y.Q. Lu, T.L. Zhu, Z.P. Zhou. Photocatalytic oxidation of TCE and TCM with thin films of TiO2. Techniques and equipment for environmental pollution control, 2003 (4):26-30 (Chinese).

Conference:

S.T. Khew, X.H. Zhu, Y.W. Tong. Collagen-mimetic peptide (CMP) for integrin-specific cellular recognition and tissue engineering. AIChE 2006 annual meeting, San Francisco, USA, Nov. 12-16, 2006

X.H. Zhu, C-H. Wang, Y.W. Tong. Combination of proteins on PHBV microsphere scaffold to regulate Hep3B cells activity and functionality for an in vitro model of liver tissue engineering. AIChE 2006 annual meeting, San Francisco, USA, Nov. 12-16, 2006

X.H. Zhu, C-H. Wang, Y.W. Tong. Growing tissue-like constructs with Hep3B/HepG2 liver cells on PHBV microsphere scaffold. AIChE 2006 annual meeting, San Francisco, USA, Nov. 12-16, 2006

X.H. Zhu, C-H Wang, Y. W. Tong. PHBV microspheres as scaffold for liver tissue engineering. ICMAT, Suntec City, Singapore, July 3-8, 2005.

Others:

S.T. Khew, X.H. Zhu, Y.W. Tong. Engineering of integrin-specific bioadhesive surfaces to promote cell adhesion and spreading using self-assembled collagen-mimetic peptides (CMPs). OLS-NUSNNI Workshop on Nanobiotechnology and Nnomedicine, NUS, Singapore, Sept. 1, 2006.

X. H. Zhu, S.K. Gan, C-H Wang, Y. W. Tong. Biomimetic surface modification of PHBV microsphere scaffold with extracellular matrix proteins to regulate Hep3B cells proliferation and function. 2nd Graduate Student Symposium, NUS, Singapore, October 6, 2005.

Zhang Yan

Personal Particulars:

B.Eng. Polymer of Chemical Engineering, Tianjin University, 2000

Research Interests:

Electrostatic character & attrition of granular flow in pneumatic conveying system.

The induced current measurement was arranged on inclined pipe to test electrostatic current on the pipe wall, which was generated by the frictional contacts between the solid particles and pipe wall, during the pneumatic conveying process. With proper pipe connections, current induced on the surface of the pipe wall can be measured as a function of time. The details of the measurement methods have been described previously by Yao et al. (2004) and the measurement section is enlarged in figure 1, where the test section is divided into two parts and the experiment data can be obtained from top pipe and bottom pipe respectively in order to demonstrate if the electrostatic charge distribute on the pipe wall uniformly or not.

Figure 1 Induced current measurement section

Figure 2 Wall charge from integration of induced current

In order to verify whether electrostatic charge distributes on the pipe wall evenly or not, the induced current was measured on the top of pipe and bottom of pipe respectively, and then induced currents were integrated with time to obtain the charge on pipe wall (Yao et al. 2004) as shown in figure 2. It is observed that wall charge: at the top of pipe is greater than that at the bottom of pipe, which may be the explanation of the ring structure and demonstrate that charge distributed unevenly on the pipe wall. Therefore, according to the theory of the switch capacitor configuration, electrostatic charge would bring the influence to the ECT measurement.

Publication:

Yao, J., Zhang, Y., Wang, C.-H., Matsusaka, S. and Masuda. H. Electrostatics of the granular flow in a pneumatic conveying system, Industrial and Engineering Chemistry Research, 43(22), 7181–7199, 2004.

Yao, J., Zhang, Y., Wang, C.-H. and Liang, Y.C. On the Electrostatic Equilibrium og Granular Flow in Pneumatic Conveying Systems, AIChE Journal, 52 (11), 3775-3793, 2006.

Zhang, Y., Wang, C.-H., Particle Attrition due to Rotary Valve Feeder in a Pneumatic Conveying System: Electrostatics and Mechanical Characteristics, Canadian Journal of Chemical Engineering, 84, 663-679, 2006.

