Journal: ACS Nano

Article Title: Illuminating the Underlying Mechanism of Intracellular Optoelectronic Modulation Using Silicon Nanowires

doi: 10.1021/acsnano.5c11146

Figure Lengend Snippet: The effect of photoanodic, photocathodic, and pure photothermal modulation on intracellular calcium dynamics: (A) Fluorescence images of stimulated normal human dermal fibroblasts (NHDF) cells loaded with a calcium indicator (green) and containing silicon nanowires (SiNWs, yellow). The top panels show NHDF-p–i–n hybrids, the middle panels NHDF-n–i–p hybrids, and the bottom panels NHDF-i–i–i hybrids. Red arrows indicate the stimulated SiNW using a 640 nm laser, for 3 ms, at 1.6 mW. Scale bars are 20 μm. (B) d F / F image captured at 13.5 s after stimulation, with a white arrow marking the line used to generate the kymograph shown in panel (C). Scale bars are 20 μm. (C) Representative kymographs of d F / F traces used to quantify intracellular calcium flux in the stimulated cells shown in (A). The top and middle panels show high calcium propagation rate following stimulation of p–i–n and n–i–p SiNWs, respectively. In contrast, the bottom panel shows slower propagation in i–i–i SiNW-stimulated cells. (D) Generated binary mask using MATLAB, with a white dashed line representing the slope of calcium propagation. Linear regression was applied to estimate the calcium flux velocity ( v = d x /d t ). (E) Box plots showing intracellular calcium propagation velocities (μm/s), derived from kymographs in (C) for cells stimulated with a 640 nm laser (3 ms, 1.6 mW). Data represent measurements from 12 samples. * p < 0.05, ** p < 0.01.

Article Snippet: Normal human dermal fibroblasts (NHDF) (PCS-201-010) were purchased from ATCC.

Techniques: Fluorescence, Generated, Derivative Assay

Journal: ACS Nano

Article Title: Illuminating the Underlying Mechanism of Intracellular Optoelectronic Modulation Using Silicon Nanowires

doi: 10.1021/acsnano.5c11146

Figure Lengend Snippet: Intracellular optoelectronic modulation and calcium response characterization. (A) Left-confocal imaging of a normal human dermal fibroblast (NHDF) cell with an internalized n–i–p silicon nanowire (SiNW) (reflection, yellow) and loaded with a calcium indicator (fluo-4, green), scale bar is 20 μm. The red arrow highlights the stimulated SiNW inside the cell, and a cross-sectional view of the z -stack along the white arrow (right) verifies that the SiNW is internalized, scale bar is 3 μm. (B) Illustration of intracellular stimulation via optical modulation of the SiNW. (C,D) Fluorescent (C) and derived d F / F (D) images of the stimulated cell (using 640 nm laser, for 3 ms at 1.6 mW) captured at different time points: 54 ms before stimulation, and 68 ms, 2.154 s, and 13.41 s after stimulation. The white arrow in (D) (right image) indicates the line used for cross-sectional kymograph analysis (see panel (F)). Scale bars are 20 μm. (E) Heatmap of the cell showing d F / F analysis from a time-series data set, illustrating calcium propagation using time color code, scale bar is 20 μm. (F) Kymograph of d F / F presenting the spatial and temporal dynamics of calcium flux originating from the stimulated SiNW. (G). d F / F plot of calcium response following stimulation of the n–i–p SiNW with a 1.6 mW laser at t = 2.7 s.

Article Snippet: Normal human dermal fibroblasts (NHDF) (PCS-201-010) were purchased from ATCC.

