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Advanced Science (Weinheim,... Feb 2022Spider silk is a natural polymeric fiber with high tensile strength, toughness, and has distinct thermal, optical, and biocompatible properties. The mechanical... (Review)
Review
Spider silk is a natural polymeric fiber with high tensile strength, toughness, and has distinct thermal, optical, and biocompatible properties. The mechanical properties of spider silk are ascribed to its hierarchical structure, including primary and secondary structures of the spidroins (spider silk proteins), the nanofibril, the "core-shell", and the "nano-fishnet" structures. In addition, spider silk also exhibits remarkable properties regarding humidity/water response, water collection, light transmission, thermal conductance, and shape-memory effect. This motivates researchers to prepare artificial functional fibers mimicking spider silk. In this review, the authors summarize the study of the structure and properties of natural spider silk, and the biomimetic preparation of artificial fibers from different types of molecules and polymers by taking some examples of artificial fibers exhibiting these interesting properties. In conclusion, biomimetic studies have yielded several noteworthy findings in artificial fibers with different functions, and this review aims to provide indications for biomimetic studies of functional fibers that approach and exceed the properties of natural spider silk.
Topics: Biomimetics; Fibroins; Protein Structure, Secondary; Silk; Tensile Strength
PubMed: 34927397
DOI: 10.1002/advs.202103965 -
Biomacromolecules May 2022The tiny spider makes dragline silk fibers with unbeatable toughness, all under the most innocuous conditions. Scientists have persistently tried to emulate its natural... (Review)
Review
The tiny spider makes dragline silk fibers with unbeatable toughness, all under the most innocuous conditions. Scientists have persistently tried to emulate its natural silk spinning process using recombinant proteins with a view toward creating a new wave of smart materials, yet most efforts have fallen short of attaining the native fiber's excellent mechanical properties. One reason for these shortcomings may be that artificial spider silk systems tend to be overly simplified and may not sufficiently take into account the true complexity of the underlying protein sequences and of the multidimensional aspects of the natural self-assembly process that give rise to the hierarchically structured fibers. Here, we discuss recent findings regarding the material constituents of spider dragline silk, including novel spidroin subtypes, nonspidroin proteins, and possible involvement of post-translational modifications, which together suggest a complexity that transcends the two-component MaSp1/MaSp2 system. We subsequently consider insights into the spidroin domain functions, structures, and overall mechanisms for the rapid transition from disordered soluble protein into a highly organized fiber, including the possibility of viewing spider silk self-assembly through a framework relevant to biomolecular condensates. Finally, we consider the concept of "biomimetics" as it applies to artificial spider silk production with a focus on key practical aspects of design and evaluation that may hopefully inform efforts to more closely reproduce the remarkable structure and function of the native silk fiber using artificial methods.
Topics: Amino Acid Sequence; Animals; Fibroins; Recombinant Proteins; Silk; Spiders
PubMed: 35378031
DOI: 10.1021/acs.biomac.1c01682 -
Journal of Internal Medicine Aug 2016There are around 30 human diseases associated with protein misfolding and amyloid formation, each one caused by a certain protein or peptide. Many of these diseases are... (Review)
Review
There are around 30 human diseases associated with protein misfolding and amyloid formation, each one caused by a certain protein or peptide. Many of these diseases are lethal and together they pose an enormous burden to society. The prion protein has attracted particular interest as being shown to be the pathogenic agent in transmissible diseases such as kuru, Creutzfeldt-Jakob disease and bovine spongiform encephalopathy. Whether similar transmission could occur also in other amyloidoses such as Alzheimer's disease, Parkinson's disease and serum amyloid A amyloidosis is a matter of intense research and debate. Furthermore, it has been suggested that novel biomaterials such as artificial spider silk are potentially amyloidogenic. Here, we provide a brief introduction to amyloid, prions and other proteins involved in amyloid disease and review recent evidence for their potential transmission. We discuss the similarities and differences between amyloid and silk, as well as the potential hazards associated with protein-based biomaterials.
Topics: Amyloid; Animals; Humans; Protein Folding; Proteostasis Deficiencies; Silk
PubMed: 27002185
DOI: 10.1111/joim.12499 -
Molecules (Basel, Switzerland) Aug 2022Silk protein products have been used for a wide range of applications. This review focuses on the studies conducted relative to cognitive functions with silk fibroin... (Review)
Review
Silk protein products have been used for a wide range of applications. This review focuses on the studies conducted relative to cognitive functions with silk fibroin enzyme hydrolysates (FEH) in humans and animals. All known studies reported in PubMed and Google Scholar have been included. Studies have been conducted on children, high school and college students, adults and seniors, ranging in ages from 7-92 years. Doses of 200-600 mg silk FEH per day for three weeks to 16 weeks have been used. Based on these studies, it can be concluded that silk FEH exhibit beneficial cognitive effects with respect to memory and learning, attention, mental focus, accuracy, memory recall, and overall memory and concentration. These conclusions are supported by studies in rats and mice. Mechanistic studies that have been conducted in animals and cell culture systems are also reviewed. These studies indicate that silk FEH exerts its positive effects on memory and learning by providing neuroprotection via a complex mechanism involving its potent antioxidant and inflammation-inhibiting activities. Acetylcholine (ACh) is secreted by cholinergic neurons, and plays a role in encoding new information. Silk FEH were shown to decrease the levels of the pro-oxidant and pro-inflammatory mediators interlukin-1 (IL-1β), IL-6 and tumor necrosis factor-alpha (TNF-α), protecting the cholinergic system from oxidative stress, thus enhancing ACh levels in the brain, which is known to promote cognitive functions. In addition, the expression of brain-derived neurotrophic factor (BNDF), which is involved in the survival of neurons, is enhanced, and an increase in the expression of the phosphorylated cAMP response element-binding protein (p-CREB) occurs, which is known to play a positive role in cognitive functions. No adverse effects have been reported in association with the use of silk FEH.
