15502-m-pleumeekers

ABSTRACT It is key for successful ear cartilage tissue-engineering to ensure that the engineered cartilage mimics the mechanics of the native tissue. This study provides a spatial map of the mechanical and biochemical properties of human auricular cartilage, thus establishing a benchmark for the evaluation of functional competency in ear cartilage tissue engineering. Stress-relaxation indentation (instantaneous modulus, Ein; maximum stress, σ max ; equilibrium modulus, Eeq; relaxation half-life time, t 1/2 ; thickness, h) and biochemical parameters (content of DNA; sulfated-glycosaminoglycan, sGAG; hydroxyproline; elastin) of fresh human ear cartilage were evaluated. Samples were categorized into age groups and according to their harvesting region in the human auricle (for ear cartilage only). Ear cartilage displayed significantly lower Ein, σ max , Eeq, sGAG content; and significantly higher t 1/2 , and DNA content than nasal cartilage. Large amounts of elastin were measured in ear cartilage (>15% elastin content per sample wet mass). No effect of gender was observed for either ear or nasoseptal samples. For auricular samples, significant differences between age groups for h, sGAG and hydroxyproline, and significant regional variations for Ein, σ max , Eeq, t 1/2 , h, DNA and sGAG were measured. However, only low correlations between mechanical and biochemical parameters were seen ( R <0.44). In conclusion, this study established the first comprehensive mechanical and biochemical map of human ear cartilage. Regional variations in mechanical and biochemical properties were demonstrated in the auricle. This finding highlights the importance of focusing future research on efforts to produce cartilage grafts with spatially tunable mechanics. 28 CHAPTER 2