Fibrous protein fusions and use thereof in the formation of advanced organic/inorganic composite materials
Inventors
Kaplan, David L. • Huang, Jia • Wong Po Foo, Cheryl • Naik, Rajesh • George, Anne
Assignees
Tufts University • University of Illinois System • United States Department of the Air Force
Publication Number
US-8501437-B2
Publication Date
2013-08-06
Expiration Date
2026-01-17
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Abstract
The claimed invention provides a fusion polypeptide comprising a fibrous protein domain and a mineralization domain. The fusion is used to form an organic-inorganic composite. These organic-inorganic composites can be constructed from the nano- to the macro-scale depending on the size of the fibrous protein fusion domain used. In one embodiment, the composites can also be loaded with other compounds (e.g., dyes, drugs, enzymes) depending on the goal for the materials, to further enhance function. This can be achieved during assembly of the material or during the mineralization step in materials formation.
Core Innovation
The claimed invention provides fusion polypeptides comprising a fibrous protein domain and a mineralization domain, which are used to form organic-inorganic composite materials. These composites can be constructed from the nano- to the macro-scale depending on the size of the fibrous protein fusion domain utilized. Additionally, these composite materials can be loaded with other compounds such as dyes, drugs, or enzymes during the assembly or mineralization steps to enhance their function.
The fibrous protein domain can be derived from proteins such as silk, collagens, coiled-coil leucine zipper proteins, elastins, keratins, actins, and tubulins. Preferred embodiments utilize sequences from spider silk protein Spidroin 1, with repeat units like SEQ ID NO: 1 or SEQ ID NO: 3 repeated multiple times. The mineralization domain is capable of inducing the formation of inorganic materials including hydroxyapatite, silica, cadmium sulfide, or magnetite, and can be derived from dentin matrix protein 1 (DMP1), bone sialoprotein (BSP), or peptides from the Silaffin-1 (Sil1) protein.
The invention addresses a need in tissue engineering and biomaterials for improved composite materials with better capacity to support complex tissue growth in vitro and in vivo. The problem being solved arises from the shortage of tissues available for transplantation and the challenge of designing biomaterials that can combine mechanical robustness with biological functionality. Conventional methods focused on chemical or mechanical modifications lacked sufficient control over mineralization and biological interactions. The present fusion proteins combine structural properties of fibrous proteins with functional mineralization domains, enabling controlled formation of biomaterials suited for scaffolds, tissue engineering, and drug delivery that mimic biological extracellular matrices and possess tunable mechanical and biological properties.
Claims Coverage
The patent includes two independent claims covering fusion polypeptides comprising fibrous protein domains derived from silk and mineralization domains, and methods of forming fibrous protein inorganic composites using these fusion proteins. Four main inventive features are identified from these claims.
Fusion polypeptide combining fibrous protein and mineralization domains
The fusion polypeptide comprises a fibrous protein domain obtained from silk incorporating repeat units as set forth in SEQ ID NO: 1 or SEQ ID NO: 3, linked with a mineralizing domain capable of inducing mineralization, derived from bone sialoprotein (BSP), silaffin-1 (Sil1) protein, or their functional fragments.
Method for forming fibrous protein inorganic composites using fusion proteins
A method comprises contacting a fusion protein with an inorganic material capable of mineralizing for a sufficient period to form mineralized coatings. The fusion protein includes the specified fibrous protein and mineralizing domain, with inorganic materials forming hydroxyapatite or silica.
Structural and compositional details of fusion proteins and materials
The fibrous protein domain is from Spidroin 1 silk protein with specific amino acid sequences as per SEQ ID NOs: 4 and 5. The mineralizing domain induces formation of hydroxyapatite, silica, cadmium sulfide, or magnetite and includes amino acid sequences set forth in SEQ ID NOs: 8 and 17-23. The fusion proteins can be formed into fibers, films, or sponges which may further comprise agents such as proteins, peptides, nucleic acids, PNAs, aptamers, antibodies, or small molecules for enhanced functionality.
Use of fusion proteins with specific sequences for biomaterials fabrication
Fusion proteins with amino acid sequences including SEQ ID NOs: 11, 12, 24, and 25 are claimed; these fusion polypeptides combine silk-derived fibrous domains and mineralizing domains from BSP or Sil1 peptides, enabling the formation of composite biomaterials with controlled mineralization properties.
The claims cover fusion polypeptides composed of silk-derived fibrous domains combined with mineralizing domains, and methods for fabricating organic-inorganic composites by mineralization of such fusion proteins. The inventive features focus on specific sequence compositions, mineralization capabilities, formation of biomaterial forms, and incorporation of functional agents to enhance performance.
Stated Advantages
Ability to form organic-inorganic composite materials at nano- to macro-scale with tunable mechanical and biological properties.
Fusion polypeptides combine the robust mechanical features of fibrous proteins like silk with mineralization domains able to induce controlled formation of inorganic materials such as hydroxyapatite and silica.
Composite materials can be loaded with functional compounds such as dyes, drugs, and enzymes during assembly or mineralization to enhance biological function.
The method allows production of biomaterial scaffolds that mimic extracellular matrices, support complex tissue growth, and provide controlled mechanical properties for specific tissue engineering applications.
Capability to incorporate and stabilize growth factors, biological regulators, enzymes, therapeutics, or cells in constructs for long-term release and activity control.
Documented Applications
Use in biomaterials, tissue engineering, and advanced material composites for scaffold formation.
Formation of medical biomaterial products including wound closure systems, hemostatic dressings, sutures, drug delivery platforms, ligament prosthetics, and bio-degradable implants.
Tissue engineering scaffolds such as non-woven networks of electrospun fibers for nerve conduits, bone conduits, and other tissue regeneration applications.
Applications in organ repair, replacement, and regeneration for tissues including spinal discs, cranial tissue, dura, nerve tissue, liver, pancreas, kidney, bladder, spleen, cardiac and skeletal muscle, tendons, ligaments, and breast tissue.
Delivery systems for therapeutic agents including antibiotics, antiviral agents, chemotherapeutics, anti-inflammatory agents, hormones, growth factors, and other bioactive compounds incorporated in the fusion protein materials or inorganic coatings.
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