Fabrication and characterization of an injectable reinforced composite scaffold for cartilage tissue engineering: an in vitro study

There are limitations in current medications of articular cartilage injuries. Injectable bioactive hydrogels are promising options; however, they suffer from low biomechanical performance. Few solutions have been proposed to overcome these challenges, yet there are many considerations that need to be taken into account. In this study, an injectable composite hydrogel was made from chitosan and human acellular cartilage extracellular matrix (ECM) particles. In order to enhance the mechanical properties of the hydrogel, it was reinforced with microporous microspheres composed of the same materials as the structural building blocks of the scaffold. Articular cartilage was obtained from human donors and decellularized by a combinatorial physical, chemical, and enzymatic method. The decellularization efficiency was assessed by histological analysis and DNA content. The composite constructs were characterized in terms of storage modulus, gelation time, biocompatibility, and likely differentiation potential. Experimental results showed that the mechanical behavior increased by increasing the microsphere content and the sample with 10% microsphere showed an enhanced storage modulus up to 90 kPa. Biocompatibility and preliminary differentiation investigations revealed that the presented composite hydrogel might have potentials in cartilage tissue engineering.