Abstract
Mesoporous silica shell-coated gold nanorods (AuNRs@mSiO2) can be employed as promising multifunctional orientation probes in biological studies owing to their anisotropic optical properties, enhanced stability, excellent biocompatibility, etc. In this study, the optical properties of single AuNRs@mSiO2 are characterized under dark-field and differential interference contrast (DIC) microscopy. Furthermore, we presented polarization-dependent, periodic DIC images and intensities of single AuNRs@mSiO2 at their localized surface plasmon resonance wavelength and investigated their use as multifunctional orientation probes in dynamic biological environments. Moreover, the real-time rotational motions of the AuNRs@mSiO2 on the HeLa cell membranes were tracked with millisecond temporal resolution. Overall, AuNRs@mSiO2 demonstrated their capacity to act as multifunctional optical probes owing to the combined effect of the Au core, which can serve as an orientation probe and a local heat generator for phototherapy, and the mesoporous silica shell, which can be used as a reservoir of chemotherapeutics owing to its excellent loading capacity.