Silk Fibroin Protein Research Articles

Fabrication of elastomeric silk fibers.

Methods to generate fibers from hydrogels, with control over mechanical properties, fiber diameter, and crystallinity, while retaining cytocompatibility and degradability, would expand options for biomaterials. Here, we exploited features of silk fibroin protein for the formation of tunable silk hydrogel fibers. The biological, chemical, and morphological features inherent to silk were combined with elastomeric properties gained through enzymatic crosslinking of the protein. Postprocessing via methanol and autoclaving provided tunable control of fiber features. Mechanical, optical, and chemical analyses demonstrated control of fiber properties by exploiting the physical cross-links, and generating double network hydrogels consisting of chemical and physical cross-links. Structure and chemical analyses revealed crystallinity from 30 to 50%, modulus from 0.5 to 4 MPa, and ultimate strength 1-5 MPa depending on the processing method. Fabrication and postprocessing combined provided fibers with extensibility from 100 to 400% ultimate strain. Fibers strained to 100% exhibited fourth order birefringence, revealing macroscopic orientation driven by chain mobility. The physical cross-links were influenced in part by the drying rate of fabricated materials, where bound water, packing density, and microstructural homogeneity influenced cross-linking efficiency. The ability to generate robust and versatile hydrogel microfibers is desirable for bottom-up assembly of biological tissues and for broader biomaterial applications.

Bioengineered silkworms with butterfly cytotoxin-modified silk glands produce sericin cocoons with a utility for a new biomaterial

Genetically manipulated organisms with dysfunction of specific tissues are crucial for the study of various biological applications and mechanisms. However, the bioengineering of model organisms with tissue-specific dysfunction has not progressed because the challenges of expression of proteins, such as cytotoxins, in living cells of individual organisms need to be overcome first. Here, we report the establishment of a transgenic silkworm (Bombyx mori) with posterior silk glands (PSGs) that was designed to express the cabbage butterfly (Pieris rapae) cytotoxin pierisin-1A (P1A). P1A, a homolog of the apoptosis inducer pierisin-1, had relatively lower DNA ADP ribosyltransferase activity than pierisin-1; it also induced the repression of certain protein synthesis when expressed in B. mori-derived cultured cells. The transgene-derived P1A domain harboring enzymatic activity was successfully expressed in the transgenic silkworm PSGs. The glands showed no apoptosis-related morphological changes; however, an abnormal appearance was evident. The introduced truncated P1A resulted in the dysfunction of PSGs in that they failed to produce the silk protein fibroin. Cocoons generated by the silkworms solely consisted of the glue-like glycoprotein sericin, from which soluble sericin could be prepared to form hydrogels. Embryonic stem cells could be maintained on the hydrogels in an undifferentiated state and proliferated through stimulation by the cytokines introduced into the hydrogels. Thus, bioengineering with targeted P1A expression successfully produced silkworms with a biologically useful trait that has significant application potential.

A bioinspired dual-crosslinked tough silk protein hydrogel as a protective biocatalytic matrix for carbon sequestration

The development of carbonic anhydrase (CA)-based materials for the environment-friendly sequestration of carbon dioxide (CO2) under mild conditions would be highly valuable for controlling emissions to the environment and for producing value-added chemicals. Here, a highly tough and stable CA-encapsulating silk protein hydrogel was developed as a robust biocatalyst for CO2 sequestration through a bioinspired dual-crosslinking strategy that employed photoinduced dityrosine chemical crosslinking followed by dehydration-mediated physical crosslinking. The target enzyme was efficiently encapsulated in the silk hydrogel with ~60% retention of the activity of free CA, and the encapsulated CA exhibited excellent overall multi-use, storage and thermal stabilities. The dual-crosslinked CA-encapsulating silk hydrogel exhibited a significant compressive modulus, which surpassed the moduli of most traditional and double-network hydrogels as well as those of enzyme-encapsulated hydrogels. This hydrogel also showed high resiliency and elasticity and outstanding structural stability. Importantly, the dual-crosslinked CA-encapsulating silk hydrogel facilitated the sequestration of CO2 into calcium carbonate with high CO2 hydration activity. Thus, the unique combination of bioinspired dual-crosslinking with silk fibroin protein and CA enzyme demonstrates the successful application of this protein hydrogel as a promising biocatalyst for CO2 sequestration by showing high activity, strong mechanical properties and outstanding structural stability.