Topics: Adolescent; Adult; Aged; Aged, 80 and over; Animals; Child; Cognition; Fibroins; Humans; Learning; Memory; Mice; Middle Aged; Rats; Silk; Young Adult
PubMed: 36080178
DOI: 10.3390/molecules27175407 -
International Journal of Molecular... Aug 2016Spiders and silkworms spin silks that outcompete the toughness of all natural and manmade fibers. Herein, we compare and contrast the spinning of silk in silkworms and... (Review)
Review
Spiders and silkworms spin silks that outcompete the toughness of all natural and manmade fibers. Herein, we compare and contrast the spinning of silk in silkworms and spiders, with the aim of identifying features that are important for fiber formation. Although spiders and silkworms are very distantly related, some features of spinning silk seem to be universal. Both spiders and silkworms produce large silk proteins that are highly repetitive and extremely soluble at high pH, likely due to the globular terminal domains that flank an intermediate repetitive region. The silk proteins are produced and stored at a very high concentration in glands, and then transported along a narrowing tube in which they change conformation in response primarily to a pH gradient generated by carbonic anhydrase and proton pumps, as well as to ions and shear forces. The silk proteins thereby convert from random coil and alpha helical soluble conformations to beta sheet fibers. We suggest that factors that need to be optimized for successful production of artificial silk proteins capable of forming tough fibers include protein solubility, pH sensitivity, and preservation of natively folded proteins throughout the purification and initial spinning processes.
Topics: Animals; Bombyx; Carbonic Anhydrases; Fibroins; Protein Conformation; Silk; Spiders
PubMed: 27517908
DOI: 10.3390/ijms17081290 -
International Journal of Molecular... Jul 2022Silk is a naturally occurring material and has been widely used in biomedical and cosmetic applications owing to its unique properties, including blood compatibility,...
Silk is a naturally occurring material and has been widely used in biomedical and cosmetic applications owing to its unique properties, including blood compatibility, excellent cytocompatibility, and a low inflammatory response in the body. A natural silk nonwoven fabric with good mechanical properties was recently developed using the binding property of sericin. In this study, silk/rayon composite nonwoven fabrics were developed to increase productivity and decrease production costs, and the effect of the silk/rayon composition on the structure and properties of the fabric was examined. The crystalline structure of silk and rayon was maintained in the fabric. As the silk content increased, the porosity and moisture regain of the silk/rayon web and nonwoven fabric decreased. As the silk content increased, the maximum stress of the web and nonwoven fabric increased, and the elongation decreased. Furthermore, the silk/rayon web exhibited the highest values of maximum stress and elongation at ~200 °C. Regardless of the silk/rayon composition, all silk/rayon nonwoven fabrics showed good cytocompatibility. Thus, the silk/rayon fabric is a promising material for cosmetic and biomedical applications owing to its diverse properties and high cell viability.
Topics: Cellulose; Sericins; Silk; Textiles
PubMed: 35886857
DOI: 10.3390/ijms23147511 -
Biomolecules Dec 2022The skin, acting as the outer protection of the human body, is most vulnerable to injury. Wound healing can often be impaired, leading to chronic, hard-to-heal wounds.... (Review)
Review
The skin, acting as the outer protection of the human body, is most vulnerable to injury. Wound healing can often be impaired, leading to chronic, hard-to-heal wounds. For this reason, searching for the most effective dressings that can significantly enhance the wound healing process is necessary. In this regard, silk fibroin, a protein derived from silk fibres that has excellent properties, is noteworthy. Silk fibroin is highly biocompatible and biodegradable. It can easily make various dressings, which can be loaded with additional substances to improve healing. Dressings based on silk fibroin have anti-inflammatory, pro-angiogenic properties and significantly accelerate skin wound healing, even compared to commercially available wound dressings. Animal studies confirm the beneficial influence of silk fibroin in wound healing. Clinical research focusing on fibroin dressings is also promising. These properties make silk fibroin a remarkable natural material for creating innovative, simple, and effective dressings for skin wound healing. In this review, we summarise the application of silk fibroin biomaterials as wound dressings in full-thickness, burn, and diabetic wounds in preclinical and clinical settings.
