Design, Manufacture, and In vivo Testing of a Tissue Scaffold for Permanent Female Sterilization by Tubal Occlusion

Abstract

Current FDA-approved permanent female sterilization procedures are invasive and/or require the implantation of non-biodegradable materials. These techniques pose risks and complications, such as device migration, fracture, and tubal perforation. We propose a safe, non-invasive biodegradable tissue scaffold to effectively occlude the Fallopian tubes within 30 days of implantation. Specifically, the Fallopian tubes are mechanically de-epithelialized, and a tissue scaffold is placed into each tube. It is anticipated that this procedure can be performed in less than 30 minutes by an experienced obstetrics and gynaecology practitioner. Advantages of this method include the use of a fully bio-resorbable polymer, low costs, lower risks, and the lack of general anaesthesia. The scaffold devices are freeze-cast allowing for the custom-design of structural, mechanical, and chemical cues through material composition, processing parameters, and functionalization. The performance of the biomaterial and de-epithelialization procedure was tested in an in vivo rat uterine horn model. The scaffold response and tissue-biomaterial interactions were characterized microscopically post-implantation. Overall, the study resulted in the successful fabrication of resilient, easy-to-handle devices with an anisotropic scaffold architecture that encouraged rapid bio-integration through notable angiogenesis, cell infiltration, and native collagen deposition. Successful tubal occlusion was demonstrated at 30 days, revealing the great promise of a sterilization biomaterial.

Multiscale Toughening Mechanisms in Biological Materials and Bioinspired Designs

“…Porous hydroxyapatite scaffolds which possess micropores (1–10 µm) and macropores (90–110 µm) by changing the solvent compositions (water–glycerol for micropores and water–dioxane for macropores) have been reported . More recently, collagen was freeze cast to create scaffolds for permanent female sterilization that was tested on successfully with rats . The effect of processing conditions was further tested and showed that lower freezing rate produced larger pores and thicker lamellar walls, resulting in decreased modulus but higher yield strength .…”

Freeze-casting porous chitosan ureteral stents for improved drainage

“…We anticipate this mechanism of stabilization and biopolymer conformity in tubular structures [81] to translate to the ureter thereby eliminating the need for the double-J design in current clinical devices.…”

Anisotropic freeze-cast collagen scaffolds for tissue regeneration: How processing conditions affect structure and properties in the dry and fully hydrated states

“…In this study, we focus on confocal microscopy (CM) as a means of biopolymer scaffold characterization in the fully hydrated state to illustrate a new CM-based method for the semi-automated rigorous quantification of pore architecture and morphology. Highlighted is, how the new technique complements strengths of scanning electron microscopy (SEM) such as a high resolution and depth of field (Deville, 2017;Ratner et al, 2004) and how it helps overcome its weaknesses such as the typical limitation to the imaging of dry samples (Bozkurt et al, 2007;Divakar et al, 2018Divakar et al, , 2017Francis et al, 2017Francis et al, , 2013Lien et al, 2009;Loh and Choong, 2013;Re et al, 2015;Scotti and Dunand, 2018;Yin et al, 2018a).…”