Event Abstract Back to Event The effect of biomimetic proteoglycans on collagen self-assembly Tao Yang1, Kate Wofford2, Parmpuneet Kaur2, Carli Moorehead1, Joseph Sincavage2, Katsiaryna Prudnikova1, Adrian C. Shieh2 and Michele Marcolongo1 1 Drexel University, Department of Material Science and Engineer, United States 2 Drexel University, School of Biomedical Engineering, Science & Health Systems, United States Introduction: Collagen is one of the leading components in extracellular matrix (ECM), providing durability, structural integrity, and functionality for many tissues. Excessive collagen degradation has been associated with a number of disorders, such as arthritis, atherosclerotic heart disease, and tumor metastasis[1]. Materials capable of preserving tissue function and preventing tissue degradation have attracted attentions intensively. Recently, we developed a novel, biocompatible, semi-synthetic proteoglycan Biomimetic Aggrecan (BA) with a high (BA250) and low (BA10) molecular weight. BA250 and BA10 consist of an enzymatically resistant synthetic polymer core (poly(acrylic acid)) and natural chondroitin sulfate bristles arranged in a three-dimensional bottle-brush configuration similar to the natural proteoglycan aggrecan[2]. We examined the impact of BA on collagen gelation kinetics and quantified the fibril characteristics during collagen self-assembly. Materials and Methods: Soluble type 1 rat-tail was neutralized with 1N NaOH and mixed with appropriate amounts of BA and 1xPBS for a final concentration of 2.0 mg/mL. Collagen gels were kept at 4°C for 30 minutes, followed up by incubation at 37°C for 2 hours. All gels were imaged on an Olympus FV1000-laser scanning confocal with a 60x oil-emersion objective at 488nm. Fibrils were traced in each image manually using ImageJ. After tracing, the data of fibril length was binned in 10μm increments to determine length distributions in each gel type. Average number of fibrils was obtained by summing fibrils tracings within each treatment. For fibrillogenesis study, after neutralization for 30 minutes, collagen solutions were transferred into a 96 well plate and incubated in the Tecan spectrometer (Infinite M200) at 37°C for 1 hour. The absorbance was measured at a wavelength of 313 nm every minute during incubation (n=5). Results and Discussion: Confocal images (Fig.1A) showed significant variance with the addition of BA. Turbidity measurement during gel incubation revealed a prolonged period of gelation with addition of BA10 or BA250 indicating that addition of BA can affect fibriollegensis (Fig.1B).Compared to collagen-only gels, BA10-gels slightly differed in length distribution while BA250-gels showed a trend towards forming longer fibrils as BA250 concentration increased (Fig.1C). Average number of fibrils was larger in BA-gels with lower concentrations (0.01mg/ml and 0.05mg/mL) than those with the highest concentration (0.1mg/mL), indicating lower concentrations of BA create more fibrils while higher concentrations of BA create longer fibrils. Conclusion: A three-dimensional collagen scaffold was fabricated and collagen fibril organization was modulated by two aggrecan mimics developed in our lab, indicating that collagen self-assembly could be structurally altered by incorporation of a biomimetic proteoglycan, such as BA. Therefore, biomimetic proteoglycan is a promising material that could be used to tune collagen scaffold characteristics for tissue engineering applications. Coulter Foundation