Biological Assessment of Zn–Based Absorbable Metals for Ureteral Stent Applications

Abstract

The use of ureteral stents to relieve urinary tract obstruction is still challenged by the problems of infection, encrustation, and compression, leading to the need for early removal procedures. Biodegradable ureteral stents, commonly made of polymers, have been proposed to overcome these problems. Recently, absorbable metals have been considered as potential materials offering both biodegradation and strength. This work proposed zinc-based absorbable metals by firstly evaluating their cytocompatibility toward normal primary human urothelial cells using 2D and 3D assays. In the 2D assay, the cells were exposed to different concentrations of metal extracts (i.e., 10 mg/mL of Zn–1Mg and 8.75 mg/mL of Zn–0.5Al) for up to 3 days and found that their cytoskeletal networks were affected but were recovered at day 3, as observed by immunofluorescence. In the 3D ureteral wall tissue construct, the cells formed a multilayered urothelium, as found in native tissue, with the presence of tight junctions at the superficial layer and laminin at the basal layer, indicating a healthy tissue condition even with the presence of the metal samples for up to 7 days of exposure. The basal cells attached to the metal surface as seen in a natural spreading state with pseudopodia and fusiform morphologies, indicating that the metals were non-toxic.

In vitro cytocompatibility and antibacterial studies on biodegradable Zn alloys supplemented by a critical assessment of direct contact cytotoxicity assay

“…In this work, it was presented that the amount of Zn 2+ ions below 100.8 μM (11.4 mg/L) in pure Zn, 98.2 μM (11.1 mg/L) in the Zn‐3Ag alloy, and 118.5 μM (13.4 mg/L) in the Zn‐3Ag‐0.5Mg provide a favorable environment for cell survival and proliferation. This result is consistent with other already mentioned results for Zn‐based materials 45,62,68–71 . Furthermore, it can be seen that in the current study, the chemical composition variations of the investigated samples revealed almost no significant differences.…”

“…It has also been reported that at low concentrations, Zn had no adverse effects on endothelial cell viability, while the amount of Zn 2+ over 100 μM significantly decreased cell viability, and above 80 μM inhibited cell proliferation 67 . In general, high Zn 2+ concentrations contribute to cell death, however, at a much lower Zn 2+ ion concentration, Zn can even be beneficial for cell proliferation 45,62,68–70 . In this work, it was presented that the amount of Zn 2+ ions below 100.8 μM (11.4 mg/L) in pure Zn, 98.2 μM (11.1 mg/L) in the Zn‐3Ag alloy, and 118.5 μM (13.4 mg/L) in the Zn‐3Ag‐0.5Mg provide a favorable environment for cell survival and proliferation.…”

Evaluation of a Zn–2Ag–1.8Au–0.2V Alloy for Absorbable Biocompatible Materials

“…Obviously, "crystal-like" degradation products were observed at high magnification (Figure 4b,e), in line with previous studies [19,37]. Moreover, EDX analysis (Figure 4c,f) showed that these degradation products were mainly composed of Zn, P, O, and C, indicating that these degradation layers might be phosphates and carbonates, as previously reported [38][39][40]. magnification (Figure 4b,e), in line with previous studies [19,37].…”

Considerations for the clinical use of stem cells in genitourinary regenerative medicine

“…Furthermore, electron microscopy indicated the maturation of uroplakin plaques and the presence of discoid and fusiform vesicles near the plasma membranes, and immunostaining of uroplakins, tight junction proteins, and various markers such as keratins. These reconstructed tissues were used as models to study several pathologies such as bladder cancer[ 196 ], ketamine-induced cystitis[ 197 ] or the effect of metallic stent use[ 198 ]. Soon after, the preservation of epithelial SCs ( i.e.…”