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Enhancing sustainability and elasticity of synthetic fibers by tandem repeat proteins

Smart Materials and Structures

February 2022
31(4):044001

DOI:10.1088/1361-665X/ac51ea

Authors:

Ramiz Boy

Adnan Menderes University

Show all 5 authorsHide

Protein fiber production in heterologous organisms, such as bacteria, provides a new possibility for engineering high-performance materials and composites. The discovery and design of sustainable materials that are biological or inspired by biological principles are essential for the development and production of the next generation of circular bioeconomy. Here, we created a hybrid of biological and synthetic materials by combining bio-engineered proteins with synthetic acrylic polymers to enhance the sustainability and elasticity of the blend fibers. First, we developed an optimized expression (i.e. yield exceeding 1 g l⁻¹) and purification method (>80% purity) for squid ring teeth inspired by tandem proteins at the facility scale. We showed that our protein-based powder, produced via industrial fermentation, can be manufactured into braided yarns with acrylic using wet-spinning. Our fibers have enhanced elasticity when hydrated due to the hydrogen network between the protein and acrylic fibers.

Protein production: (a) design of a squid-inspired tandem protein sequence; (b) SDS protein gel of TR-n11 shows ∼40 kDa protein with different purification method: (1) buffer purification with 1xLB feedstock, (2) DMSO purification with 4xLB feedstock, (3) buffer purification with 4xLB feedstock and (4) DMSO purification with 4xLB feedstock; (c) 100 l fermentation and down stream processes of centrifucation and purification, which yields of 1.5 g l⁻¹ dry protein TR-n11 powder.

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Wet spinning and blend fiber production: schematic of (a) extrusion of acyclic copolymer with TR-n11 protein, and (b) wet-spinning process. Optical images of (c) wet-spinning equipment, (d) filaments, and (e) brained yarn made by TR-n11 and acrylic blends.

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Fiber characterization: cross-sectional, top, and surface view of electron microscopy images for (a) acyrlic, and its protein blend fibers at (b) 20:80, (c) 40:60, and (c) 60:40% weight ratio.

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Chemical characterization: x-ray diffraction (a) and FTIR (b) analysis of acrylic and protein blend fibers. Diffraction peaks originating from acrylic crystals (16.7° peak), as well as crystalline structures of TR proteins (19.15° peak) are marked with dashed lines in the XRD figure. Amide-I and C-N bands are characteristic signatures of protein and acrylic polymers, respectively. (c) Deconvolution of Amide-I shows secondary structural components of the protein fibers.

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Mechanical characterization: optical image of (a) TR-n11 and acrylic blend fibers with weight ratio of (60:40), and corresponding (b) mono-filament testing under the mechanical stage. (c) Thermogravimentric analysis shows additional water content on wet blend fibers compared to dry fibers. Engineering stress–strain data for (d) wet and (e) dry and drawn TR-n11/acrylic blended fibers.

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Smart Materials and Structures

Smart Mater. Struct. 31 (2022) 044001 (8pp) https://doi.org/10.1088/1361-665X/ac51ea

Enhancing sustainability and elasticity

of synthetic fibers by tandem repeat

proteins

Burcu Dursun1,4, Tarek El-Sayed Mazeed1,2,4, Oguzhan Colak1, Ramiz Boy1,3

and Melik C Demirel1,2,∗

1Center for Research on Advanced Fiber Technologies (CRAFT), Department of Engineering Science

and Mechanics, Materials Research Institute, Pennsylvania State University, University Park,

Pennsylvania 16802, United States of America

2Huck Institutes of Life Sciences, Pennsylvania State University, University Park, Pennsylvania 16802,

United States of America

3Polymer Technology Program, Aydin Adnan Menderes University, Buharkent Vocational School,

Aydin 09670, Turkey

E-mail: melik@psu.edu

Received 15 November 2021, revised 24 January 2022

Accepted for publication 4 February 2022

Published 25 February 2022

Abstract

Protein ber production in heterologous organisms, such as bacteria, provides a new possibility

for engineering high-performance materials and composites. The discovery and design of

sustainable materials that are biological or inspired by biological principles are essential for the

development and production of the next generation of circular bioeconomy. Here, we created a

hybrid of biological and synthetic materials by combining bio-engineered proteins with

synthetic acrylic polymers to enhance the sustainability and elasticity of the blend bers. First,

we developed an optimized expression (i.e. yield exceeding 1 g l−1) and purication method

(>80% purity) for squid ring teeth inspired by tandem proteins at the facility scale. We showed

that our protein-based powder, produced via industrial fermentation, can be manufactured into

braided yarns with acrylic using wet-spinning. Our bers have enhanced elasticity when

hydrated due to the hydrogen network between the protein and acrylic bers.

Supplementary material for this article is available online

Keywords: sustainability, squid, acrylic, protein-bers, self-assembly, synthetic proteins

(Some gures may appear in colour only in the online journal)

1. Introduction

The worldwide clothing ber market is approximately

120 million tons, of which 62% are oil-based synthetic bers

[1]. Many of the current processes in the textile market are

inexpensive, but their associated environmental costs can be

enormous, including petroleum consumption, carbon release,

and microplastic pollution [2]. There are growing health

and regulatory issues regarding plastic pollution, and most

4 These authors contributed equally to this work.

∗Author to whom any correspondence should be addressed.

European countries and some of the states in the USA are

banning single-use plastics. Therefore, new discoveries in the

circularity of plastics combined with government regulations

and subsidies are urgently needed to surpass existing plastic

technologies, which pollute the environment. According to

an Environmental Protection Agency (EPA) report, the US

generates 16 million tons of textile waste annually: 2.5 million

tons of clothing are recycled, but over three million tons are

incinerated, and a staggering 10 million tons is sent to land-

lls. The problem is not only the bulk textile but also what

comes out of the plastic as micro or nano polluters, which

are called microbers [3]. Hence, alternative production and

Preparation of Sustainable Composite Materials from Bio‐Based Domestic and Industrial Waste: Progress, Problems, and Prospects‐ A Review

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Mar 2024

Bio‐based waste from households and industries is a big problem for the world, however, turning it into valuable composite materials can offer a promising approach to deal with it. It involves the conversion of waste from different bio‐based sources such as cellulose waste from farming and forestry leftovers, chitin waste from seafood and mushrooms, and keratin waste from hair, nails, and feathers into natural fibers. These fibers are then effectively mixed with other materials to create composite materials having unique properties, such as high strength and stiffness, good thermal and electrical conductivity, and better barrier properties. Developing these materials is not just good for the environment because it reduces landfill waste and the reliance on non‐renewable resources, but it can also make economic sense for producers. In this review, the basic compounds of natural fibers and the development of composite materials from them are explored and discussed in detail. Furthermore, their chemical and mechanical properties are discussed and summarized. In the final section, a brief overview of the challenges and the future research needed in this fast‐evolving field is given.

Wet Spinning of Chitosan Fibers: Effect of Sodium Dodecyl Sulfate Adsorption and Enhanced Dope Temperature

Article

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Jul 2020

Production of fibers from non-thermoplastic polymers, such as chitosan, usually requires dissolution with subsequent fiber formation, for instance via coagulation. Good fiber-forming properties enable simultaneous spinning of multiple fibers into a yarn, which is one of the prerequisites for process scalability. Here, we report a multifilament wet spinning process that eliminates the use of such volatile organic compounds as methanol and acetone, enhances fiber formation and allows producing continuous well separated chitosan fibers after drying. This is achieved by: (i) solidification of the extruded solution by alkali and sodium acetate in the coagulation bath and (ii) further stabilization of the fibers by adsorbing the anionic surfactant, sodium dodecyl sulphate. The obtained fibers have circular cross-section and smooth surface. We demonstrate that it is possible to increase fiber breaking tenacity and Young’s modulus by applying stretching (draw ratios up to 1.77) or by incorporating cellulose nanofibrils (CNF, up to 4 wt% based on chitosan) in the spinning solutions. However, the limitation of increased viscosity when adding CNF is needed to be overcome for possible higher reinforcement effects. We demonstrate that fiber breaking tenacity, Young’s modulus and elongation at break can be enhanced even further by increasing the spin dope temperature from 22 °C to 60 °C, simultaneously with increasing the spin dope solids content to keep the same dope viscosity. The fibers with maximum breaking tenacity of ca. 10 cN tex−1 at an elongation at break of ca. 7.5% were obtained.

Investigation on structure and characteristics of alpaca‐based wet‐spun polyacrylonitrile composite fibers by utilizing natural textile waste

Article

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Aug 2019
J APPL POLYM SCI

The composite alpaca/acrylic fibers were auspiciously produced through a wet spinning technique to reduce the consumption of petroleum‐based polyacrylonitrile (PAN) and to enhance the thermal stability and moisture properties of the fibers. The waste alpaca fibers were converted into powder using a mechanical milling method without applying any chemicals. Alpaca powders were then blended with the PAN dope solution in different weight ratios of alpaca: PAN (10:90, 20:80, and 30:70) to wet spin the composite fibers. The Fourier transform infrared spectroscopy showed that all the composite fibers possess the functional groups of both alpaca and PAN. The nuclear magnetic resonance spectroscopy confirmed the presence of typical carbonyl carbon (CO) and nitrile carbon (C≡N) peaks of protein and PAN, respectively. The differential scanning calorimetry and thermogravimetric analysis revealed the enhanced thermal stability of alpaca/PAN composite fibers. The moisture properties of the composite fibers were subsequently found to increase with the incorporation of alpaca, more than three times that of pure PAN fibers. These results revealed a potential green pathway to producing composite acrylic fibers with improved thermal and moisture properties by applying textile waste materials. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48370.

Squid-Inspired Tandem Repeat Proteins: Functional Fibers and Films

Article

Full-text available

Feb 2019

Production of repetitive polypeptides that comprise one or more tandem copies of a single unit with distinct amorphous and ordered regions have been an interest for the last couple of decades. Their molecular structure provides a rich architecture that can micro-phase-separate to form periodic nanostructures (e.g., lamellar and cylindrical repeating phases) with enhanced physicochemical properties via directed or natural evolution that often exceed those of conventional synthetic polymers. Here, we review programmable design, structure, and properties of functional fibers and films from squid-inspired tandem repeat proteins, with applications in soft photonics and advanced textiles among others.

Tunable thermal transport and reversible thermal conductivity switching in topologically networked bio-inspired materials

Article

Full-text available

Oct 2018
Nat. Nanotech.

The dynamic control of thermal transport properties in solids must contend with the fact that phonons are inherently broad- band. Thus, efforts to create reversible thermal conductivity switches have resulted in only modest on/off ratios, since only a relatively narrow portion of the phononic spectrum is impacted. Here, we report on the ability to modulate the thermal conductivity of topologically networked materials by nearly a factor of four following hydration, through manipulation of the displacement amplitude of atomic vibrations. By varying the network topology, or crosslinked structure, of squid ring teeth-based bio-polymers through tandem-repetition of DNA sequences, we show that this thermal switching ratio can be directly programmed. This on/off ratio in thermal conductivity switching is over a factor of three larger than the current state-of-the-art thermal switch, offering the possibility of engineering thermally conductive biological materials with dynamic responsivity to heat.

Squid Ring Teeth–coated Mesh Improves Abdominal Wall Repair

Article

Full-text available

Aug 2018

Background:. Hernia repair is a common surgical procedure with polypropylene (PP) mesh being the standard material for correction because of its durability. However, complications such as seroma and pain are common, and repair failures still approach 15% secondary to poor tissue integration. In an effort to enhance mesh integration, we evaluated the applicability of a squid ring teeth (SRT) protein coating for soft-tissue repair in an abdominal wall defect model. SRT is a biologically derived high-strength protein with strong mechanical properties. We assessed tissue integration, strength, and biocompatibility of a SRT-coated PP mesh in a first-time pilot animal study. Methods:. PP mesh was coated with SRT (SRT-PP) and tested for mechanical strength against uncoated PP mesh. Cell proliferation and adhesion studies were performed in vitro using a 3T3 cell line. Rats underwent either PP (n = 3) or SRT-PP (n = 6) bridge mesh implantation in an anterior abdominal wall defect model. Repair was assessed clinically and radiographically, with integration evaluated by histology and mechanical testing at 60 days. Results:. Cell proliferation was enhanced on SRT-PP mesh. This was corroborated in vivo by abdominal wall histology, dramatically diminished craniocaudal mesh contraction, improved strength testing, and higher tissue failure strain. There was no increase in seroma or visceral adhesion formation. No foreign body reactions were noted on liver histology. Conclusions:. SRT applied as a coating appears to augment mesh–tissue integration and improve abdominal wall stability following bridged repair. Further studies in larger animals will determine its applicability for hernia repair in patients.

MECHANICAL PROPERTIES OF TANDEM REPEAT PROTEINS ARE GOVERNED BY THE NETWORK DEFECTS

Article

Full-text available

Jan 2018

Topological defects in highly repetitive structural proteins strongly affect their mechanical properties. However, there are no universal rules for structure-property prediction in structural proteins due to high diversity in their repetitive modules. Here, we studied the mechanical properties of tandem-repeat proteins inspired by squid-ring-teeth proteins using rheology and tensile experiments as well as spectroscopic and X-ray techniques. We also developed a network model based on entropic elasticity to predict structure-property relationships for these proteins. We demonstrated that shear modulus, elastic modulus, and toughness scale inversely with the number of repeats in these proteins. Through optimization of structural repeats, we obtained highly efficient protein network topologies with 40 MPa ultimate strength that are capable of withstanding deformations up to 400%. Investigation of topological network defects in structural proteins will improve the prediction of mechanical properties for designing novel protein-based materials.

