Cocoon Filaments Research Articles

Organic-Inorganic Hybridization of Silkworm Cocoon Filaments Using Nano Pastes of Silica-Phosphate-M (M = Cu, Fe, or Al).

Inorganic-organic hybrid biomaterials have recently attracted much attention because of their widespread use. Silkworm cocoon filaments resulting from sericulture as prospective nanobiomaterials need to be improved, and their properties need to be used for broader purposes. This study was aimed at investigating methods for siliconization of silkworm cocoon filaments and characterizing their cocoon filament properties in terms of their yarn quality, natural dyeing, and antibacterial properties. Three methods of hybridization processes were used in this experiment, namely, in situ natural dyeing of silk yarns while silk filaments were spined, feed engineering through spraying the mulberry leaves with natural dyes and silica-phosphate-M (M = Cu, Fe, or Al) nano pastes, and a combination of both methods. The resulting cocoon filaments were characterized by their siliconization of filament fibers by using FTIR, XRD, and SEM-EDS methods. The yarn tensile strength, color quality, color fastness properties affected by the siliconization of silk filament fibers, and antibacterial properties were also investigated. Results showed that the combination method produced better siliconization of silk fibers, and, consequently, the better siliconization of silk fibers produced better natural dyeing as well as antibacterial properties of their resulting silk yarns.

Fine structure of cocoon and cocoon filaments from Braconidae insect

Fine structure of cocoon and cocoon filaments from Braconidae insect

Forcibly Spinning Using Bombyx Mori Silkworm Anesthetized by the Water Narcosis Treatment

ABSTRACT Herein, the anesthetization of Bombyx mori silkworms via the water narcosis treatment by soaking in room-temperature water for 1 h was found effective in keeping the tensile strength of its forcibly spun silk filament comparable to that of naturally spun silks. However, at a treatment time of 3 h, a marked decrease in the tensile strength of the forcibly spun filaments was observed owing to the interference of the applied force in the forcibly spinning with the inherent naturally spinning system of Bombyx mori silkworms. Compared with naturally spun cocoon filaments, evidence of disordering in the crystal modification of silk fibroin by the forcibly spinning suggests that variations to the forcibly spinning conditions may affect the quality of the silkworm fibers.

Histological Reactions and the In Vivo Patency Rates of Small Silk Vascular Grafts in a Canine Model.

Objective: To evaluate in vivo patency rates of silk fibroin (SF) vascular grafts and resulting histological reactions in a canine model.Methods: To generate 3.5-mm inner diameter vessels, a combination of plaited silk fibers were wound with cocoon filaments and subsequently coated with an SF solution. The resulting SF grafts (n=35) were implanted into the carotid arteries of male beagles (age, 1–2 years; body weight: 9.0–10.5 kg). Expanded polytetrafluoroethylene (4-mm inner diameter, ePTFE) grafts (n=5) were used as controls. Graft patency was monitored via ultrasonography with histological changes analyzed via microscopic examination.Results: Compared with animals that received the ePTFE grafts, animals that received SF grafts exhibited the same thickness of luminal layers and fibrin accumulation and collagen fiber replacement with endothelialization at 3 months post-implantation via histological examination. The patency rates of the SF and the ePTFE grafts at 6 months post-implantation were 7.8% and 0%, respectively.Conclusion: This canine model study demonstrated that SF grafts induce unique histological reactions but fail to achieve long-term patency.

Relationship between adhesive properties and structure of sericin in cocoon filaments

Relationship between adhesive properties and structure of sericin in cocoon filaments

Comparison of sericin characteristics between silk glands and cocoon filaments

Comparison of sericin characteristics between silk glands and cocoon filaments

Electron microscopical observations on the sericin layers of the cocoon filaments from several wild silkworms

Electron microscopical observations on the sericin layers of the cocoon filaments from several wild silkworms

Fine structure of the cocoon filaments of the silkworm differing relative amounts of sericin

Fine structure of the cocoon filaments of the silkworm differing relative amounts of sericin

On the probability distribution of the number of remarkable cocoon filaments in a fixed size raw silk thread

On the probability distribution of the number of remarkable cocoon filaments in a fixed size raw silk thread

Degumming method for silk thread reeled from yellow cocoon filaments of a sex-limited variety “Ouhaku”

Degumming method for silk thread reeled from yellow cocoon filaments of a sex-limited variety “Ouhaku”

Electron microscopic observations of voids in cocoon filaments of silk-spinning moths

Electron microscopic observations of voids in cocoon filaments of silk-spinning moths

Cocoon quality and physical properties of the cocoon filaments produced by silkworms reared on mulberry leaves and on an artificial diet

