A strategy to improve the quality of life and orthopaedic treatment of cartilage lesions – Advanced 3D (bio)printed scaffolds for tissue regeneration

Lesions of the articular cartilage represents a major challenge for orthopaedic surgeons due to its limited intrinsic healing potential. Current treatment options used in orthopaedic practice to repair cartilage give unpredictable and often unsatisfactory results. At the site of injury, inferior fibrous tissue is formed with inferior biochemical and biomechanical properties compared to healthy cartilage tissue. The field of regenerative medicine and cartilage tissue engineering has evoked intense interest since it provides an alternative strategy to restore cartilage tissue and promises to improve clinical outcome. The state-of-the-art concept of cartilage tissue development combines the use of biocompatible and biodegradable carrier materials (scaffolds), the application of growth factors, the use of different cell types and mechanical stimulation. The important aspect of scaffolds formation represents appropriate 3-D matrices that act as an initial support for the desired cells to attach, proliferate and form their native extracellular matrix. The microstructure of the scaffolds used in cartilage tissue engineering (e.g. pore shape, size, porosity and interconnectivity) can directly affect the behavior of the seeded cells and is usually associated with the mechanical properties. Therefore, a variety of materials and techniques were utilized to control the mentioned scaffold characteristics. An interesting approach to scaffold formation represents 3D (bio)printing method which yields biocompatible and biomechanically stable scaffold with controllable pore dimensions in various shapes. Manipulation of 3D bioprinting parameters and their optimization as well as proper material selection enables production of a scaffold with desirable architecture characteristics. Moreover, 3D (bio)printing of polysaccharide-based (bio)inks and blends of polysacharides in combination with synthetic materials provide new insights in hybrid (bio)ink processability. Within the framework of this project, we will harvest, isolate and characterize human articular chondrocyte obtained from surgical waste after total knee arthroplasty, produce suitable scaffolds for cartilage tissue engineering with abovementioned method and create cartilage tissue constructs that will be incubated under mechanical stimulation (bioreactors). As prepared cartilage tissue constructs will be characterized using various analyzing methods: e.g. Live/Dead assay, confocal microscopy and histological analysis to evaluate the cell viability and the depth of cell ingrowth, immunohistochemistry and cartilage specific gene expression (Collagen type 2, Aggrecan, etc.) in order to evaluate the cartilage phenotype preservation. Additionally, mechanical properties and the degradation rates will be determined. In this manner we will develop new methods for effective cartilage regeneration, which will potentially translate into clinical practice in the future. By successfully treating cartilage injuries, we can expect reduced osteoarthritis morbidity and consequently improved quality of life of orthopedic patients with cartilage pathology.