Polyvinyl Alcohol Hydrogel Irradiated and Acetalized for Osteochondral Defect Repair: Mechanical, Chemical, and Histological Evaluation after Implantation in Rat Knees

Abstract

Polyvinyl Alcohol (PVA) hydrogel plugs were implanted in artificial osteochondral defects on the trochlear groove of rat knees. After 0, 3, 6, 12, and 24 weeks of followup, samples containing the implants were mechanically evaluated by creep indentation test, chemically, and histologically by optical microscopy. The mechanical test pointed towards an increase of the implant creep modulus and the chemical analysis exhibited an increasing concentration of calcium and phosphorus within the implants over time. Optical microscopy showed no foreign body reaction and revealed formation, differentiation, and maintenance of new tissue at the defect/implant interface. The absence of implant wear indicated that the natural articular lubrication process was not disturbed by the implant. The performance of the irradiated and acetalized PVA was considered satisfactory for the proposed application.

Use of a novel polyvinyl alcohol membrane as a pericardial substitute reduces adhesion formation and inflammatory response after cardiac reoperation

“…In these rats, few adhesions were observed between the epicardium and the surrounding structures of the thoracic cavity. Although PVA-based materials have been used in other biomedical applications, 7 to the best of our knowledge, this report represents the first time that a PVA membrane has been used as a pericardial substitute.…”

“…10,11 Various materials have been developed for diminishing pericardial adhesions, such as resorbable collagen membranes, biodegradable collagen-elastin membranes, propylene oxide-treated bovine pericardium, and bioabsorbable gelatin sheets. 5,7,[12][13][14] Herein, we evaluated a novel PVA membrane as a pericardial substitute. In vitro, the PVAM showed a high hydration capacity and no cytotoxic effect after direct or indirect contact with cultured cells.…”

“…The PVAM was made as described previously. 7 Briefly, the membrane was assembled from an aqueous solution of 10% PVA (Sigma Aldrich, São Paulo, Brazil), which was kept at room temperature for 7 days until dry. The dried membrane was 2-mm thick, and it was manipulated into a tube-like shape (1.5-cm height and 0.5-cm internal diameter).…”

“…This step has prevented PVAM dissolution for at least 24 weeks after implantation in bone tissue. 7 Electron beam irradiation, which can simultaneously accomplish the reticulation and sterilization of the membranes, was performed for the cross-linking step. Before irradiation, the material was acetylated by immersion in a solution of 40% formaldehyde, 50% sulfur acid, and 300 g of anhydrous sodium sulfate at 60 C for 24 hours.…”

Cellulose fibers-reinforced self-expanding porous composite with multiple hemostatic efficacy and shape adaptability for uncontrollable massive hemorrhage treatment

“…Acetalized PVA with porous structure, which is prepared by chemically crosslinked PVA with aldehyde (formaldehyde, glutaraldehyde, etc.) [ 31 , 32 ], not only inherits the deformability and flexibility of porous materials but also exhibits excellent liquid absorption capacity and high liquid-triggered expansion [ 33 ]. Cellulose fibers are widely used to enhance the mechanical properties of materials and carboxymethyl modification can endow them with hemostatic ability.…”