Lim, E. W. C., Y. Zhang and C. H. Wang. Effects of an Electrostatic Field in Pneumatic Conveying of Granular Materials through Inclined and Vertical Pipes. Chemical Engineering Science, 61, 7889-7908, 2006.

Y. Zhang, W.C. Lim, and C.H. Wang, “Pneumatic Transport of Granular Materials in an Inclined Conveying Pipe: Comparison of CFD-DEM, ECT and PIV Results”, Ind. Eng. Chem. Res., 46, 6066-6083, 2007.

Y. Zhang, Y.C. Liang and C. H. Wang, “Hazard of Electrostatic Generation in Pneumatic Conveying System: Electrostatic Effects on the Accuracy of Electrical Capacitance Tomography Measurements and Generation of Spark”, Measurement Science and Technology, 19, 015502, 2008.

Yao, J., Zhang, Y., Wang, C.-H. Matsusaka, S. and Masuda, H. Electrostatics of the granular flow in a pneumatic conveying system, AIChE Annual Meeting 2004, Austin, Texas, United States, 7-12 November 2004.

Zhang, Y., Yao. J., Wang, C.-H. Electrical Capacitance Tomography Measurements on Inclined Conveying Pipes, 4th World Congress on Industrial Process Tomography, Aizu, Japan, September 2005.

Yao, J., Zhang, Y., Wang, C.-H. and Liang, Y.C. On the Electrostatic Field within Space of Pipe Induced by Granular Flow in a Pneumatic Conveying System, AIChE Annual meeting, Cincinnati, Ohio, USA, November 2005.

Personal Particulars:

Undergraduate Studies: BEng (Hons) Chemical and Process Engineering (2000), University of Newcastle Upon Tyne, UK

Masters: MSc in Process Systems Engineering, Diploma of Imperial College (2001), Imperial College of Science, Medicine and Technology, London

M. Eng. in Chemical and Biomolecular Engineering, National University of Singapore (2007)

Work Experience:

Contact Engineer, ExxonMobil Chemical (2002)

Process Engineer, Singapore Refining Company (2003)

Research Experience:

Research Intern, Animal Cell Culture and Bioreactors, Bioprocessing Technology Institute, Singapore (2004)

Research Interests:

The controlled release of chemotherapeutic agents holds promise for treatments of solid tumors by prolonged cytotoxicity to tumor cells while minimizing chemotherapeutic associated side effects in patients. Often, such drug delivery systems allow the use of potential drugs with low therapeutic indexes previously administered only by continuous IV.

My work looks at optimizing the efficacy of controlled release treatment into tumors within the brain through in vivo animal models as well as computational modeling of the extravasation of drug into the tumor mass. Of special interest is the complimentary effect of irradiation on drug transport from implants (surgically inserted post tumor debulking surgery) within the brain.

Integration of process systems engineering into this problem is used to optimize the overall drug delivery system design using gams-Baron optimization complier

Previous research work at Imperial College involved modeling of supply chain dynamics in response to dynamic pricing and model predictive control forecasting.

Publications:

P. K. Naraharisetti, B. Y. S. Ong, J. Xie, T. Lee, N. Sahinidis, C. H. Wang, Paclitaxel-loaded biodegradable discs and microspheres for treatment of Glioma: Subcutaneous study, Biometerials, 28, 886-894, 2007.

B.Y.S. Ong, S.H. Ranganath, LY Lee, F. Lu, H.S. Lee, N.V. Sahinidis, C.H. Wang, “Paclitaxel delivery from PLGA foams for controlled release in post-surgical chemotherapy against glioblastoma multiforme”, Biomaterials, 30, 3189-3196, 2009.

