TY  - JOUR
A1  - Dai, Xiaolin
A1  - Mate, Diana M.
A1  - Glebe, Ulrich
A1  - Garakani, Tayebeh Mirzaei
A1  - Körner, Andrea
A1  - Schwaneberg, Ulrich
A1  - Böker, Alexander
T1  - Sortase-mediated ligation of purely artificial building blocks
JF  - Polymers
N2  - Sortase A (SrtA) from Staphylococcus aureus has been often used for ligating a protein with other natural or synthetic compounds in recent years. Here we show that SrtA-mediated ligation (SML) is universally applicable for the linkage of two purely artificial building blocks. Silica nanoparticles (NPs), poly(ethylene glycol) and poly(N-isopropyl acrylamide) are chosen as synthetic building blocks. As a proof of concept, NP-polymer, NP-NP, and polymer-polymer structures are formed by SrtA catalysis. Therefore, the building blocks are equipped with the recognition sequence needed for SrtA reaction-the conserved peptide LPETG-and a pentaglycine motif. The successful formation of the reaction products is shown by means of transmission electron microscopy (TEM), matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-ToF MS), and dynamic light scattering (DLS). The sortase catalyzed linkage of artificial building blocks sets the stage for the development of a new approach to link synthetic structures in cases where their synthesis by established chemical methods is complicated.
KW  - sortase-mediated ligation
KW  - enzymes
KW  - block copolymers
KW  - nanoparticles
Y1  - 2018
U6  - https://doi.org/10.3390/polym10020151
SN  - 2073-4360
VL  - 10
IS  - 2
PB  - MDPI
CY  - Basel
ER  - 
TY  - JOUR
A1  - Holland-Moritz, Henry
A1  - Graupner, Julia
A1  - Möller, Wolfhard
A1  - Pacholski, Claudia
A1  - Ronning, Carsten
T1  - Dynamics of nanoparticle morphology under low energy ion irradiation
JF  - Nanotechnology
N2  - If nanostructures are irradiated with energetic ions, the mechanism of sputtering becomes important when the ion range matches about the size of the nanoparticle. Gold nanoparticles with diameters of similar to 50 nm on top of silicon substrates with a native oxide layer were irradiated by gallium ions with energies ranging from 1 to 30 keV in a focused ion beam system. High resolution in situ scanning electron microscopy imaging permits detailed insights in the dynamics of the morphology change and sputter yield. Compared to bulk-like structures or thin films, a pronounced shaping and enhanced sputtering in the nanostructures occurs, which enables a specific shaping of these structures using ion beams. This effect depends on the ratio of nanoparticle size and ion energy. In the investigated energy regime, the sputter yield increases at increasing ion energy and shows a distinct dependence on the nanoparticle size. The experimental findings are directly compared to Monte Carlo simulations obtained from iradina and TRI3DYN, where the latter takes into account dynamic morphological and compositional changes of the target.
KW  - ion beam
KW  - nanoparticles
KW  - sputtering
KW  - Monte Carlo
KW  - in situ
Y1  - 2018
U6  - https://doi.org/10.1088/1361-6528/aac36c
SN  - 0957-4484
SN  - 1361-6528
VL  - 29
IS  - 31
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  -