High-throughput in-focus differential interference contrast imaging of three-dimensional orientations of single gold nanorods coated with a mesoporous silica shell

Kim, Geun Wan; Yoon, Seokyoung; Lee, Jung Heon; Ha, Ji Won

doi:10.1039/d0ra04704j

Cited by 4 publications

(8 citation statements)

References 21 publications

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“…Interestingly, Yoon et al reported the synthesis of discrete and uniformly silica-coated AuNRs with a finely tuned shell thickness by significantly suppressing the formation of undesired core-free NPs. [68][69][70] Based on the modified Lamer Theory, they adjusted the amount of silica precursor to suppress homogeneous nucleation and injected silica precursor to induce only heterogeneous nucleation. The authors were able to control the thickness of the silica shell with a high degree of precision, close to 1 nm; therefore, the rotational diffusion mode of NPs could be observed by simply controlling the silica precursor injection times (Figure 10a-c).…”

Section: Engineering Thickness Porosity and Anisotropy Of Silica Capp...mentioning

confidence: 99%

Structurally Engineered Silica Shells on Gold Nanorods for Biomedical Applications

et al. 2023

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Owing to their unique optical and chemical properties, gold nanorods (AuNRs) are among the most frequently used nanomaterials for biomedical applications, including cancer therapy, imaging, and drug delivery. In particular, the longitudinal dipole plasmon wavelength of AuNRs can be verified from the visible to the near‐infrared (NIR) region, allowing AuNRs to be used as photodynamic/photothermal and imaging contrast agents. At the same time, the silica shell is important as it enhances stability and facilitates the functionalization and biocompatibility of AuNRs, offering numerous advantages in biomedical applications. In this review, silica‐coated AuNRs from a bioapplication perspective are focused. First, the importance of AuNRs for biomedical applications is explained and the purpose of silica coating on AuNRs is discussed. Then, recent studies on the development of silica‐coated AuNRs from a biomedical perspective are reviewed. Subsequently, various strategies for engineering silica coatings and their properties in the biomedical field are reviewed. This review is expected to promote further research on next‐generation silica‐coated AuNRs for biomedical applications.

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Section: Engineering Thickness Porosity and Anisotropy Of Silica Capp...mentioning

confidence: 99%

Structurally Engineered Silica Shells on Gold Nanorods for Biomedical Applications

et al. 2023

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“…Second, when drop-casting is used for sample preparation, AuNRs lacking the shell align parallel to a glass slide, resulting in tilting angles nearly identical to those of the glass slide (see Figure S1). On the contrary, when spherical AuNRs@ m SiO 2 are placed onto a slide, the AuNRs within the silica shell exhibit random 3D orientations within the identical focal plane (Figure A). , Therefore, high-throughput characterization of image patterns as well as optical properties for individual AuNRs having random 3D orientations within the identical focal plane can be accomplished, overcoming the drawbacks of the conventional gel matrix technique involving the scanning of embedded AuNRs in a vertical direction (Figures S2 and S3). , …”

Section: Resultsmentioning

confidence: 99%

“…Next, we examined the three fixed AuNRs@ m SiO 2 (Figure ) under DIC microscopy, specifically at 700 nm near their LSPR wavelength (Figure S12). High-throughput DIC orientation imaging of individual AuNRs within the spherical shell in the same focal plane was achieved (Figure S13), , and DIC signals from the AuNRs within the silica shell were used for investigating their characteristic optical properties. , To explore the dependence on wavelength and polarization, a rotational analysis of AuNR1@ m SiO 2 was conducted by incrementally rotating a stage in 10° steps from 0 to 360° at the LSPR wavelength. Figure A illustrates the definition of the polar angle θ and azimuthal angle φ of the AuNR in DIC microscopy.…”

Section: Resultsmentioning

confidence: 99%

“…On the contrary, when spherical AuNRs@mSiO 2 are placed onto a slide, the AuNRs within the silica shell exhibit random 3D orientations within the identical focal plane (Figure 1A). 30,31 Therefore, highthroughput characterization of image patterns as well as optical properties for individual AuNRs having random 3D orientations within the identical focal plane can be accomplished, overcoming the drawbacks of the conventional gel matrix technique involving the scanning of embedded AuNRs in a vertical direction (Figures S2 and S3). 30,31 In the present study, we employed large AuNR cores (39 nm × 123 nm, aspect ratio (AR) = 3) covered by a mesoporous spherical silica shell to obtain their 3D orientation-dependent image patterns under DF and DIC microscopy and to better understand the scattering contributions to the final DIC image patterns.…”

