3D Porous Gelatin/PVA Hydrogel as Meniscus Substitute Using Alginate Micro-Particles as Porogens.

Alessandra Marrella,Elena Dellacasa,Silvia Scaglione,Fabrizio Barberis,Elisabetta Finocchio,Paolo Giannoni,Camilla Pasquini,Laura Pastorino,Alberto Lagazzo

doi:10.3390/polym10040380

Abstract

One of the current major challenges in orthopedic surgery is the treatment of meniscal lesions. Some of the main issues include mechanical consistency of meniscal implants, besides their fixation methods and integration with the host tissues. To tackle these aspects we realized a micro-porous, gelatin/polyvinyl alcohol (PVA)-based hydrogel to approach the high percentage of water present in the native meniscal tissue, recapitulating its biomechanical features, and, at the same time, realizing a porous implant, permissive to cell infiltration and tissue integration. In particular, we adopted aerodynamically-assisted jetting technology to realize sodium alginate micro-particles with controlled dimensions to be used as porogens. The porous hydrogels were realized through freezing-thawing cycles, followed by alginate particles leaching. Composite hydrogels showed a high porosity (74%) and an open porous structure, while preserving the elasticity behavior (E = 0.25 MPa) and high water content, typical of PVA-based hydrogels. The ex vivo animal model validation proved that the addition of gelatin, combined with the micro-porosity of the hydrogel, enhanced implant integration with the host tissue, allowing penetration of host cells within the construct boundaries. Altogether, these results show that the combined use of a water-insoluble micro-porogen and gelatin, as a bioactive agent, allowed the realization of a porous composite PVA-based hydrogel to be envisaged as a potential meniscal substitute.

Highlights

The soft tissues of the musculoskeletal system, such as articular cartilage and meniscus, cover an important role in the efficient and pain-free execution of the activities of daily living
The alginate micro-particles produced using the aerodynamically assisted jetting technique are shown in Figure 1, together with the Probability Density Function of the diameter distribution
Sections were stained with methylene blue, which stains both the polyvinyl alcohol (PVA)-based hydrogels and the remaining alginate micro-particles

Summary

Introduction

The soft tissues of the musculoskeletal system, such as articular cartilage and meniscus, cover an important role in the efficient and pain-free execution of the activities of daily living. Injuries of menisci are the most common in the knee joint due to the forces they are usually subjected to, causing pain, altering and locking knee joints [2]. They are placed between the femoral condyle and flat plateau and their main role is to increase congruency of shape between the curved condyle and flat plateau, as well as to confer joint stability and to transfer loads. Menisci play basically a biomechanical role, distributing loads and contact forces at the level of articulations and absorbing and dissipating biomechanical shocks [3,4]

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