A flow perfusion bioreactor with controlled mechanical stimulation: Application in cartilage tissue engineering and beyond

Articular cartilage (AC) is a semitransparent, strong connective tissue that covers the articulating surfaces of bones [1]. It contains a rubbery matrix with extensive amounts of water, collagen, and proteoglycan ibers [2], and its unique structure allows it to absorb mechanical loads while creating a near-frictionless environment in articulating joints [3]. However, because AC is avascular and aneural, it has poor intrinsic ability for self-repair after injury [4]. Damage to AC is progressive and leads to osteoarthritis, a condition that affects 5 percent of the general population and 70 percent of those over age of 65, and costs nearly $8 billion annually in health care expenses [5]. Due to the socioeconomic and human impacts of this condition there has been a concerted effort to develop innovative strategies to repair damaged AC. One promising approach is the use of grafts comprised of replacement AC tissue, engineered to have properties similar to endogenous AC.