Influence of the protocol of fibroin extraction on the antibiotic activities of the constructed composites

Abstract

The effect of the solvents for silk fibroin (SF) extraction on its antimicrobial activity was studied. Extraction protocols were performed using LiBr (SFL) and Ajisawa’s reagent (CaCl2:ethanol:H2O) (SFC). The morphological and structural characteristics of the extracted SF and their composites were assessed. Corresponding bactericidal activities against Staphylococcus aureus (ATCC 25923), Escherichia coli (ATCC 25922) and Pseudomonas aeroginosa (ATCC 27853) were performed. The resulting solutions were either casted into films or individually incorporated into composites of silver nanoparticles (NS) embedded into chitosan fragments (Cs) through γ-irradiation. Films of SF, obtained by using the two solvents, as well as the final prepared composites of SF, NS and Cs were analyzed using XRD, FTIR, SEM, TEM and zeta potential at several pH values. The band gap values were calculated. The results proved that, although SFC consumed shorter gelation time, yet SFL exerted higher antibiotic activity against the tested microorganisms. Moreover, the final composites had the ability to significantly reduce the growth of these medically relevant bacteria and are, therefore, recommended as a novel natural antibacterial biomaterial for several biomedical applications.

Synthesis and characterization of nontoxic silver nano-particles with preferential bactericidal activity

“…The silver nanoparticles spectrum exhibited clear peaks of cubic phase (JCPDS No. 03-0921) at 2θ =38.7 (1 1 1), 44.5 (2 0 0), 64.5 (2 2 0) coinciding with the TEM results [40][41].…”

Structural stability of biofilms produced from silkworm cocoon fibers

“…This peak could be ascribed to the π → π* electron transition of aromatic, tyrosine, phenylalanine and tryptophan amino acid residues in the fibroin chain. 4,9 The elevated transparency of the biofilms was a desired characteristic, given the various possible applications of this kind of material, whether in optics or even biomedical fields (encapsulating drugs, colorants, nanoparticles, etc.). Some studies in the literature show that transparency can be directly associated with the method used to obtain the fibroin solution.…”

“…One such material is the fiber produced and synthesized in the glands of the silkworm, Bombyx mori. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] At the end of the larval stage, the silkworm produces silk fibers to *Corresponding author: hensan@uel.br https://doi.org/10.2298/JSC210611054F; Published 24 July, 2021 O n L i n e F i r s t form a cocoon by a complex spinning process. Most of the cocoon consists of fibroin fibers cemented together by another protein, sericin, that acts as an adhesive.…”

“…The salts involved in both degumming and dissolution are removed by dialysis to obtain an aqueous SF solution. 1,[3][4][5] The aqueous SF solution can be used as is or to produce versatile forms of fibroin such as powder, nanofibers, films, hydrogels and sponges, according to the field of application and by virtue of its biocompatibility, controllable degradation, ease of processing and availability in the sericulture industry. 3,6 SF biofilms are one of the most important and valuable support biomaterials with applications in fields like biomedicine, electronics, textile engineering, optoelectronics, energy collection/storage, biosensors, food coatings, etc.…”

The Bombyx mori L., Nanofibroin Has Potential for Composite Filler Restoration

“…New challenges in developing nanofibroin as composite resin filler are glycine content in fibroin with high concentrations as an bacterial agent [6]. So there is a challenge to develop nanofibroin as a filler that can prevent the emergence of secondary caries.…”