Tunable green graphene-silk biomaterials: Mechanism of protein-based nanocomposites

Green graphene materials prepared by photoreduction of graphite oxide were first time blended with aqueous-based silk fibroin proteins to improve the mechanical and thermal properties of silk biomaterials, and their nanocomposite interaction mechanism was illustrated. Powder X-ray diffraction (XRD) analysis confirmed the complete exfoliation of graphite oxide to graphene in presence of focused pulses of solar radiation. By varying the concentration of graphene (0.1wt% to 10wt%), a series of free standing graphene-silk films were prepared and were systematically characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and nanoindentation measurements. The homogeneity of graphene in silk as well as the thermal stability of the composite films was demonstrated by thermal gravimetric analysis (TGA) and temperature-modulated differential scanning calorimetry (TMDSC). Surprisingly, silk composite film containing only 0.5wt% of graphene gives the highest Young's modulus of 1.65GPa (about 5.8 times higher than the pure silk's modulus), indicating a nano-composite to micro-composite transition of silk-graphene structure occurred around this mixing ratio. This finding provided an easy approach to improve the elastic modulus and other physical properties of silk materials by adding a tiny amount of graphene sheets. Fibroblast cells studies also proved that these graphene-silk materials can significantly improve cell adhesion, growth and proliferation. This protein nanocomposite study provided a useful model to understand how to manipulate the hydrophobic-hydrophobic and polar-polar interactions between high-surface-area inorganic nanomaterials and amphiphilic protein materials, which has many emerging applications in the material science and engineering, such as bio-device fabrication, drug storage and release, and tissue regeneration.

Dual growth factor loaded nonmulberry silk fibroin/carbon nanofiber composite 3D scaffolds for invitro and invivo bone regeneration.

In recent years the potential application of nanocomposite biomaterials in tissue engineering field is gaining importance because of the combined features of all the individual components. A bottom-up approach is acquired in this study to recreate the bone microenvironment. The regenerated silk protein fibroin obtained from nonmulberry tropical tasar Antheraea mylitta species is reinforced with functionalized carbon nano fiber (CNF) and the composite sponges are fabricated using facile green aqueous based method. Biophysical investigations show that the matrices are porous and simultaneously bioactive when incubated in simulated body fluid. The reinforcement of CNF influences the mechanical property of the matrices by increasing the compressive modulus up to 46.54MPa (∼4.3 times of the control fibroin sponge) in hydrated state, which is higher than the minimum required human trabecular bone modulus (10MPa). The composite matrices are found to be non-hemolytic as well as cytocompatible. The growth factors (BMP-2 and TGF-β1) loaded composites show sustained release kinetics and an early attachment, growth, proliferation, and osteogenic differentiation of the osteoblasts and mesenchymal stem cells. The matrices are immunocompatible as evidenced by minimal release of pro-inflammatory cytokines both invitro and invivo. In order to support the invitro study, invivo analysis of new bone formation within the implants is performed through radiological, μ-CT, fluorochrome labeling and histological analysis, which show statistically better bone formation on growth factor loaded composite scaffolds. The study clearly shows the potential attributes of these composite matrices as an extra cellular matrix for supporting successful osseointegration process.

ATR-FTIR study of the interaction of CO2 with bacterial cellulose-based membranes

Bacterial cellulose (BC) was used as an active material for fabrication of the membrane for CO2 capture. The BC-membrane is further modified with silk fibroin protein and ZnO nanoparticles in order to increase the number of sites that may bind CO2. The interaction of the CO2 with the membranes was investigated by means of ATR-FTIR spectroscopy. The argon purged membranes were used as the control samples. After pressurizing the membranes in CO2 at 3bar, FTIR spectra were recorded and compared to the spectra of the controls. The interaction of the membrane materials with CO2 were studied by examining two regions of the spectra: 740–610cm−1 (bending vibrations of CO2) and 2400–2320cm−1 (asymmetric stretching vibrations of CO2). The envelope of the bending mode peak in 740–610cm−1 region is resolved into particular peaks and the appearance of the additional line at 654cm−1 suggested that the absorption bands of CO2 alters because of the Lewis acid-base type of interaction with membranes. The changes in the region of asymmetric stretching vibrations of CO2 were even more pronounced after pressurization. The presence of the number of different sites (active groups) for the CO2 adsorption reflected in the appearance of several additional asymmetric stretching peaks. Also, due to the entrapment of the CO2 in the membrane, a typical CO asymmetric stretching vibration line at ∼2340cm−1 is shifted towards lower frequencies. The analysis of the results suggested that there is a strong interaction of CO2 with BC membrane, which is additionally improved by its modification with silk fibroin and ZnO nanoparticles. From the results of CO2 permeation experiment, the basic BC membrane, silk fibroin-modified BC membrane and ZnO nanoparticles-modified BC membrane exhibited the CO2 permeability of 2.73, 2.69 and 2.66 Barrer, respectively.

