Bio

Academic Appointments


Boards, Advisory Committees, Professional Organizations


  • Editorial Board, AIM Materials Science (2013 - Present)

Professional Education


  • Ph.D., Stanford University (2010)
  • B.S., POSTECH (2001)

Research & Scholarship

Current Research and Scholarly Interests


The overall research theme of my resarch is to identify and reconstruct the key morphodynamic features of the hierarchical neural organizations in developmental, pathological, and remodeling phases. The insights from these investigations have direct implications for developing tissue regenerative strategies that could induce desirable behaviors of endogenous or exogenously grafted cells. My experimental model is developed on hydrogel-based 3D engineered tissues to elucidate the roles of the biomechanical stimuli, the temporospatial conditions of the soluble biological factor gradients, and the relative spatial distribution of the different cell types. In addition, there is a parallel effort to translate the 3D tissue design strategies into a cell-based high-throughput platform for efficient screening of the biologically active molecules. The multiscale features of these investigations are implemented by interdisciplinary collaboration across the fields of microfabrication, drug delivery, microfluidics, biomaterials, bioimaging, computational analysis and cell biology.

Publications

All Publications


  • Directed axonal outgrowth using a propagating gradient of IGF-1 ADVANCED MATERIALS Lee, W., Frank, C. W., Park, J. 2014; 26: 4936–4940

    View details for DOI 10.1002/adma.201305995

  • The Design of a Heterocellular 3D Architecture and its Application to Monitoring the Behavior of Cancer Cells in Response to the Spatial Distribution of Endothelial Cells ADVANCED MATERIALS Lee, W., Park, J. 2012; 24 (39): 5339-5344

    Abstract

    The spatial cell distribution is one of the critical features for governing cellular interactions and their consequent behaviors. Here we suggest a novel method of building a hierarchical cellular structure by stacking cell-attached microplate structures with specific configurations within hydrogel layers. This method is applied to the reconstruction of the 3D architecture of a liver lobule and the development of an experimental model of the various phases of cancer angiogenesis.

    View details for DOI 10.1002/adma.201200687

    View details for Web of Science ID 000309405200006

    View details for PubMedID 22927197

  • Hydrophobic nanoparticles improve permeability of cell-encapsulating poly(ethylene glycol) hydrogels while maintaining patternability PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Lee, W., Cho, N., Xiong, A., Glenn, J. S., Frank, C. W. 2010; 107 (48): 20709-20714

    Abstract

    Cell encapsulating poly(ethylene glycol) hydrogels represent a promising approach for constructing 3D cultures designed to more closely approximate in vivo tissue environment. Improved strategies are needed, however, to optimally balance hydrogel permeability to support metabolic activities of encapsulated cells, while maintaining patternability to restore key aspects of tissue architecture. Herein, we have developed one such strategy incorporating hydrophobic nanoparticles to partially induce looser cross-linking density at the particle-hydrogel interface. Strikingly, our network design significantly increased hydrogel permeability, while only minimally affecting the matrix mechanical strength or prepolymer viscosity. This structural advantage improved viability and functions of encapsulated cells and permitted micron-scale structures to control over spatial distribution of incorporated cells. We expect that this design strategy holds promise for the development of more advanced artificial tissues that can promote high levels of cell metabolic activity and recapitulate key architectural features.

    View details for DOI 10.1073/pnas.1005211107

    View details for Web of Science ID 000284762400026

    View details for PubMedID 21071674

  • The reliable targeting of specific drug release profiles by integrating arrays of different albumin-encapsulated microsphere types BIOMATERIALS Lee, W., Wiseman, M. E., Cho, N., Glenn, J. S., Frank, C. W. 2009; 30 (34): 6648-6654

    Abstract

    Biodegradable polymer microspheres have been successfully utilized as a medium for controlled protein or peptide-based drug release. Because the release kinetics has been typically controlled by modulating physical or chemical properties of the medium, these parameters must be optimized to obtain a specific release profile. However, due to the complexity of the release mechanism and the complicated interplay between various design parameters of the release medium, detailed prediction of the resulting release profile is a challenge. Herein we suggest a simple method to target specific release profiles more efficiently by integrating release profiles for an array of different microsphere types. This scheme is based on our observation that the resulting release profile from a mixture of different samples can be predicted as the linear summation of the individually measured release profiles of each sample. Hence, by employing a linear equation at each time point and formulating them as a matrix equation, we could determine how much of each microsphere type to include in a mixture in order to have a specific release profile. In accordance with this method, several targeted release profiles were successfully obtained. We expect that the proposed method will allow us to overcome limitations in controlling complicated release mechanisms so that drug delivery systems can be reliably designed to satisfy clinical demands.

    View details for DOI 10.1016/j.biomaterials.2009.08.035

    View details for Web of Science ID 000271347900010

    View details for PubMedID 19775742

  • Viral infection of human progenitor and liver-derived cells encapsulated in three-dimensional PEG-based hydrogel BIOMEDICAL MATERIALS Cho, N., Elazar, M., Xiong, A., Lee, W., Chiao, E., Baker, J., Frank, C. W., Glenn, J. S. 2009; 4 (1)

    Abstract

    We have studied the encapsulation of human progenitor cells into 3D PEG hydrogels. Replication-incompetent lentivirus promoter reporter vectors were found to efficiently detect the in vivo expression of human hepatic genes in hydrogel-encapsulated liver progenitor cells. Similarly, hydrogel-encapsulated cells could be efficiently infected with hepatitis C virus, and progeny infectious virus could be recovered from the media supernatants of the hydrogels. Provocatively, the diameters of these virus particles range from approximately 50 to 100 nm, while the calculated mesh size of the 8 k hydrogel is 44.6 +/- 1.7 A. To reconcile how viral particles can penetrate the hydrogels to infect the encapsulated cells, we propose that microfractures/defects of the hydrogel result in a functional pore size of up to 20 fold greater than predicted by theoretical mesh calculations. These results suggest a new model of hydrogel structure, and have exciting implications for tissue engineering and hepatitis virus studies.

    View details for DOI 10.1088/1748-6041/4/1/011001

    View details for Web of Science ID 000263071200001

    View details for PubMedID 18981544

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