Tailorable Hydrogel Fibers from High-Yield Recombinant Hagfish Intermediate Filament Proteins: A New Frontier in Biomimetic Materials

Bell BE, Wasserman O, et al.

ACS Omega

Utah State University, Naval Surface Warfare Center Panama City Division

RESEARCH SUMMARY

This study developed aqueous hydrogel fibers from recombinant hagfish intermediate filament proteins and investigated how protein identity, protein concentration, and coagulation conditions influence their hydration, structure, and mechanics. Recombinant rHIF-α, rHIF-γ(C387S), and their natural 1:1 blend were dissolved in formic acid and spun into either deionized water or artificial saltwater to form hydrogel fibers in fully aqueous environments. The resulting fibers retained high water content, approximately 66 to 81% by mass, and showed substantial mass and diameter swelling. Mechanical performance was highly tailorable, with elastic moduli spanning roughly 10^2 to 10^3 kPa depending on formulation and processing, placing the materials within a range relevant to a variety of soft tissues. FTIR-ATR suggested substantial ordered secondary-structure content, while the authors noted that apparent beta-sheet assignments should be interpreted carefully because coiled-coil alpha-helical structures can contribute overlapping signals. SEM imaging revealed nanoporous internal architectures aligned along the fiber axis. Overall, the work establishes recombinant hagfish intermediate filament hydrogel fibers as a scalable and sustainably processed biomimetic material platform with tunable mechanics and hydrated fiber morphology.

Mechanical characterization of the hydrated recombinant hagfish hydrogel fibers was performed using a CellScale MicroTester G2. The authors adapted the instrument for submerged three-point bending using the included bath, either deionized water or saltwater as the testing medium, a custom 2 mm spacer, and a 0.4064 mm or 0.5588 mm tungsten beam. Individual hydrated fibers were mounted across the spacer gap under slight tension, clamped in place, and loaded downward at 0.0167 mm/s until failure or completion of the programmed test. Force and displacement data were recorded and combined with measured hydrated diameter to calculate stress, strain, energy to break, and elastic modulus using equations adapted for the three-point geometry. The MicroTester results showed that fiber mechanics were strongly tunable with formulation and environment: for example, 25% alpha and 25% 1:1 alpha/gamma fibers spun and tested in saltwater achieved the highest stresses and energy-to-break values within their groups, while deionized-water conditions generally reduced tensile performance. These measurements were central to the paper because they demonstrated that recombinant hagfish protein hydrogel fibers can be engineered across a broad mechanical range while remaining hydrated.

AUTHORS

Brianne E. Bell, Oran Wasserman, Thomas I. Harris, Hayden B. Johns, Paula E. Oliveira, Justin A. Jones.

PUBLICATION DETAILS

JOURNAL

ACS Omega

YEAR

2026

INSTITUTIONS

Utah State University, Naval Surface Warfare Center Panama City Division

COUNTRIES

United States

INSTRUMENT USED

MicroTester

TESTING METHODS

Flexural and Bending TestingHydrated and Temperature Controlled TestingMicro-Mechanical Testing

RESEARCH APPLICATIONS

Hydrogel Mechanical TestingMembranes and Thin Films Mechanics

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