Silk nanoparticles: from inert supports to bioactive natural carriers for drug delivery

Abstract

Silk proteins have been studied and employed for the production of drug delivery (nano)systems. They show excellent biocompatibility, controllable biodegradability and non-immunogenicity and, if needed, their properties can be modulated by blending with other polymers. Silk fibroin (SF), which forms the inner core of silk, is a (bio)material officially recognized by the Food and Drug Administration for human applications. Conversely, the potential of silk sericin (SS), which forms the external shell of silk, could still be considered under evaluation. At the best of our knowledge, nanoparticles based on silk sericin "alone" cannot be produced, due to its physicochemical instability influenced by extreme pH, high water solubility and temperature; for these reasons, it almost always needs to be combined with other polymers for the development of drug delivery systems. In this review, we focused on silk proteins as bioactive natural carriers, since they show not only optimal features as inert excipients, but also remarkable intrinsic biological activities. SF has anti-inflammatory properties, while SS presents antioxidant, anti-tyrosine, anti-aging, anti-elastase and anti-bacterial features. Here, we give an overview on SF or SS silk-based nanosystems, with particular attention on the production techniques.

Production of Curcumin-Loaded Silk Fibroin Nanoparticles for Cancer Therapy

“…Recently, Crivelli et al [ 64 ] have reviewed the SFNs preparation methods and highlighted that SFNs can even act as bioactive natural carriers, since they show not only optimal features as inert excipients, but also remarkable intrinsic biological activities such as anti-inflammatory properties. This point is especially interesting because SFNs can be considered bioactive compounds able to improve and support some active principle ingredient effects.…”

Comparative Study of Silk-Based Magnetic Materials: Effect of Magnetic Particle Types on the Protein Structure and Biomaterial Properties

“…The highly crosslinked silk fibril network structure through β-sheet crystals is believed to also cause the insolubility of the regenerated silk materials in water and many mild organic solvents [ 10 , 21 ]. Different types of silk materials, such as silk films, gels, particles and fibers, have shown great potential in biomedical applications [ 22 , 23 , 24 , 25 ], and by manipulating their secondary structure, one can control the release time and dose during targeted drug delivery [ 18 , 26 ]. A high content of β-sheet crystals, which can be stimulated through alcohol solutions or water annealing, also helps to improve cell adhesion and tissue growth [ 25 , 27 , 28 ].…”

Water‐insoluble amorphous silk fibroin scaffolds from aqueous solutions

“…Regenerated silk fibroin (RSF), derived from the silkworm cocoon, is a useful biomaterial as a cell‐support matrix for osteoblasts, endothelial cells, nerve cells and various stem cells, as a scaffold for bone, cartilage, muscle, blood vessels, skin and nerves, and as a carrier for hydrophilic and hydrophobic drugs and growth factors (Chen, Chen, Kuo, Li, & Chen, ; Crivelli et al, ; Farè et al, ; Font Tellado et al, ; Font Tellado et al, ; Hennecke et al, ; Jo et al, ; Kundu, Rajkhowa, Kundu, & Wang, ; Le, Liaudanskaya, Bonani, Migliaresi, & Motta, ; Moses, Nandi, & Mandal, ; Musson et al, ; Sell, McClure, Ayres, Simpson, & Bowlin, ; Teuschl et al, ; Woloszyk, Buschmann, Waschkies, Stadlinger, & Mitsiadis, ; Y. P. Zhang et al, ). Besides the inherent virtues of silk fibroin, such as biocompatibility, a green formation process, and tunable biodegradability, another feature is its diversity of conformations, hierarchical microstructures and various material states, endowing the possibility of designing biomaterials with selective and useful performance (Gorenkova et al, ; Hu et al, ; Kumar, Nandi, Kaplan, & Mandal, ; Qi et al, ; Rockwood et al, ).…”