Zn(2+) release behavior and surface characteristics of Zn/LDPE nanocomposites and ZnO/LDPE nanocomposites in simulated uterine solution

Nanomaterials Solutions for Contraception: Concerns, Advances, and Prospects

Preventing unintentional pregnancy is one of the goals of a global public health policy to minimize effects on individuals, families, and society. Various contraceptive formulations with high effectiveness and acceptance, including intrauterine devices, hormonal patches for females, and condoms and vasectomy for males, have been developed and adopted over the last decades. However, distinct breakthroughs of contraceptive techniques have not yet been achieved, while the associated long-term adverse effects are insurmountable, such as endocrine system disorder along with hormone administration, invasive ligation, and slowly restored fertility after removal of intrauterine devices. Spurred by developments of nanomaterials and bionanotechnologies, advanced contraceptives could be fulfilled via nanomaterial solutions with much safer and more controllable and effective approaches to meet various and specific needs for women and men at different reproductive stages. Nanomedicine techniques have been extended to develop contraceptive methods, such as the targeted drug delivery and controlled release of hormone using nanocarriers for females and physical stimulation assisted vasectomy using functional nanomaterials via photothermal treatment or magnetic hyperthermia for males. Nanomaterial solutions for advanced contraceptives offer significantly improved biosafety, noninvasive administration, and controllable reversibility. This review summarizes the nanomaterial solutions to female and male contraceptives including the working mechanisms, clinical concerns, and their merits and demerits. This work also reviewed the nanomaterials that have been adopted in contraceptive applications. In addition, we further discuss safety considerations and future perspectives of nanomaterials in nanostrategy development for next-generation contraceptives. We expect that nanomaterials would potentially replace conventional materials for contraception in the near future.

Feasibility evaluation of a Zn-Cu alloy for intrauterine devices: In vitro and in vivo studies

The comprehensively adopted copper-containing intrauterine devices (Cu-IUDs) present typical adverse effects such as bleeding and pain at the initial stage of post-implantation. The replacement of Cu material is demanded. Zinc and its alloys, the emerging biodegradable materials, exhibited contraceptive effects since 1969. In this work, we evaluated the feasibility of bulk Zn alloys as IUD active material. Using pure Cu and pure Zn as control groups, we investigated the contraceptive performance of Zn-0.5Cu and Zn-1Cu alloys via in vitro and in vivo tests. The results showed that the main corrosion product of Zn-Cu alloys is ZnO from both in vitro and in vivo studies. CaZn₂(PO₄)₂·2H₂O is formed atop after long-term immersion in simulated uterine fluid, whereas CaCO₃ is generally formed atop after implantation in the rat uterine environment. The cytocompatibility of the Zn-1Cu alloy was significantly higher than that of the pure Zn and pure Cu to the human endometrial epithelial cell lines. Furthermore, the in vivo results showed that the Zn-1Cu alloy presented much improved histocompatibility, least damage and the fastest recovery on endometrium structure in comparison to pure Zn, Zn-0.5Cu and pure Cu. The systematic and comparing studies suggest that Zn-1Cu alloy can be considered as a possible candidate for IUD with great biochemical and biocompatible properties as well as high contraceptive effectiveness. STATEMENT OF SIGNIFICANCE: The existing adverse effects with the intrinsic properties of copper materials for copper-containing intrauterine devices (Cu-IUD) are of concerns in their employment. Such as burst release of cupric ions (Cu²⁺) at the initial stage of the Cu-IUD. Zinc and its alloys which have been emerging as a potential biodegradable material exhibited contraceptive effects since 1969. In this study, Zn-1Cu alloys displayed significantly improved biocompatibility with human uterus cells and a decreased inflammatory response within the uterus. Therefore, high antifertility efficacy of the Zn-1Cu alloy was well maintained, while the adverse effects are significantly eased, suggesting that the Zn-1Cu alloy is promising for IUD.

Effective easing of the side effects of copper intrauterine devices using ultra-fine-grained Cu-0.4Mg alloy

