2.12 Silk Biomaterials ☆

Stoppel, Whitney L.; Raia, Nicole; Kimmerling, Erica P.; Wang, Shu; Ghezzi, Chiara E.; Kaplan, David L.

doi:10.1016/b978-0-12-803581-8.10247-4

Cited by 12 publications

(9 citation statements)

References 225 publications

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“…e main AAs of SF are glycine (43.7%) and alanine (28.8%) that form the dominant crystalline β-sheet regions that act as reinforcements and contribute to the strength and stiffness of silk [9,10]. Although silk is defined as a nondegradable material by the United States Pharmacopeia owing to a negligible loss in tensile strength in vivo, the enzymatic degradation behaviors of SF as biomaterials have been reviewed for the medical application in vivo [11,12]. e in vitro biodegradation of B. mori SF was studied using proteolytic enzymes (collagenase F, α-chymotrypsin I-S, and protease type XXI) to degrade SF fibers and films [13].…”

Section: Introductionmentioning

confidence: 99%

Application of Food-Grade Proteolytic Enzyme for the Hydrolysis of Regenerated Silk Fibroin fromBombyx mori

Joung

Park

You

et al. 2018

Journal of Chemistry

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In vitro biodegradation of Bombyx mori silk fibroin (SF) was studied using food-grade proteolytic enzymes to replace acid hydrolysis. Based on the residual protein quantity and yield of amino acids (AAs) after enzymatic hydrolysis, we evaluated the proteolytic enzyme process of SF. FoodPro and Alcalase that are classified as alkaline proteases are selected as two of the best candidate enzymes for hydrolysis of SF. e activity of these enzymes exhibits a broad range of pH (6.5 to 9.0) and temperature (50°C to 65°C). e single enzyme treatment of SF using FoodPro exhibited a hydrolytic efficiency of 20-25%, and >2 g/L AAs were released after reaction for 3 h. A 2-stage enzymatic treatment using a combination of FoodPro and Flavourzyme in a sequence for a reaction time of 6 h was developed to enhance the efficiency of the proteolytic process. e yield of AAs and residual protein quantity in the enzymatic hydrolysates obtained from FoodPro-treated regenerated SF in the 1st step was 2,040 ± 23.7 mg/L and 70.6%, respectively. e yield of AAs was > two-fold (4,519 ± 42.1 mg/L), whereas the residual protein quantity decreased to 55.1% after the Flavourzyme treatment (2nd step) compared to those of the single FoodPro treatment. In the mixed treatment by simultaneously using FoodPro and Flavourzyme, approximately 45% of SF was degraded and 4.5 g/L of AAs were released within 3 h of reaction time. e regenerated SF and its enzymatic hydrolysates were characterized by performing UV-visible spectra, gel electrophoresis, and size-exclusion chromatography analyses. In the 2-stage treatment using FoodPro initially and subsequently Flavourzyme, the aggregates and high molecular weight proteins of SF were dissociated and degraded into the low molecular weight proteins/peptides (10-15 kDa and 27 kDa). SF hydrolysates as functional food might be enzymatically produced using the commercial food-grade proteolytic enzymes.

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Section: Introductionmentioning

confidence: 99%

Application of Food-Grade Proteolytic Enzyme for the Hydrolysis of Regenerated Silk Fibroin fromBombyx mori

Joung

Park

You

et al. 2018

Journal of Chemistry

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“…Alanine provides extraordinary strength, while glycine gives elasticity to the spider silk [ 41 , 45 ]. Recently, spider silk has been used in a wide range of biomaterials, such as films, matrices, and hydrogels, and spider silk-based materials are involved in diverse biomedical applications [ 46 , 47 , 48 , 49 , 50 ]. Recombinant spider silk produced in different host organisms has commonly been used in recent silk-based material synthesis studies with artificial repetitions of known amino acid sequences and predesigned secondary structural advancements.…”

