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Effects of hydroxyapatite particle size on PAH-GMA hydrogel. Venkata Damaraju Mentor: Dr. Sidney Sit. What is a hydrogel?. Biocompatible jello-like substance A matrix of polymers Poly(allylamine hydrochloride) (PAH) Glycidyl methacrylate (GMA) Poly (ethylene glycol) diacrylate (PEG-DA).
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Effects of hydroxyapatite particle size on PAH-GMA hydrogel Venkata Damaraju Mentor: Dr. Sidney Sit
What is a hydrogel? • Biocompatible jello-like substance • A matrix of polymers • Poly(allylamine hydrochloride) (PAH) • Glycidyl methacrylate (GMA) • Poly (ethylene glycol) diacrylate (PEG-DA)
Uses of hydrogel • Cell and tissue repair/regeneration • Drug delivery systems • Wound dressing Cornea implants
Problem? • Cells don’t stick to the hydrogel!
Solution? • Add adhesive peptides • Add particles • Particles create pores • Allow cells to filter in and self adhere
Which particles? • Hydroxyapatite • Micro size (~100-300 µm) • Nano size (~100 nm) • Found in bones
My experiment setup Negative control Experimental Group 1 Sonicated for 20 min. Both nano and micro particles Experimental Group 2 Sonicated for 40 min. Both nano and micro particles
Electrochemical Impedance Spectroscopy • Non-destructive way of characterizing the physical properties • Measures the impedance (Resistance) over a frequency range • Constant AC current of 0.1 mA
SEM Imaging Control hydrogel without particles
SEM Images Hydrogel with hydroxyapatite particles
Conclusion • Addition of particles decreased the overall impedance • Lower impedance means more pores • Sonication for 40 min gave better dispersion of particles • SEM shows particles settled in the hydrogel, but as very small fragments
Future work • Perform cell culture on the hydrogel with particles • Add other particles to achieve larger pores
Acknowledgement • Dr. Sidney Sit • Stephanie Tully • Dillip • Praveen • Syeda • Karen Xu • Nicolas McHughes