Decreased astroglial cell adhesion and proliferation on zinc oxide nanoparticle polyurethane composites

Figures & data

Table 1 X-ray photoelectron spectroscopy data for ZnO/PU composites. Zinc was detected at the surface for samples with weight ratios of 50:50 (PU:ZnO) wt.% and 75:25 (PU:ZnO) wt.%. No zinc was detected at the surface of samples with a lower concentration of ZnO nanoparticles

Weight ratio (PU:ZnO)	ZnO surface area (% coverage)
100:0	ND
98:2	ND
90:10	ND
75:25	2.11
50:50	3.98

Abbreviation: ND, not detectable.

Figure 1 Scanning electron micrographs of the ZnO/PU composites. 50:50 (PU:ZnO) wt.% at 6,000X (a) and 30,000X (b); 75:25 (PU:ZnO) wt.% at 6,000X (c) and 30,000X (d); 90:10 (PU: ZnO) wt.% at 6,000X (e) and 30,000X (f); 98:2 (PU:ZnO) wt.% at 6,000X (g) and 30,000X (h); 100:0 (PU:ZnO) wt.% at 6,000X (i) and 30,000X (j).

Notes: Scale bar for images in left column = 5 μm. Scale bar for images in right column = 1 μm.

Table 2 Contact angles of three liquids on sample surfaces. Contact angle data was used to determine surface energy via the Owens-Wendt equation

Weight ratio (PU:ZnO)	Contact angle of DI water	Contact angle of 1,2-dichloroethane	Contact angle of PEG 2000
100:0	86.51 ± 0.19	31.56 ± 2.42	55.88 ± 3.48
98:2	81.75 ± 2.24	26.34 ± 1.42	51.14 ± 1.96
90:10	80.08 ± 0.47	24.08 ± 1.37	47.6 ± 1.93
75:25	77.71 ± 1.51	21.33 ± 3.06	43.38 ± 2.07
50:50	73.49 ± 1.73	16.41 ± 0.029	36.51 ± 0.82

Note: Values are mean ± SEM.

Figure 2 Surface energy of ZnO/PU composites. Surface energy was calculated for each sample by measuring the contact angle of three liquids at the sample surface and entering values into the Owens-Wendt equation.

Notes: Values are mean ± SEM; n = 3; *p < 0.05 (compared to 100:0 [PU:ZnO] wt.%), **p < 0.05 (compared to 90:10 [PU:ZnO] wt.%).

Figure 3 Fluorescence microscope images of astrocyte adhesion after 4 h. Astrocytes were seeded at a density of 5000 cells/cm² on each sample for 4 h. Cells seeded on glass (a), 100:0 (PU:ZnO) wt.% (b), 98:2 (PU:ZnO) wt.% (c), 90:10 (PU:ZnO) wt.% (d), 75:25 (PU:ZnO) wt.% (e), and 50:50 (PU:ZnO) wt.% (f).

Notes: Samples were stained with Calcein-AM prior to imaging. Scale bar = 200 μm.

Figure 4 Results of astrocyte 4 h adhesion assay. 5000 cells/cm² were seeded on each sample and incubated for 4 h. Cell density was determined from images taken at five random locations on each sample.

Notes: Values are mean ± SEM; n = 3; *p < 0.05 (compared to 100:0 [PU:ZnO] wt.%), **p < 0.05 (compared to 90:10 [PU:ZnO] wt.%).

Figure 5 Results of 1, 2, and 3 day astrocyte proliferation assay. Cells were seeded at t = 0 with 2500 cells/cm². Values are mean ± SEM; n = 3; *p < 0.05 (compared to 100:0 [PU:ZnO] wt.% at the same time point), **p < 0.05 (compared to 90:10 [PU:ZnO] wt.% at the same time point), ^‡p < 0.05 (compared to same sample composition at the 24 h time point), ^⋄p < 0.05 (compared to same sample composition at 48 h time point).