Silk electrogel coatings for titanium dental implants

Abstract

The aim of this study was to develop biocompatible, biodegradable dental implant coatings capable of withstanding the mechanical stresses imparted during implant placement. Two techniques were developed to deposit uniform silk fibroin protein coatings onto dental implants. Two novel coating techniques were implemented to coat titanium shims, studs, and implants. One technique involved electrodeposition of the silk directly onto the titanium substrates. The second technique consisted of melting electrogels and dispensing the melted gels onto the titanium to form the coatings. Both techniques were tested for coating reproducibility using a stylus profilometer and a dial thickness gauge. The mechanical strength of adhered titanium studs was assessed using a universal mechanical testing machine. Uniform, controllable coatings were obtained from both the electrodeposition and melted electrogel coating techniques, tunable from 35 to 1654 µm thick under the conditions studied, and able to withstand delamination during implantation into implant socket mimics. Mechanical testing revealed that the adhesive strength of electrogel coatings, 0.369 ± 0.09 MPa, rivaled other biologically derived coating systems such as collagen, hydroxyapatite, and chitosan (0.07-4.83 MPa). These novel silk-based techniques offer a unique approach to the deposition of safe, simple, mechanically robust, biocompatible, and degradable implant coatings.

Controlled release of cytokines using silk-biomaterials for macrophage polarization

“…Modulation of macrophage phenotype through burst release from silk as well as sustained control of attached macrophage may be useful for preventing giant cell formation and cannula occlusion. Silk solutions have previously been demonstrated to be capable of coating various surfaces such as glass 61 , plastics 62 , and metal 63,64 , and therefore the cytokine loaded silk films studied here could represent a good model for biomaterials and medical device coatings for the control of macrophage giant cell responses as well.…”

Silk Fibroin Aqueous-Based Adhesives Inspired by Mussel Adhesive Proteins

“…This indicates that silk itself, without catechol, can bond aluminum shims, a finding that is consistent with previous reports on silk hydrogels formed by electrogelation, although it is important to note that electrogelled silk hydrogel previously reported is reversible rather than permanent. 54,55 While the bonding strengths between CarboxySF(0)-dopamine and CarboxySF(6)-dopamine are not statistically different, a potential advantage of the catechol coupling is the exploitation of the catechol’s ability to associate with a variety of materials. Furthermore, a small amount of PEG conjugation in CarboxySF(6)-dopamine renders the material completely soluble and therefore increases handleability compared with CarboxySF(0)-dopamine .…”

3,4-Dihydroxyphenylalanine (DOPA)-Containing Silk Fibroin: Its Enzymatic Synthesis and Adhesion Properties

“…It also should be noted that a linear relationship between the concentrations of nonmodified SF and adhesive strength was confirmed, indicating that silk itself can bond mica substrates without a catechol moiety. Kaplan and co-workers reported similar features when they applied SF to the adhesion of titanium 46,47 and aluminum sheets, 39 while other groups demonstrated biocompatibility and strong adhesion of SF for skin. 48,49 Besides, we also investigated the adhesive properties of SF toward chamois leather.…”