S. Roberts, M. Anderson, E. Budziszewski, R. Putnam, S. Hollenbeck, A. Chilkoti
inSoma Bio, Inc.,
United States
Keywords: protein, polymer, reconstruction, disorder, regeneration, vascularization, fat grafting, nerve
Summary:
Fractomer™ represents a new commercial class of intrinsically disordered protein (IDP) biomaterials designed to bridge the gap between synthetic polymers and native extracellular matrices. Engineered from elastin-inspired recombinant polypeptides, Fractomer™ exhibits a tunable thermal liquid–solid phase transition that enables precise control over injectability, structure formation, and tissue integration. Below its transition temperature, Fractomer™ remains a low-viscosity liquid that can be readily delivered through fine-gauge needles or mixed directly with autologous tissue. Upon exposure to physiological temperature, it self-assembles into a cohesive, viscoelastic scaffold that mimics the mechanical and biological characteristics of soft tissue. This behavior provides physicians with a unique capability—to inject a shapable material that conforms to complex anatomical geometries and then transitions in situ into a stable, vascular-permissive matrix. At the molecular level, Fractomer™ is composed of partially ordered domains embedded within a disordered protein backbone, enabling reversible, non-covalent crosslinking without chemical initiators or exogenous catalysts. This intrinsic “thermal switch” offers both manufacturing and clinical advantages, facilitating a chromatography-free purification process while yielding a biocompatible material free of synthetic crosslinkers or reactive residues. The result is a recombinant polymer platform that combines scalability with consistent biological performance. The first clinical indication for Fractomer™ is autologous fat grafting, where the material is combined with lipoaspirate to restore the structural and mechanical integrity lost during liposuction. The procedure is increasingly chosen by patients seeking natural reconstruction instead of synthetic implants or fillers, yet current methods often require multiple sessions to achieve stable outcomes due to graft resorption and loss of structure. Fractomer™ addresses these limitations by acting as a transient, viscoelastic scaffold that restores the mechanical framework of adipose tissue and supports early revascularization. In small and large animal models, Fractomer™ combined with lipoaspirate produced grafts with improved mechanical strength, reduced fibrosis, and enhanced host vessel infiltration compared with fat alone. Comprehensive ISO 10993 biocompatibility testing—including cytotoxicity, sensitization, genotoxicity, systemic and intracutaneous reactivity, and sub-chronic toxicity—has confirmed a highly favorable safety profile, with no evidence of adverse inflammatory or immune reactions. Histological evaluations across multiple species show mild, resolving macrophage activity and progressive tissue integration without encapsulation, supporting its readiness for human use. Building on this foundation, Fractomer™ is now advancing into first-in-human studies under an Investigational Device Exemption (IDE). Beyond fat grafting, the Fractomer™ platform is being extended to peripheral nerve repair, where tailored formulations serve as injectable nerve wraps or fillers that guide axonal regrowth while minimizing fibrosis. Early preclinical data indicate improved organization of regenerating fibers and reduced scarring compared with existing synthetic or allogeneic matrices, suggesting broader potential for neural and soft-tissue interface repair. Fractomer™ represents a clinically advancing example of how recombinant protein engineering can be applied to create scalable, thermally responsive polymers for tissue reconstruction. Its modular design and biocompatibility profile support broad applicability across reconstructive indications where soft-tissue structure and vascularization are critical. As Fractomer™ enters first-in-human evaluation, it stands to define a new class of intrinsically disordered protein materials translated from molecular design to clinical use.