SERS and micro-SERS analysis of doxorubicin interaction in vitro and in living human cancer cells

A new technique for selective measurement of small amounts of antitumor drugs in the nucleus and cytoplasm of a living cancer cell, based on surface-enhanced Raman spectroscopy (SERS), is proposed. The ability to detect SERS signals from very diluted (up to 10^-10 N) solutions of doxorubicin (DOX) as well as from its complex with DNA in vitro and in living cells, has been demonstrated. SERS spectra were obtained from a population as well as. from single living erythroleukemia K562 cells treated with DOX. The SERS spectrum obtained from nucleus of living cells correlated well with the spectrum of the in vitro complex of DOX with Calf thymus DNA. The spectrum obtained from cytoplasm is different from the spectrum of free DOX. This means that DOX in the cytoplasm has some kind of target different from its target (DNA) in the cell nucleus.