Lee So Young, Ha Ji Won
Advanced Nano Bio Imaging and Spectroscopy (ANBIS) Laboratory, Department of Chemistry, University of Ulsan, 93 Daehak-Ro, Nam-Gu, Ulsan 44610, South Korea.
Phys Chem Chem Phys. 2016 Dec 7;18(48):32682-32685. doi: 10.1039/c6cp07280a.
Bimetallic core-shell gold nanorods are promising multifunctional orientation probes due to the synergetic effect of two different metals, as examined under an optical microscope. Herein, we performed a single particle study to characterize the optical properties of palladium-coated core-shell gold nanorods (Pd-AuNRs) using scattering-based dark-field (DF) and differential interference contrast (DIC) microscopy, and to examine their use as multifunctional orientation probes in biological and physical studies. The longitudinal surface plasmon resonance (SPR) was strongly damped with the increased SPR linewidth for single Pd-AuNRs due to Pd metals coated on the AuNR surface under single particle scattering spectroscopy. Despite the strong plasmon damping with much reduced scattering intensity, DIC microscopy allowed us to detect single Pd-AuNRs with much higher sensitivity. We found polarization-dependent DIC images and intensities of single Pd-AuNRs, which enabled the determination of their orientation angle under DIC microscopy. Furthermore, we found that DIC polarization anisotropy can be obtained from the orthogonally polarized bright and dark intensities for more accurate and reliable angle measurements of the Pd-AuNR probes. The results support the idea that bimetallic Pd-AuNRs can be used to develop multifunctional orientation probes.
双金属核壳金纳米棒由于两种不同金属的协同效应，有望成为多功能取向探针，这已在光学显微镜下得到验证。在此，我们进行了单颗粒研究，以利用基于散射的暗场（DF）和微分干涉对比（DIC）显微镜表征钯包覆的核壳金纳米棒（Pd-AuNRs）的光学性质，并研究它们在生物和物理研究中作为多功能取向探针的用途。在单颗粒散射光谱下，由于金纳米棒表面包覆了钯金属，单个Pd-AuNRs的纵向表面等离子体共振（SPR）因SPR线宽增加而受到强烈阻尼。尽管等离子体强烈阻尼且散射强度大幅降低，但DIC显微镜使我们能够以更高的灵敏度检测单个Pd-AuNRs。我们发现了单个Pd-AuNRs的偏振相关DIC图像和强度，这使得在DIC显微镜下能够确定它们的取向角。此外，我们发现可以从正交偏振的亮暗强度获得DIC偏振各向异性，以更准确可靠地测量Pd-AuNR探针的角度。这些结果支持了双金属Pd-AuNRs可用于开发多功能取向探针的观点。
