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No.11(2016)6.Required conditions for the fabrication of collagen gels comprising aligned collagen fibrils using shear stress
Hirosuke Hatayama,Shunji Yunoki,Mizue Ebisawa,Yoshimi Ohyabu,Eiji Kondo,Kazunori Yasuda
Shear stress to collagen sols is useful for fabricating aligned collagen fibrils, but the fibrils are thinly deposited on hard substrates and do not form three-dimensional constructs. In this paper, we report required conditions for undestructive production of thick collagen gel constructs comprising uniaxially aligned fibrils. The fabrication method using a rheometer involved application of rotary shearing to dense collagen sols and warming the sols from 23°C to 37°C to trigger gelation upon rotation. When the collagen fibril formation slowly occurred in a neutral phosphate buffer (1×NPB) of which the ionic strength was similar to that of PBS, the shearing during collagen fibril formation resulted in slurry of fibrils (i.e. destructed collagen gel). The acceleration of collagen fibril formation by increased concentrations of NPB allowed for undestructive fabrication of collagen gels between the parallel sensors of the rheometer. The fibril alignment was determined only in 20 s at the early stage of the rapid gelation, producing undestructed collagen gels comprising uniaxially aligned fibrils. In contrast, rotary shearing to dense collagen sols before gelation had little effect on collagen fibril alignment. We have revealed the shearing conditions for creating collagen gels of uniaxially aligned fibrils undestructively: rapid fibril formation during shearing.
Keywords
Aligned collagen fibrils, Fibril formation, Shear stress, Cell scaffold