TY  - JOUR
A1  - Schürmann, Robin Mathis
A1  - Vogel, Stefanie
A1  - Ebel, Kenny
A1  - Bald, Ilko
T1  - The physico-chemical basis of DNA radiosensitization
BT  - implications for cancer radiation therapy
JF  - Chemistry - a European journal
N2  - High-energy radiation is used in combination with radiosensitizing therapeutics to treat cancer. The most common radiosensitizers are halogenated nucleosides and cisplatin derivatives, and recently also metal nanoparticles have been suggested as potential radiosensitizing agents. The radiosensitizing action of these compounds can at least partly be ascribed to an enhanced reactivity towards secondary low-energy electrons generated along the radiation track of the high-energy primary radiation, or to an additional emission of secondary reactive electrons close to the tumor tissue. This is referred to as physico-chemical radiosensitization. In this Concept article we present current experimental methods used to study fundamental processes of physico-chemical radiosensitization and discuss the most relevant classes of radiosensitizers. Open questions in the current discussions are identified and future directions outlined, which can lead to optimized treatment protocols or even novel therapeutic concepts.
KW  - cancer
KW  - dissociative electron attachment
KW  - low-energy electrons
KW  - radiation therapy
KW  - radiosensitizers
Y1  - 2018
U6  - https://doi.org/10.1002/chem.201800804
SN  - 0947-6539
SN  - 1521-3765
VL  - 24
IS  - 41
SP  - 10271
EP  - 10279
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Meiling, Till Thomas
A1  - Schürmann, Robin Mathis
A1  - Vogel, Stefanie
A1  - Ebel, Kenny
A1  - Nicolas, Christophe
A1  - Milosavljevic, Aleksandar R.
A1  - Bald, Ilko
T1  - Photophysics and Chemistry of Nitrogen-Doped Carbon Nanodots with High Photoluminescence Quantum Yield
JF  - The journal of physical chemistry : C, Nanomaterials and interfaces
N2  - Fluorescent carbon nanodots (CNDs) are very promising nanomaterials for a broad range of applications because of their high photostability, presumed selective luminescence, and low cost at which they can be produced. In this respect, CNDs are superior to well-established semiconductor quantum dots and organic dyes. However, reported synthesis protocols for CNDs typically lead to low photoluminescence quantum yield (PLQY) and low reproducibility, resulting in a poor understanding of the CND chemistry and photophysics. Here, we report a one-step synthesis of nitrogen-doped carbon nanodots (N-CNDs) from various carboxylic acids, Tris, and ethylenediaminetetraacetic acid resulting in high PLQY of up to 90%. The reaction conditions in terms of starting materials, temperature, and reaction time are carefully optimized and their influence on the photophysical properties is characterized. We find that citric acid-derived N-CNDs can result in a very high PLQY of 90%, but they do not show selective luminescence. By contrast, acetic acid-derived N-CNDs show selective luminescence but a PLQY of 50%. The chemical composition of the surface and core of these two selected N-CND types is characterized among others by high-resolution synchrotron X-ray photoelectron spectroscopy using single isolated N-CND clusters. The results indicate that photoexcitation occurs in the N-CND core, whereas the emission properties are determined by the N-CND surface groups.
Y1  - 2018
U6  - https://doi.org/10.1021/acs.jpcc.8b00748
SN  - 1932-7447
VL  - 122
IS  - 18
SP  - 10217
EP  - 10230
PB  - American Chemical Society
CY  - Washington
ER  -