Cocoon quality and physical properties of the cocoon filaments produced by silkworms reared on mulberry leaves and on an artificial diet

Development of the silk bed pad using a mass of cocoon filaments reeled in wet state

Development of the silk bed pad using a mass of cocoon filaments reeled in wet state

Reconstruction of a Hard Connective Tissue Utilizing a Pressed Silk Sheet and Type-I Collagen as the Scaffold for Fibroblasts

A pressed silk sheet is a new biomaterial composed of a network of numerous cocoon filaments and having excellent mechanical strength and shape stability compared to a cotton-gauze sheet. To reconstruct a hard connective tissue using the silk sheet and type-I collagen as the scaffold for fibroblasts, three different three-dimensional floating culture systems were designed. "On sheet" system: fibroblasts were seeded on the silk sheet coated with collagen and the cell-attached sheet was cultured. "In gel" system: fibroblasts and the silk sheet were co-embedded in a collagen gel and the gel was cultured. "On vitrigel" system: fibroblasts were seeded on both sides of a collagen vitrigel involving the silk sheet and the vitrigel was cultured. The fibroblasts in all culture systems grew and formed disk-shaped connective tissue models involving the silk sheet by 14 days of culture. The "on sheet" and "on vitrigel" models retained a maximum elastic load of about 23 kgf and an ultimate tensile load of about 3.6 kgf, which were almost the same as for the individual silk sheet. However, the "in gel" system showed a low value for the tensile load. Cell damage following application of mechanical stress was lowest in the "on vitrigel" system. These data demonstrated the advantage of the "on vitrigel" system in reconstructing hard connective tissues. Such a novel culture method would contribute to a regenerative medicine for the failure of ligaments, tendons, and other connective tissues.

Development of the fine artifical blood tube by cocoon filaments

Development of the fine artifical blood tube by cocoon filaments

Pattern Recognition of Non-Stationary Time Series with Finite Length

Statistical learning and recognition methods were used to extract the characteristics of size series measurements of cocoon filaments that are non-stationary in terms of mean and auto-covariance, by using the time varying parameter auto-regressive (TVPAR) model. After the system was taught to recognize the size data, the system correctly recognized the size of series of cocoon filaments as much as 96.95% of the time for a single series and 98.72% of the time for the mean of two series. The correct recognition rate was higher after suitable filtering. The theory and method can be used to analyze other types of non-stationary finite length time series.

Auto-Regressive Models of Non-Stationary Time Series with Finite Length

To analyze and simulate non-stationary time series with finite length, the statistical characteristics and auto-regressive (AR) models of non-stationary time series with finite length are discussed and studied. A new AR model called the time varying parameter AR model is proposed for solution of non-stationary time series with finite length. The auto-covariances of time series simulated by means of several AR models are analyzed. The result shows that the new AR model can be used to simulate and generate a new time series with the auto-covariance same as the original time series. The size curves of cocoon filaments regarded as non-stationary time series with finite length are experimentally simulated. The simulation results are significantly better than those obtained so far, and illustrate the availability of the time varying parameter AR model. The results are useful for analyzing and simulating non-stationary time series with finite length.

Adsorption of acid dyes into silk fibers derived from cocoon filaments with different sizes

Adsorption of acid dyes into silk fibers derived from cocoon filaments with different sizes

Optical method for detection of many cocoon filaments

Optical method for detection of many cocoon filaments

Yellowing of Cocoon Filament Obtained from Silkworm, Bombyx mori Reared on Artificial Diet Containing Tofu-Cake Powder.

Yellowing of two types of cocoon filaments was investigated. One type is the cocoon produced by silkworms reared with mulberry leaf diet at 4th and 5th instar (Mulberry sample). The other is that with an artificial diet containing Tofu-cake powder as a main component (Tofu-cake sample). The yellowing of Mulberry sample was remarkable after irradiation with ultraviolet light, while it was scarcely observed for Tofu-cake sample and the extent of yellowing decreased with increasing Tofu-cake content up to 50%. Tofu-cake sample contained relatively a large amount of nucleotide compounds, such as deoxycytidylic acid (dCMP) and cytidylic acid (CMP) in a hot-water-soluble fraction, and the contents of these compounds increased with increasing Tofu-cake content. On the other hand, Mulberry sample contained little amount of nucleotide compounds. The difference in the yellowing behavior between these two samples was attributed to the difference in the contents of nucleotide compounds. This was also confirmed by the fact that yellowing of Mulberry sample was drastically suppressed after immersing it in 3% dCMP aqueous solution.