In previous studies, we showed that it was able to determine mechanical properties of cartilages by measuring NIR absorbance after indentation test. In this study, calibration curves for gelatins and human articular cartilages were obtained to estimate their water content quantitatively. NIR absorbance and water content in gelatin and human articular cartilages were measured, and their relations were discussed. Gelatin showed NIR absorbance was proportion to water content. Linear relations between water content per thickness and thickness and NIR absorbance and between thickness and NIR absorbance were found in human articular cartilage. These results enabled us to estimate water content in both gelatin and cartilage by the NIR absorbance. The discrepancy between measured and estimated water content in cartilage was 2.95%.
