[Raman micro-spectroscopy of single blood platelets]

The authors collected the Raman spectra of single blood platelets of human, pig, rat and rabbit suspended in saline so-lution by using a laser tweezers Raman spectroscopy (LTRS) setup. A single platelet cell was trapped in the focus of a near-infrared laser beam at 785 nm and the excited Raman spectrum was acquired. For each species, the Raman spectra of up to 20 platelet cells were acquired and were used to perform a principal components analysis (PCA) or a discriminate function analysis (DFA). The average Raman spectra indicate that the vibration bands at 1 524 and 1 157 cm(-1) of human platelets are obviously different from those of the platelets from pig, rat and rabbit. The Raman intensities at 1 157 and 1 524 cm(-1) bands are significantly high for human platelets. The ratio I1 157 / I1 003 of human platelets was 0.795, but those of pig, rat and rabbit were 0.532, 0.502 and 0.485, respectively. In addition, the platelets from four different species can be discriminated with multivariate analysis. These findings demonstrate that the LTRS, combined with multivariate analysis, could be used to rapidly discriminate platelets from various species and may find valuable application in rapid sensing of biochemical changes in a single cell.