Sheet-like Film Research Articles

Physicochemical and Microstructural Analyses of Pepsin-Soluble Collagens Derived from Lizardfish (Saurida tumbil Bloch, 1795) Skin, Bone and Scales.

Reducing food waste is critical for sustainability. In the case of fish processing, more than sixty percent of by-products are generated as waste. Lizardfish (Saurida tumbil Bloch, 1795) is an economically important species for surimi production. To address waste disposal and maximize income, an effective utilization of fish by-products is essential. This study aims to isolate and characterize pepsin-soluble collagens from the skin, bone and scales of lizardfish. Significant differences (p < 0.05) in the yields of collagen were noted with the highest yield recorded in pepsin-soluble skin collagen (PSSC) (3.50 ± 0.11%), followed by pepsin-soluble bone collagen (PSBC) (3.26 ± 0.10%) and pepsin-soluble scales collagen (PSCC) (0.60 ± 0.65%). Through SDS–polyacrylamide gel electrophoresis, the presence of two alpha chains were noted and classified as type I. From Fourier transform infrared spectroscopy (FTIR) analysis, the triple-helix structure of the collagen was maintained. The X-ray diffraction and UV visible spectra characteristics of the lizardfish collagens in this study are similar to the previously reported fish collagens. In terms of thermostability, PSSC (Tmax = 43.89 °C) had higher thermostability in comparison to PSBC (Tmax = 31.75 °C) and PSCC (Tmax = 30.54 °C). All pepsin-soluble collagens were highly soluble (>70%) in acidic conditions (particularly at pH 4.0) and at low sodium chloride concentrations (0–30 g/L). Microstructural analysis depicted that all extracted collagens were multi-layered, irregular, dense, sheet-like films linked by random coiled filaments. Overall, pepsin-soluble collagens from lizardfish skin, bone and scales could serve as potential alternative sources of collagens.

Effect of ultrasound-assisted extraction on the extractability and physicochemical properties of acid and pepsin soluble collagen derived from Sharpnose stingray (Dasyatis zugei) skin

This study aims to investigate the effect of ultrasound-assisted extraction on the extractability and physico-chemical properties of acid (UASC) and pepsin (UPSC) soluble collagen derived from Sharpnose stingray (Dasyatis zugei) skin. Pre-treated skins were extracted using 0.5M acetic acid under ultrasonication for UASC, and 0.5M acetic acid with 1.5% (w/w) pepsin under ultrasonication for UPSC. The yield of UPSC (61.50 ± 0.79%) was higher than UASC (42.34 ± 0.62%) while, no significant different in chemical compositions except for protein content between UASC and UPSC. The enzymatic hydrolysis results in the molecular weight of α-2 chain for UPSC. Freeze dried UASC and UPSC had similar morphological structures, with loose, irregular dense sheet-like film and irregular pore size. The extracted UASC and UPSC were thermally stable, with high thermal denaturation (Td), and had no significant differences in their maximum temperature (Tmax). UASC and UPSC also showed highly solubilized at acidic pH range and had the lowest solubility at pH 8. In conclusion, ultrasound-assisted extraction showed a potential technique to improve the yields of collagen extracted without affecting other properties of Sharpnose stingray collagen.

Cu3Si enhanced crystallinity and dopamine derived nitrogen doping into carbon coated micron-sized Si/Cu3Si as anode material in lithium-ion batteries

