TY  - JOUR
A1  - Olejko, Lydia
A1  - Cywiński, Piotr J.
A1  - Bald, Ilko
T1  - An ion-controlled four-color fluorescent telomeric switch on DNA origami structures
JF  - Nanoscale
N2  - The folding of single-stranded telomeric DNA into guanine (G) quadruplexes is a conformational change that plays a major role in sensing and drug targeting. The telomeric DNA can be placed on DNA origami nanostructures to make the folding process extremely selective for K+ ions even in the presence of high Na+ concentrations. Here, we demonstrate that the K+-selective G-quadruplex formation is reversible when using a cryptand to remove K+ from the G-quadruplex. We present a full characterization of the reversible switching between single-stranded telomeric DNA and G-quadruplex structures using Förster resonance energy transfer (FRET) between the dyes fluorescein (FAM) and cyanine3 (Cy3). When attached to the DNA origami platform, the G-quadruplex switch can be incorporated into more complex photonic networks, which is demonstrated for a three-color and a four-color FRET cascade from FAM over Cy3 and Cy5 to IRDye700 with G-quadruplex-Cy3 acting as a switchable transmitter.
KW  - resonance energy-transfer
KW  - g-quadruplex
KW  - quantum dots
KW  - strand breakage
KW  - photonic wires
KW  - 3-color fret
KW  - nanostructures
KW  - recognition
KW  - sensitivity
KW  - assemblies
Y1  - 2016
U6  - https://doi.org/10.1039/C6NR00119J
SN  - 2040-3372
SN  - 2040-3364
VL  - 8
SP  - 10339
EP  - 10347
PB  - RSC Publ.
CY  - Cambridge
ER  - 
TY  - GEN
A1  - Meiling, Till Thomas
A1  - Cywiński, Piotr J.
A1  - Bald, Ilko
T1  - White carbon: Fluorescent carbon nanoparticles with tunable quantum yield in a reproducible green synthesis
N2  - In this study, a new reliable, economic, and environmentally-friendly one-step synthesis is established to obtain carbon nanodots (CNDs) with well-defined and reproducible photoluminescence (PL) properties via the microwave-assisted hydrothermal treatment of starch and Tris-acetate-EDTA (TAE) buffer as carbon sources. Three kinds of CNDs are prepared using different sets of above mentioned starting materials. The as-synthesized CNDs: C-CND (starch only), N-CND 1 (starch in TAE) and N-CND 2 (TAE only) exhibit highly homogenous PL and are ready to use without need for further purification. The CNDs are stable over a long period of time (>1 year) either in solution or as freeze-dried powder. Depending on starting material, CNDs with PL quantum yield (PLQY) ranging from less than 1% up to 28% are obtained. The influence of the precursor concentration, reaction time and type of additives on the optical properties (UV-Vis absorption, PL emission spectrum and PLQY) is carefully investigated, providing insight into the chemical processes that occur during CND formation. Remarkably, upon freeze-drying the initially brown CND-solution turns into a non-fluorescent white/slightly brown powder which recovers PL in aqueous solution and can potentially be applied as fluorescent marker in bio-imaging, as a reduction agent or as a photocatalyst.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 264 
KW  - Fluorescence spectroscopy
KW  - Nanoparticles
KW  - Synthesis and processing
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-97087
ER  - 
TY  - JOUR
A1  - Meiling, Till Thomas
A1  - Cywiński, Piotr J.
A1  - Bald, Ilko
T1  - White carbon: Fluorescent carbon nanoparticles with tunable quantum yield in a reproducible green synthesis
JF  - Scientific reports
N2  - In this study, a new reliable, economic, and environmentally-friendly one-step synthesis is established to obtain carbon nanodots (CNDs) with well-defined and reproducible photoluminescence (PL) properties via the microwave-assisted hydrothermal treatment of starch and Tris-acetate-EDTA (TAE) buffer as carbon sources. Three kinds of CNDs are prepared using different sets of above mentioned starting materials. The as-synthesized CNDs: C-CND (starch only), N-CND 1 (starch in TAE) and N-CND 2 (TAE only) exhibit highly homogenous PL and are ready to use without need for further purification. The CNDs are stable over a long period of time (>1 year) either in solution or as freeze-dried powder. Depending on starting material, CNDs with PL quantum yield (PLQY) ranging from less than 1% up to 28% are obtained. The influence of the precursor concentration, reaction time and type of additives on the optical properties (UV-Vis absorption, PL emission spectrum and PLQY) is carefully investigated, providing insight into the chemical processes that occur during CND formation. Remarkably, upon freeze-drying the initially brown CND-solution turns into a non-fluorescent white/slightly brown powder which recovers PL in aqueous solution and can potentially be applied as fluorescent marker in bio-imaging, as a reduction agent or as a photocatalyst.
KW  - Fluorescence spectroscopy
KW  - Nanoparticles
KW  - Synthesis and processing
Y1  - 2016
U6  - https://doi.org/10.1038/srep28557
VL  - 6
PB  - Nature Publishing Group
CY  - London
ER  -