Section: Introductionmentioning

confidence: 99%

Native Spider Silk-Based Antimicrobial Hydrogels for Biomedical Applications

et al. 2021

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Novel antimicrobial natural polymeric hybrid hydrogels based on hyaluronic acid (HA) and spider silk (Ss) were prepared using the chemical crosslinking method. The effects of the component ratios on the hydrogel characteristics were observed parallel to the primary physicochemical characterization of the hydrogels with scanning electron microscopic imaging, Fourier-transform infrared spectroscopy, and contact angle measurements, which confirmed the successful crosslinking, regular porous structure, exact composition, and hydrophilic properties of hyaluronic acid/spider silk-based hydrogels. Further characterizations of the hydrogels were performed with the swelling degree, enzymatic degradability, viscosity, conductivity, and shrinking ability tests. The hyaluronic acid/spider silk-based hydrogels do not show drastic cytotoxicity over human postnatal fibroblasts (HPF). Hydrogels show extraordinary antimicrobial ability on both gram-negative and gram-positive bacteria. These hydrogels could be an excellent alternative that aids in overcoming antimicrobial drug resistance, which is considered to be one of the major global problems in the biomedical industry. Hyaluronic acid/spider silk-based hydrogels are a promising material for collaborated antimicrobial and anti-inflammatory drug delivery systems for external use. The rheological properties of the hydrogels show shear-thinning properties, which suggest that the hydrogels could be applied in 3D printing, such as in the 3D printing of antimicrobial surgical meshes.

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“…Biodegradable synthetic ( Agrawal and Ray, 2001 ; Tyler et al, 2016 ; Chen et al, 2019 ) and natural ( Aamodt and Grainger, 2016 ; Stoppel et al, 2017 ; Huang et al, 2018 ; Park and Woo, 2018 ; Wang et al, 2019 ) biomaterials have been utilized as scaffolds for tissue engineering and as platforms for in vitro culture to aid in tissue reconstruction and fundamental studies of developmental biology and disease pathology. For in vivo applications, knowledge of degradation rates is essential as the implanted materials should have controllable and predictable break down that complements the rate of neo-tissue formation and regeneration, providing necessary or complementary signaling modulators for wound healing and tissue repair ( Tabata, 2001 ; Shin et al, 2003 ).…”

Section: Introductionmentioning

confidence: 99%

Estimating Kinetic Rate Parameters for Enzymatic Degradation of Lyophilized Silk Fibroin Sponges

Jameson

Pacheco

Butler

et al. 2021

Front. Bioeng. Biotechnol.

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Sponge-like biomaterials formed from silk fibroin are promising as degradable materials in clinical applications due to their controllable breakdown into simple amino acids or small peptides in vivo. Silk fibroin, isolated from Bombyx mori silkworm cocoons, can be used to form sponge-like materials with a variety of tunable parameters including the elastic modulus, porosity and pore size, and level of nanocrystalline domains. These parameters can be independently tuned during formulation resulting in a wide parameter space and set of final materials. Determining the mechanism and rate constants for biomaterial degradation of these tunable silk materials would allow scientists to evaluate and predict the biomaterial performance for the large array of tissue engineering applications and patient ailments a priori. We first measured in vitro degradation rates of silk sponges using common protein-degrading enzymes such as Proteinase K and Protease XIV. The concentration of the enzyme in solution was varied (1, 0.1, 0.01 U/mL) along with one silk sponge formulation parameter: the level of crystallinity within the sponge. Additionally, two experimental degradation methods were evaluated, termed continuous and discrete degradation methods. Silk concentration, polymer chain length and scaffold pore size were held constant during experimentation and kinetic parameter estimation. Experimentally, we observed that the enzyme itself, enzyme concentration within the bulk solution, and the sponge fabrication water annealing time were the major experimental parameters dictating silk sponge degradation in our experimental design. We fit the experimental data to two models, a Michaelis-Menten kinetic model and a modified first order kinetic model. Weighted, non-linear least squares analysis was used to determine the parameters from the data sets and Monte-Carlo simulations were utilized to obtain estimates of the error. We found that modified first order reaction kinetics fit the time-dependent degradation of lyophilized silk sponges and we obtained first order-like rate constants. These results represent the first investigations into determining kinetic parameters to predict lyophilized silk sponge degradation rates and can be a tool for future mathematical representations of silk biomaterial degradation.

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2.12 Silk Biomaterials ☆

Cited by 12 publications

References 225 publications

Application of Food-Grade Proteolytic Enzyme for the Hydrolysis of Regenerated Silk Fibroin fromBombyx mori

Application of Food-Grade Proteolytic Enzyme for the Hydrolysis of Regenerated Silk Fibroin fromBombyx mori

Native Spider Silk-Based Antimicrobial Hydrogels for Biomedical Applications

Estimating Kinetic Rate Parameters for Enzymatic Degradation of Lyophilized Silk Fibroin Sponges

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