Weldon School of Biomedical Engineering;
Purdue University;
West Lafayette;
IN 47907;
USA;
Department of Biological Sciences;
Purdue University;
West Lafayette;
IN 47907;
USA;
Department of Chemistry;
Purdue University;
West Lafayette;
IN 47907;
USA;
optical microscopy; Raman scattering; vibrational spectroscopy;