Personal Particulars

Master Student

Education

B. Eng. (Chemical Engineering), National University of Singapore, Singapore, 2008.

Research Interests

Physical Modelling and Simulation of Taylor Cone-Jet Formation in Electrohydrodynamic Atomization

Electrohydrodynamic atomization in the cone-jet mode has been studied to model fabrication process of co-axial double-wall fibers and particles for drug and gene delivery applications. In this process, a liquid contained polymer solution is supplied to a coaxial-nozzle at a low rate. A droplet is formed at this nozzle. When a strong electric field is applied over this droplet, then the electric field induces free charge in the liquid surface. As a result, electric stresses occur in this surface. These stresses transform the droplet shape into a conical shape. At the cone apex a liquid jet with a high charge density occurs. In certain circumstances, this jet will break up into highly charged main droplets with a narrow size distribution, and a number of smaller secondary and satellite droplets. After evaporation of the liquid, the droplets will turn into double-wall microsphere particles.

Journal Publication

Q. Xu, H. Qin, Z. Yin, J. Hua, D. W. Pack, C.H. Wang, “Coaxial electrohydrodynamic atomization process for production of polymeric composite microspheres”, Chem. Eng. Sci. 104, 330-346 (2013).

Personal Particulars

Ph.D. Student

Education

B.Sc. (Biological Science), Peking University, China, 2007.

Research Interests

Development and evaluation of biodegradable controlled release devices for synergetic therapy of malignant brain tumors

Microfiber delivering RNAi plasmid for glioma therapy.

Fig. 1: Microfibers encapsulated with RNAi plasmid-PEI complex (shown by the arrows in the locally enlarged diagram).

Surface-coated nanoparticles for paclitaxel delivery through the blood-brain barrier.

Fig. 2: FESEM images of paclitaxel-loaded PLGA nanoparticles with various surface coatings.

Publications

J.Xie, C. Lei, Y. Hu, G.K. Gay, N. H. B. Jamali, C.H. Wang, “Nanoparticulate Formulations for Paclitaxel Delivery across MDCK Cell Monolayer “, Current Pharmaceutical Design, 16, 2331-2340 (2010).

P.C. Chang, L.P. Lim, L.Y. Chong, A..S.M. Dovban, L.Y. Chien, M.C. Chung, C Lei, C.H. Chen, H.C. Chiang, Y.P. Kuo, C.H. Wang, “PDGF-Simvastatin Delivery Stimulates Osteogenesis in Heat-induced Osteonecrosis”, Journal of Dental Research, 91(6) 618-624 (2012).

P.C. Chang, L.P. Lim, L.Y. Chong, A..S.M. Dovban, L.Y. Chien, M.C. Chung, C Lei, C.H. Chen, H.C. Chiang, Y.P. Kuo, C.H. Wang, “PDGF-Simvastatin Delivery Stimulates Osteogenesis in Heat-induced Osteonecrosis”, Journal of Dental Research, 91(6) 618-624 (2012).

C. Lei, Y. Cui , L. Zheng, P.K.H. Chow, C.H. Wang, “Development of a gene/drug dual delivery system for brain tumor therapy: Potent inhibition via RNA interference and synergistic effects”, Biomaterial, 34(30), 7483-7494 (2013).

Personal Particulars

Research Engineer

Education

M. Med., Nephrology, Southern Medical University, China, 2007.

B. Med., Clinical Medicine, Central South University, China, 2003.

Work expeiences

2007-2008, Nephrologist, Zhujiang Hospital, Guangzhou, China.

Research Interests

Toxicity Assessment of Gasification Process

Like incineration, the gasification process produces emissions, including air emission (acid gases, dioxins and furans, nitrogen oxides, sulphur dioxide, particulates, etc.), solid residue (inert mineral ash, inorganic compounds, and unreformed carbon), and water (used to wash the original waste in pre-treatment and clean the syngas). In order to evaluate their effects on human health, we develop various models (human primary cells or cell lines from liver/kidney/lung, human mesenchymal stem cells, zebrafish/fly model) and check the toxic effects on cell viability, morphology and functionality accordingly.

Journal Publication

L. Rong, T. Maneerung, J. C. Ng , K. G. Neoh, B. H. Bay, Y. W. Tong, Y. Dai, C.H. Wang, Co-Gasification of Sewage Sludge and Woody Biomass in a Fixed-bed Downdraft Gasifier: Toxicity Assessment of Solid Residues, Waste Management, 36, 241-255 (2015).