Clinical Spectroscopic Diagnostics

For Raman spectroscopic analyses of the cells and other biological samples, the choice of the right substrate material is very im-portant to avoid loss of information in characteristic spectral features because of competing background signals. In the currentstudy, Raman spectroscopy is used to characterize several potential Raman substrates. Raman vibrational bands of the substratematerial are discussed. The surface topography is analyzed by atomic force microscopy, and the root mean square surface rough-ness values are reported. Biocompatibility of the substrates is tested with Hep G2 cells evaluating cellular morphology as well aslive/dead staining. Calcium fluoride, silicon, fused silica, borofloat glass, and silicon nitride membranes support cell growth andadherence. Silicon, borofloat glass, and fused silica give rise to Raman signals in the region of interest. Calcium fluoride substrate(UV grade) is suitable for Raman spectroscopic investigation of living cells. Nickel foil is suitable substrate for Raman spectroscopicinvestigation but cellular adherence and viability depend on the quality of the foil. Silicon nitride membranes coated with nickelchrome is a suitable Raman substrate in closed microfluidic systems.