pHEMA Hydrogels In Porous Substrates for Use as Artificial Articular Cartilage

Synovial or diartrodial joints constitute the majority of the joints of the human body, making possible the movement and daily activities and, therefore, when damaged, restoration is of great importance. Given this, studies with biomaterials in the manufacture of joint surfaces, aiming at the use of prostheses or grafts of small defects to facilitate functional restoration of the joints, is becoming of great interest among researchers. This is because these materials exhibit similar tribological behavior of the natural joints. A class of materials which have interesting features to mimic such behavior are polymeric hydrogels: three-dimensional crosslinking polymers which have the ability to swell in aqueous solutions without dissolving, realeasing, when compressed, fluid contained inside.  This favors a scheme of lubrication between the articular surfaces with consequent reduction of friction and wear, allowing longer life of of the prosthesis. Among the broad class of hydrogels studied, poly 2-hydroxy ethyl methacrylate (pHEMA) gets special attention. Initially developed for use as contact lens, this hydrogel is very versatile in the field of medicine due to its properties: it is biocompatible, has high permeability, high hydrophilicity, chemical stability and has been studied as artificial articular cartilage, whose mechanical strength for this application is still critical. However, when the pHEMA hydrogel is implanted substrates mechanically resistant covering, their toughness makes it ideal for the desired application, which is to support and distribute the load applied on prosthesis during movement. Therefore, the objective of this work is to characterize and cover pHEMA hydrogels in porous substrates with different resistance to tension and abrasion, studying the tribology of the system. In addition to assessing the physical, chemical and surface intrinsic to each material for applying of the pHEMA as artificial articular cartilage through improved mechanical strength of system.

Keywords: hydrogel, pHEMA, porous substrates, tribology, articular cartilage