Bio

Bio


Soah is a biomaterials scientist and bio engineer who specializes in developing artificial cell niche using hydrogels for various tissue engineering/drug delivery applications.

During 5 years of Ph.D. training in Stem Cell and Biomaterials Laboratory under Dr. Fan Yang's guidance, Soah has focused on developing novel hydrogel-based cell niche platforms and examining effect of biophysical properties of the cell niche using various natural polymers (Matrigel, collagen, alginate, etc.) and synthetic polymers (poly(ethylene glycol), poly(acryl amide) etc.).

After completion of her Ph.D. training, she has joined Sean Wu's lab in CVI to extend her expertise in biomaterials to develop a bioink for bioprinting 3D cardiac tissues.

Honors & Awards


  • Centennial TA Awards 2015, Stanford University (June. 2015)
  • Bio-X Fellowship, Stanford Bio-X, Stanford University (Sep. 2012 - Aug. 2015)
  • Department Fellowship, Department of Materials Science and Engineering, Stanford University (Sep. 2011 - Aug. 2012)
  • National Scholarship for Science and Engineering, Korea Student Aid Foundation (Mar. 2007 - Feb. 2011)

Professional Education


  • Doctor of Philosophy, Stanford University, MATSC-PHD (2016)
  • Master of Science, Stanford University, MATSC-MS (2015)
  • Bachelor of Science, Seoul National University, Materials Science& Engineering (2011)

Research & Scholarship

Lab Affiliations


Publications

All Publications


  • Winner of the Young Investigator Award of the Society for Biomaterials (USA) for 2016, 10th World Biomaterials Congress, May 17-22, 2016, Montreal QC, Canada: Aligned microribbon-like hydrogels for guiding three-dimensional smooth muscle tissue regeneration JOURNAL OF BIOMEDICAL MATERIALS RESEARCH PART A Lee, S., Tong, X., Han, L., Behn, A., Yang, F. 2016; 104 (5): 1064-1071

    Abstract

    Smooth muscle tissue is characterized by aligned structures, which is critical for its contractile functions. Smooth muscle injury is common and can be caused by various diseases and degenerative processes, and there remains a strong need to develop effective therapies for smooth muscle tissue regeneration with restored structures. To guide cell alignment, previously cells were cultured on 2D nano/microgrooved substrates, but such method is limited to fabricating 2D aligned cell sheets only. Alternatively, aligned electrospun nanofiber has been employed as 3D scaffold for cell alignment, but cells can only be seeded post fabrication, and nanoporosity of electrospun fiber meshes often leads to poor cell distribution. To overcome these limitations, we report aligned gelatin-based microribbons (µRBs) as macroporous hydrogels for guiding smooth muscle alignment in 3D. We developed aligned µRB-like hydrogels using wet spinning, which allows easy fabrication of tissue-scale (cm) macroporous matrices with alignment cues and supports direct cell encapsulation. The macroporosity within µRB-based hydrogels facilitated cell proliferation, new matrix deposition, and nutrient diffusion. In aligned µRB scaffold, smooth muscle cells showed high viability, rapid adhesion, and alignment following µRB direction. Aligned µRB scaffolds supported retention of smooth muscle contractile phenotype, and accelerated uniaxial deposition of new matrix (collagen I/IV) along the µRB. In contrast, cells encapsulated in conventional gelatin hydrogels remained round with matrix deposition limited to pericellular regions only. We envision such aligned µRB scaffold can be broadly applicable in growing other anisotropic tissues including tendon, nerves and blood vessel. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 1064-1071, 2016.