Topics: Animals; Humans; Fibroins; Biocompatible Materials; Silk; Wound Healing; Skin; Burns
PubMed: 36551280
DOI: 10.3390/biom12121852 -
Colloids and Surfaces. B, Biointerfaces Jul 2015To investigate the structure of silk and its degradation properties, we have monitored the structure of silk using scanning electron microscopy and frozen sections. Raw...
To investigate the structure of silk and its degradation properties, we have monitored the structure of silk using scanning electron microscopy and frozen sections. Raw silk and degummed raw silk were immersed in four types of degradation solutions for 156 d to observe their degradation properties. The subcutaneous implants in rats were removed after 7, 14, 56, 84, 129, and 145 d for frozen sectioning and subsequent staining with hematoxylin and eosin (H.E.), DAPI, Beta-actin and Collagen I immunofluorescence staining. The in vitro weight loss ratio of raw silk and degummed raw silk in water, PBS, DMEM and DMEM containing 10% FBS (F-DMEM) were, respectively, 14%/11%, 12.5%/12.9%, 11.1%/14.3%, 8.8%/11.6%. Silk began to degrade after 7 d subcutaneous implantation and after 145 d non-degraded silk was still observed. These findings suggest the immunogenicity of fibroin and sericin had no essential difference. In the process of in vitro degradation of silk, the role of the enzyme is not significant. The in vivo degradation of silk is related to phagocytotic activity and fibroblasts may be involved in this process to secrete collagen. This study also shows the developing process of cocoons and raw silk.
Topics: Animals; Bombyx; Female; Fibroins; Insect Proteins; Male; Microscopy, Confocal; Microscopy, Electron, Scanning; Prostheses and Implants; Proteolysis; Rats, Sprague-Dawley; Sericins; Silk; Subcutaneous Tissue; Time Factors
PubMed: 25982316
DOI: 10.1016/j.colsurfb.2015.04.040 -
Chemical Society Reviews Aug 2018Silks are natural fibrous protein polymers that are spun by silkworms and spiders. Among silk variants, there has been increasing interest devoted to the silkworm silk... (Review)
Review
Silks are natural fibrous protein polymers that are spun by silkworms and spiders. Among silk variants, there has been increasing interest devoted to the silkworm silk of B. mori, due to its availability in large quantities along with its unique material properties. Silk fibroin can be extracted from the cocoons of the B. mori silkworm and combined synergistically with other biomaterials to form biopolymer composites. With the development of recombinant DNA technology, silks can also be rationally designed and synthesized via genetic control. Silk proteins can be processed in aqueous environments into various material formats including films, sponges, electrospun mats and hydrogels. The versatility and sustainability of silk-based materials provides an impressive toolbox for tailoring materials to meet specific applications via eco-friendly approaches. Historically, silkworm silk has been used by the textile industry for thousands of years due to its excellent physical properties, such as lightweight, high mechanical strength, flexibility, and luster. Recently, due to these properties, along with its biocompatibility, biodegradability and non-immunogenicity, silkworm silk has become a candidate for biomedical utility. Further, the FDA has approved silk medical devices for sutures and as a support structure during reconstructive surgery. With increasing needs for implantable and degradable devices, silkworm silk has attracted interest for electronics, photonics for implantable yet degradable medical devices, along with a broader range of utility in different device applications. This Tutorial review summarizes and highlights recent advances in the use of silk-based materials in bio-nanotechnology, with a focus on the fabrication and functionalization methods for in vitro and in vivo applications in the field of tissue engineering, degradable devices and controlled release systems.
Topics: Animals; Biocompatible Materials; Bioengineering; Bombyx; Drug Delivery Systems; Equipment Design; Genetic Engineering; Humans; Nanostructures; Nanotechnology; Silk; Tissue Engineering
PubMed: 29938722
DOI: 10.1039/c8cs00187a -
Molecules (Basel, Switzerland) Feb 2020Due to its properties, such as biodegradability, low density, excellent biocompatibility and unique mechanics, spider silk has been used as a natural biomaterial for a... (Review)
Review
Due to its properties, such as biodegradability, low density, excellent biocompatibility and unique mechanics, spider silk has been used as a natural biomaterial for a myriad of applications. First clinical applications of spider silk as suture material go back to the 18th century. Nowadays, since natural production using spiders is limited due to problems with farming spiders, recombinant production of spider silk proteins seems to be the best way to produce material in sufficient quantities. The availability of recombinantly produced spider silk proteins, as well as their good processability has opened the path towards modern biomedical applications. Here, we highlight the research on spider silk-based materials in the field of tissue engineering and summarize various two-dimensional (2D) and three-dimensional (3D) scaffolds made of spider silk. Finally, different applications of spider silk-based materials are reviewed in the field of tissue engineering in vitro and in vivo.
Topics: Animals; Biocompatible Materials; Blood Vessels; Bone and Bones; Cartilage; Cell Culture Techniques; Humans; Hydrogels; Peripheral Nerves; Recombinant Proteins; Regeneration; Silk; Skin; Spiders; Tissue Engineering; Viscoelastic Substances
PubMed: 32046280
DOI: 10.3390/molecules25030737