New opportunities for an ancient material.

Department of Biomedical Engineering, Tufts University, Medford, MA 02155, USA.
Science (Impact Factor: 31.48). 07/2010; 329(5991):528-31. DOI: 10.1126/science.1188936
Source: PubMed

ABSTRACT Spiders and silkworms generate silk protein fibers that embody strength and beauty. Orb webs are fascinating feats of bioengineering in nature, displaying magnificent architectures while providing essential survival utility for spiders. The unusual combination of high strength and extensibility is a characteristic unavailable to date in synthetic materials yet is attained in nature with a relatively simple protein processed from water. This biological template suggests new directions to emulate in the pursuit of new high-performance, multifunctional materials generated with a green chemistry and processing approach. These bio-inspired and high-technology materials can lead to multifunctional material platforms that integrate with living systems for medical materials and a host of other applications.

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    ABSTRACT: A paradigm shift for implantable medical devices lies at the confluence between regenerative medicine, where materials remodel and integrate in the biological milieu, and technology, through the use of recently developed material platforms based on biomaterials and bioresorbable technologies such as optics and electronics. The union of materials and technology in this context enables a class of biomedical devices that can be optically or electronically functional and yet harmlessly degrade once their use is complete. We present here a fully degradable, remotely controlled, implantable therapeutic device operating in vivo to counter a Staphylococcus aureus infection that disappears once its function is complete. This class of device provides fully resorbable packaging and electronics that can be turned on remotely, after implantation, to provide the necessary thermal therapy or trigger drug delivery. Such externally controllable, resorbable devices not only obviate the need for secondary surgeries and retr
    Proceedings of the National Academy of Sciences. 01/2014; 111(49):17385-17389.
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    ABSTRACT: In this study, we reported a novel silk fibroin (SF) nanofibrous films with robust mechanical properties which was fabricated by directly dissolving silk in CaCl2-Formic Acid (FA) solution for the first time. CaCl2-FA dissolved silk rapidly at room temperature, and more importantly, it disintegrated silk into nanofibrils instead of separated molecules. The morphology of nanofibrils crucially depended on CaCl2 concentrations, which resulted in different aggregation nanostructure in SF films. The SF film after drawing had maximum elastic modulus, ultimate tensile strength, and strain at break reaching 4 GPa, 106 MPa, and 29% in dry state, and reaching 206 MPa, 28 MPa, and 188% in wet state. Moreover, multiple yielding phenomena and substantially strain-hardening behavior was also observed in the stretched films, indicating the important role played by preparation method in regulating the mechanical properties of SF films. These exceptional and unique mechanical properties were suggested to be caused by preserving silk nanofibril during dissolution and stretching to align these nanofibrils. Furthermore, the SF films exhibit excellent biocompatibility, supporting marrow stromal cells (MSCs) adhesion and proliferation. The film preparation was facile, and the resulting SF films manifested enhanced mechanical properties, unique nanofibrous structures, and good biocompability.
    ACS Applied Materials & Interfaces 01/2015; · 5.90 Impact Factor
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    Wound Healing: Cellular Mechanisms, Alternative Therapies and Clinical Outcomes, Edited by L.E. Wade, 01/2015: pages 49-104; Nova Science Publishers., ISBN: 􀀜􀀚􀀛􀀐􀀔􀀐􀀙􀀖􀀗􀀙􀀖􀀐􀀗􀀚􀀘􀀐􀀘􀀜􀀚􀀛􀀐􀀔􀀐􀀙􀀖􀀗􀀙􀀖􀀐􀀗􀀚􀀘􀀐􀀘978-1-63463-475-5


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