Fabrication and Characterization of Sericin-PVA Composite Films from Gonometa postica, Gonometa rufobrunnea, and Argema mimosae: Potentially Applicable in Biomaterials

Kanono Comet Manesa; Temesgen Girma Kebede; Simiso Dube; Mathew Muzi Nindi

doi:10.1021/acsomega.2c00897

Fabrication and Characterization of Sericin-PVA Composite Films from Gonometa postica, Gonometa rufobrunnea, and Argema mimosae: Potentially Applicable in Biomaterials

ACS Omega. 2022 May 31;7(23):19328-19336. doi: 10.1021/acsomega.2c00897. eCollection 2022 Jun 14.

Authors

Kanono Comet Manesa¹, Temesgen Girma Kebede¹, Simiso Dube¹, Mathew Muzi Nindi²

Affiliations

¹ Department of Chemistry, University of South Africa, Florida Science Campus, Roodepoort 1709, South Africa.
² Institute for Nanotechnology and Water Sustainability (iNanoWS), College of Science, Engineering and Technology, University of South Africa, Florida Science Campus, 28 Pioneer Avenue, Roodepoort 1709, South Africa.

Abstract

This study deals with the fabrication and characterization of sericin-poly(vinyl alcohol) (PVA) composite films from three southern African silkworm cocoons. The sericin-PVA films were achieved by chemically cross-linking poly(vinyl alcohol) (PVA) with pure silk sericin protein using glutaraldehyde (GA) as a cross-linking agent. Fourier transform infrared (FTIR) results confirmed the overall cross-linking of pure silk sericin into PVA-GA networks to form cross-linked sericin-PVA films. This incident was shown by the incorporation of distinct major amide I (ν = 1640-1650 cm^-1), amide II (ν = 1538-1540 cm^-1), and amide III (ν = 1238-1244 cm^-1) peaks. X-ray diffraction (XRD) showed sericin-PVA films to have two features, one representing amorphous and crystalline regions of silk sericin and the other representing sharp high-intensity PVA peaks at around 2θ = 20.2°, demonstrating a high crystallinity in the films as a result of the hydroxyl groups in its side chain. The swelling capacity of the three sericin-PVA films was influenced by the glutaraldehyde content used during the cross-linking process and pH of the aqueous medium into which the films were immersed after a period of time. The water contact angles of the sericin-PVA films were low, at 56.6 ± 0.56 and 60.2 ± 0.86, indicating further their hydrophilic nature. The scanning electron microscopy (SEM) images of the sericin-PVA films showed a rough texture with a granular network pattern on their surface. From the preliminary results, it was observed that the cytotoxicity of three sericin strains (Gonometa rufobrunnea, Argema mimosae, and Gonometa postica) had a cell viability percentage of 103, 90, and 80% respectively, demonstrating their biocompatibility in providing a favorable natural microenvironment for cell culture. The characterization results of the three silk sericin-PVA films demonstrated their potential for application in biomedical and biomaterial fields.