Anodized 20 nm diameter nanotubular titanium for improved bladder stent applications

Figures & data

Figure 1 Schematic of the anodization system.

Abbreviation: HF, hydrofluoric acid.

Figure 2 Scanning electron microscope micrographs of A) 20 nm and B) 80 nm anodized nanotubular titanium, as well as C) conventional titanium. Scale bars = 200 nm.

Table 1 Qualitative data obtained from AFM analysis indicating that substrates created by anodization contained more nanofeatured surface features than conventional titanium

Sample	rms_nano (nm)	rms_micro (nm)
Anod_20 nm	9.97 ± 0.83	316.38 ± 18.16
Anod_80 nm	9.01 ± 0.40	309.53 ± 9.76
Conventional titanium	6.54 ± 0.37*	276.86 ± 9.36

Notes: Values are mean ± standard error of mean, n = 3;

* P < 0.01 compared to all other samples (student t-tests).

Abbreviation: AFM, atomic force microscopy.

Figure 3 Atomic force microscopy micrographs showing the topography of A) and B) 20 nm, C) and D) 80 nm, and E) and F) conventional titanium. The images in A, C), and E) show higher magnification scans, highlighting the nanotopography of the samples, and the images in B, D), and F) show lower magnification scans, highlighting the micron-topography of the samples.

Table 2 Atomic percentages of elements in the outermost layers, as determined by ESCA

Material (titanium)	Elemental concentration (%)
	Ti2p	O1s	C1s	F1s	Ti/O
Conventional	19.93	51.29	28.79	0	0.39
Anod_80 nm	26.69	40.35	21.35	11.61	0.66
Anod_20 nm	22.70	40.21	23.50	13.59	0.56

Notes: The analysis indicated the presence of fluorine in the outermost layer of anodized samples

Abbreviations: ESCA, electron spectroscopy for chemical analysis.

Figure 4 Electron spectroscopy for chemical analysis for A) 20 nm, B) 80 nm anodized nanotubular titanium, and C) conventional titanium.

Figure 5 Urothelial cell densities from 4 hours to 3 days on 20 nm and 80 nm diameter anodized nanotubular titanium, as well as conventional titanium.

Notes: Data are mean ± SEM n = 3; *P < 0.01 compared to respective counterparts at the same time period; ^#P < 0.05 compared to respective sample 4-hour time point; ^##P < 0.05 compared to conventional titanium at the respective time point. Conv. = conventional titanium. Statistics evaluated using Student t-tests.