A chemical vapor decomposition (CVD) enhanced carbon coated Si/Cu3Si composite aggregate (C-Si/Cu3Si@C) is prepared as anode material to alleviate volume expansion and improve the electrochemical performance for lithium-ion batteries (LIBs). In this work, micron-sized C-Si/Cu3Si@C is fabricated through self-assembling of dopamine as first carbon precursor on irregularly shaped and sub-micron-sized Si/Cu3Si composite, followed by CVD with ethylene (C2H4) as second carbon precursor. Besides, dopamine not only self-assembles on the surface of Si/Cu3Si composite but also grows into sheet-like film that supports and connects Si/Cu3Si composite into micron-sized aggregate. In addition to CVD, Cu3Si induces catalytic chemical vapor deposition (CCVD), which enhances integrality of the carbon shell as well as reinforce nitrogen doping into carbon shell to enhance conductivity. Therefore, the C-Si/Cu3Si@C composite performs in optimum condition when the cycle is stable, attaining delithiation capacity of 2101 mAh g−1, coulombic efficiency of 84.7% for the 1st cycle and achieves capacity retention of 82.9% after 100 cycles.

Electrolytic nitrate reduction using Co3O4 rod-like and sheet-like cathodes with the control of (220) facet exposure and Co2+/Co3+ ratio

Co3O4 rod and sheet-like films with different crystal facet exposure and Co2+/Co3+ ratio are synthesized on Ti substrate through a facile hydrothermal method with the adjusting of hydrothermal pressure and duration. Low pressure and short hydrothermal duration is likely to obtain rod-like film with almost pure (220) facet exposure, while the sheet-like film with the mixture of (220) and (222) facets is formed with relatively high pressure. Moreover, the Co2+/Co3+ ratio is 2.067 for Co3O4 rods and 1.717 for Co3O4 sheets. The FT-IR and the XPS results indicate that the improvement of Co2+/Co3+ ratio possibly results from the doping of CO32−/OH−, and the introduction of oxygen vacancies. The films are employed as cathodes for electrocatalytic NO3−-N reduction. Because of the larger electrochemical active area and the lower internal resistance, better conversion of NO3−-N to NH4+-N is obtained by Co3O4 sheets film at constant voltage condition. However, the results are opposite when the constant current is applied. The larger exposure of (220) facet and the more amount of Co2+ and oxygen vacancies result in the better NO3−-N removal and NH4+-N conversion kinetics of Co3O4 rods film than that of Co3O4 sheets.

Biochemical and structural characterization of sturgeon fish skin collagen (Huso huso).

The potential use of sturgeon fish skin waste (Huso huso), an Iranian major sturgeon species, as a rich source for collagen extraction was evaluated. Yields of ASC and PSC obtained by acidic and enzymatic extractions were 9.98% and 9.08% (based on wet weight), respectively. SDS-PAGE profiles of both collagens led to classification of the proteins as type I with two different α chains (α1 and α2 ). Scanning electron microscopy (SEM) of the collagen sponges indicated dense sheet-like film linked by random-coiled filaments. Glycine was the most predominant amino acid, and the imino acids contents were 21.14% and 21.58% for ASC and PSC, respectively. Fourier-transform infrared spectra (FTIR) confirmed that pepsin digestion did not disrupt PSC triple helical structure. Denaturation and melting temperatures of ASC and PSC were 29.34°C, 92.03°C, and 29.89°C, 88.93°C, respectively. Thus, the sturgeon fish skin waste could serve as an alternative collagenous source for biomedical materials, food, and pharmaceutical applications. PRACTICAL APPLICATIONS: Beluga (Huso huso) is one of the most important sturgeon fish on the Caspian Sea and aquaculture industries. With the exception of the meat and caviar, wastes generated after their processing are usually discarded. Skin and cartilage of sturgeon fish are the by-products of the processing, and they are often discarded as waste or used for low-value purposes, although they are a good source for production of collagen-based biomaterials. Collagen type I is the most abundant collagen in the skin and this work reports the sturgeon fish skin as an important collagen resource with potential for use in the food, biomedical, and cosmetic industries.

