1. Engineering Science and Mechanics Department, Penn State University, University Park, PA 16802, USA.
2. The Huck Institutes of the Life Sciences, Penn State University, University Park, PA 16802, USA.
3. Department of Dental Materials, School of Dentistry, Kyung Hee University, Seoul 02447, Republic of Korea.
4. Department of Chemistry, Penn State University, University Park, PA 16802, USA.
5. Biomedical Engineering Department, Penn State University, University Park, PA 16802, USA.
6. Materials Research Institute, Penn State University, University Park, PA 16802, USA.