Bioengineered nanostructures from silk proteins

AGFD 49

Amanda Murphy, Amanda.Murphy@tufts.edu1, Olena S. Rabotyagova, Olena.Rabotyagova@tufts.edu2, Rashid Juma1, Peggy Cebe, peggy.cebe@tufts.edu3, Carole C Perry, carole.perry@ntu.ac.uk4, and David L. Kaplan, David.Kaplan@tufts.edu1. (1) Department of Biomedical Engineering, Biotechnology & Bioengineering Center, Tufts University, 4 Colby Street, Medford, MA 02155, (2) Departments of Chemistry and Biomedical Engineering, Tufts University, 4 Colby St., Medford, MA, MA 02155, (3) Department of Physics and Astronomy, Tufts University, 4 Colby Street, Medford, MA 02155, (4) School of Biomedical and Natural Sciences, Nottingham Trent University, Clifton lane, Nottingham, NG11 8NS, United Kingdom
Silks from spiders and silkworms provide instructive fibrous proteins for study due to their self-assembly into novel materials. These protein systems have become models for new biomaterials to regulate cell and tissue functions, and provide an environmentally friendly alternative to synthetic materials. Silk proteins are also amenable to a variety of modification strategies, either via genetic engineering or selective organic chemistry, offering useful inroads into novel variants of the native proteins to add new functions. One approach with these systems has been to genetically redesign spider silk genes to import new functional features – i.e. protein chimeras. This approach establishes a new opportunity in biomaterials design and function where features such as the nanoscale beta sheet crystallites of the native spider silk protein are preserved, while new functional features are appended in genetically encoded additions. A few examples of the features that can be incorporated into these protein chimeras include cell-surface integrin binding domains (RGD), silica polymerization domains (from marine diatoms), and hydroxyapatite nucleating domains (from bone dentin matrix protein). A parallel synthetic chemistry approach can be utilized, where the use of selective chemical modifications can add function to native silk proteins, such as silkworm fibroin. Side-chain modification of the native fibroin can be tailored to promote selective cell interactions by attaching integrin-binding peptides or by incorporating moieties that can bind growth factors or ions that promote cell growth or differentiation. Particular side-chain modifications have also been shown to induce gellation of the protein, providing control of the physical as well as the chemical properties of the material. Both genetic and chemical approaches toward the goal of control of nanoscale features of silk materials will be described. The approaches establish a new and unique protein-based biomaterials platform upon which the native features of the silk proteins are exploited.
 

Advances in Biobased Nanostructures and Nanomaterials
1:30 PM-4:55 PM, Monday, August 20, 2007 BCEC -- 255, Oral

Division of Agricultural & Food Chemistry

The 234th ACS National Meeting, Boston, MA, August 19-23, 2007