David Lasne | Searcharxiv

arXiv2007

Photothermal Heterodyne Imaging of Individual Metallic Nanoparticles: Theory versus Experiments

We present the theoretical and detailed experimental characterizations of Photothermal Heterodyne Imaging. An analytical expression of the photothermal heterodyne signal is derived using the theory of light scattering from a fluctuating medium. The amplitudes of the signals detected in the backward and forward configurations are compared and their frequency dependences are studied. The application of the Photothermal Heterodyne detection technique to the absorption spectroscopy of individual gold nanoparticles is discussed and the detection of small individual silver nanoparticles is demonstrated.

physics.optics↗

arXiv2007

Single NanoParticle Photothermal Tracking (SNaPT) of 5 nm gold beads in live cells

Tracking individual nano-objets in live cells during arbitrary long times is an ubiquitous need in modern biology. We present here a method for tracking individual 5 nm gold nanoparticles on live cells. It relies on the photothermal effect and the detection of the Laser Induced Scattering around a NanoAbsorber (LISNA). The key point for recording trajectories at video rate is the use of a triangulation procedure. The effectiveness of the method is tested against Single fluorescent Molecule Tracking in live COS7 cells on subsecond time scales. We further demonstrate recordings for several minutes of AMPA receptors trajectories on the plasma membrane of live neurons. SNaPT has the unique potential to record arbitrary long trajectory of membrane proteins using non-fluorescent nanometer sized labels.

physics.bio-ph↗