0000000000075897
AUTHOR
Andreas Neiser
Single Particle Plasmon Sensors as Label-Free Technique To Monitor MinDE Protein Wave Propagation on Membranes.
We use individual gold nanorods as pointlike detectors for the intrinsic dynamics of an oscillating biological system. We chose the pattern forming MinDE protein system from Escherichia coli (E. coli), a prominent example for self-organized chemical oscillations of membrane-associated proteins that are involved in the bacterial cell division process. Similar to surface plasmon resonance (SPR), the gold nanorods report changes in their protein surface coverage without the need for fluorescence labeling, a technique we refer to as NanoSPR. Comparing the dynamics for fluorescence labeled and unlabeled proteins, we find a reduction of the oscillation period by about 20%. The absence of photoble…
Multiplexed plasmon sensor for rapid label-free analyte detection.
Efficient and cost-effective multiplexed detection schemes for proteins in small liquid samples would bring drastic advances to fields like disease detection or water quality monitoring. We present a novel multiplexed sensor with randomly deposited aptamer functionalized gold nanorods. The spectral position of plasmon resonances of individual nanorods, monitored by dark-field spectroscopy, respond specifically to different proteins. We demonstrate nanomolar sensitivity, sensor recycling, and the potential to upscale to hundreds or thousands of targets.
Narrowing the Plasmonic Sensitivity Distribution by Considering the Individual Size of Gold Nanorods
The plasmonic nanoparticle sensitivity, sensing volume, and the signal-to-noise ratio are strongly dependent on the nanoparticle dimensions. It is difficult to chemically produce or purify nanoparticles with a size variation of less than 10%. This size variation induces a systematic error in sensing experiments that can be reduced when the exact size of each individual nanoparticle is known. In this work, we show how the size of gold nanorods can be estimated directly from the optical spectra of single nanoparticles by using the increase of radiation damping with the nanoparticle size. We verify our approach by comparing these spectrally estimated sizes with the precise sizes of exactly the…