Structure–property relationships of meta-kerateine biomaterials derived from human hair

Richter, Jillian R.; Guzman, Roche C. de; Greengauz-Roberts, Olga K.; Dyke, Mark Van

doi:10.1016/j.actbio.2011.08.020

Cited by 48 publications

(40 citation statements)

References 33 publications

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“…KOS 14 and KTN 37 were extracted by proprietary methods similar to those previously reported. Mass percentage ratios of KOS:KTN investigated in these studies were 100:0, 70:30, 50:50, 30:70, and 0:100, where we use the nomenclature throughout this manuscript of KOS:KTN to represent the weight percentages of each component in the mixture.…”

Section: Methodsmentioning

confidence: 99%

Tunable Keratin Hydrogels for Controlled Erosion and Growth Factor Delivery

et al. 2015

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Tunable erosion of polymeric materials is an important aspect of tissue engineering for reasons that include cell infiltration, controlled release of therapeutic agents, and ultimately to tissue healing. In general, the biological response to proteinaceous polymeric hydrogels is favorable (e.g., minimal inflammatory response). However, unlike synthetic polymers, achieving tunable erosion with natural materials is a challenge. Keratins are a class of intermediate filament proteins that can be obtained from several sources including human hair and have gained increasing levels of use in tissue engineering applications. An important characteristic of keratin proteins is the presence of a large number of cysteine residues. Two classes of keratins with different chemical properties can be obtained by varying the extraction techniques: (1) keratose by oxidative extraction and (2) kerateine by reductive extraction. Cysteine residues of keratose are “capped” by sulfonic acid and are unable to form covalent crosslinks upon hydration, whereas cysteine residues of kerateine remain as sulfhydryl groups and spontaneously form covalent disulfide crosslinks. Here, we describe a straightforward approach to fabricate keratin hydrogels with tunable rates of erosion by mixing keratose and kerateine. SEM imaging and mechanical testing of freeze-dried materials showed similar pore diameters and compressive moduli, respectively, for each keratose-kerateine mixture formulation (~1200 kPa for freeze-dried materials and ~1.5 kPa for hydrogels). However, the elastic modulus (G’) determined by rheology varied in proportion with the keratose-kerateine ratios, as did the rate of hydrogel erosion and the release rate of thiol from the hydrogels. The variation in keratose-kerateine ratios also led to tunable control over release rates of recombinant human insulin-like growth factor 1.

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Section: Methodsmentioning

confidence: 99%

Tunable Keratin Hydrogels for Controlled Erosion and Growth Factor Delivery

et al. 2015

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“…After placing into the 1mL syringe, the keratin was injected into a 5 mm diameter by 5 mm high mold (made of Sylgard 184) and allowed to incubate overnight at 37°C to gel. The swelling ratio, Q, was determined as described previously by others [42]. In brief, the keratin gel cylinders were weighed after gelation (dry mass, M d ) and placed into phosphate buffered saline until they reached an equilibrium swelling point (swelling mass, M s ).…”

Section: Methodsmentioning

confidence: 99%

“…The swelling time was found to be 2 hours by a pilot experiment, and we noted that keratose gels began to erode after this time point. The swelling ratio was determined from the equation [42]:

Q = 1 + true(\frac{ρ_{k}}{ρ_{s}} true) true(\frac{M_{s}}{M_{d}} - 1 true)

where ρ k is the density of the keratin (assumed to be 0.35 mg/mL for all keratin forms) and ρ s is the density of phosphate buffered saline (1.006 mg/mL). The swollen gels were measured for diameter and height and then subjected to an unconfined compression test at room temperature (23°C) on an Instron 3344 mechanical tester equipped with Bluehill.…”

Section: Methodsmentioning

confidence: 99%

“…The compressive modulus (K) was calculated from the optimized shear modulus (μ) as K = 3μ. The effective crosslink density (ν e ) and the molecular weight between crosslinks (M c ) were determined by the two following equations [42]:

ν_{e} = \frac{K}{R T Q^{1 / 3}}

M_{c} = \frac{ρ_{k}}{υ_{e}}

where R is the ideal gas constant (8.314 m 3 *Pa/K/mol) and T is temperature (296 K). All formulations of keratin were tested in quadruplicate (n = 4) for swelling and compression testing on the swollen gels.…”

Section: Methodsmentioning

confidence: 99%

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Alkylation of human hair keratin for tunable hydrogel erosion and drug delivery in tissue engineering applications

et al. 2015

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Polymeric biomaterials that provide a matrix for cell attachment and proliferation while achieving delivery of therapeutic agents are an important component of tissue engineering and regenerative medicine strategies. Keratins are a class of proteins that have received attention for numerous tissue engineering applications because, like other natural polymers, they promote favorable cell interactions and have non-toxic degradation products. Keratins can be extracted from various sources including human hair, and they are characterized by a high percentage of cysteine residues. Thiol groups on reductively extracted keratin (kerateine) form disulfide bonds, providing a more stable cross-linked hydrogel network than oxidatively extracted keratin (keratose) that cannot form disulfide crosslinks. We hypothesized that an iodoacetamide alkylation (or “capping”) of cysteine thiol groups on the kerateine form of keratin could be used as a simple method to modulate the levels of disulfide crosslinking in keratin hydrogels, providing tunable rates of gel erosion and therapeutic agent release. After alkylation, the alkylated kerateines still formed hydrogels and the alkylation led to changes in the mechanical and visco-elastic properties of the materials consistent with loss of disulfide crosslinking. The alkylated kerateines did not lead to toxicity in MC3T3-E1 pre-osteoblasts. These cells adhered to keratin at levels comparable to fibronectin and greater than collagen. Alkylated kerateine gels eroded more rapidly than non-alkylated kerateine and this control over erosion led to tunable rates of delivery of rhBMP-2, rhIGF-1, and ciprofloxacin. These results demonstrate that alkylation of kerateine cysteine residues provides a cell-compatible approach to tune rates of hydrogel erosion and therapeutic agent release within the context of a naturally-derived polymeric system.

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“…Predicated on ethnicity there are three types of human hair African, Asian, and Caucasian [3]. All these hair, however, regardless of its ethnic inchoation, exhibits prevalent characteristics of morphology, chemical makeup, and molecular structure.…”

Section: Human Hairmentioning

confidence: 98%

Optimization of Human Hair Length in a Natural Rubber Based Composite

Babu¹,

Mathew²,

Jacob³

et al. 2015

Trans Indian Inst Met

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Human hair is a non-biodegradable waste available in plenty throughout the world but is rarely explored for applications in engineering fields. Tensile strength of human hair ranges from 170 to 220 MPa (Xiao et al., Nano Tensile Study Single Hum Hair Fiber, 2006). This property of human hair can be made use in the field of making bio-composites. The composite is prepared by commixing the human hair and natural rubber in a two roll mill along with additives followed by vulcanization. Here the length of the human hair is varied by fine-tuning the fibre loading as 20 parts per hundred rubber and sundry tests like tensile, abrasion, tear and hardness were conducted. While incrementing the fibre length up to a certain range the mechanical properties shows superior amendments.

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Structure–property relationships of meta-kerateine biomaterials derived from human hair

Cited by 48 publications

References 33 publications

Tunable Keratin Hydrogels for Controlled Erosion and Growth Factor Delivery

Tunable Keratin Hydrogels for Controlled Erosion and Growth Factor Delivery

Alkylation of human hair keratin for tunable hydrogel erosion and drug delivery in tissue engineering applications

Optimization of Human Hair Length in a Natural Rubber Based Composite

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