Controlled release from multilayer silk biomaterial coatings to modulate vascular cell responses

Wang, Xianyan; Zhang, Xiaohui; Castellot, John J.; Herman, Ira M.; Iafrati, Mark D.; Kaplan, David L.

doi:10.1016/j.biomaterials.2007.10.055

Cited by 111 publications

(91 citation statements)

References 35 publications

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“…Silk fibroin is a biologically-derived protein polymer purified from domesticated silkworm (Bombyx mori) cocoons that has demonstrated excellent properties for biomedical applications, including biocompatibility (11)(12)(13)(14), robust mechanical strength (15), and slow, controlled degradation to nontoxic products in vivo (16). Silk can be prepared in a range of material formats, including films, hydrogels and microspheres (17,18).…”

mentioning

confidence: 99%

RETRACTED: Stabilization of vaccines and antibiotics in silk and eliminating the cold chain

Zhang

Pritchard

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

156

148

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Sensitive biological compounds, such as vaccines and antibiotics, traditionally require a time-dependent “cold chain” to maximize therapeutic activity. This flawed process results in billions of dollars worth of viable drug loss during shipping and storage, and severely limits distribution to developing nations with limited infrastructure. To address these major limitations, we demonstrate self-standing silk protein biomaterial matrices capable of stabilizing labile vaccines and antibiotics, even at temperatures up to 60 °C over more than 6 months. Initial insight into the mechanistic basis for these findings is provided. Importantly, these findings suggest a transformative approach to the cold chain to revolutionize the way many labile therapeutic drugs are stored and utilized throughout the world.

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mentioning

confidence: 99%

RETRACTED: Stabilization of vaccines and antibiotics in silk and eliminating the cold chain

Zhang

Pritchard

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

156

148

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“…For example, a hand-held gelforming and delivery device could be used for topical treatment of burns or filling tissue voids due to the material features and biocompatibility of silk-based biomaterials. [13][14][15][16] Even raw chicken meat was successfully used as a positive electrode, as tissue is sufficiently conductive to act as an electrogelation electrode, allowing the formation/deposition of silk e-gel on the surface. This result suggests applications in situ and in vivo.…”

mentioning

confidence: 99%

Electrogelation for Protein Adhesives

et al. 2010

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Adhesives are common in biology as critical elements in motility, adhesion, and survival for many land and sea creatures.[1] Despite many attempts to mimic such features with natural or synthetic polymers, this has proven to be challenging due to the subtle and metastable state of the polymeric material properties that are required to control the functional attributes of such systems including during storage, processing, adhesion, and release. The viscoelastic behavior also limits the types of material systems that can be exploited for biomimetic approaches to this important material behavior. Most often, modified polysaccharides are found associated with mucoadhesives from biological systems, due to their hydration and charge density. [2] We report the discovery of a novel, electrically mediated adhesive formed from silkworm silk. This process, termed electrogelation provides a protein-based adhesive that offers biomimetic features when used in conjunction with devices. Further, we report on the solution behavior, morphology, and structural features of electrogels (e-gels), to demonstrate the mechanisms involved in the process. The adhesion can be controlled via electrical inputs. Most importantly, and quite unexpectedly, this is a reversible process, depending on voltage, time, and conditions used. This finding is very novel, as silkbased protein systems in particular are usually considered irreversible in terms of polymer transitions from the solution to solid state, mediated most often by solvents and mechanical shear forces.The basis for the current discovery comes from recent observations where aqueous solutions of silkworm silk were exposed to direct current (DC). Under certain electric fields, the solution began to gel on the positive electrode (Fig. 1). This observation prompted further investigation into the conditions and responses of the solution under different electric fields. While electrospinning of polymers, including silks, is performed at voltage potentials as high as >30 kV, [3] the utilization of low DC voltages to generate a controlled volume of silk gel is novel. In the basic setup (Fig. 1), electrodes are immersed in an aqueous solution of silk protein and 25 V DC is applied over a 3 min period to a pair of mechanical pencil leads. As the process progresses, bubbles evolve on both electrodes. Since the silk solution has a high water content, electrolysis occurs during electrogelation. The bubbles reflect the generation of oxygen gas at the positive electrode and hydrogen gas at the negative electrode during electrolysis. Within seconds of the application of the voltage, a visible gel forms at the positive electrode, locking in some oxygen bubbles at the electrode surface as the gel emanates outward. While the gel appears to have formed symmetrically about the electrode in Figure 1, it is typical that the forming gel front is directed toward the negative electrode.When silk electrogelation is executed in a voltage-controlled format, the current draw in the process follows a repeated trend; ...

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“…3,[5][6][7][8] Silk fibroin (SF) is a natural polymer that is biocompatible, biodegradable and has various processing abilities, which makes it an ideal material for small diameter artificial vascular grafts. [9][10][11][12][13] Silk fibers are primarily composed of 2 types of proteins, sericin and SF. Sericin is an antigenic gum-like protein surrounding the fibers.…”

Section: Introductionmentioning

confidence: 99%

Effect of fibroin sponge coating on in vivo performance of knitted silk small diameter vascular grafts

et al. 2015

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ABSTRACT. Vascular grafts under 5 mm or less in diameter are not developed due to a problem caused by early thrombus formation, neointimal hyperplasia, etc. Bombyx mori silk fibroin (SF) which has biodegradability and tissue infiltration is focused as tube and coating material of vascular grafts. Coating is an important factor to maintain the strength of the anastomotic region of vascular grafts, and to prevent the blood leak from the vascular grafts after implantation. Therefore, in this research, we focused on the SF concentration of the coating solution, and tissue infiltration and remodeling were compared among each SF concentration. Silk poly (-ethylene) glycol diglycidyl ether (PGDE) coating with concentrations of 1.0%, 2.5%, 5.0%, and 7.5% SF were applied for the double-raschel knitted small-sized vessel with 1.5 mm diameter and 1cm in length. The grafts were implanted in the rat abdominal aorta and removed after 3 weeks or 3 months. Vascular grafts patency was monitored by ultrasound, and morphological evaluation was performed by histopathological examination. SF concentration had no significant effects on the patency rate. However, tissue infiltration was significantly higher in the sample of 2.5% SF in 3 weeks, and 1.0% and 2.5% SF in 3 months. Also, in comparison of length inside of the graft, stenosis were not found in 3 weeks, however, found with 5.0% and 7.5% in 3 months. From these results, it is clear that 2.5% SF coating is the most suitable concentration, based on the characteristics of less stenosis, early tissue infiltration, and less neointimal hyperplasia.

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Controlled release from multilayer silk biomaterial coatings to modulate vascular cell responses

Cited by 111 publications

References 35 publications

RETRACTED: Stabilization of vaccines and antibiotics in silk and eliminating the cold chain

RETRACTED: Stabilization of vaccines and antibiotics in silk and eliminating the cold chain

Electrogelation for Protein Adhesives

Effect of fibroin sponge coating on in vivo performance of knitted silk small diameter vascular grafts

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