Collagens, the most abundant protein in mammals, provide a structural framework during tissue development and repair, and their structural and metabolic abnormalities are common to many chronic diseases (e.g. fibrosis and tumor growth). A simple synthetic molecule with selective binding affinity to collagen may offer new pathways for diagnosis and treatment of such diseases as well as facilitate production of functionalized collagen scaffolds for new and improved biomaterials applications in tissue engineering and drug delivery. This project focuses on i) developing new synthetic collagen mimetic peptides (CMPs) that bind specifically to natural collagen by a unique helix hybridization mechanism, and ii) creating collagen-based tissue engineering scaffolds that display morphogenic signals in a spatially and temporally defined manner. The long-term goals are to develop diagnostic and therapeutic methods that target disease-related fibrosis and to develop revolutionary methods for encoding cell-instructive signals onto collagen scaffolds in vivo for tissue regeneration and in vitro for transplantation therapy. As part of the efforts in achieving these long-term goals, the following specific aims are set forth in the proposed work: 1) Acquire a molecular level understanding of CMP-collagen hybridization interactions, 2) Develop new CMP architectures that will allow precise patterning of collagen scaffolds, and 3) Demonstrate spatial control of angiogenic events in collagen scaffolds with collagen- bound morphogenic factors by employment of CMPs.
In aim 1, a key hypothesis for CMP-collagen binding- that CMPs interact with the unfolded domains of collagen molecules by forming a hybrid triple helical complex- is tested by identifying molecular factors that affect binding events such as CMP's helical propensity and collagen's level of unfolding, and by isolating and studying the biophysical properties of CMP-collagen complexes.
In aim 2, new methods for spatio-temporal modification of collagen scaffolds are proposed that involve the design and synthesis of caged-CMPs that can be photo-triggered to fold and bind to collagen;the photo-triggered binding event will be investigated in the context of 2D and 3D collagen scaffold patterning.
And aim 3 attempts to control spatial organization of microvasculature formation in collagen scaffolds (for both in vivo and in vitro systems) by employment of CMPs and caged-CMPs conjugated to cell-instructive molecules. In the long run, completion of the proposed work will allow engineering of microvasculature networks for re-vascularizing native ischemic tissues as well as vascularizing ex-vivo engineered tissues. It may also offer new pathways for imaging pathologic scar tissue as well as facilitate production of functionalized collagen scaffolds for new and improved biomaterials applications in tissue engineering and drug delivery.

Public Health Relevance

This research project focuses on developing new synthetic molecules with a unique binding affinity to natural collagens, and creating collagen-based, cell-instructive tissue scaffolds that can control microvasculature network formation. This may allow revascularizing native ischemic tissues as well as vascularizing ex-vivo engineered tissues. In addition, collagen-targeting molecules may offer new pathways for imaging and treatment of pathological scar tissues such as fibrosis, arterial plaques, and tumors.

National Institute of Health (NIH)
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Research Project (R01)
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Biomaterials and Biointerfaces Study Section (BMBI)
Program Officer
Wang, Fei
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University of Utah
Biomedical Engineering
Schools of Engineering
Salt Lake City
United States
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Wahyudi, Hendra; Reynolds, Amanda A; Li, Yang et al. (2016) Targeting collagen for diagnostic imaging and therapeutic delivery. J Control Release :
Li, Yang; San, Boi Hoa; Kessler, Julian L et al. (2015) Non-covalent photo-patterning of gelatin matrices using caged collagen mimetic peptides. Macromol Biosci 15:52-62
Chan, Tania R; Stahl, Patrick J; Li, Yang et al. (2015) Collagen-gelatin mixtures as wound model, and substrates for VEGF-mimetic peptide binding and endothelial cell activation. Acta Biomater 15:164-72
Stahl, Patrick J; Chan, Tania R; Shen, Yu-I et al. (2014) Capillary Network-Like Organization of Endothelial Cells in PEGDA Scaffolds Encoded with Angiogenic Signals via Triple Helical Hybridization. Adv Funct Mater 24:3213-3225
Li, Yang; Foss, Catherine A; Pomper, Martin G et al. (2014) Imaging denatured collagen strands in vivo and ex vivo via photo-triggered hybridization of caged collagen mimetic peptides. J Vis Exp :e51052
Santos, José Luis; Li, Yang; Culver, Heidi R et al. (2014) Conducting polymer nanoparticles decorated with collagen mimetic peptides for collagen targeting. Chem Commun (Camb) 50:15045-8
Li, Yang; Yu, S Michael (2013) Targeting and mimicking collagens via triple helical peptide assembly. Curr Opin Chem Biol 17:968-75
Li, Yang; Ho, Daniel; Meng, Huan et al. (2013) Direct detection of collagenous proteins by fluorescently labeled collagen mimetic peptides. Bioconjug Chem 24:9-16
Li, Yang; Foss, Catherine A; Summerfield, Daniel D et al. (2012) Targeting collagen strands by photo-triggered triple-helix hybridization. Proc Natl Acad Sci U S A 109:14767-72
Stahl, Patrick J; Yu, S Michael (2012) Encoding Cell-Instructive Cues to PEG-Based Hydrogels via Triple Helical Peptide Assembly. Soft Matter 8:10409-10418

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