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AbstractIntroduction In recent decades, hydrogels have gained increasing interest as potential cartilage replacement materials. Among these, polyvinyl alcohol (PVA) hydrogels have shown to be very promising candidates due to their biocompatibility, high degree of swelling, and elastic and rubbery nature, which allows them to mimic the natural tissues [1]. The properties of PVA-based hydrogels can be tailored by adding different compounds. The main objective of this study is to investigate the effect of adding two distinct crosslinking agents to the polymeric mixture, on the microstructure, water content, hydrophilicity, and mechanical behaviour of PVA hydrogels.Materials and Methods Four types of materials were prepared using a PVA aqueous solution (7.75% w/w) containing two different crosslinking agents: glyoxal at 0.2% and 1%, and glutaraldehyde at 5.95% and 11.9% (where the percentages indicated refer to the mass of the crosslinker relative to that of the PVA). The mixtures were poured into Petri dishes and dried at 37 °C (4 days) and then at 60 °C (2 days). The surface morphology of the samples was analysed by scanning electron microscopy (SEM) after they had been lyophilised for 48 h and coated with an Au/Pd layer. To determine the equilibrium water content (EWC), samples hydrated in pure water were weighed, dried at 60 °C until reached a constant weight, and weighed again. The water contact angles were determined in hydrated samples by the captive bubble method. To evaluate the mechanical properties, compression tests were performed with a texturometer on samples placed in an aqueous medium, using a test speed of 0.1 mm/s until a force of 5 kg was reached.Results The results showed that all materials are non-porous and have a similar surface morphology. The hydrogels crosslinked with glyoxal present higher EWC values (69.1% and 69.7% for 0.2% and 1% of glyoxal, respectively), while those with glutaraldehyde have an EWC of 52.8% and 41.5% for 5.95% and 11.9% of glutaraldehyde, correspondingly. Concerning wettability, all samples are hydrophilic and exhibit a water contact angle

Polyvinyl alcohol (PVA) hydrogels have been widely studied for cartilage replacement due to their biocompatibility, chemical stability, and ability to be modified such that they approximate natural tissue behavior. Additionally, they may also be used with advantages as local drug delivery systems. However, their properties are not yet the most adequate for such applications. This work aimed to develop new PVA-based hydrogels for this purpose, displaying improved tribomechanical properties with the ability to control the release of diclofenac (DFN). Four types of PVA-based hydrogels were prepared via freeze-thawing: PVA, PVA/PAA (by polyacrylic acid (PAA) addition), PVA/PAA+PEG (by polyethylene glycol (PEG) immersion), and PVA/PAA+PEG+A (by annealing). Their morphology, water uptake, mechanical and rheological properties, wettability, friction coefficient, and drug release behavior were accessed. The irritability of the best-performing material was investigated. The results showed that the PAA addition increased the swelling and drug release amount. PEG immersion led to a more compact structure and significantly improved the material’s tribomechanical performance. The annealing treatment led to the material with the most suitable properties: besides presenting a low friction coefficient, it further enhanced the mechanical properties and ensured a controlled DFN release for at least 3 days. Moreover, it did not reveal irritability potential for biological tissues.

ABSTRACT Objectives: Diseases of the genitourinary tract can lead to significant damage. Current reconstructive techniques are limited by tissue availability and compatibility. This study aims to assess if the decellularized human glans can be used as a biomaterial for penile reconstruction. Materials and Methods: Samples of the glans matrices were descellularized. We evaluate the presence of collagen type I and III, and elastic fibers. Biocompatibility assays were performed to assess the cytotoxic and non-cytotoxic interactions between the acellular matrix and 3T3 cells. The matrices were seeded with mesenchymal stem cells and were assessed for viability and integration of these cells. Biomechanical tests in native tissue, descellularized matrix and seeded matrix were performed to characterize their biomechanical properties. Results: The tissue architecture of the decellularized matrix of human glans was preserved as well as the maintenance of the biomechanical and biological properties. The analyzes of glans seeded with mesenchymal stem cells revealed the integration of these cells to the matrices, and its viability during two weeks "in vitro". Conclusion: The decellularization process did not alter the biological and biomechanical characteristics of the human glans. When these matrices were seeded they were able to maintain the cells integrity and vitality.