Copper intrauterine device is one of the most adopted contraceptive methods with high effectiveness (over 99 %), low cost, spontaneous reversibility and long-lasting usage. However, the side effects induced from the initial burst release of copper ions (Cu²⁺) hinder the continuation of the Cu-IUD made of Coarse-Grained Copper (CG Cu). We proposed to tailor the bio-corrosion behaviors of better control of Cu²⁺ release via the addition of bioactive Mg into the Ultra-Fine Grained (UFG) Bulk Cu. Thus, UFG bulk Cu with 0.4 wt.% Mg was produced via equal-channel angular pressing. The microstructures of the UFG Cu-0.4Mg was observed using electron backscatter diffraction and transmission electron microscopy techniques. The in vitro long-term corrosion behaviors in simulated uterine fluid, cytotoxicity to four cell lines, in vivo biocompatibility and contraceptive efficacy were all studied on CG Cu, UFG Cu and UFG Cu-0.4Mg materials. The results demonstrate that both the ultrafine grains and the addition of bioactive Mg into Cu contribute to the suppression of the burst release of Cu²⁺ in the initial stage and the maintenance of high level Cu²⁺ in long-term release. Moreover, the UFG Cu-0.4Mg also exhibited much improved cell and tissue biocompatibility from both the in vitro and in vivo evaluations. Therefore, the contraceptive efficacy of UFG Cu-0.4Mg is still maintained as high as the CG Cu and UFG Cu while the side effects are significantly eased, suggesting the high potential of the UFG Cu-0.4Mg alloy as a new upgrading or alternative material for Cu-IUD. STATEMENT OF SIGNIFICANCE: The side effects from burst release of Cu²⁺ at the initial implantation stage of Cu-containing intrauterine devices (Cu-IUD) is one of the main drawbacks of these devices. In this work, an ultra-fine-grained Cu (UFG Cu) alloyed with a low amount of bioactive Mg was used for a Cu-IUD. The UFG Cu-0.4Mg alloy exhibited suppressed burst release of Cu²⁺ at initial implantation, while active Cu²⁺ release for long-term usage was maintained, comparable to coarse-grained pure Cu. Furthermore, the UFG Cu-0.4Mg alloy displayed significantly improved biocompatibility with human uterus cells and a much decreased inflammatory response within the uterus. Therefore, the side effects from Cu-IUD were eased, while high antifertility efficacy of the UFG Cu-0.4Mg alloy was maintained. The UFG Cu-0.4Mg alloy is promising for Cu-IUD.

Effects of palygorskite composites on growth performance and antioxidant status in broiler chickens

This work aimed to investigate the effects of the palygorskite (PAL) composites on the growth performance and antioxidant status in broiler chickens. A total of 192 one-day-old Ross 308 broilers were randomly divided into 3 treatment groups. Broilers were fed basal diets supplemented with either 50 mg/kg chlortetracycline (CTC group), 1 g/kg ZnO/PAL (ZnO/PAL group), or 1 g/kg chitooligosaccharides/ZnO/PAL (COS/ZnO/PAL group), respectively. The results showed that PAL composites were found to exhibit similar effects on growth performance as CTC (P > 0.05). ZnO/PAL and COS/ZnO/PAL enhanced the activity of serum glutathione peroxidase (GSH-Px) compared with CTC both at 21 and 42 d (P < 0.05). Compared with the CTC group, COS/ZnO/PAL enhanced serum catalase (CAT) activity at 21 d (P < 0.05), and decreased serum malondialdehyde (MDA) content at 42 d (P < 0.05). Compared with the CTC group, ZnO/PAL decreased duodenal mucous MDA content at 21 d, while ZnO/PAL did not affect activities of superoxide dismutase (SOD) and GSH-Px in the duodenum (P > 0.05). The duodenal mucous activities of SOD and GSH-Px were the highest in the COS/ZnO/PAL group at 42 d (P < 0.05). At 21 d, broilers in the COS/ZnO/PAL group had the lowest MDA content and the highest total antioxidant capacity (T-AOC) in the jejunum (P < 0.05). Palygorskite composites decreased ileum mucous MDA content compared with CTC treated broilers at 21 d (P < 0.05). At 42 d, ileum mucous T-AOC was increased both in the ZnO/PAL and COS/ZnO/PAL groups compared with the CTC group (P < 0.05). The ileum mucous GSH-Px activities both in the ZnO/PAL and COS/ZnO/PAL groups were increased compared with the CTC group (P < 0.05). In conclusion, the broilers given the basal diet supplemented with the PAL composites exhibited similar growth performance to their counterparts in the AGP group. Additionally, the PAL composites improved the antioxidant status of broilers and the beneficial effects of COS/ZnO/PAL on the antioxidant status are more pronounced.

An approach to give prospective life-span of the copper/low-density-polyethylene nanocomposite intrauterine device

As a novel copper-containing intrauterine device (IUD), the prospective life-span of the copper/low-density-polyethylene (Cu/LDPE) nanocomposite IUD is very important for the future clinical use and should be given in advance. Here a novel approach, cupric ions accelerated release in diluted nitric acid solution and cupric ions concentration release in various volume of simulated uterine solution (SUS), is reported to verify the type of cupric ions release model of the cylindrical matrix-type nanocomposite IUD, and to obtain the minimal cupric ions release rate that need to ensure contraceptive efficacy and the thickness of copper particles exhausted layer of the cylindrical matrix-type nanocomposite IUD within two difficult immersion durations in experimental volume of SUS, respectively. Using these results, the prospective life-span of the cylindrical matrix-type nanocomposite IUD can be obtained. For instance, the prospective life-span of the novel γ-shape nanocomposite IUD with 25 wt% of copper nanoparticles and 2 mm of diameter and a total weight of 285 mg can be given in advance and it is about 5 years in the future clinical use.