Biomedical applications of silk and its role for intervertebral disc repair

Abstract

Intervertebral disc (IVD) degeneration (IDD) is the main contributor to chronic low back pain. To date, the present therapies mainly focus on treating the symptoms caused by IDD rather than addressing the problem itself. For this reason, researchers have searched for a suitable biomaterial to repair and/or regenerate the IVD. A promising candidate to fill this gap is silk, which has already been used as a biomaterial for many years. Therefore, this review aims first to elaborate on the different origins from which silk is harvested, the individual composition, and the characteristics of each silk type. Another goal is to enlighten why silk is so suitable as a biomaterial, discuss its functionalization, and how it could be used for tissue engineering purposes.The second part of this review aims to provide an overview of preclinical studies using silk-based biomaterials to repair the inner region of the IVD, the nucleus pulposus (NP), and the IVD's outer area, the annulus fibrosus (AF). Since the NP and the AF differ fundamentally in their structure, different therapeutic approaches are required.Consequently, silk-containing hydrogels have been used mainly to repair the NP, and silk-based scaffolds have been used for the AF.

Review of Spider Silk Applications in Biomedical and Tissue Engineering

“…Ligament tissue regeneration is complex and still under research, whereas silk-based materials show great promise [ 25 ]. For the repair of damaged intervertebral discs by using silk (hydrogels with silk and silk-based scaffolds), preclinical studies have shown excellent results [ 26 ], but clinical studies are still missing.…”

The osteogenic effects of sponges synthesized with biomaterials and nano-hydroxyapatite

“…Several researchers and doctors use surgical methods to minimize pain while treating patients (Chaudhary and Chakraborty 2022). A common method is to isolate specific cells of a tissue from a patient, grow them on a threedimensional scaffold under previous culture conditions, and transplant them to a suitable site such that human tissue is fused with a degradable scaffold (Croft et al 2022). Scaffolds are known to play an important role in fracture healing, bone defect healing, and renal cartilage formation, as reported in various previous studies (Dou et al 2021).…”

Repairing Annulus Fibrosus Fissures Using Methacrylated Gellan Gum Combined with Novel Silk

“…However, to fulfil these demanding requirements and to improve the chances of success, the combination of two or more biomaterials could be necessary. A promising biomaterial for tackling this challenge is silk fibroin, which has a relatively long and extensive history for IVD repair [19], as well as gellan gum (GG) and its derivatives. Silk fibroin has proven to be a very encouraging biomaterial because of its excellent biocompatible properties, low immunogenicity, and the fact that it can be processed into many different scaffold morphologies [20,21].…”

“…Silk fibroin has proven to be a very encouraging biomaterial because of its excellent biocompatible properties, low immunogenicity, and the fact that it can be processed into many different scaffold morphologies [20,21]. For the regeneration of the NP, silk fibroin has mainly been used as a hydrogel, whereas firm scaffolds have been the preferred choice for regenerating the AF in past studies [19]. GG, the second biomaterial used in this study, is an exopolysaccharide which is produced through microbial fermentation by bacteria from the Sphingomonas group [22].…”