Making silk into an adhesive

March 11, 2019

The key: adding an amino acid structure to silk via enzymatic reaction

RIKEN CSRS researchers have found that enzymatically treating silk proteins (the core component of spider silk and silkworm thread) imparts adhesive-like physical properties.

It is well known that 3,4-dihydroxy-l-phenylalanine (DOPA), which is found in large amounts in blue mussels, contributes to the expression of excellent adhesive property that help mollusks stick to rocks, etc.

Researchers focused on the fact that silk proteins in silkworm threads contain appropriate amounts of tyrosine residues, a DOPA precursor, and using the enzyme tyrosinase to selectively catalyze those tyrosine residues to DOPA residues.

The DOPA-modified proteins clearly showed a large increase in adhesion when applied to the surface of various substances such as mica. Researchers also found no direct relationship between adhesion strength and beta-sheet formation when they examined the relationship between the modified protein’s secondary structure and its adhesive properties.

These results mark the first step in extending the use of silk proteins, a natural material, and should contribute to the realization of a sustainable society.

Original article
ACS Biomaterials Science and Engineering doi:10.1021/acsbiomaterials.8b01309
H. Sogawa, N. Ifuku, K. Numata,
"3,4-Dihydroxyphenylalanine (DOPA)-containing silk fibroin: its enzymatic synthesis and adhesion properties".
Hiromitsu Sogawa; Research Scientist
Nao Ifuku; Technical Staff
Keiji Numata; Team Leader
Biomacromolecules Research Team