Techniques: Imaging, Derivative Assay

Journal: ACS Nano

Article Title: Illuminating the Underlying Mechanism of Intracellular Optoelectronic Modulation Using Silicon Nanowires

doi: 10.1021/acsnano.5c11146

Figure Lengend Snippet: Optically induced calcium transients in normal human dermal fibroblasts are driven by internal calcium sources. (A) Left image, confocal image of an untreated normal human dermal fibroblast (NHDF)-p–i–n hybrid (top) or NHDF treated with 5 μM thapsigargin (bottom), loaded with calcium indicator. Right panels: d F / F images of the stimulated cells captured at multiple time points: 54 ms before stimulation, and 54 ms, and 13.5 s after stimulation (640 nm laser, 3 ms, 2.2 mW). Scale bars are 20 μm. (B) Box plots showing the maximum d F / F values of Fluo-4 AM fluorescence after stimulation of NHDF-p–i–n hybrids with a 640 nm laser (3 ms, 2.2 mW). n > 6. *** p < 0.001.

Article Snippet: Normal human dermal fibroblasts (NHDF) (PCS-201-010) were purchased from ATCC.

Techniques: Fluorescence

Journal: ACS Nano

Article Title: Illuminating the Underlying Mechanism of Intracellular Optoelectronic Modulation Using Silicon Nanowires

doi: 10.1021/acsnano.5c11146

Figure Lengend Snippet: Photoelectrochemical induction of reactive oxygen species (ROS) release in normal human dermal fibroblasts (NHDF). (A) d F / F images of NHDF cells with internalized silicon nanowires (SiNWs), stained with the fluorescent ROS indicator CellROX Orange, acquired at t = 58 s. Cells were stained with CellROX and imaged for ∼1 min without stimulation. Scale bars are 20 μm. (B) d F / F images of NHDF cells with internalized SiNWs, stained with the fluorescent ROS indicator CellROX Orange. Cells were imaged for ∼1 min and optically stimulated during imaging at t = 5.7 s (640 nm, 3 ms, and 1.6 mW), while presented images were acquired at t = 58 s. (A,B) Left to right tilescells without SiNWs, NHDF-p–i–n hybrids, NHDF-n–i–p hybrids, and NHDF-i–i–i hybrids. Cells without SiNWs and cells with p–i–n and i–i–i SiNWs showed minimal d F / F changes, while n–i–p hybrids exhibited strong d F / F increases. The graph on the right shows d F / F trends for each group. Scale bars are 20 μm. (C) Leftwithout stimulation: Box plots showing the maximum d F / F values during the 1 min recording without stimulation ( n > 30). Rightwith stimulation: Box plots displaying the maximum d F / F values in response to optical stimulation (1.6 mW, 640 nm) at t = 2.7 s, during a 1 min recording ( n > 8). (D) Box plots displaying the RFU values indicating H 2 O 2 generation in response to optical stimulation of SiNWs in suspension. SiNWs were stimulated using red and lime LEDs at 2.5 Hz for 1 h at 0.25 W. For (C,D), the statistical tests were two-way ANOVA, * p < 0.05, *** p < 0.001, and **** p < 0.0001.

Article Snippet: Normal human dermal fibroblasts (NHDF) (PCS-201-010) were purchased from ATCC.

Techniques: Staining, Imaging, Suspension

Journal: ACS Nano

Article Title: Illuminating the Underlying Mechanism of Intracellular Optoelectronic Modulation Using Silicon Nanowires

doi: 10.1021/acsnano.5c11146

Figure Lengend Snippet: Investigation of calcium signaling induced by non-Faradaic p–i–n silicon nanowires (SiNWs) in normal human dermal fibroblasts (NHDFs). (A) Confocal images of NHDF-p–i–n hybrids loaded with the calcium indicator Fluo-4 AM. The panels show untreated cells, cells treated with 20 μM 2-APB (2APB), 40 μM 2-APB, or 20 μM dantrolene sodium (DS). Scale bars are 20 μm. (B) Corresponding d F / F images of the same cells shown in (A), captured at 13.5 s after optical stimulation of the internalized p–i–n SiNWs using a 640 nm laser (8 mW, 3 ms). Scale bars are 20 μm. (C) Box plots displaying the maximum Δ F / F values in response to the stimulation (*** p < 0.001), and (* p < 0.05) n > 7.

Article Snippet: Normal human dermal fibroblasts (NHDF) (PCS-201-010) were purchased from ATCC.

Techniques: