Silk fibroin as a water-soluble bio-resist and its thermal properties. Issue 14 (28th January 2016)

• Record Type: Journal Article
• Authors: Morikawa, Junko; Ryu, Meguya; Maximova, Ksenia; Balčytis, Armandas; Seniutinas, Gediminas; Fan, Linpeng; Mizeikis, Vygantas; Li, Jingliang; Wang, Xuewen; Zamengo, Massimiliano; Wang, Xungai; Juodkazis, Saulius
• Is Part Of: RSC advances. Volume 6:Issue 14(2016)
• Page Start: 11863
• Page End: 11869
• Publication Date: 2016-01-28
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/c5ra20201a
• Languages: English
• ISSNs: 2046-2069

Abstract

Abstract : E-beam exposure unzips beta-sheets in crystalline domains of silk fibroin and makes it water-soluble, enabling its usage as an aqueous-based electron beam lithography resist. Abstract : Thermal diffusivity of silk fibroin films, α = (1.6 ± 0.24) × 10 −7 m 2 s −1, was measured by a direct contact method. It was shown to be reduced down to ∼1 × 10 −7 m 2 s −1 in the crystallized phase, consistent with the multi-domain composition of β-sheet assemblies. Crystalline silk with β-sheets was made by dipping into alcohol and was used as a positive electron beam lithography (EBL) resist. It is shown by direct IR imaging of the 1619 cm −1 amide-I CO spectral signature and 3290 cm −1 amide-A N–H stretching band that an e-beam is responsible for unzipping β-sheets, which subsequently results in exposed areas returning to a water soluble state. This makes it possible to develop a water-based biocompatible silk resist and use it in lithography applications. The general principles of protein crystallization, traceable to spectral changes in IR amide bands of silk, can be used as a guide for the creation of new protein EBL resists and to quantify the electron dose required for solubility. Foam formation and laser treatments of silk can provide new approaches in surface functionalization and fabrication of 3D bio-scaffolds.