Encapsulation of oil in silk fibroin biomaterials

Abstract

Microencapsulation is becoming increasingly important in the food, cosmetics, and medicinal industries due to its potential for stabilization and delivery of volatile and delicate compounds. Novel food-safe techniques for encapsulating oil in silk biomaterials using emulsion-based processes that exploit silk's unique properties (including amphiphilicity, biocompatibility, aqueous and ambient processing, and tunable physical crosslinking behavior) are described. The sonication-induced self-assembly of silk previously applied to hydrogel fabrication replaced the use of the thermal or chemical suspension crosslinking traditionally used to stabilize the aqueous protein phase in emulsions. Stable, physically crosslinked silk micro-and macro-particles loaded with oil or water-soluble dye were produced by aliquoting sonicated silk solutions into an oil bath. Oil micro-droplets emulsified in aqueous silk solutions did not impede the self-assembly of silk into films or hydrogel networks. In O/W/O emulsions, particle morphology and silk permeability to a model lipophilic dye in the interior phase were controllable via processing.

Silk Fibroin as Edible Coating for Perishable Food Preservation

“…In this study, we report the use of silk fibroin suspension as an edible coating material for perishable fruit preservation. Silk fibroin is generally considered flavorless and odorless, which are compelling properties for food coating and packaging applications 33 34 . A Silk fibroin suspension was used to coat freshly picked strawberries through dip coating ( Fig.…”

Challenges and opportunities of silk protein hydrogels in biomedical applications

“…The synergistic effect of hydrogen bonding, hydrophobic forces, and static electricity leads to dehydration of the molecular chains, causing the aggregation of silk fibroin molecules and accelerating the ''sol-gel'' transformation. 99 Wang et al 44 used the ultrasonic method to treat silk fibroin aqueous solution and optimized the parameters to obtain degradable hydrogels with elastic moduli up to 369-1712 kPa, with a treatment time of 0.5-2.0 h. After ultrasound, silk fibroin hydrogels of different concentrations can achieve a three-dimensional uniform loading of human bone marrow mesenchymal stem cells (hBMSCs). After 21 days of incubation, the cells maintained high survival and growth rates.…”

Extended release formulations using silk proteins for controlled delivery of therapeutics

“…Injectable formats including nanoparticles, microparticles and hydrogels; implantable forms like films, wafers, foams, tubes, rods, reservoirs and transdermal systems like microneedles are among the silk-based delivery systems reported (Figure 1). Silk-based O/W/O micro-emulsions were used to encapsulate and control the delivery of oils and volatile compounds such as fragrances, also applicable to deliver hydrophobic therapeutic molecules 56 . Silk fibroin has also been used as a coating material to increase residence time and cell recognition 57 .…”