scholarly journals Silkworm spinning: the programmed self-assembly from natural silk fibroin to superfibre

2021 ◽  
Author(s):  
Kai Song ◽  
Yejing Wang ◽  
Wenjie Dong ◽  
Zhenzhen Li ◽  
Huawei He ◽  
...  
Keyword(s):  
Metal Ions ◽  
Silk Fibroin ◽  
Self Assembly ◽  
High Performance ◽  
Liquid Crystalline ◽  
Silk Gland ◽  
Natural Silk ◽  
Random Coils ◽  
Protein Fibers ◽  
Silkworm Silk

AbstractSilkworm silk is one of the best natural protein fibers spun by the silkworm at ambient temperature and pressure using aqueous silk protein solution. It is a great challenge to reproduce high-performance artificial fibers comparable to natural silk by bionics for the incomplete understanding of silkworm spinning mechanism, especially the structure and assembly of natural silk fibroin (NSF) in the silk gland. Here, we studied the structure and assembly of NSF with the assistance of amphipol and digitonin. Our results showed NSFs were present as nanofibrils primarily composed of random coils in the silk gland. Metal ions were vital for the formation of NSF nanofibrils. The successive decrease in pH from posterior silk gland (PSG) to anterior silk gland (ASG) resulted in a gradual increase in NSF hydrophobicity. NSF nanofibrils were randomly arranged from PSG to ASG-1, and then self-assembled into herringbone-like patterns near the spinneret (ASG-2) ready for silkworm spinning. Our study reveals the mechanism by which silkworms cleverly utilize metal ions and pH gradient in the silk gland to drive the programmed self-assembly of NSF from disordered nanofibrils to anisotropic liquid crystalline spinning dope (herringbone-like patterns) for silkworm spinning, thus providing novel insights into silkworm/spider spinning mechanism and bionic creation of high-performance fibers.

scholarly journals Bioactive hierarchical silk fibers created by bioinspired self-assembly

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Linpeng Fan ◽  
Jing-Liang Li ◽  
Zengxiao Cai ◽  
Xungai Wang
Keyword(s):  
Self Assembly ◽  
Liquid Crystalline ◽  
Umbilical Vein ◽  
Fibrous Materials ◽  
Silk Fibers ◽  
Natural Silk ◽  
Protein Fibers ◽  
Fibrous Network ◽  
Spinning Process ◽  
Umbilical Vein Endothelial Cells

AbstractArtificial recapitulation of the hierarchy of natural protein fibers is crucial to providing strategies for developing advanced fibrous materials. However, it is challenging due to the complexity of the natural environment. Inspired by the liquid crystalline spinning of spiders, we report the development of natural silk-like hierarchical fibers, with bundles of nanofibrils aligned in their long-axis direction, by self-assembly of crystallized silk fibroin (SF) droplets. The formation of self-assembled SF fibers is a process of coalesced droplets sprouting to form a branched fibrous network, which is similar to the development of capillaries in our body. The as-assembled hierarchical SF fibers are highly bioactive and can significantly enhance the spreading and growth of human umbilical vein endothelial cells compared to the natural SF fibers. This work could help to understand the natural silk spinning process of spiders and provides a strategy for design and development of advanced fibrous biomaterials for various applications.

A pseudo threefold helical structure found in silk Langmuir-Blodgett films by electron diffraction

1993 ◽  
Vol 51 ◽  
pp. 1216-1217
Author(s):  
Weiping Zhang ◽  
Samual P. Gido ◽  
Wayne S. Muller ◽  
Stephen A. Fossey ◽  
David L. Kaplan
Keyword(s):  
Protein Structure ◽  
Silk Fibroin ◽  
High Performance ◽  
Helical Structure ◽  
Silk Gland ◽  
Fiber Spinning ◽  
Silk Fiber ◽  
Helical Chain ◽  
Langmuir Blodgett ◽  
Β Sheet

The high performance tensile properties of silkworm (Bombyx mori) silk fiber has resulted in a long standing interest in the semicrystalline morphology of this material. The properties of silk fiber depend not only on the chemical composition (primary protein structure) but also on the fiber spinning conditions present in the silk gland which induce the formation of a (β-sheet based crystalline morphology (secondary protein structure). Knowledge of the silk structure is essential for understanding how the natural spinning processes results in such excellent material properties, but surprisingly few experimental results are available concerning the detailed structures of silk proteins. Two β-sheet based silk fibroin crystalline structures (e.g. silk I and silk II) have been studied by many authors, but the silk I structure remains largely uncharacterized. Here we report results from thin silk films prepared by the Langmuir-Blodgett (LB) technique which display a new silk fibroin structure with a threefold helical chain conformation.

scholarly journals Disruption of the Metal Ion Environment by EDTA for Silk Formation Affects the Mechanical Properties of Silkworm Silk

