FIG. 3.
Custom bioreactor systems for strain of 3D constructs. (A) Application of uniaxial strain to six cell-laden collagen hydrogels or Matrigel® with 50 μm resolution. System capable of measuring passive force.71 (B) This system holds up to 10 naturally derived decellularized collagen constructs.5 (C) The application of uniaxial strain to four electrospun fibrin constructs. The system controls for zero pretensioning of the fiber, and can measure active contractile forces produced in response to electrical stimulation. The system is compatible with use of a confocal microscope.70 (D) Gelatin methacrylate substrate with embedded magnetic particles at one end to apply strain to the microgel, which is the cell-containing region of the construct. This system allows the application of large static strains up to 60%.72 (E) The system uses a combination of magnetic elements and a stepper motor to apply strain to the cell-seeded fibrin gel construct molded into a ring structure. The bottom hook has a magnetic element that is moved by an external plate, allowing for contactless strain. The bottom magnetic plate is controlled by a stepper motor. This system can hold up to 36 constructs.14