Silk Proteins as Biomaterial Additives for DMSO-Reduced Cryopreservation

Area of Science:

• Biomaterials Science
• Cell Biology
• Cryobiology

Background:

• Cryopreservation is vital for cell therapies, but cryoprotective agent toxicity, like dimethyl sulfoxide (DMSO), limits its use.
• Developing safer cryopreservation methods is crucial for applications needing repeated cell administration or long-term storage.

Purpose of the Study:

• To investigate silk-derived proteins (silk fibroin and silk sericin) as additives for DMSO-sparing cryopreservation.
• To evaluate the efficacy of hybrid silk-protein/DMSO formulations for preserving mouse fibroblasts (3T3 cells).

Main Methods:

• Mouse fibroblasts (3T3) were cryopreserved using conventional DMSO, silk-only, and hybrid silk-protein/reduced DMSO formulations.
• Post-thaw cell adhesion, metabolic activity, membrane integrity, and cytoskeletal organization were assessed over 7 days.

Main Results:

• Complete replacement of DMSO with silk proteins did not ensure cell survival, highlighting the need for permeating cryoprotectants.
• Hybrid formulations with silk fibroin or sericin and 5% DMSO significantly improved post-thaw viability, cytoskeletal integrity, and recovery kinetics.
• Cell viability in hybrid formulations exceeded thresholds and outperformed DMSO-only groups.

Conclusions:

• Biomaterial-based additives can be integrated into hybrid cryopreservation formulations to reduce DMSO toxicity.
• These findings offer design principles for preserving complex multicellular systems using silk-protein-based cryoprotective strategies.