1. Jessica Gidzinski, David Pearson, Travis Weiss
Advisor: 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
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2. Problem Statement
Problem: As skin ages, it dehydrates and loses
compliance.
• Vulnerability to wounds/infection
o 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)
3. 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.uk
headandneckcancerguide.org
4. 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 healing
1. Cell migration/proliferation (fibroblasts)
2. Remodelling: bind to type I collagen fibers
in skin to align them in organized fashion
4sci.utah.edu
5. Proposed Solution - Biomimetic Proteoglycans (BPGs)
• Increased hydration & compliance
• Restored PG content could potentially
enhance wound healing
o PGs align collagen fibers during
wound healing
o High PG content→less scarring
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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
6. 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
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7. 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)
10. Confocal Microscopy Results
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● 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.
11. 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.
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Editor's Notes
Images: http://remeka.hu/index.php/magazinxmszakmai-frissxm/single-column-blog-190/kozmetikus-szemmel/805-az-antiaging, http://www.isaywhatever.com/handling-elderly-skin-needs
One study at a long-term care facility of approximately 1800 patients showed that 92% of institutionalized elderly sustain at least 1 skin tear every year; these wounds increase the risk of infection
To gain insight into the problem, here’s some background on the composition of the skin
Our project consisted of two main objectives that made use of different methods. Our first objective involved determining whether the BPGs had any significant effects on the tissue compliance by measuring the elastic modulus of the porcine skin samples post-injection with the piezoelectric finger. Our second objective involved evaluating the diffusion behavior of the BPGs by quantifying the percent area fluorescence of tagged BPGs at varying distances from the injection site.
These are the results we obtained from the piezoelectric finger method. Each bar represents 75 values and each sample group was tested at both 1 and 24 hours. The circled bars in green and red represent Restylane injected samples and BA-10 injected samples at a concentration of 50 mg/mL. BA-10 at 50 mg/mL resulted in a 48% reduction in tissue modulus and increased compliance over Restylane injected samples through 24 hours. This is a significant finding because Restylane is a currently available anti-wrinkle treatment. These circled bars in blue and red represent non-injected control samples and BA-10 injected samples at a concentration of 50 mg/mL. It can be seen that BA-10 at 50 mg/mL resulted in a 32% reduction in tissue modulus and increased compliance over normal, untreated skin through 24 hours. Both of these reductions exceeded our target of 25% reduction in compliance.
Injection of BA-10 at 50 mg/mL resulted in a 32% reduction of tissue modulus over non-injected control specimens and 48% reduction of tissue modulus compared to commercially available hyaluronic acid (Restylane) 24 hours after injection. This exceeded the target of 25% reduction in tissue modulus (increased compliance).
BA-10 molecules diffused over a 4 mm area, which could be beneficial for treating the entire area of a wound. The molecules integrated with the ECM, molecularly engineering the tissue. This is the first time this approach has been demonstrated in skin.
Hydrating molecules could be delivered to skin through injections (including through small gage microneedles (ref) which has been demonstrated in the lab.
Image: https://aswomenage.wordpress.com/
Injection of BA-10 at 50 mg/mL resulted in a 32% reduction of tissue modulus over non-injected control specimens 24 hours after injection. In addition, the BA-10 at 50 mg/mL resulted in a 48% reduction of tissue modulus compared to commercially available hyaluronic acid (Restylane). This exceeded the target of 25% reduction in tissue modulus (increased compliance). In addition, it was demonstrated that BA-10 molecules diffused over a 4 mm area, which could be beneficial for treating the entire area of a wound. The molecules integrated with the ECM, molecularly engineering the tissue. This is the first time this approach has been demonstrated in skin. Because BA-10 can be injected via microneedles to allow for application throughout the wound area, minimally invasive delivery of the molecule over the skin surface is possible. Microneedle application is less painful than standard needle application, which could potentially increase patient compliance. The feasibility of modulating tissue mechanics for the dermis to increase compliance by molecularly engineering the ECM of the tissue was demonstrated. This approach could be used to treat wounds, skin tears, and promote efficient healing, limiting scar formation.
Synthetic biomimetic aggrecan is much cheaper and can be synthesized easily. An injection of natural aggrecan can cost $300 while an injection of BA typically costs $0.06. Two to three cubic centimeters (cc’s) are the typical injection volumes for these types of applications, meaning that an injection of BA-10 at 10 and 50 mg/mL would cost approximately $0.60 and $3.00, respectively, in material.