Research Update: Programmable tandem repeat proteins inspired by squid ring teeth

Article

Full-text available

Jan 2018

Cephalopods have evolved many interesting features that can serve as inspiration. Repetitive squid ring teeth (SRT) proteins from cephalopods exhibit properties such as strength, self-healing, and biocompatibility. These proteins have been engineered to design novel adhesives, self-healing textiles, and the assembly of 2d-layered materials. Compared to conventional polymers, repetitive proteins are easy to modify and can assemble in various morphologies and molecular architectures. This research update discusses the molecular biology and materials science of polypeptides inspired by SRT proteins, their properties, and perspectives for future applications.

Quantifying shedding of synthetic fibers from textiles; a source of microplastics released into the environment

Article

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Jan 2018
ENVIRON SCI POLLUT R

Microplastics in the environment are a subject of intense research as they pose a potential threat to marine organisms. Plastic fibers from textiles have been indicated as a major source of this type of contaminant, entering the oceans via wastewater and diverse non-point sources. Their presence is also documented in terrestrial samples. In this study, the amount of microfibers shedding from synthetic textiles was measured for three materials (acrylic, nylon, polyester), knit using different gauges and techniques. All textiles were found to shed, but polyester fleece fabrics shed the greatest amounts, averaging 7360 fibers/m⁻²/L⁻¹ in one wash, compared with polyester fabrics which shed 87 fibers/m⁻²/L⁻¹. We found that loose textile constructions shed more, as did worn fabrics, and high twist yarns are to be preferred for shed reduction. Since fiber from clothing is a potentially important source of microplastics, we suggest that smarter textile construction, prewashing and vacuum exhaustion at production sites, and use of more efficient filters in household washing machines could help mitigate this problem.

Structural Protein-based Flexible Whispering Gallery Mode Resonators

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Jun 2017

Nature provides a set of solutions for photonic structures that are finely tuned, organically diverse and optically efficient. Exquisite knowledge of structure-property relationships in proteins aids in the design of materials with desired properties for building devices with novel functionalities, which are difficult to achieve or previously unattainable. Here we report whispering-gallery-mode (WGM) microresonators fabricated entirely from semi-crystalline structural proteins (i.e., squid ring teeth, SRT, from Loligo vulgaris and its recombinant) with quality factors as high as 105. We first demonstrate versatility of protein-based devices via facile doping, engaging secondary structures. Then we investigate thermo-refractivity and find that it increases with beta-sheet crystallinity which can be altered by methanol exposure and is higher in the selected recombinant SRT protein than its native counterpart. We present a set of photonic devices fabricated from SRT proteins such as add-drop filters and fibers. Protein based microresonators demonstrated in this work are highly flexible and robust where quality factors and spectral position of resonances are unaffected from mechanical strain. We find that the thermo-optic coefficients of SRT proteins are nearly hundred times larger than silica and more than ten times larger than polydimethylsiloxane. Finally, we demonstrate an optical switch utilizing the surprisingly large thermo-refractivity of SRT proteins. Achieving 41 dB isolation at an input power of 1.44 µW, all-protein optical switch is ten times more energy efficient than a conventional (silica) thermo-optic switch.

Experimental and Predictive Description of the Morphology of Wet-Spun Fibers

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May 2019

The prediction of the morphology of wet-spun fibers has so far been only possible by complex and experimentally-intensive approaches that include the construction of ternary phase diagrams. Ultimately, however, the available models give approximate information. Here we propose an alternative predictive approach that uses design principles based on the combination of (1) Relative Energy Difference (RED) of Hansen solubility and, (2) a kinetic parameter ‘T’ that considers mass transfer effects. Such model is applied and experimentally validated for a priori determination of the diameter and internal morphology of wet-spun fibers. Remarkably, only three variables relevant to wet-spinning are needed, namely, the choice of polymer, solvent, and non-solvent types. A combination of systems are tested and the morphology of the obtained fibers determined via electron microscopy. Aspects related to demixing, internal specific surface area (BET) and layer formation on the fibers are described qualitatively. The facile implementation of the design parameters is further confirmed through comparison with data published on the subject. Our proposed model is expected to accelerate future developments in nanomaterials, especially in the context of ongoing efforts related to fiber spinning with biopolymers.

Enhancing sustainability and elasticity of synthetic fibers by tandem repeat proteins

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