Section: Synthesis and Characterization Of Spherical Aunrs@msiomentioning

confidence: 99%

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Direct Observation of In-Focus Plasmonic Cargos via Breaking Angular Degeneracy in Differential Interference Contrast Microscopy

Kim,

2023

JACS Au

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Breaking the angular degeneracy arising from the 2-fold optical symmetry of plasmonic anisotropic nanoprobes is critical in biological studies. In this study, we propose differential interference contrast (DIC) microscopy-based focused orientation and position imaging (dFOPI) to break the angular degeneracy of single gold nanorods (AuNRs). Single in-focus AuNRs (39 nm × 123 nm) within a spherical mesoporous silica shell were characterized with high throughput and produced distinct doughnut-shaped DIC image patterns featuring two lobes in the peripheral region, attributed to the scattering contribution of the AuNRs with large scattering cross sections. Interestingly, rotation of the lobes was observed in the focal plane for a large AuNR (>100 nm) tilted by more than ∼20° from the horizontal plane as the rotational stage was moved by 10° in a rotational study. From the rotation-dependent characteristic patterns, we directly visualized counterclockwise/clockwise rotations without the angular degeneracy at the localized surface plasmon resonance wavelength. Therefore, our dFOPI method can be applied for in vivo studies of important biological systems. To validate this claim, we tracked the three-dimensional rotational behavior of transferrin-modified in-focus AuNRs during clathrin-mediated endocytosis in real time without sacrificing the temporal and spatial resolution. In the invagination and scission stage, one or two directed twist motions of the AuNR cargos detached the AuNR-containing vesicles from the cell membrane. Furthermore, the dFOPI method directly visualized and revealed the right-handed twisting action along the dynamin helix in dynamin-catalyzed fission in live cells.

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“…Because the optical properties of gold nanoparticles are significantly affected by the morphological properties of individual nanoparticles, including their size and shape, − the statistical distribution of the entire population of nanoparticles is expected to significantly affect their optical properties. For this experiment, we prepared five sets of gold nanorods with different aspect ratios (ARs), and according to their localized surface plasmon resonance (LSPR) peak wavelengths at 880, 843, 759, 714, and 648 nm, we labeled these sets as E1, E2, E3, E4, and E5, respectively (Figure a,b).…”

Section: Resultsmentioning

confidence: 99%

Statistical Characterization of the Morphologies of Nanoparticles through Machine Learning Based Electron Microscopy Image Analysis

et al. 2020

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Although transmission electron microscopy (TEM) may be one of the most efficient techniques available for studying the morphological characteristics of nanoparticles, analyzing them quantitatively in a statistical manner is exceedingly difficult. Herein, we report a method for mass-throughput analysis of the morphologies of nanoparticles by applying a genetic algorithm to an image analysis technique. The proposed method enables the analysis of over 150,000 nanoparticles with a high precision of 99.75% and a low false discovery rate of 0.25%. Furthermore, we clustered nanoparticles with similar morphological shapes into several groups for diverse statistical analyses. We determined that at least 1,500 nanoparticles are necessary to represent the total population of nanoparticles at a 95% credible interval. In addition, the number of TEM measurements and the average number of nanoparticles in each TEM image should be considered to ensure a satisfactory representation of nanoparticles using TEM images. Moreover, the statistical distribution of polydisperse nanoparticles plays a key role in accurately estimating their optical properties. We expect this method to become a powerful tool and aid in expanding nanoparticle-related research into the statistical domain for use in big data analysis.

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High-throughput in-focus differential interference contrast imaging of three-dimensional orientations of single gold nanorods coated with a mesoporous silica shell

Abstract: Spherical AuNRs@mSiO2 have randomly oriented AuNR cores in 3D space, which could be resolved on the same focal plane by interference-based DIC microscopy.

Cited by 4 publications

References 21 publications

Structurally Engineered Silica Shells on Gold Nanorods for Biomedical Applications

Structurally Engineered Silica Shells on Gold Nanorods for Biomedical Applications

Direct Observation of In-Focus Plasmonic Cargos via Breaking Angular Degeneracy in Differential Interference Contrast Microscopy

Statistical Characterization of the Morphologies of Nanoparticles through Machine Learning Based Electron Microscopy Image Analysis

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