Journal: Biomaterials

Article Title: A comparative study assessing neural recording quality and inflammatory tissue response between stiff and flexible microelectrode arrays

doi: 10.1016/j.biomaterials.2025.123929

Figure Lengend Snippet: Heightened piezo1 expression around the stiff implant. A) Representative images showing Piezo1 expression around the flexible (left) and stiff (right) implant site (*). B) Quantification of normalized intensity as a function of distance from the implant (μm). C) Normalized intensity averaged across the first 50 μm from the implant site. 19 images for the flexible and 22 images for the stiff group were analyzed. D) Representative images showing Piezo1 (cyan), Iba-1 (green), GFAP (red), and merged expression around a stiff implant, with the zoomed inset with DAPI (blue) overlay. E) Correlation of total piezo1 expression with total Iba-1 expression per image for flexible (left, blue) and stiff (right, red) groups. The slope is significant for the stiff group, indicating a strong correlation between Piezo1 expression and Iba-1 intensity. F) Correlation of total piezo1 expression with total GFAP expression per image for flexible (left, blue) and stiff (right, red). 4 animals were implanted in each group. C) Two-way ANOVA with Sidak’s multiple comparison test was used, E-F) Data was normalized per image and the mean set to 0. A simple linear regression was performed, dashed lines indicate 95 % confidence intervals, *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001. The scale bar is 100 μm in A) and D) and 50 μm in the zoomed inset in D). C) Data are mean ± SEM. E-F) Data is sum.

Article Snippet: Antibodies to visualize astrocytes (GFAP, 1:500, Z033401 Dako), macrophage/microglia IBA-1(microglia, 1:500, NC9288364 Fisher), Piezo1 mechanosensitive ion channels (Piezo1,1:100, NBP275617 Novus Biologicals), neuronal nuclei (NeuN, 1:750, CAD69 Abcam), and neural filament (NF200, 1:250 MAB5256 Millipore) were used.

Techniques: Expressing, Comparison

Journal: Biomaterials

Article Title: A comparative study assessing neural recording quality and inflammatory tissue response between stiff and flexible microelectrode arrays

doi: 10.1016/j.biomaterials.2025.123929

Figure Lengend Snippet: Cell-specific intensity analysis. A) Microglia mask of a sample image using Iba-1. Black portions represent the extracted cell structures. This mask was used to identify the sample microglia shown in B). B) Piezo1 (blue) stained image showing activated microglia expressing Piezo1. C) Average within-microglia Piezo1 intensity with distance from the probe center. D) Average within-microglia Iba-1 intensity with distance from the probe center. E) Astrocyte mask of the above image using GFAP. Black portions represent the extracted cell structures. This mask was used to identify the sample astrocyte processes shown in F). F) Piezo1 (blue) stained image showing astrocyte processes expressing Piezo1. G) Average within-astrocyte Piezo1 intensity with distance from the probe center. H) Average within-astrocyte GFAP intensity with distance from the probe center. For all microglia and astrocyte analysis, the increase in intensity with proximity to the injury is highly significant for both probe substrates, and the cells surrounding stiff probes have higher intensity expression than the flexible. I) Piezo1 (red) stained image overlayed with NeuN ROIs produced by Cellpose. J) Piezo1 (red) stained image merged with NeuN (green). K) Average within-neuron Piezo1 intensity with distance from the probe center. Sample DAPI (white) stained image for a L) stiff and M) flexible probe implant. N) Average DAPI circularity index for all images analyzed above. Bar plot is the same data, but binned into two large bins rather than 10 evenly spaced bins. For A) and E), DAPI is overlayed on the mask. DAPI that passes through masked cell structures is seen as red, while DAPI covered by the mask is seen as yellow. Scale bar is 100 μm and 50 μm in zoomed insets in M&N. * Indicates implantation site. For comparisons between stiff and flexible, a two-way ANOVA with Sidak’s multiple comparison test was used. For correlation of intensity with distance from the probe, a Spearman’s r correlation test was used due to the non-normality of many of the datasets, **p < 0.01, ***p < 0.001, ****p < 0.0001. All data is mean ± SEM.

Article Snippet: Antibodies to visualize astrocytes (GFAP, 1:500, Z033401 Dako), macrophage/microglia IBA-1(microglia, 1:500, NC9288364 Fisher), Piezo1 mechanosensitive ion channels (Piezo1,1:100, NBP275617 Novus Biologicals), neuronal nuclei (NeuN, 1:750, CAD69 Abcam), and neural filament (NF200, 1:250 MAB5256 Millipore) were used.

Techniques: Staining, Expressing, Produced, Comparison