"twofold role" is correct and usable in written English.
You can use it when referring to two distinct yet deeply interconnected roles. For example, "The government has a twofold role to play in ensuring the health and safety of its citizens."
The combined results support the hypothesis for a twofold role of K in the mechanism of membrane fusion: 1) to bring opposing membranes into close proximity via coiled-coil formation and 2) to destabilize both membranes thereby promoting fusion.
The presence of ferroelectric particles into the chitosan matrix plays a twofold role resulting in increasing tunability: (i) increase the values of local fields in the polymer matrix by local field engineering, (ii) contribute with its own tunability to increase the field-variation of the effective permittivity.
Ralston: Western countries can play a twofold role.
Water in SCWG has a twofold role as reaction medium and reactant.
Technology has a twofold role to play in the future of the sports industry: amplifying its reach and intensifying the effects of its empowerment.
Valgus osteotomy and internal fixation with dynamic hip screw and 120° double angle barrel plate plays a twofold role: it converts the shearing forces into the compression forces by placing the fracture site perpendicular to the resultant of body weight forces; and it buttresses the head of femur from below to improve stability provided by the internal fixation [12].
Rollins saw his new role as twofold: implementing the faculty's most promising ideas, and ensuring accountability.
Saraa explains her role as twofold - to help the West understand Islam and to be a role model for Palestinian youth.
In this little group, Fletcher's role is twofold: he is MOM's main "investigative researcher" and its frequent spokesman, particularly when it comes to television, because his unexceptional mien is less unnerving than the hairy, glaring, Old Testament face of John Trochmann, 51.
