Hydrogels are hydrophilic polymeric matrices that can support cell and tissue growth in three-dimension. With careful design, hydrogels serve not only as a 3D platform for studying cell behaviors, but also as scaffolds for culturing and differentiating stem/progenitor cells.
We aim to develop a multifunctional hydrogel system that initially supports cell proliferation, but at a later stage can be "switched" into a microenvironment that promotes cell/tissue differentiation into a specific cell type. Our central hypothesis is that cell expansion and differentiation can be achieved in a single hydrogel matrix incorporated with dynamic biophysical and biochemical cues. We will test this hypothesis by developing a versatile hydrogel system using multiple cytocompatible thiol-ene "click" reactions. In the initial stage, we will design locally degradable thiol-ene gels to promote proliferation of PANC-1 cells (a pancreatic ductal epithelial cell line) (Aim 1). We will incorporate matrix metalloproteinase 2 (MMP-2) specific peptide substrates as hydrogel crosslinkers. This allows the gels to degrade locally (thus creating additional space for cell proliferation) by MMP-2 secreted from PANC-1 cells. The proliferation of encapsulated cells will be promoted by tuning cell-ECM and cell-cell interactions in hydrogels, as well as providing the encapsulated cells with diffusible soluble growth factors. Next, we will "switch" the cell-laden hydrogels from a "pro-proliferation" to a "pro-differentiation" microenvironment (Aim 2a). We will achieve this by performing a second thiol-ene click reaction to introduce pro-differentiation cues within the cell-laden hydrogels, thus promoting the formation of islet-like, insulin secreting cell clusters. The differentiation process will be a combinatorial result of using serum-free culture media, affinity-based recruitment of basic fibroblast growth factor (bFGF), and timely conjugation of glucagon-like peptide 1 (GLP-1). The differentiated cell clusters can be retrieved from the erodible gels (due to specific enzyme activity) for further characterization and biological/clinical applications (Aim 2b). The differentiated clusters are expected to form tight aggregates due to strong cell-cell interactions. Together, our strategies facilitate the formation of islet-like cell clusters with natural cell-cell interactions and normal insulin secretion profiles.

Public Health Relevance

This proposal aims to design biomaterial devices that incorporate signals to promote the proliferation of epithelial cells and to enhance the differentiation of these cells into insulin-producing cells. If successful, this strategy will provide alternative cell sources to benefit type 1 diabetic patients.

Agency
National Institute of Health (NIH)
Institute
National Institute of Biomedical Imaging and Bioengineering (NIBIB)
Type
Exploratory/Developmental Grants (R21)
Project #
5R21EB013717-02
Application #
8299028
Study Section
Biomaterials and Biointerfaces Study Section (BMBI)
Program Officer
Hunziker, Rosemarie
Project Start
2011-07-15
Project End
2014-06-30
Budget Start
2012-07-01
Budget End
2014-06-30
Support Year
2
Fiscal Year
2012
Total Cost
$192,500
Indirect Cost
$67,500
Name
Indiana University-Purdue University at Indianapolis
Department
Biomedical Engineering
Type
Schools of Engineering
DUNS #
603007902
City
Indianapolis
State
IN
Country
United States
Zip Code
46202
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Ki, Chang Seok; Lin, Tsai-Yu; Korc, Murray et al. (2014) Thiol-ene hydrogels as desmoplasia-mimetic matrices for modeling pancreatic cancer cell growth, invasion, and drug resistance. Biomaterials 35:9668-77
Raza, Asad; Lin, Chien-Chi (2013) The influence of matrix degradation and functionality on cell survival and morphogenesis in PEG-based hydrogels. Macromol Biosci 13:1048-58
Shih, Han; Fraser, Andrew K; Lin, Chien-Chi (2013) Interfacial thiol-ene photoclick reactions for forming multilayer hydrogels. ACS Appl Mater Interfaces 5:1673-80
Shih, Han; Lin, Chien-Chi (2013) Visible-light-mediated thiol-ene hydrogelation using eosin-Y as the only photoinitiator. Macromol Rapid Commun 34:269-73
Raza, Asad; Ki, Chang Seok; Lin, Chien-Chi (2013) The influence of matrix properties on growth and morphogenesis of human pancreatic ductal epithelial cells in 3D. Biomaterials 34:5117-27
Ki, Chang Seok; Shih, Han; Lin, Chien-Chi (2013) Facile preparation of photodegradable hydrogels by photopolymerization. Polymer (Guildf) 54:2115-2122
Lin, Chien-Chi; Raza, Asad; Shih, Han (2011) PEG hydrogels formed by thiol-ene photo-click chemistry and their effect on the formation and recovery of insulin-secreting cell spheroids. Biomaterials 32:9685-95