Isolation and Characterization of Acid-soluble Collagen and Pepsin-soluble Collagen from the Skin of Hybrid Sturgeon

By using the wastes fish skin of sturgeon processed as a raw material, a macromolecule biomaterial of collagen was extracted. Acid-soluble collagen (ASC) and pepsin-soluble collagen (PSC) were successfully isolated from the skin of hybrid sturgeon with two extraction methods. The yields of ASC and PSC based on the wet weight of skin were 5.73 ± 0.11% and 10.26 ± 0.39%, respectively. The denaturation and melting points of ASC (26.83 °C and 110.49 °C) and PSC (26.54 °C and 102.99 °C) were assessed by Circular dichroism (CD) and Differential scanning calorimetry (DSC). ASC and PSC appeared to be dense sheet-like film linked by random-coiled filaments under scanning electron microscopy (SEM). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Fourier transform infrared spectroscopy (FTIR) confirmed that both the ASC and PSC were Type I collagen and maintained a complete triple helix structure. These results indicated that both ASC and PSC possessed good biological activity and could be widely used in medical biomaterials and other fields.

Isolation and Comparative Study on the Characterization of Guanidine Hydrochloride Soluble Collagen and Pepsin Soluble Collagen from the Body of Surf Clam Shell (Coelomactra antiquata).

The aim of this study was to characterize the collagens from the body of surf clam shell (Coelomactra antiquata). Guanidine hydrochloride and pepsin were used to extract collagens. Guanidine hydrochloride soluble collagen (GSC) and pepsin soluble collagen (PSC) were separately isolated from the body of surf clam shell. Results showed that the moisture, protein, carbohydrate, and ash contents of the body of surf clam shell were 82.46%, 11.56%, 3.05%, and 2.38%, respectively, but the fat content was only 0.55%. The yields were 0.59% for GSC and 3.78% for PSC. Both GSC and PSC were composed of α1 and α2 chains and a β chain, however, GSC and PSC showed distinct differences from each other and the type I collagen from grass carp muscle on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). GSC and PSC contained glycine as the major amino acid and had imino acid of 150 and 155 residues/1000 residues, respectively. Fourier transform infrared spectroscopy (FTIR) spectra of GSC and PSC revealed the presence of a triple helix. The GSC appeared to have a dense sheet-like film linked by random-coiled filaments and PSC had fine globular filaments under scanning electron microscopy (SEM). The maximum transition temperature (Tmax) of GSC and PSC was 33.05 °C and 31.33 °C, respectively. These results provide valuable scientific information for the texture study and development of surf clam shell or other bivalve mollusks.

Physicochemical properties of acid- and pepsin-soluble collagens from the cartilage of Siberian sturgeon.

To look for the collagen alternatives of mammalian cartilages from aquatics and their by-products, acid-soluble collagen (ASC-SC) and pepsin-soluble collagen (PSC-SC) were extracted from cartilages of Siberian sturgeon (Acipenser baerii) with yields of 27.13 ± 1.15 and 14.69 ± 0.85% on dry weight basis. ASC-SC and PSC-SC had glycine as the major amino acid with the contents of 326.8 and 327.5 residues1000 residues-1, and their contents of proline and hydroxyproline were 205.9 and 208.0 residues1000 residues-1. ASC-SC and PSC-SC comprised type I collagen ([α1(I)]2α2(I)) and type II collagen ([α1(II)]3) on the literatures and results of amino acid composition, SDS-PAGE pattern, UV, and FTIR spectra. Meanwhile, FTIR spectra data indicated that there were more hydrogen bonds in ASC-SC and more intermolecular crosslinks in PSC-SC. The maximum transition temperature (Tmax) of the ASC (28.3°C) and PSC (30.5°C) was lower than those of collagens from mammalian cartilages (> 37°C). ASC-SC and PSC-SC showed high solubility in the acidic pH ranges and the solubility decreased in the presence of NaCl at concentrations above 3%. Zeta potential studies indicated that both ASC-SC and PSC-SC exhibited a net zero charge at pH6.30 and 6.32. SEM results indicated that ASC-SC and PSC-SC presented irregular dense sheet-like film linked by random-coiled filaments. Therefore, collagens from Siberian sturgeon cartilages might be the suitable alternatives of the collagens of mammal cartilages as functional ingredient to treat some diseases.