    View details for DOI 10.1002/jbm.a.35662

    View details for PubMedID 26799256

  • Effects of the poly(ethylene glycol) hydrogel crosslinking mechanism on protein release. Biomaterials science Lee, S., Tong, X., Yang, F. 2016; 4 (3): 405-411

    Abstract

    Poly(ethylene glycol) (PEG) hydrogels are widely used to deliver therapeutic biomolecules, due to high hydrophilicity, tunable physicochemical properties, and anti-fouling properties. Although different hydrogel crosslinking mechanisms are known to result in distinct network structures, it is still unknown how these various mechanisms influence biomolecule release. Here we compared the effects of chain-growth and step-growth polymerization for hydrogel crosslinking on the efficiency of protein release and diffusivity. For chain-growth-polymerized PEG hydrogels, while decreasing PEG concentration increased both the protein release efficiency and diffusivity, it was unexpected to find out that increasing PEG molecular weight did not significantly change either parameter. In contrast, for step-growth-polymerized PEG hydrogels, both decreasing PEG concentration and increasing PEG molecular weight resulted in an increase in the protein release efficiency and diffusivity. For step-growth-polymerized hydrogels, the protein release efficiency and diffusivity were further decreased by increasing crosslink functionality (4-arm to 8-arm) of the chosen monomer. Altogether, our results demonstrate that the crosslinking mechanism has a differential effect on controlling protein release, and this study provides valuable information for the rational design of hydrogels for sophisticated drug delivery.

    View details for DOI 10.1039/c5bm00256g

    View details for PubMedID 26539660

  • Long-Term Controlled Protein Release from Poly(Ethylene Glycol) Hydrogels by Modulating Mesh Size and Degradation MACROMOLECULAR BIOSCIENCE Tong, X., Lee, S., Bararpour, L., Yang, F. 2015; 15 (12): 1679-1686

    Abstract

    Poly(ethylene glycol) (PEG)-based hydrogels are popular biomaterials for protein delivery to guide desirable cellular fates and tissue repair. However, long-term protein release from PEG-based hydrogels remains challenging. Here, we report a PEG-based hydrogel platform for long term protein release, which allows efficient loading of proteins via physical entrapment. Tuning hydrogel degradation led to increase in hydrogel mesh size and gradual release of protein over 60 days of with retained bioactivity. Importantly, this platform does not require the chemical modification of loaded proteins, and may serve as a versatile tool for long-term delivery of a wide range of proteins for drug-delivery and tissue-engineering applications.

    View details for DOI 10.1002/mabi.201500245

    View details for Web of Science ID 000368456500007

    View details for PubMedCentralID PMC5127624

  • The effects of varying poly(ethylene glycol) hydrogel crosslinking density and the crosslinking mechanism on protein accumulation in three-dimensional hydrogels ACTA BIOMATERIALIA Lee, S., Tong, X., Yang, F. 2014; 10 (10): 4167-4174

    Abstract

    Matrix stiffness has been shown to play an important role in modulating various cell fate processes such as differentiation and cell cycle. Given that the stiffness can be easily tuned by varying the crosslinking density, poly(ethylene glycol) (PEG) hydrogels have been widely used as an artificial cell niche. However, little is known about how changes in the hydrogel crosslinking density may affect the accumulation of exogenous growth factors within 3-D hydrogel scaffolds formed by different crosslinking mechanisms. To address such shortcomings, we measured protein diffusivity and accumulation within PEG hydrogels with varying PEG molecular weight, concentration and crosslinking mechanism. We found that protein accumulation increased substantially above a critical mesh size, which was distinct from the protein diffusivity trend, highlighting the importance of using protein accumulation as a parameter to better predict the cell fates in addition to protein diffusivity, a parameter commonly reported by researchers studying protein diffusion in hydrogels. Furthermore, we found that chain-growth-polymerized gels allowed more protein accumulation than step-growth-polymerized gels, which may be the result of network heterogeneity. The strategy used here can help quantify the effects of varying the hydrogel crosslinking density and crosslinking mechanism on protein diffusion in different types of hydrogel. Such tools could be broadly useful for interpreting cellular responses in hydrogels of varying stiffness for various tissue engineering applications.

    View details for DOI 10.1016/j.actbio.2014.05.023

    View details for Web of Science ID 000342523800011

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