Different properties of electrospun fibrous scaffolds of separated heavy-chain and light-chain fibroins of Bombyx mori

This study is the first to report on the fabrication and properties of electrospun scaffolds derived from separated light-chain fibroin and heavy-chain fibroin, two major proteins of silk fibroin. Among seven different extraction conditions, which were commonly used to extract fibroin from cocoons of Bombyx mori, only Ajisawa's reagent and 9 M lithium thiocyanate could extract both heavy-chain fibroin and light-chain fibroin, while the other conditions could yield only the light-chain fibroin. Mixed fibroin, light-chain fibroin, and heavy-chain fibroin were fabricated using electrospinning methods. Average diameters of the fibers were 658 +/- 208, 517 +/- 162, and 518 +/- 171 nm, respectively and their sizes after treatment with 50% methanol for 60 min were slightly increased to 747 +/- 244, 556 +/- 164 and 521 +/- 201 nm, respectively. FIR spectra showed similar predominant beta-sheet conformation of mixed fibroin and heavy-chain fibroin scaffolds after treated with methanol, whereas the predominant structure of light-chain fibroin was random coil conformation. Although, scaffolds derived from mixed fibroin and heavy-chain fibroin showed similar properties, the light-chain fibroin scaffold clearly exhibited different properties, including more hydrophilic character, water uptake ability, degradation rate, and cell adhesion capability. (C) 2010 Elsevier B.V. All rights reserved.