Apoptosis, also known as programmed cell death, is a process in which cells initiate a series of events to trigger their
own demise. Normal cells use this mechanism in the regulation of their life cycle. On the contrary, abnormal or cancer
cells have lost the ability to regulate themselves by this process. Because of this, there is much interest in the study of
the apoptotic process. Currently, there are many commercial assays available to detect apoptosis in cells, most of which
are fluorescence based. Limitations of such fluorescent assays lead to arbitrary or inclusive results.
Raman spectroscopy is a powerful technique that yields specific molecular information on samples under study. The
Raman spectra obtained from cell samples are very complex, yet the differences in the complex Raman spectra analyzed
using chemometric techniques can identify chemical and physiological information about cells. Furthermore, Raman
spectroscopy is a sensitive, rapid, reagentless, low-cost technique, making it a superior alternative to traditional
fluorescence based apoptosis assays.
In this study, we have employed Raman spectroscopy and Raman chemical imaging, along with chemometric
techniques, to distinguish apoptotic cells from non-apoptotic cells in two prostate cancer cell lines, PC3 and LnCAP.
Initial results indicate that Raman spectra of apoptotic and non-apoptotic cells are different in both cell lines.
Furthermore, chemometric analysis of the data shows that the spectra separate into two distinct populations, apoptotic
and non-apoptotic. Traditional fluorescence based apoptotic assays confirm the results. This work provides ample
evidence that Raman spectroscopy is a valuable tool in biomedical imaging.