Regenerated Silk Fibroin Films with Controllable Nanostructure Size and Secondary Structure for Drug Delivery

Abstract

The ability of drug release from SF materials was governed largely by their secondary structure. It is known that the breakage degree of the peptide chain during the silk fibroin (SF) dissolution can affect the structure, property, and applications of SF materials. To deeply understand this effect, we designed a reaction system based on CaCl2/H2O/C2H5OH ternary solvent with different ethanol content to obtain the regenerated SF films with different morphologies and secondary structures. The results showed that the globule-like nanostructure was observed in all regenerated SF films, and their size decreased significantly with reducing the ethanol content in the solvent. Correspondingly, the β-sheet structure content of the SF films increased. In addition, the contact angle and the elongation ratio increased, and water absorption decreased significantly with decreasing the ethanol content in the solvent. The accumulated release percents of doxorubicin from these SF films were significantly different with increasing the time. With smaller nanostructure size and more β-sheet content, the SF films had a slower drug release at the beginning. This study indicated the importance of the ethanol content in the solvent in controlling the structure and properties of the regenerated SF films, which would improve the application of SF in drug delivery.

A Review of Structure Construction of Silk Fibroin Biomaterials from Single Structures to Multi-Level Structures

“…Jiang et al developed an ultrathin SF film (45 ± 5 nm) fabricated by the layer-by-layer assembly technique; the resulting film displayed high elastic modulus and ultimate tensile strength due to its gradual self-reinforcing structure [54]. The stability of SF films used as biomaterial is significant; this property can be improved by stretching [55], water annealing [56], slow-drying [57], and alcohol immersion [58]. Methanol or ethanol are most often used to prepare water-insoluble SF films with increased β-sheet content.…”

“…It was found that the structure and properties of SF films affected the release rate of drug delivery. SF films exhibited a slower doxorubicin release with smaller nanostructure and more β-sheet structure content [58]. Ceftazidime (CTZ) was successfully encapsulated into SF/gelatin mats and showed antibacterial effects during a release process of over six hours [71].…”

Self‐assembly of regenerated silk fibroin from random coil nanostructures to antiparallel β‐sheet nanostructures

“…Until now, regenerated silk fibroin (RSF) has been widely used to fabricate RSF‐based biomaterials for tissue engineering, drug delivery, and etc. The study of RSF self‐assembly mechanism could be useful for understanding the nanoscale structure formation of RSF‐based biomaterials.…”

Peptide and Protein-Based Nanomaterials in Applications for the Skin

“…Another type of fi broin-based nanomaterial reported were fi lms with controllable nanostructure (made of nanoglobules) and secondary structure, adequate as drug delivery systems. They proved successful in the sustained delivery, after an initial burst, of doxorubicin (chemotherapy drug) [ 52 ]. Electrospun silk fi broin nanofi bers were used by another research group to make nanoscaffolds (Chap.…”