Fluorescence detection of the anticancer drug topotecan in plasma and whole blood by two-photon excitation

Thomas G. Burke, Henryk Malak, Ignacy Gryczynski, Zihou Mi, Joseph R. Lakowicz

Research output: Contribution to journalArticle

31 Scopus citations

Abstract

The anticancer drug topotecan was detected in human plasma and whole blood using two-photon excitation at 730 or 820 nm. These wavelengths are longer than the main absorption bands of hemoglobin. Two-photon excitation of topotecan was demonstrated by a quadratic dependence of the emission intensity on the incident power, compared to a linear dependence for one- photon excitation at 410 nm. The observed emission centered at 525 nm was shown to be topotecan from the similarity of the emission spectrum and decay times observed for one-photon and two-photon excitation. Topotecan was detected at concentrations as low as 0.05 and 1 μM in plasma and whole blood, respectively. Since skin blood and tissues are translucent at long wavelengths, these results suggest the possibility of homogeneous or noninvasive clinical sensing with two-photon excitation.

Original languageEnglish
Pages (from-to)266-270
Number of pages5
JournalAnalytical Biochemistry
Volume242
Issue number2
DOIs
StatePublished - 15 Nov 1996

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