2019 ◽  
Vol 20 (12) ◽  
pp. 3026 ◽  
Author(s):  
Qingsong Liu ◽  
Xin Wang ◽  
Xiaoyin Tan ◽  
Xiaoqian Xie ◽  
Haonan Dong ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Secondary Structure ◽  
Metal Ions ◽  
Silk Fibroin ◽  
Metal Ion ◽  
Conformational Transition ◽  
Direct Injection ◽  
Silk Gland ◽  
Silk Fiber ◽  
Edta Treatment

Silk fiber has become a research focus because of its comprehensive mechanical properties. Metal ions can influence the conformational transition of silk fibroin. Current research is mainly focused on the role of a single ion, rather than the whole metal ion environment. Here, we report the effects of the overall metal ion environment on the secondary structure and mechanical properties of silk fibers after direct injection and feeding of silkworms with EDTA. The metal composition of the hemolymph, silk gland, and silk fiber changed significantly post EDTA treatment. Synchrotron FTIR analysis indicated that the secondary structure of silk fiber after EDTA treatment changed dramatically; particularly, the β-sheets decreased and the β-turns increased. Post EDTA treatment, the silk fiber had significantly decreased strength, Young’s modulus, and toughness as compared with the control groups, while the strain exhibited no obvious change. These changes can be attributed to the change in the metal ion environment in the silk fibroin and sericin in the silk gland. Our investigation provides a new theoretical basis for the natural silk spinning process, and our findings could help develop a method to modify the mechanical properties of silk fiber using metal ions.

scholarly journals Chemical Synthesis of Silk-Mimetic Polymers

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4086
Author(s):  
Amrita Sarkar ◽  
Alexander J. Connor ◽  
Mattheos Koffas ◽  
R. Helen Zha
Keyword(s):  
Chemical Synthesis ◽  
Silk Fibroin ◽  
Material Properties ◽  
High Performance ◽  
Bulk Material ◽  
Control Strategies ◽  
Synthetic Approach ◽  
Primary Sequence ◽  
Natural Silk ◽  
Molecular Weights

Silk is a naturally occurring high-performance material that can surpass man-made polymers in toughness and strength. The remarkable mechanical properties of silk result from the primary sequence of silk fibroin, which bears semblance to a linear segmented copolymer with alternating rigid (“crystalline”) and flexible (“amorphous”) blocks. Silk-mimetic polymers are therefore of great emerging interest, as they can potentially exhibit the advantageous features of natural silk while possessing synthetic flexibility as well as non-natural compositions. This review describes the relationships between primary sequence and material properties in natural silk fibroin and furthermore discusses chemical approaches towards the synthesis of silk-mimetic polymers. In particular, step-growth polymerization, controlled radical polymerization, and copolymerization with naturally derived silk fibroin are presented as strategies for synthesizing silk-mimetic polymers with varying molecular weights and degrees of sequence control. Strategies for improving macromolecular solubility during polymerization are also highlighted. Lastly, the relationships between synthetic approach, supramolecular structure, and bulk material properties are explored in this review, with the aim of providing an informative perspective on the challenges facing chemical synthesis of silk-mimetic polymers with desirable properties.

Self-assembly fabrication of microencapsulated n-octadecane with natural silk fibroin shell for thermal-regulating textiles

2016 ◽  
Vol 99 ◽  
pp. 495-501 ◽  
Author(s):  
Liang Zhao ◽  
Jie Luo ◽  
Hao Wang ◽  
Guolin Song ◽  
Guoyi Tang
Keyword(s):  
Silk Fibroin ◽  
Self Assembly ◽  
Natural Silk

Morphology of High-Performance Rigid-Rod Polymer Fibers and Molecular Composites

1989 ◽  
Vol 47 ◽  
pp. 338-339
Author(s):  
W.W. Adams ◽  
S. J. Krause
Keyword(s):  
Tensile Strength ◽  
High Performance ◽  
Liquid Crystalline ◽  
Molecular Level ◽  
Synergistic Effects ◽  
Tensile Modulus ◽  
Commercial Development ◽  
The Matrix ◽  
Molecular Composites ◽  
Rigid Rod

Rigid-rod polymers such as PBO, poly(paraphenylene benzobisoxazole), Figure 1a, are now in commercial development for use as high-performance fibers and for reinforcement at the molecular level in molecular composites. Spinning of liquid crystalline polyphosphoric acid solutions of PBO, followed by washing, drying, and tension heat treatment produces fibers which have the following properties: density of 1.59 g/cm3; tensile strength of 820 kpsi; tensile modulus of 52 Mpsi; compressive strength of 50 kpsi; they are electrically insulating; they do not absorb moisture; and they are insensitive to radiation, including ultraviolet. Since the chain modulus of PBO is estimated to be 730 GPa, the high stiffness also affords the opportunity to reinforce a flexible coil polymer at the molecular level, in analogy to a chopped fiber reinforced composite. The objectives of the molecular composite concept are to eliminate the thermal expansion coefficient mismatch between the fiber and the matrix, as occurs in conventional composites, to eliminate the interface between the fiber and the matrix, and, hopefully, to obtain synergistic effects from the exceptional stiffness of the rigid-rod molecule. These expectations have been confirmed in the case of blending rigid-rod PBZT, poly(paraphenylene benzobisthiazole), Figure 1b, with stiff-chain ABPBI, poly 2,5(6) benzimidazole, Fig. 1c A film with 30% PBZT/70% ABPBI had tensile strength 190 kpsi and tensile modulus of 13 Mpsi when solution spun from a 3% methane sulfonic acid solution into a film. The modulus, as predicted by rule of mixtures, for a film with this composition and with planar isotropic orientation, should be 16 Mpsi. The experimental value is 80% of the theoretical value indicating that the concept of a molecular composite is valid.

