[1] Rice Univ, Dept Chem, Houston, TX 77251 USA
[2] Rice Univ, Dept Biochem & Cell Biol, Houston, TX USA
[3] Rice Univ, Ctr Biol & Environm Nanotechnol, Houston, TX USA
[4] Rice Univ, RE Smalley Inst Nano Scale Sci & Technol, Houston, TX USA
[5] Rice Univ, Inst Biosci & Bioengn, Houston, TX USA
[6] Trinity Univ, San Antonio, TX USA