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

Abstract

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.