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Protein Paper from Exfoliated Eri Silk Nanofibers
journal contribution
posted on 2020-02-21, 17:36 authored by Yujia Liang, Benjamin James Allardyce, Sanjeeb Kalita, Mohammad Gias Uddin, Sajjad Shafei, Dinidu Perera, Rechana Chandra
Nair Remadevi, Sharon Leanne Redmond, Warren Jeffrey Batchelor, Colin J. Barrow, Rodney J. Dilley, Hannes C. Schniepp, Xungai Wang, Rangam RajkhowaThe
exfoliation of silk fiber is an attractive method to produce
silk micro- and nanofibers that retain the secondary structure of
native silk. However, most fibrillation methods used to date require
the use of toxic and/or expensive solvents and the use of high energy.
This study describes a low cost, scalable method to produce microfibrillated
silk nanofibers without the use of toxic chemicals by controlling
the application of shear using commercially scalable milling and homogenization
equipment. Manipulation of the degumming conditions (alkaline concentration
and degumming temperature) and the shear in milling and/or homogenization
enabled control over the degree of fibrillation. The microfibrillated
silk was then characterized to determine structural change during
processing and the stability of the resulting suspensions at different
pH. Silk nanofibers obtained from milling degummed silk were characterized
using atomic force microscopy. Nanofibers obtained both with and without
high-pressure homogenization were then used to produce silk “protein
paper” through casting. Silk degumming conditions played a
critical role in determining the degree of microfibrillation and the
properties of the cast silk papers. The silk papers produced from
homogenized nanofibers showed excellent mechanical properties, high
water absorption, and wicking properties. The silk papers were excellent
for supporting the attachment and growth of human skin keratinocytes,
demonstrating application possibilities in healthcare such as wound
healing.