Date of Award

May 2021

Degree Type


Degree Name

Master of Science



First Advisor

Priyatha Premnath

Committee Members

Mahsa Dabagh, Mohammad H Rahman


Bone biomaterial, Chondrogenesis, Cobalt chloride, Double walled microsphere, Hydroxyapatite, Osteoinductive


The purpose of this study was to fabricate double-walled microspheres loaded with specific drugs to improve bone healing properties. The proposed microsphere design consists of hydroxyapatite-loaded poly(L-lactic acid) (PLLA) as the core layer and cobalt (II) chloride-loaded poly(DL-lactic–co-glycolic) (PLGA) as the shell layer. Cobalt (II) chloride and hydroxyapatite were the chosen drugs because they have previously shown to aid chondrogenesis and osteogenesis, respectively. The morphology, layer identification, and elemental composition of the prepared microspheres were evaluated using a combination of scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), 3D laser microscope, and selective dissolution techniques. With the help of these characterization methods, the shell and core layers identified as PLGA and PLLA, respectively, and the surface appeared porous/smooth for small particles and porous/rough for larger particles (>400um). Lastly the presence of hydroxyapatite and cobalt(II) chloride were identified throughout both the shell and core layers.