Figure 1.
Transmission electron microscopy (TEM) of negatively stained low-density lipoprotein conjugated to gold nanoparticles (LDL gold nanoparticles).
(A) LDL gold nanoparticles of 14 nm diameter (of the gold nanoparticle). (B) A gold nanoparticle (white arrow) is surrounded by low-density lipoproteins (black arrow). (C) 5 nm-diameter nanoparticle.
Figure 2.
Scanning TEM (STEM) images recorded of whole-mount macrophage cells.
(A) Nucleus and surrounding cellular materials. Clusters of LDL gold nanoparticles are visible as bright spots. The magnification was 5,000×. (B) Nucleus and section of cell containing many gold nanoparticles. (C) Image from a tilt-series showing gold nanoparticles of different sizes, recorded as a magnification of 115,000×. The location of this image is shown as square with * in A.
Figure 3.
STEM tomography of nanoparticle clusters with LDL gold nanoparticles.
(A) Selected region of a horizontal (xy) slice of a tomogram depicting a LDL gold nanoparticles cluster. The tilt series was recorded with a tilt range of 76° and 4° increments. The magnification was 115,000×. The pixel size was 0.67 nm. (B) Side view (xz) projection of the tomogram along the white dashed line in A. The arrow points towards the same nanoparticle depicted in A. (C) Side view (yz) projection of the tomogram along the black dashed line in A. (D) Intensity profile in xy direction of the nanoparticle depicted in (A). Intensity is plotted along the white dashed line in A. (E) Intensity profile in xz direction of the nanoparticle depicted in A. The intensity is plotted along the white dashed line in B.
Figure 4.
Generating a 3D model of a nanoparticle cluster.
(A) Schematics explaining the construction a 3D model of a nanoparticle. (B) 3D model of LDL gold nanoparticles cluster shown in (A) viewed along the y-axis, (C) rotated +90°, and (D) +180°. Scale bars, 100 nm.
Figure 5.
Quantitative characterization of the three main types of clusters formed after sequential incubation with large, and small LDL gold nanoparticles.
(A–C) Representative images of the three main categories of clusters. (D) Population of each cluster type in an average thickness of 0.73±0.29 µm. Scale bars, 100 nm.
Figure 6.
STEM tomography of a whole macrophage after sequential incubation with large (14 nm diameter), and small (5 nm) LDL gold nanoparticles.
(A) 0° STEM view through the thickness of a whole-mount macrophage. The magnification was 57,000×. The pixel size was 1.35 nm. (B) Tomogram reconstructed from an 80° tilt series with 2° increments containing the 0° view in A. The vertical position of the LDL gold nanoparticles clusters is color-coded. (C) Quantification of the vertical positions of the LDL gold nanoparticles clusters within 0.9±0.1 µm thick perinuclear regions. The mean number of clusters per 100 nm-thick virtual cell region (color bars), and standard deviations (black bars) are represented.
Figure 7.
Interpretative scheme of the mechanism that causes the different categories of LDL gold nanoparticles clusters.