Single molecule mechanical properties of type Ⅱ collagen and hyaluronan measured by optical tweezers

摘要

Type Ⅱ collagen and hy aluronan are the two major components of extracellular molecules in cartilage and play an important role in mechanical functions of extracellular matrix. Currently, their mechanical properties have been investigated only at the gross-level. In this study, the mechanical properties of single type Ⅱ collagen and hyaluronan molecules were directly measured using optical tweezers technique. The persistence length was found to be 11.2 +- 8.4 nm in type Ⅱ collagen and 4.5 +- 1.2 nm in hyaluronan. This result suggested that type Ⅱ collagen is stiffer than hyaluronan at the individual molecule level, which supports the general concept that collagen is responsible for resisting tensile force. The experimental system developed here also provides a powerful tool for quantifying mechanical properties of extracellular matrix at the single molecule level.