Rapid formation of flexible silk fibroin gel‐like films

Abstract

Flexible silk fibroin gel-like films with microporous morphology were prepared from B. mori silk fibroin fibers directly solubilized in formic acid/CaCl 2 solvent. These films were characterized by several analysis techniques to determine the structure and properties of films. The pore size of gel-like films can be adjusted through SF concentration and Ca ions concentration. The controllable pore size in gel-like films was grew from 3-5 lm to 100 lm under the increase of fibroin concentration from 1.0 wt % to 8.0 wt %. At the same time, the water content of silk fibroin gel-like film decreased from 83.5 6 3.4% to 68.2 6 2.6%. With increasing Ca ions contents from 2.0 wt % to 10.0 wt % in dissolution process, the pore size and water content of silk fibroin gel-like films grew larger, especially its water content values reached 86.2 6 4.0% at 10.0 wt % Ca ions concentration. At wet condition, the gel-like film with b-sheet structure showed higher breaking stress (4.26 6 0.31 MPa) and elongation (45.45 6 15.79%) at 8.0 wt % concentration. With the preparation method, the membrane is hydrophilic and the pore size is adjustable, which contributes to high toughness and favorable cell growth environment, suggesting that these silk fibroin gel-like films can be a potential candidate scaffold for biomedical applications, such as wound dressing, facial mask, contact lenses, etc.

Influence of the Casting Concentration on the Mechanical and Optical Properties of FA/CaCl2-Derived Silk Fibroin Membranes

“…Although no definitive statement can be made in terms of significance due to the incremental standard deviations, an increase in fibroin concentration does seem to generate ameliorated mechanical properties (tensile strength) of fibroin membranes. The mechanical properties of the membranes manufactured in this study lie slightly below those described in other studies [38][39][40]. However, the different manufacturing processes and test procedures applied in this study must be considered.…”

“…In the present study, an alternative approach employing formic acid and calcium chloride as solvents for the production of B. mori derived silk fibroin membranes was used. As previously reported, silk may be efficiently and simply dissolved with a process containing formic acid and CaCl 2 solution [38][39][40]. Compared to other dissolution technologies, degummed silk transferred to FA/CaCl 2 was readily soluble at room temperature.…”

“…For instance, there exists no published literature on membranes produced in an analogous manner, which were then assessed in a wetted state. Even if direct comparisons remain difficult, the comprehensive results suggest, that the membranes produced inhabit lower elasticity values than other wetted membranes, while their tension strength prevails at comparable magnitude [38,39]. This could be due to the manufacturing process used, as it may potentially lead to a formation of merely impaired beta sheet structures.…”

Analysis of the Fibroin Solution State in Calcium Chloride/Water/Ethanol for Improved Understanding of the Regeneration Process

“…A distinct advantage results from the high biocompatibility and processability into a wide range of shapes, e.g. fibres, sponges, films, hydrogels and composites [8][9][10][11][12][13][14][15][16]. Fibroin dissolves in a number of concentrated aqueous salt solutions, such as CaCl 2 /water/ethanol (CWE) [12,15,[17][18][19][20], CaNO 3 /methanol/water [21] and LiBr [14,20,[22][23][24][25][26], NaSCN [27].…”

Surface modification of textile material through deposition of regenerated silk fibroin

“…The high biocompatibility of the biopolymer and the possibility to dissolve and regenerate the silk protein makes this protein of particular interest for preparation of medical material, i.e., composites for bone repair, vascular prostheses, implants, material for controlled drug release. [13][14][15][16][17][18][19] Degummed silk can be dissolved in a number of different highly concentrated salt solutions, representative examples are CaCl 2 /water/ethanol (CWE), [20][21][22][23][24][25][26] CaNO 3 / methanol/water, 27 LiBr, 7,29,30 NaSCN 31 and ionic liquids i.e., 1-allyl-3-methylimidazolium chloride. 32 In the majority of regeneration processes as a first step destabilization of the solution state of fibroin is achieved through reduction of the salt concentration by dialysis.…”