Fabrication of Nanoscale Patternable Films of Silk Fibroin Using Benign Solvents

The silk protein fibroin is a wondrous biopolymer widely used to form structures that interface with biological entities. In addition to tissue scaffolds, sponges, and films, biochemically modified fibroins can be used in conjunction with techniques such as photolithography and soft lithography to expand their repertoire for micro‐ and nanofabricated systems. To date, the use of hexafluoro‐2‐isopropanol (HFIP) has been prevalent as a solvent for fibroin and fibroin “resists.” However, high volatility, toxicity, cost, and need for specialized disposal render the necessity for alternative solvents. Additionally, for applications such as in optics and bioelectronics, smooth, thin (≈100 nm and below) fibroin films are a prerequisite, which are not easily achieved using HFIP. Here, the use of formic acid (FA) as a sustainable solvent is presented for silk fibroin and fibroin “resist” materials, specifically for micro‐ and nanoscale applications. The reproducible formation and characterization of stable thin films of high homogeneity, smoothness, and optical transparency are demonstrated. Critically, these films can be used for high‐resolution photopatterning of proteins using benchtop lithographic techniques. The study indicates that FA is a relatively benign and optimal solvent for forming smooth, thin films, and microscale architectures for the fabrication of next generation silk‐based optical devices. image

Silk fibroin-Thelebolan matrix: A promising chemopreventive scaffold for soft tissue cancer

Research of improved functional bio-mimetic matrix for regenerative medicine is currently one of the rapidly growing fields in tissue engineering and medical sciences. This study reports a novel bio-polymeric matrix, which is fabricated using silk protein fibroin from Bombyx mori silkworm and fungal exopolysaccharide Thelebolan from Antarctic fungus Thelebolus sp. IITKGP-BT12 by solvent evaporation and freeze drying method. Natural cross linker genipin is used to imprison the Thelebolan within the fibroin network. Different cross-linked and non-cross-linked fibroin/Thelebolan matrices are fabricated and biophysically characterized. Cross-linked thin films show robustness, good mechanical strength and high temperature stability in comparison to non-cross-linked and pure matrices. The 3D sponge matrices demonstrate good cytocompatibility. Interestingly, sustained release of the Thelebolan from the cross-linked matrices induce apoptosis in colon cancer cell line (HT-29) in time dependent manner while it is nontoxic to the normal fibroblast cells (L929).The findings indicate that the cross-linked fibroin/Thelebolan matrices can be used as potential topical chemopreventive scaffold for preclusion of soft tissue carcinoma.

Enzymatically crosslinked silk-hyaluronic acid hydrogels.

In this study, silk fibroin and hyaluronic acid (HA) were enzymatically crosslinked to form biocompatible composite hydrogels with tunable mechanical properties similar to that of native tissues. The formation of di-tyrosine crosslinks between silk fibroin proteins via horseradish peroxidase has resulted in a highly elastic hydrogel but exhibits time-dependent stiffening related to silk self-assembly and crystallization. Utilizing the same method of crosslinking, tyramine-substituted HA forms hydrophilic and bioactive hydrogels that tend to have limited mechanics and degrade rapidly. To address the limitations of these singular component scaffolds, HA was covalently crosslinked with silk, forming a composite hydrogel that exhibited both mechanical integrity and hydrophilicity. The composite hydrogels were assessed using unconfined compression and infrared spectroscopy to reveal of the physical properties over time in relation to polymer concentration. In addition, the hydrogels were characterized by enzymatic degradation and for cytotoxicity. Results showed that increasing HA concentration, decreased gelation time, increased degradation rate, and reduced changes that were observed over time in mechanics, water retention, and crystallization. These hydrogel composites provide a biologically relevant system with controllable temporal stiffening and elasticity, thus offering enhanced tunable scaffolds for short or long term applications in tissue engineering.

