Immune Response to Silk Sericin–Fibroin Composites: Potential Immunogenic Elements and Alternatives for Immunomodulation

Abstract

The unique properties of silk proteins (SPs), particularly silk sericin (SS) and silk fibroin (SF), have attracted attention in the design of scaffolds for tissue engineering over the past decades. Since SF has good mechanical properties, while SS displays bioactivity, scaffolds combining both proteins should exhibit complementary properties enhancing the potential of these materials. Unfortunately, SS-SF composites can generate chronic immune responses and their immunogenic element is not completely clear. The potential of SS-SF composites in tissue engineering, elements which may contribute to their immunogenicity, and alternatives for their preparation and design, to modulate the immune response and take advantage of their useful properties, are discussed in this review. It is known that SS can enhance 𝜷-sheet formation in SF, which may act as hydrophobic regions with a strong affinity for adsorption proteins inducing the chronic recruitment of inflammatory cells. Therefore, tailoring the exposure of hydrophobic regions at the scaffold surface should represent a viable strategy to modulate the immune response. This can be achieved by coating SS-SF composites with SS or other hydrophilic polymers, to take advantage of their antibiofouling properties. Research is still needed to realize the full potential of these composites for tissue engineering.

Silk Fibroin as a Bioink – A Thematic Review of Functionalization Strategies for Bioprinting Applications

“…Sericin extracted during the degumming process of raw silk from B. mori can also serve as an interesting additive to enhance SF bioink printability and cytocompatibility. While it was initially thought that sericin could produce an immunogenic response, it was later found that it was the native combined fibroin–sericin structure that causes such immunogenic response. , Sericin alone does not elicit immunogenicity and has been widely used in the cosmetic industry and as a cell culture serum and cryoprotectant . The use of sericin as a hydrogel was explored as a wound dressing material and was found to elicit a minimal inflammatory response .…”

Biomedical applications of silk and its role for intervertebral disc repair

“…SS has been recognized as the immunogenic element of the silk filament for years, which has fuelled research into the purification of SF and its regeneration. However, researchers demonstrated that the immunogenicity of the silk fiber is mainly due to the combination of SS with SF, although the mechanism responsible for initiating the immune response is not yet fully understood 163 …”

“…However, researchers demonstrated that the immunogenicity of the silk fiber is mainly due to the combination of SS with SF, although the mechanism responsible for initiating the immune response is not yet fully understood. 163 …”

In Situ Synthesized Porous Bacterial Cellulose/Poly(vinyl alcohol)‐Based Silk Sericin and Azithromycin Release System for Treating Chronic Wound Biofilm

“…[ 22 ] Moreover, it possesses antioxidant activity against the overexpression of free radicals and has the ability to reduce inflammation, which together contribute to accelerate the wound healing process. [ 22,23 ] In wounds, SS induces proliferation and adhesion of fibroblasts and keratinocytes, leading to collagen synthesis and epithelialization. [ 22,23 ] These properties justify the adequacy of SS as a wound‐healing biocompatible material.…”

“…[ 22,23 ] In wounds, SS induces proliferation and adhesion of fibroblasts and keratinocytes, leading to collagen synthesis and epithelialization. [ 22,23 ] These properties justify the adequacy of SS as a wound‐healing biocompatible material. However, SS alone cannot be used as a biomaterial due to its amorphous structure.…”