Abstract

Magnesium (Mg) and its alloys have received increasing interest as a new generation of biodegradable metallic biomaterials. Current metallic orthopedic implants cause stress shielding effects and may require removal surgery as permanent implants. The biocompatibility, biodegradability, close mechanical properties to human cortical bone tissue, osteogenic properties, and angiogenic properties of Mg alloys make them potential candidates for bone repair. However, the low corrosion resistance of Mg alloys that results in hydrogen release and loss of mechanical integrity has restricted their application as orthopedic implants. Also, two critical factors facilitating bone regeneration are angiogenesis which enhances new vessel formation for providing oxygen and nutrients, and osteogenesis, which promotes formation of new bones at the fracture site. In this research, we developed a new biodegradable Mg alloy (Mg-Sc-Sr) using scandium (Sc; 2wt.%) and strontium (Sr; 2wt.%). In the first part of the research, our results showed a 49 % reduction in the corrosion rate of Mg-Sc-Sr compared to Mg. Furthermore, the Mg-Sc-Sr demonstrated a significant decrease in bacterial biofilm formation (62.8%) compared to Mg. Also, a substantial increase in osteoblastic differentiation of hBM-MSCs was shown by Alizarin red staining (1.9-fold increase vs. control) and alkaline phosphatase activity after the addition of Mg-Sc-Sr extract. In this work, the effect of heat treatment at two different temperatures (300°C and 400°C) was evaluated. In the second part of the research, the angiogenesis evaluation of Mg-Sc-Sr alloy on Human umbilical vein endothelial cells (HUVECs) exhibited that adding Mg-Sc-Sr extract significantly enhanced the VEGF release (85%) and significantly reduced scratch width (100%) after 24 h compared to the control group (HUVECs cultured with growth medium). The osteogenic properties of Mg-Sc-Sr were also confirmed using co-culture of hBM-MSCs and HUVECs that showed a significant increase in osteoblastic differentiation in vitro by Von kossa staining and alkaline phosphatase staining.

Notes

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Graduation Date

2022

Semester

Fall

Advisor

Razavi, Mehdi

Degree

Doctor of Philosophy (Ph.D.)

College

College of Engineering and Computer Science

Department

Materials Science and Engineering

Degree Program

Materials Science and Engineering

Identifier

CFE0009819; DP0027760

URL

https://purls.library.ucf.edu/go/DP0027760

Language

English

Release Date

June 2026

Length of Campus-only Access

3 years

Access Status

Doctoral Dissertation (Campus-only Access)

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Restricted to the UCF community until June 2026; it will then be open access.

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