[1] Johns Hopkins Sch Med, Dept Biomed Engn, Baltimore, MD 21205 USA
[2] Johns Hopkins Univ, Inst NanoBioTechnol, Baltimore, MD 21218 USA
[3] Johns Hopkins Sch Med, Inst Cell Engn, Baltimore, MD 21205 USA
[4] Johns Hopkins Sch Med, Translat Tissue Engn Ctr, Baltimore, MD 21287 USA
[5] Johns Hopkins Univ, Dept Mat Sci & Engn, Baltimore, MD 21218 USA
[6] Johns Hopkins Univ, Whitaker Biomed Engn Inst, Baltimore, MD 21218 USA