Post on 14-Apr-2017
Jessica Gidzinski, David Pearson, Travis WeissAdvisor: Dr. Michele Marcolongo
Mentors: Alicia Kriete, Evan Phillips, Dr. Katsiaryna Prudnikova
Novel Use of Biomimetic Proteoglycans to Molecularly Engineer the Extracellular Matrix of Damaged Skin
1
Problem Statement
Problem: As skin ages, it dehydrates and loses compliance.
• Vulnerability to wounds/infectiono 92% of institutionalized elderly
sustain at least 1 skin tear every year• Wrinkles
2MALONE, ML, et al. "the Epidemiology of Skin Tears in the Institutionalized Elderly."JOURNAL OF THE AMERICAN GERIATRICS SOCIETY 39.6 (1991): 591-5. Web.
and proteoglycans (ECM molecules)
Skin Layers and Molecular Composition● Epidermis● Dermis● Hypodermis● ECM: offers structural and
biochemical support○ Structural proteins○ Glycoproteins○ Proteoglycans (PGs): embed
structural proteins & are critical for wound healing■ PG breakdown over time
causes dehydration and reduced compliance
ECM
3reading.ac.ukheadandneckcancerguide.org
Proteoglycans
Protein core with covalently attached glycosaminoglycan (GAG) chains
Functions:
• Mechanical: o Increased water uptake (hydration)→
negatively charged GAG chains• Biological:
○ PGs aid in last 2 stages of wound healing1. Cell migration/proliferation (fibroblasts)2. Remodelling: bind to type I collagen fibers
in skin to align them in organized fashion
4sci.utah.edu
Proposed Solution - Biomimetic Proteoglycans (BPGs)
• Increased hydration & compliance• Restored PG content could potentially
enhance wound healingo PGs align collagen fibers during
wound healingo High PG content→less scarring
5
Degenerated Tissue
Restored Tissue (Hydration/Swelling)
Marcolongo, M. "Matrix Molecular Engineering Using Biomimetic Proteoglycans." 26 Oct. 2015. Lecture.Lightfoot Vidal, Sarah Eugenia, Michele S. Marcolongo and Drexel University. College of Engineering. "Novel Biomimetic Aggrecan for the Acellular Regeneration of the Intervertebral Disc: Synthesis, Enzymatic Stability and Molecular Engineering." 2013. Web.
PAA
CS GAG Chains
Objectives and Methods
Objective 1: Determine if BPGs have a statistically significant effect on skin compliance
Method: Employ piezoelectric finger (PEF) method to measure elastic modulus of BPG-injected porcine skin samples
Objective 2: Evaluate the diffusion behavior of BPGs in skin
Method: Cryosection samples thin enough to view under confocal microscope; quantify percent area fluorescence of tagged BPGs at varying distances from injection site
6
Piezoelectric Finger (PEF) Method
Xu, Xin, Cynthia Gifford-Hollingsworth, Richard Sensenig, Wei-Heng Shih, Wan Shih, and Ari D. Brooks. "Breast Tumor Detection Using Piezoelectric Fingers: First Clinical Report." Vol. 216, No. 6. Drexel University, June 2013.
7
Exceeded target of 25% reduction in modulus (increased compliance)
Confocal MicroscopyEmbedding Mold
Leica 1850 Cryostat
8
Confocal Microscopy Images
9
Confocal Microscopy Results
10
● Decrease in amount of molecule near injection sites over 24 hr period
● Overall, molecular level integration with existing extracellular matrix and diffusion around injection site is shown over a 24 hr period.
Overall Conclusions and Design Considerations• For the first time, demonstrated molecular
engineering of the ECM of porcine skin using
biomimetic proteoglycans.
• The skin hydration and increased compliance
caused by injectable BPGs offers potential for
treatment of diseased and aged skin against
tearing and subsequent infection. o An injection of natural PGs can cost $300/mg
while an injection of BPGs typically costs
$0.06/mg. 11