Researchers at Tufts University have developed novel silk biomaterials that are surface-modified with polyethylene glycol (PEG).  These materials have utility in various biomedical applications where cell adhesion or thrombosis must be controlled.  The degree of PEGylation on each surface can be varied to tune the properties of the silk biomaterials.

Background

        Regulation of cell behavior on biomaterials is an essential element of wound repair and tissue engineering. Cell-to-biomaterial surface interactions are critical to the success of biomaterial design. Cell responses, such as attachment and proliferation, are dependent upon the biomaterial surface properties such as topography, surface energy, charge, mechanical properties, and the presence and concentration of cell recognition peptides.

        Modification of biomaterial surfaces may be used to convey information to cells without alteration of bulk material properties. Surface modification eliminates the need to blend materials or to synthesize new materials to achieve desired cell responses, which might negatively impact mechanical properties and/or degradation profiles. In addition, FDA-approved biomedical materials can be significantly enhanced by modification of their surfaces; in some cases reducing regulatory hurdles when compared to introducing or altering bulk material features.

Invention

        Tufts researchers have developed methods to surface-PEGylate silk matrices by reacting a functional group-activated PEG with the silk protein. Controlling the degree of PEGylation on surface of silk fibroin matrix regulates both the degradation rate of the silk matrix, and the differential adhesion of cells or adsorption of proteins on the surface of the silk matrix. The present invention also provides for silk fibroin matrices having one or more surfaces possessing differential adhesion properties, which allows for tissue integration on the adherent side and inhibition of tissue adhesion to the opposing tissues or organs. Embedding bioactive agents in silk fibroin matrices provides more benefits, such as promoting tissue ingrowth on the adherent side of the matrix.

Advantages

Silk is a revolutionary material that can outperform plastics, inorganic polymers, foams, and glass and add unforeseen functions to technologies where conventional materials are used.

- It is the strongest natural fiber available

- It is biocompatible, with controllable biodegradability

- It has insulating properties comparable to the best ceramics

- It is >99 percent transparent across the visible spectrum

- It can be manufactured in a variety of shapes and sizes

Intellectual Property

US Patent 9,427,499, Issued August 30, 2016

Inventors

David L. Kaplan, Ph.D., Charu P. Vepari, Ph.D., Tufts University School of Engineering

Tufts reference # T001537

Licensing Contact

Martin Son
martin.son@tufts.edu