Characterizing the Rheological Behavior of Novel Biomimetic Proteoglycans:
Proteoglycans (PGs) found within the body are responsible for encouraging cell growth,organizing the extracellular matrix (ECM) of tissues, influencing collagen fibrillogenesis, and regulating skin tensile strength. These macromolecules are composed of protein cores with attached glycosaminoglycan (GAG) chains. With aging, enzymes responsible for breaking down PGs become more active, reducing the overall concentration of PGs in the body. Therapy designed to increase the concentration of PGs in the body is challenging because natural PGs introduced into the body are still susceptible to enzymatic degradation. Biomimetic proteoglycans (BPGs) can be created using an enzymatically resistant polyacrylic acid (PAA) core with covalently attached natural chondroitin sulfate(CS) bristles that mimic the three dimensional bottlebrush architecture and hydrating properties of natural PGs. In this project, the rheological behavior of aqueous solutions of CS and BPGs was characterized using small amplitude oscillatory shear on a DHR-3 rheometer in order to better understand the flow behavior and molecular structure of BPGs in solution. Experimental variables include the concentration of CS and BPGs (10 mg/mL, 50 mg/mL) dissolved in aqueous solution, ionic strength (0.1X PBS, 1XPBS), and two different PAA sizes (PAA10kDa-CS, PAA250kDa-CS). This study explores how these variables affect the various solutions’ elastic modulus (G’), loss modulus (G”) and viscosity (η). An improved understanding of the underlying molecular structure and flow behavior of BPGs in solution would enable us to better predict how these solutions will behave when introduced into the body.
Proteoglycans (PGs) found within the body are responsible for encouraging cell growth,organizing the extracellular matrix (ECM) of tissues, influencing collagen fibrillogenesis, and regulating skin tensile strength. These macromolecules are composed of protein cores with attached glycosaminoglycan (GAG) chains. With aging, enzymes responsible for breaking down PGs become more active, reducing the overall concentration of PGs in the body. Therapy designed to increase the concentration of PGs in the body is challenging because natural PGs introduced into the body are still susceptible to enzymatic degradation. Biomimetic proteoglycans (BPGs) can be created using an enzymatically resistant polyacrylic acid (PAA) core with covalently attached natural chondroitin sulfate(CS) bristles that mimic the three dimensional bottlebrush architecture and hydrating properties of natural PGs. In this project, the rheological behavior of aqueous solutions of CS and BPGs was characterized using small amplitude oscillatory shear on a DHR-3 rheometer in order to better understand the flow behavior and molecular structure of BPGs in solution. Experimental variables include the concentration of CS and BPGs (10 mg/mL, 50 mg/mL) dissolved in aqueous solution, ionic strength (0.1X PBS, 1XPBS), and two different PAA sizes (PAA10kDa-CS, PAA250kDa-CS). This study explores how these variables affect the various solutions’ elastic modulus (G’), loss modulus (G”) and viscosity (η). An improved understanding of the underlying molecular structure and flow behavior of BPGs in solution would enable us to better predict how these solutions will behave when introduced into the body.