Hydroxyapatite reinforced inherent RGD containing silk fibroin composite scaffolds: Promising platform for bone tissue engineering

Replacement and repair of ectopic bone defects and traumatized bone tissues are done using porous scaffolds and composites. The prerequisites for such scaffolds include high mechanical strength, osseoconductivity and cytocompatibility. The present work is designed to address such requirements by fabricating a reinforced cytocompatible scaffold. Biocompatible silk protein fibroin collected from tropical non-mulberry tasar silkworm (Antheraea mylitta) is used to fabricate fibroin-hydroxyapatite (HAp) nanocomposite particles using chemical precipitation method. In situ reinforcement of fibroin-HAp nanocomposite and external deposition of HAp particles on fibroin scaffold is carried out for comparative evaluations of bio-physical and biochemical characteristics. HAp deposited fibroin scaffolds provide greater mechanical strength and cytocompatibility, when compared with fibroin-HAp nanoparticles reinforced fibroin scaffolds. Minimal immune responses of both types of composite scaffolds are observed using osteoblast-macrophage co-culture model. Nanocomposite reinforced fibroin scaffold can be tailored further to accommodate different requirements depending on bone type or bone regeneration period.

Silk Fibroin Microneedles for Transdermal Vaccine Delivery.

Microneedles represent an exciting departure from the existing parenteral injection paradigm for drug delivery, particularly for the administration of vaccines. While the benefit of delivering vaccine antigens to immunocompetent tissue in the skin has been established, there have been varying degrees of success using microneedles to do so. Here, we investigate the use of silk fibroin protein to produce microneedles and evaluate their ability to deliver vaccines against influenza, Clostridium difficile, and Shigella. Fibroin protein from the silkworm Bombyx mori possesses suitable properties for use in a microneedle system, including all-aqueous processing, mechanical strength in dried formats, biocompatibility, and the ability to temperature stabilize biomacromolecules. As such, this biomaterial combines the processing and biocompatibility advantages of a dissolving microneedle system with the product stability and mechanical strength of coated insoluble microneedles. Through successful vaccination of mice against three separate antigens, we establish that silk fibroin is well-suited for use as a solid-coated microneedle delivery system and offers long-term potential similar to that of the leading microneedle biomaterials.

Monodisperse phase transfer and surface bioengineering of metal nanoparticles via a silk fibroin protein corona.

Uniform hydrophobic nanoparticles synthesized in nonpolar solvents possess excellent physio-chemical properties, showing great potential in biomedical applications. However, the presence of hydrophobic ligands on their surfaces limits their use under physiological conditions. Inspired by protein coronas present at the nano-bio interface, here we report a facile and universal method for phase transfer and surface bioengineering of hydrophobic nanoparticles using β-sheet-rich silk fibroin, a FDA-approved natural protein. Due to its amphiphilicity and high mechanical stiffness, the β-sheet-rich silk fibroin not only readily drags nanoparticles from an organic phase into aqueous media but also endows them with excellent monodispersity and long-term stability. The silk fibroin-coated nanoparticles can retain the magnetic and optical properties of the original nanoparticles, acting effectively as probes for biomedical imaging and biosensing. Furthermore, hydrophobic drugs can be easily adsorbed onto the protein coating via hydrophobic interaction, allowing the construction of promising theranostic nanoagents. Given these unique features, the strategy developed here possesses great promise in facilitating biomedical applications of hydrophobic nanomaterials.

Natural Non-Mulberry Silk Nanoparticles for Potential-Controlled Drug Release.

Natural silk protein nanoparticles are a promising biomaterial for drug delivery due to their pleiotropic properties, including biocompatibility, high bioavailability, and biodegradability. Chinese oak tasar Antheraea pernyi silk fibroin (ApF) nanoparticles are easily obtained using cations as reagents under mild conditions. The mild conditions are potentially advantageous for the encapsulation of sensitive drugs and therapeutic molecules. In the present study, silk fibroin protein nanoparticles are loaded with differently-charged small-molecule drugs, such as doxorubicin hydrochloride, ibuprofen, and ibuprofen-Na, by simple absorption based on electrostatic interactions. The structure, morphology and biocompatibility of the silk nanoparticles in vitro are investigated. In vitro release of the drugs from the nanoparticles depends on charge-charge interactions between the drugs and the nanoparticles. The release behavior of the compounds from the nanoparticles demonstrates that positively-charged molecules are released in a more prolonged or sustained manner. Cell viability studies with L929 demonstrated that the ApF nanoparticles significantly promoted cell growth. The results suggest that Chinese oak tasar Antheraea pernyi silk fibroin nanoparticles can be used as an alternative matrix for drug carrying and controlled release in diverse biomedical applications.