Self-Assembly Optical Components

2003 ◽  
Vol 771 ◽  
Author(s):  
Pavel I. Lazarev ◽  
Michael V. Paukshto ◽  
Elena N. Sidorenko
Keyword(s):  
Optical Properties ◽  
Self Assembly ◽  
Crystalline State ◽  
Liquid Crystalline ◽  
Film Deposition ◽  
X Ray Diffraction ◽  
Optical Components ◽  
Crystal Film ◽  
Solid Film ◽  
Thin Crystal

AbstractWe report a new method of Thin Crystal Film deposition. In the present paper we describe the method of crystallization, structure, and optical properties of Bisbenzimidazo[2,1-a:1',2',b']anthra[2,1,9-def:6,5,10-d'e'f']-diisoquinoline-6,9-dion (mixture with cis-isomer) (abbreviated DBI PTCA) sulfonation product. The Thin Crystal Film has a thickness of 200-1000 nm, with anisotropic optical properties such as refraction and absorption indices. X-ray diffraction data evidences a lyotropic liquid crystalline state in liquid phase and crystalline state in solid film. Anisotropic optical properties of the film make it useful in optical devices, e.g. liquid crystal displays.

Interfacial self-assembly engineering for constructing a 2D flexible superlattice polyoxometalate/rGO heterojunction for high-performance photovoltaic devices

2020 ◽  
Vol 49 (12) ◽  
pp. 3766-3774 ◽  
Author(s):  
Jianping Li ◽  
Dai Wu ◽  
Chunlei Wang ◽  
Ding Liu ◽  
Weilin Chen ◽  
...  
Keyword(s):  
Conversion Efficiency ◽  
Self Assembly ◽  
High Performance ◽  
Photoelectric Conversion Efficiency ◽  
Photovoltaic Devices ◽  
Photoelectric Conversion

The strategy of constructing a 2D flexible superlattice polyoxometalate/rGO heterojunction is proposed to improve the photoelectric conversion efficiency of photovoltaic devices.

scholarly journals Steady state charge conduction through solution processed liquid crystalline lanthanide bisphthalocyanine films

2019 ◽  
Vol 23 (11n12) ◽  
pp. 1603-1615
Author(s):  
Chandana Pal ◽  
Isabelle Chambrier ◽  
Andrew N. Cammidge ◽  
A. K. Sharma ◽  
Asim K. Ray
Keyword(s):  
Metal Ions ◽  
Liquid Crystalline ◽  
Microscopy Study ◽  
Individual Characteristics ◽  
Central Metal ◽  
Force Microscopy ◽  
Atomic Force ◽  
Double Decker ◽  
Order Of Magnitude ◽  
Chain Lengths

In-plane electrical characteristics of non-peripherally octyl(C[Formula: see text]H[Formula: see text]- and hexyl(C[Formula: see text]H[Formula: see text]-substituted liquid crystalline (LC) double decker lanthanide bisphthalocyanine (LnPc[Formula: see text] complexes with central metal ions lutetium (Lu), and gadolinium (Gd) have been measured in thin film formulations on interdigitated gold (Au) electrodes for the applied voltage ([Formula: see text] range of [Formula: see text]. The conduction mechanism is found to be Ohmic within the bias of [Formula: see text] while the bulk limited Poole–Frenkel mechanism is responsible for the higher bias. The compounds show individual characteristics depending on the central metal ions, substituent chain lengths and their mesophases. Values of 67.55 [Formula: see text]cm[Formula: see text] and 42.31 [Formula: see text]cm[Formula: see text] have been obtained for room temperature in-plane Ohmic conductivity of as-deposited octyl lutetium (C[Formula: see text]LuPc[Formula: see text] and hexyl gadolinium (C[Formula: see text]GdPc[Formula: see text] films, respectively while C[Formula: see text]GdPc[Formula: see text] films exhibit nearly two orders of magnitude smaller conductivity. On annealing at 80[Formula: see text]C, Ohmic conductivities of C[Formula: see text]LuPc[Formula: see text] and C[Formula: see text]GdPc[Formula: see text] are found to have increased but the conductivity of C[Formula: see text]GdPc[Formula: see text] decreased by more than one order of magnitude to 1.5 [Formula: see text]cm[Formula: see text]. For physical interpretation of the charge transport behavior of these three molecules, their UV-vis optical absorption spectra in the solution and in as-deposited and annealed solid phases and atomic force microscopy study have been performed. It is believed that both orientation and positional reorganizations are responsible, depending upon the size of the central ion and side chain length.

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