Cartilage Tissue Engineering with Recombinant Human Type II Collagen Gel Infiltrated in PLDLA-scaffolds

INTRODUCTION: Autologous chondrocyte transplantation (ACT) is a routine technique to regenerate cartilage tissue in chondral lesions [1]. Instead of using periosteal patch, the method can be enhanced by seeding the cultureexpanded chondrocytes into a biodegradable 3-dimensional scaffold (matrix-associated ACT). These new generation ACT techniques lead to less surgical time, morbidity, and abolish periosteal patch hypertrophy. Even though extensive research in the field of cartilage tissue regeneration, the goals of successful cartilage repair has not yet been completely achieved and none of the techniques today can be called as "the golden standard". This study aims to improve the current standard of care by introducing new techniques for improvement of regenerated articular cartilage by producing scaffold constructs that enable the maintenance of chondrogenic capacity of the ex vivo expanded autologous chondrocytes. Collagen type II is the major component of cartilage and, according to our previous studies, could be an eligible matrix material for matrixassociated autologous chondrocyte implantation [2, 3]. But due to its weak mechanical properties, type II collagen by itself is not optimal for tissue-engineered reconstruction of injured cartilage. In this preliminary in vitro study, we have used novel biomaterials based on biodegradable polylactide polymers (PLDLA; poly-L-D-lactic acid) in combination with the recombinant human type II collagen gel. With these hybrid constructs we aim to provide suitable environment for chondrocytes to proliferate and phenotypically express chondrocytic functions within a 3D-environment that also provides an adequate load-sharing structural matrix.