Raman and SERS recognition of Beta-Carotene and Haemoglobin fingerprints in Human Whole Blood

The present work reports on Raman and Surface Enhanced Raman Scattering (SERS) vibrational fingerprints of beta-carotene and haemoglobin in fresh whole blood (i.e. right after blood test) with different laser excitations, i.e. visible (514 nm) and near-infrared (NIR, 785 nm). The use of colloidal silver nanoparticles significantly increases the Raman signal, thus providing a clear SERS spectrum of blood. The collected spectra have been examined and marker bands of beta-carotene and of the haem prosthetic group of haemoglobin have been found. In particular, the fundamental features of beta-carotene (excited with 514 nm laser line), blood proteins and haem molecules (excited with 785 nm laser line) were recognized and assigned. Moreover haemoglobin SERS signals can be identified and related with its oxygenation state (oxy- haemoglobin). The data reported show the prospects of Raman and SERS techniques to detect important bio-molecules in a whole blood sample with no pre-treatment.