In Vitro/In Vivo Electrochemical Detection of Pt(II) Species.

The biodistribution of chemotherapy compounds within tumor tissue is one of the main challenges in the development of antineoplastic drugs, and novel techniques for simple, non-expensive, sensitive, and selective detection of various analytes in tumors are of great importance. In this paper we propose the use of platinized carbon nanoelectrodes (PtNE) for electrochemical detection of platinum-based drugs in various biological models, including single cells and tumor spheroids in vitro, and inside solid tumors in vivo. We have demonstrated quantitative direct detection of Pt(II) in breast adenocarcinoma MCF-7 cells treated with cisplatin and cisplatin-based DNP prodrug. To realize the potential of this technique in advanced tumor models, we measured Pt(II) in 3D tumor spheroids in vitro and tumor-bearing mice in vivo. The concentration gradient of Pt (II) species correlated with the distance from the sample surface in MCF-7 tumor spheroids. We then performed detection of Pt(II) species in tumor-bearing mice treated intravenously with cisplatin and DNP. We found that there was deeper penetration of DNP in comparison to cisplatin. This research demonstrates a novel minimally invasive, real-time electrochemical technique for the study of platinum-based drugs.