Preparation, Physicochemical and Antioxidant Properties of Acid- and Pepsin-Soluble Collagens from the Swim Bladders of Miiuy Croaker (Miichthys miiuy).

Collagen is one of the most useful biomaterials and widely applied in functional food and cosmetics. However, some consumers have paid close attention to the safety of mammalian collagens because of the outbreaks of bovine spongiform encephalopathy (BSE), foot-and-mouth disease (FMD), and other prion diseases. Therefore, there is a strong demand for developing alternative sources of collagen, with one promising source being from the process by-products of commercial fisheries. In this report, acid-soluble collagen (ASC-SB) and pepsin-soluble collagen (PSC-SB) from swim bladders of miiuy croaker (Miichthys miiuy) were isolated with yields of 1.33 ± 0.11% and 8.37 ± 0.24% of dry swim bladder weight. Glycine was the major amino acid present, with a content of 320.5 (ASC-SB) and 333.6 residues/1000 residues (PSC-SB). ASC-SB and PSC-SB had much lower denaturation temperatures compared to mammalian collagen, a consequence of low imino acid contents (196.7 and 199.5 residues/1000 residues for ASC-SB and PSC-SB, respectively). The data of amino acid composition, SDS-PAGE pattern, UV and FTIR spectra confirmed that ASC-SB and PSC-SB were mainly composed of type I collagen. FTIR spectra data indicated there were more hydrogen bonding and intermolecular crosslinks in ASC-SB. These collagens showed high solubility in the acidic pH ranges and low NaCl concentrations (less than 2%). The Zeta potential values of ASC-SB and PSC-SB were 6.74 and 6.85, respectively. ASC-SB and PSC-SB presented irregular, dense, sheet-like films linked by random-coiled filaments under scanning electron microscopy. In addition, ASC-SB and PSC-SB could scavenge DPPH radical, hydroxyl radical, superoxide anion radical, and ABTS radical in a dose-dependent manner. Overall, the results indicate that collagens from the swim bladders of miiuy croaker are a viable substitute for mammalian collagen, with potential functional food and cosmeceutical applications.

Regulation on the aggregation-induced emission (AIE) of DNA-templated silver nanoclusters by BSA and its hydrolysates

The aggregation-induced emission (AIE) phenomenon of the metal nanoclusters (NCs) has been discovered quite recently, which is considered to be creative to improve the optical properties of NCs upon ligand aggregation. In the present study, we report an AIE system for double-stranded DNA-templated silver nanoclusters (AgNCs-dsDNA) by using bovine serum albumin (BSA) in solution, which induce a moderate emission enhancement of AgNCs (5-fold) and a blue-shift through a loosen interaction. In addition, significant luminescence enhancement (30-fold) is further stimulated by the addition of digestive enzyme to the system by altering the surface structure of the aggregated particles. The processes are observed directly through transmission electron microscopy (TEM), where the dispersed AgNCs spheres are aggregated in a large incompact sheet-like film by BSA; while further trypsin addition lead them into larger particles (>50nm) with higher density. And the intrinsic mechanism is explained well by UV–vis absorption and time-resolved luminescence spectra. The observed luminescence enhancement in step-II is attributed to the AIE through stronger interaction between the hydrolysates of BSA and the ligand dsDNA. Therefore, the optical properties of AgNCs-dsDNA are regulated well by the addition of BSA and trypsin in different amounts, which relates directly to the degree of aggregation and can be extended to other metal nanoclusters by employing the pairs of protein and related enzyme.

Isolation and Characterization of Pepsin-soluble Collagens from Bones, Skins, and Tendons in Duck Feet.

