TY  - JOUR
A1  - Liebig, Ferenc
A1  - Sarhan, Radwan Mohamed
A1  - Schmitt, Clemens Nikolaus Zeno
A1  - Thünemann, Andreas F.
A1  - Prietzel, Claudia Christina
A1  - Bargheer, Matias
A1  - Koetz, Joachim
T1  - Gold nanotriangles with crumble topping and their influence on catalysis and surface-enhanced raman spectroscopy
JF  - ChemPlusChem
N2  - By adding hyaluronic acid (HA) to dioctyl sodium sulfosuccinate (AOT)-stabilized gold nanotriangles (AuNTs) with an average thickness of 7.5 +/- 1 nm and an edge length of about 175 +/- 17 nm, the AOT bilayer is replaced by a polymeric HA-layer leading to biocompatible nanoplatelets. The subsequent reduction process of tetrachloroauric acid in the HA-shell surrounding the AuNTs leads to the formation of spherical gold nanoparticles on the platelet surface. With increasing tetrachloroauric acid concentration, the decoration with gold nanoparticles can be tuned. SAXS measurements reveal an increase of the platelet thickness up to around 14.5 nm, twice the initial value of bare AuNTs. HRTEM micrographs show welding phenomena between densely packed particles on the platelet surface, leading to a crumble formation while preserving the original crystal structure. Crumbles crystallized on top of the platelets enhance the Raman signal by a factor of around 20, and intensify the plasmon-driven dimerization of 4-nitrothiophenol (4-NTP) to 4,4 '-dimercaptoazobenzene in a yield of up to 50 %. The resulting crumbled nanotriangles, with a biopolymer shell and the absorption maximum in the second window for in vivo imaging, are promising candidates for biomedical sensing.
KW  - gold nanostructures
KW  - HRTEM
KW  - hyaluronic acid
KW  - monolayer formation
KW  - SERS
Y1  - 2020
U6  - https://doi.org/10.1002/cplu.201900745
SN  - 2192-6506
VL  - 85
IS  - 3
SP  - 519
EP  - 526
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Henning, Ricky
A1  - Liebig, Ferenc
A1  - Prietzel, Claudia Christina
A1  - Klemke, Bastian
A1  - Koetz, Joachim
T1  - Gold nanotriangles with magnetite satellites
JF  - Colloids and surfaces : an international journal devoted to the principles and applications of colloid and interface science ; A, Physicochemical and engineering aspects
N2  - This work describes the synthesis of hybrid particles of gold nanotriangles (AuNTs) with magnetite nanoparticles (MNPs) by using 1-mercaptopropyl-3-trimethoxysilan (MPTMS) and L-cysteine as linker molecules. Due to the combination of superparamagnetic properties of MNPs with optical properties of the AuNTs, nanoplatelet-satellite hybrid nanostructures with combined features become available. By using MPTMS with silan groups as linker molecule a magnetic "cloud" with embedded AuNTs can be separated. In presence of L-cysteine as linker molecule at pH > pH(iso) a more unordered aggregate structure of MNPs is obtained due to the dimerization of the L-cysteine. At pH < pH(iso) water soluble positively charged AuNTs with satellite MNPs can be synthesized. The time-dependent loading with MNP satellites under release of the extinction and magnetization offer a hybrid material, which is of special relevance for biomedical applications and plasmonic catalysis.
KW  - nanotriangles
KW  - Superparamagnetic magnetite
KW  - Satellite hybrid
KW  - nanostructures
KW  - L-Cysteine
KW  - UV-Vis-NIR
KW  - HRTEM
Y1  - 2020
U6  - https://doi.org/10.1016/j.colsurfa.2020.124913
SN  - 0927-7757
SN  - 1873-4359
VL  - 600
PB  - Elsevier
CY  - Amsterdam
ER  -