Single Particle Rotational Tracking Research Articles

Retraction: Single gold nanostars with multiple branches as multispectral orientation probes in single-particle rotational tracking.

Retraction of 'Single gold nanostars with multiple branches as multispectral orientation probes in single-particle rotational tracking' by Geun Wan Kim et al., Chem. Commun., 2021, 57, 3263-3266, https://doi.org/10.1039/D1CC00731A.

Single gold nanostars with multiple branches as multispectral orientation probes in single-particle rotational tracking.

Herein, we performed a single-particle correlation study to characterize the optical properties of gold nanostars (AuNSs) with multiple sharp branches under dark-field (DF) and differential interference contrast (DIC) microscopy, and to examine their use as multispectral orientation probes. We presented the polarization-dependent, periodic DIC images and intensities of single AuNSs at their localized surface plasmon resonance (LSPR) wavelengths with high sensitivity. Furthermore, we demonstrated that single AuNSs protrude multiple branches that can be used as individual sensors with DIC polarization anisotropy. Thus, unlike conventional Au nanorod (AuNR) probes, single AuNSs were presented as multispectral optical sensors that can provide detailed information such as rotational motions and rotational speeds at different branches of their star-like structure in dynamic environments.

Lipid membrane-assisted condensation and assembly of amphiphilic Janus particles.

Amphiphilic Janus particles self-assemble into complex metastructures, but little is known about how their assembly might be modified by weak interactions with a nearby biological membrane surface. Here, we report an integrated experimental and molecular dynamics simulation study to investigate the self-assembly of amphiphilic Janus particles on a lipid membrane. We created an experimental system in which Janus particles are allowed to self-assemble in the same medium where zwitterionic lipids form giant unilamellar vesicles (GUVs). Janus particles spontaneously concentrated on the inner leaflet of the GUVs. They exhibited biased orientation and heterogeneous rotational dynamics as revealed by single particle rotational tracking. The combined experimental and simulation results show that Janus particles concentrate on the lipid membranes due to weak particle-lipid attraction, whereas the biased orientation of particles is driven predominantly by inter-particle interactions. This study demonstrates the potential of using lipid membranes to influence the self-assembly of Janus particles.

Dual-Wavelength Detection of Rotational Diffusion of Single Anisotropic Nanocarriers on Live Cell Membranes

Single-particle rotational tracking is of great importance to monitor orientation changes of biomolecules and to understand their functions and mechanisms in biological systems. Differential interference contrast (DIC) microscopy has been found to be an excellent tool to measure polarization anisotropy for tracking rotational dynamics of gold nanorod (AuNR) probes. DIC polarization anisotropy can be conveniently obtained from the bright and dark intensities of a single DIC image of an AuNR. Here, DIC microscopy-based dual-wavelength detection of rotational motions of AuNRs at both transverse and longitudinal surface plasmon resonance (SPR) wavelengths is demonstrated. The transverse SPR mode was successfully used to track fast rotational dynamics of individual AuNRs on live cell membranes. This is important since the transverse SPR mode is mostly insensitive to the medium refractive index, AuNR aspect ratio, and adsorption of biomolecules. DIC polarization anisotropy was simultaneously obtained from the t...