The objectives of this study were conducted to characterize pepsin-soluble collagen (PSC) extracted from bones (PSC-B), skins (PSC-S), and tendons (PSC-T) of duck feet and to determine their thermal and structural properties, for better practical application of each part of duck feet as a novel source for collagen. PSC was extracted from each part of duck feet by using 0.5 M acetic acid containing 5% (w/w) pepsin. Electrophoretic patterns showed that the ratio between α1 and α2 chains, which are subunit polypeptides forming collagen triple helix, was approximately 1:1 in all PSCs of duck feet. PSC-B had slightly higher molecular weights for α1 and α2 chains than PSC-S and PSC-T. From the results of differential scanning calorimetry (DSC), higher onset (beginning point of melting) and peak temperatures (maximum point of curve) were found at PSC-B compared to PSC-S and PSC-T (p<0.05). Fourier transform infrared spectroscopy (FT-IR) presented that PSC-S and PSC-T had similar intermolecular structures and chemical bonds, whereas PSC-B exhibited slight difference in amide A region. Irregular dense sheet-like films linked by random-coiled filaments were observed similarly. Our findings indicate that PSCs of duck feet might be characterized similarly as a mixture of collagen type I and II and suggest that duck feet could be used for collagen extraction without deboning and/or separation processes.

Enzymatic extraction and characterisation of a thermostable collagen from swim bladder of rohu (Labeo rohita).

The fish swim bladder is considered as a potential source of realistic collagen. Currently, processing of the Indian major carp rohu (Labeo rohita) generates an enormous quantity of non-edible by-products, including swim bladders, which are discarded as waste with no commercial value. In the present study, collagen was prepared from rohu swim bladder and its physicochemical and fibril-forming capacities were assessed. The collagen isolated from rohu swim bladder was characterised as type I, containing α1 and α2 chains with triple helical structure by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, fourier transform infrared spectroscopy and amino acid analysis. The extracted collagen denaturation temperature was found to be 42.16 °C by differential scanning calorimetry analysis and also exhibited a high solubility in the presence of low NaCl concentrations (0-0.6 mol L-1 ). The extracted collagen exhibited a high fibril-formation capacity at a NaCl concentration of 1.5 mol L-1 . Examination of the microstructure of collagen by scanning electron microscopy (SEM) showed a porous, sheet-like film and a multilayered structure. The fibril formation capacity of collagen was also confirmed using SEM analysis. The rohu swim bladder type I collagen was successfully extracted using an enzymatic method with a yield of 465.2 g kg-1 (dry weight basis) and was characterised as a well maintained triple helical structure. The extracted collagen exhibited a high fibril-forming ability. The results of the present study confirm that utilisation of rohu swim bladder will open up a new avenue for the better disposal of by-products and also help to minimise environmental pollution issues. © 2016 Society of Chemical Industry.

Isolation and characterization of collagen from the muscle of Amur sturgeon (Acipenser schrenckii)

The collagen in Amur sturgeon muscle was isolated using sodium chloride (salt-solubilized collagen, SSC, 3.02%), followed by acetic acid (acid-solubilized collagen, ASC, 31.56%) and then pepsin (pepsin-solubilized collagen, PSC, 58.49%). The collagens appeared to be dense sheet-like film linked by random-coiled filaments under SEM. There was no obvious difference in denaturation temperature (about 33°C) assessed by CD, while the melting temperature of SSC (115.82°C) was significantly lower than ASC and PSC (120.23 and 118.80°C, respectively) determined by DSC. SDS-PAGE showed that the collagens were mainly type I with similar amino acid profiles. FTIR confirmed the triple helical structure of the collagens, and indicated more hydrogen bond in PSC and more intermolecular crosslinks in ASC. These results provide some basis for elucidating the function of collagen in the development of meat texture during postmortem aging and processing.

