Silk Fibroin: An Ancient Material for Repairing the Injured Nervous System

Abstract

Silk refers to a family of natural fibers spun by several species of invertebrates such as spiders and silkworms. In particular, silkworm silk, the silk spun by Bombyx mori larvae, has been primarily used in the textile industry and in clinical settings as a main component of sutures for tissue repairing and wound ligation. The biocompatibility, remarkable mechanical performance, controllable degradation, and the possibility of producing silk-based materials in several formats, have laid the basic principles that have triggered and extended the use of this material in regenerative medicine. The field of neural soft tissue engineering is not an exception, as it has taken advantage of the properties of silk to promote neuronal growth and nerve guidance. In addition, silk has notable intrinsic properties and the by-products derived from its degradation show anti-inflammatory and antioxidant properties. Finally, this material can be employed for the controlled release of factors and drugs, as well as for the encapsulation and implantation of exogenous stem and progenitor cells with therapeutic capacity. In this article, we review the state of the art on manufacturing methodologies and properties of fiber-based and non-fiber-based formats, as well as the application of silk-based biomaterials to neuroprotect and regenerate the damaged nervous system. We review previous studies that strategically have used silk to enhance therapeutics dealing with highly prevalent central and peripheral disorders such as stroke, Alzheimer’s disease, Parkinson’s disease, and peripheral trauma. Finally, we discuss previous research focused on the modification of this biomaterial, through biofunctionalization techniques and/or the creation of novel composite formulations, that aim to transform silk, beyond its natural performance, into more efficient silk-based-polymers towards the clinical arena of neuroprotection and regeneration in nervous system diseases.

Electrospun Poly(ethylene Terephthalate)/Silk Fibroin Composite for Filtration Application

“…The majority of the amino acids in silk fibroin are glycine (45.9%) and alanine (30.3%), which show minimal chemical reactivity and give the SF unique features including biocompatibility, biodegradability, and host–implantation integration. Silk fibroin has been due to its biocompatibility studied in many applications such as tissue and nervous system regeneration [ 114 , 115 ], wound dressing [ 58 , 116 ], drug release systems [ 117 ], and sutures [ 118 ]. Herein, the cytotoxic effects of 24 and 48 h exposure of the investigated samples were evaluated in HaCaT cells by the MTT assay.…”

Bombyx mori cocoon as a promising pharmacological agent: A review of ethnopharmacology, chemistry, and biological activities

“…The amino acid sequence and the by-products generated after silk degradation exhibited antioxidant and anti-inflammatory properties as well as affected different pathways involved in the pathogenesis of neurodegenerative disorders. Moreover, biomaterial properties of silk by itself (scaffold structure and biomechanical features) give it the capacity to interact with the target tissue providing tissue and cellular anchorage, stem cells, and/or drug delivery [ 103 ]. The theory in traditional medicine is that the heart produces the animal spirit, and the animal spirit enhances the physical spirit, and the natural spirit, and the spiritual spirit means the brain, and the natural spirit means the liver, and so the drugs that enhance the animal spirit That is, the heart is followed by the strengthening of the physical and natural spirits, which strengthen the spiritual soul to bring about happiness and relieve depression, which is why people with heart problems also show symptoms of depression and so Silk can be used in neurological studies.…”

Bioinspired silk fibroin materials: From silk building blocks extraction and reconstruction to advanced biomedical applications

“…Results showed that the cell-scaffold complex resulted in a smaller glial scar in the damaged spinal cord tissue and a marked improvement in motor function than that treated with pure SF scaffolds. These optimal multi-disciplinary approaches of combining SF biomaterials, seeding cells and bioactive factors also offered a promising treatment for the injured central nerves [ [152] , [153] , [154] ].…”