Foam dressing incorporating herbal extract: An all-natural dressing for potential use in wound healing

Silk fibroin protein, gastrodia elata, and tea tree oil are naturally derived and have been used throughout human history. This work develops an all-natural and highly porous foam-containing silk fibroin protein and above herbal extract, as a dressing for wound management. Scanning electron microscopic analyses and measurements of porosity by Archimedes method revealed a highly porous structure with porosity ranging from 40%–80%, depending on the preparation condition. In vitro, cytotoxicity test of a series of gastrodia elata–containing silk fibroin protein and tea tree oil–containing silk fibroin protein foam dressings on 3T3 fibroblast cells showed 90%–100% cell viability, which indicated that the produced all-natural dressings have no significant cytotoxicity toward skin cells. In another anti-inflammatory assay using the lipopolysaccharide-induced inflammatory Raw 264.7 macrophages model, the produced two dressings exhibited up to 70% and 90.1% of reduction in the formation of nitrite, in comparison with the untreated group. In vivo studies showed that all herbal extract–containing foam dressings accelerated wound recovery and achieved full closure of the wound within 21 days, and the histological analysis of regenerative skin tissues indicated that the produced foam dressings enhance the generation of thicker, denser, and more abundant collagen fibers in the dermis layer in comparison with the positive and negative control groups.

Silk scaffolds connected with different naturally occurring biomaterials for prostate cancer cell cultivation in 3D.

In the present work, different biopolymer blend scaffolds based on the silk protein fibroin from Bombyx mori (BM) were prepared via freeze-drying method. The chemical, structural, and mechanical properties of the three dimensional (3D) porous silk fibroin (SF) composite scaffolds of gelatin, collagen, and chitosan as well as SF from Antheraea pernyi (AP) and the recombinant spider silk protein spidroin (SSP1) have been systematically investigated, followed by cell culture experiments with epithelial prostate cancer cells (LNCaP) up to 14 days. Compared to the pure SF scaffold of BM, the blend scaffolds differ in porous morphology, elasticity, swelling behavior, and biochemical composition. The new composite scaffold with SSP1 showed an increased swelling degree and soft tissue like elastic properties. Whereas, in vitro cultivation of LNCaP cells demonstrated an increased growth behavior and spheroid formation within chitosan blended scaffolds based on its remarkable porosity, which supports nutrient supply matrix. Results of this study suggest that silk fibroin matrices are sufficient and certain SF composite scaffolds even improve 3D cell cultivation for prostate cancer research compared to matrices based on pure biomaterials or synthetic polymers.

Prospects of peripheral nerve tissue engineering using nerve guide conduits based on silk fibroin protein and other biopolymers

ABSTRACTPeripheral nerve injuries face some clinical obstacles and unsatisfactory functional outcomes. The slow regeneration rate of defected nerve delays functional recovery. To date, various therapeutic agents are used to enhance the survival and regeneration capacity of damaged neurons. Among these, nerve guide conduits held promise for peripheral nerve regeneration, through the physical guidance of the injured nerve across the lesions. Many natural and synthetic polymers are used to produce nerve conduits. Biopolymer-based biomaterials offer important options in control of structure, morphology, and chemistry as reasonable substitutes or mimics of extracellular matrix systems. Silk protein fibroin as a biocompatible natural polymer, possesses biodegradability, tunable mechanical properties, process ability, and suitable for the peripheral nerve conduits. This review highlights recent advances in the use of silk-based conduits for peripheral nerve regeneration. Further, the development of nerve conduits based on other biopolymers, including chitosan, alginate, collagen, and gelatin is discussed and compared.

Silk Fibroin-Sophorolipid Gelation: Deciphering the Underlying Mechanism.

