TY  - JOUR
A1  - Heck, Christian
A1  - Kanehira, Yuya
A1  - Kneipp, Janina
A1  - Bald, Ilko
T1  - Placement of Single Proteins within the SERS Hot Spots of Self-Assembled Silver Nanolenses
JF  - Angewandte Chemie : a journal of the Gesellschaft Deutscher Chemiker ; International edition
N2  - This study demonstrates the bottom-up synthesis of silver nanolenses. A robust coating protocol enabled the functionalization of differently sized silver nanoparticles with DNA single strands of orthogonal sequence. Coated particles 10nm, 20nm, and 60nm in diameter were self-assembled by DNA origami scaffolds to form silver nanolenses. Single molecules of the protein streptavidin were selectively placed in the gap of highest electric field enhancement. Streptavidin labelled with alkyne groups served as model analyte in surface-enhanced Raman scattering (SERS) experiments. By correlated Raman mapping and atomic force microscopy, SERS signals of the alkyne labels of a single streptavidin molecule, from a single silver nanolens, were detected. The discrete, self-similar aggregates of solid silver nanoparticles are promising for plasmonic applications.
KW  - DNA origami
KW  - protein analysis
KW  - SERS
KW  - silver nanoparticles
KW  - streptavidin
Y1  - 2018
U6  - https://doi.org/10.1002/anie.201801748
SN  - 1433-7851
SN  - 1521-3773
VL  - 57
IS  - 25
SP  - 7444
EP  - 7447
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Heck, Christian
A1  - Kanehira, Yuya
A1  - Kneipp, Janina
A1  - Bald, Ilko
T1  - Amorphous Carbon Generation as a Photocatalytic Reaction on DNA-Assembled Gold and Silver Nanostructures
JF  - Molecules
N2  - Background signals from in situ-formed amorphous carbon, despite not being fully understood, are known to be a common issue in few-molecule surface-enhanced Raman scattering (SERS). Here, discrete gold and silver nanoparticle aggregates assembled by DNA origami were used to study the conditions for the formation of amorphous carbon during SERS measurements. Gold and silver dimers were exposed to laser light of varied power densities and wavelengths. Amorphous carbon prevalently formed on silver aggregates and at high power densities. Time-resolved measurements enabled us to follow the formation of amorphous carbon. Silver nanolenses consisting of three differently-sized silver nanoparticles were used to follow the generation of amorphous carbon at the single-nanostructure level. This allowed observation of the many sharp peaks that constitute the broad amorphous carbon signal found in ensemble measurements. In conclusion, we highlight strategies to prevent amorphous carbon formation, especially for DNA-assembled SERS substrates.
KW  - amorphous carbon
KW  - DNA origami
KW  - SERS
KW  - nanoparticle dimers
KW  - nanolenses
Y1  - 2019
U6  - https://doi.org/10.3390/molecules24122324
SN  - 1420-3049
VL  - 24
IS  - 12
PB  - MDPI
CY  - Basel
ER  -