1. Department of Materials Science and Engineering, Ohio State University, 446 MacQuigg Laboratory, 105 W Woodruff Avenue, Columbus, OH 43210, USA
2. Department of Orthopaedics and Rehabilitation, University of Iowa, University of Iowa Hospitals and Clinics, 200 Hawkins Drive, 01008 JPP, Iowa City, IA 52242, USA
3. Department of Biomedical Engineering, University of Iowa, 1402 Seamans Center, Iowa City, IA 52242, USA