Silk fibroin (SF) protein, produced by silkworm Bombyx mori, is a promising biomaterial, while sophorolipid (SL) is an amphiphilic functional biosurfactant synthesized by nonpathogenic yeast Candida bombicola. SL is a mixture of two forms, acidic (ASL) and lactonic (LSL), which when added to SF results in accelerated gelation of silk fibroin. LSL is known to have multiple biological functionalities and hence hydrogels of these green molecules have promising applications in the biomedical sector. In this work, SANS, NMR, and rheology are employed to examine the assembling properties of individual and mixed SLs and their interactions with SF to understand the mechanism that leads to rapid gelation. SANS and NMR studies show that ASL assembles to form charged micelles, while LSL forms micellar assemblies and aggregates of a mass fractal nature. ASL and LSL together form larger mixed micelles, all of which interact differently with SF. It is shown that preferential binding of LSL to SF causes rapid unfolding of the SF chain leading to the formation of intermolecular beta sheets, which trigger fast gelation. Based on the observations, a mechanism for gelation of SF in the presence of different sophorolipids is proposed.

Recombinant spider silk fibroin protein produces a non-cytotoxic and non-inflammatory response

Silk fibroin proteins serve as biomaterials for diverse applications. Previous studies have shown that silk fibroin proteins can be used in biomedical applications for treating diabetes. In the present study, we investigated the cytotoxicity and inflammatory response induced by spider silk fibroin protein in vitro. By using recombinant AvMaSp-R spider silk fibroin protein, which consists of the 240 amino acid repetitive domain of the spider (Araneus ventricosus) silk fibroin protein and was expressed in baculovirus-infected insect cells, we tested the cytotoxicity, apoptosis, macrophage stimulation, and release of proinflammatory mediators and cytokines in vitro. We found that recombinant AvMaSp-R was not cytotoxic and did not activate macrophages. Consequently, our results provide evidence that recombinant AvMaSp-R produces a non-cytotoxic and non-inflammatory response, suggesting that recombinant AvMaSp-R silk fibroin protein could be a biomaterial for biomedical applications.

Regenerated silk fibroin as an inkjet printable biomaterial

Regenerated silk fibroin (RSF) protein is an FDA approved biomaterial and has been used as a bio-ink to fabricate structures using inkjet printing. Silk can be present in water soluble amorphous (Silk I) and water insoluble crystalline conformations (Silk II) made up of beta-sheet structures. Here we show the generation of silk scaffolds by inkjet printing of water soluble RSF inks and then converting them into insoluble beta-sheet (Silk II) structure via a second ink containing methanol. This paper focuses on optimising printing conditions of RSF bio-ink through establishing the relationships between RSF peptide concentrations, number of layers and the total thickness of the printed layers. Various patterns such as dot arrays, lines, films, particles and logos have successfully been fabricated. The emerging of inkjet printing of RSF ink allows us to print delicate silk scaffold patterns for different applications specifically in biomedical field.

Carbon Nanofiber Reinforced Nonmulberry Silk Protein Fibroin Nanobiocomposite for Tissue Engineering Applications.

Natural silk protein fibroin based biomaterial are exploited extensively in tissue engineering due to their aqueous preparation, slow biodegradability, mechanical stability, low immunogenicity, dielectric properties, tunable properties, sufficient and easy availability. Carbon nanofibers are reported for their conductivity, mechanical strength and as delivery vehicle of small molecules. Limited evidence about their cytocompatibility and their poor dispersibility are the key issues for them to be used as successful biomaterials. In this study, carbon nanofiber is functionalized and dispersed using the green aqueous-based method within the regenerated nonmulberry (tropical tasar: Antheraea mylitta) silk fibroin (AmF), which contains inherent - R-G-D- sequences. Carbon nanofiber (CNF) reinforced silk films are fabricated using solvent evaporation technique. Different biophysical characterizations and cytocompatibility of the composite matrices are assessed. The investigations show that the presence of the nanofiber greatly influence the property of the composite films in terms of excellent conductivity (up to 6.4 × 10-6 Mho cm, which is 3 orders of magnitude of pure AmF matrix), and superior tensile modulus (up to 1423 MPa, which is 12.5 times more elastic than AmF matrix). The composite matrices (composed of up to 1 mg of CNF per mL of 2% AmF) also support better fibroblast cell growth and proliferation. The fibroin-carbon nanofiber matrices can lead to a novel multifunctional biomaterial platform, which will support conductive as well as load bearing tissue (such as, muscle, bone, and nerve tissue) regenerations.