Characterization of collagen from the skin of Amur sturgeon (Acipenser schrenckii)

The collagen in Amur sturgeon skin was isolated using sodium chloride (SSC, 4.55%), acetic acid (ASC, 37.42%) and pepsin (PSC, 52.80%), respectively. The collagens appeared to be dense sheet-like film linked by random-coiled filaments under SEM. The denaturation and melting temperature were 32.15 °C and 116.62 °C for SSC, 32.78 °C and 120.66 °C for ASC, 32.46 °C and 115.42 °C for PSC, assessed by CD and DSC. SDS-PAGE showed that the collagens were mainly type I with two different α chains. The amino acid profiles of them was similar to each other with high imino acid content and hydroxylation degree. FTIR confirmed the triple helical structure of the collagens, and indicated more hydrogen bond in PSC and more intermolecular crosslinks in ASC. These results suggested that the collagens have potential in commercial applications as alternatives to mammalian collagen.

Isolation and characterization of collagen from the cartilage of Amur sturgeon (Acipenser schrenckii)

The collagen in Amur sturgeon cartilage was isolated using sodium chloride (salt-solubilized collagen, SSC, 2.18%), followed by acetic acid (acid-solubilized collagen, ASC, 27.04%) and then pepsin (pepsin-solubilized collagen, PSC, 55.92%). These collagens appeared to be dense sheet-like film linked by random-coiled filaments under SEM. The denaturation and melting temperatures of PSC (35.71 and 123.90°C) were significantly higher than SSC (32.64 and 114.51°C) and ASC (32.98 and 120.72°C) assessed by circular dichroism and differential scanning calorimetry, which could be attributed to its high imino acid content (22.57%) and degree of hydroxylation (47.29%). Electrophoresis pattern showed that the SSC and ASC were type I collagen, while PSC was predominantly type II collagen along with other minor types. Infrared spectra confirmed their triple helical structure, and indicated more hydrogen bonding in ASC and more intermolecular crosslinks in PSC. These results provide some basis for their large-scale production and further application as alternatives to mammalian collagen.

Preparation and characterisation of type I and V collagens from the skin of Amur sturgeon (Acipenser schrenckii)

The collagen in Amur sturgeon was extracted by pepsin digestion and separated into two fractions, P2.4 (92.40%) and P4.0 (2.16%), by sodium chloride precipitation. SDS–PAGE and amino acid profile suggested that the P2.4 and P4.0 might be classified as type I collagen (PSC-I) and type V collagen (PSC-V), respectively. These collagens appeared to be dense sheet-like film linked by random-coiled filaments under SEM. The denaturation and melting temperatures of PSC-V (35.92 and 122.86°C) were significantly higher than PSC-I (32.52 and 116.01°C) assessed by CD and DSC, which could be attributed to its higher imino acid content (23.43%) and degree of hydroxylation (52.18%). FTIR confirmed their triple helical structure, and indicated more intermolecular crosslinks in PSC-I and more hydrogen bond in PSC-V. These results provide some basis for their large-scale production and further application as alternatives to mammalian collagen.

Substrate Dependence of the Properties of MgO Films Produced Using an Aqueous Chemical Growth Method

Using a simple solution route based on the reaction between magnesium tetrahydrate ((CH3COO)2Mg.4H2O)) and hexamethylenetetramine (C6H12N4), MgO films were grown on Mg and MgO. Morphological observations revealed that porous MgO films were obtained on Mg, while sheet-like films were produced when MgO was used as the substrate. The EDX results indicated that only Mg and O were present in all of the films. When Mg was used as the substrate, the resistivity of the MgO film decreased from 2.060 x 102 Ω cm to 1.990 x 102 Ω cm as the temperature was increased to 150° C. In contrast, the resistivity decreased to 1.820 x 102 Ω cm when MgO was used as the substrate at 150° C. The morphology and crystallinity of the material likely played a role in the reduced resistivity of the films. The bandgap of MgO films was dependent on the type of substrate and the reaction temperature. The bandgap of MgO films grown on Mg increased from 5.18 eV to 5.27 eV as the temperature increased from 90° C to 150° C. A similar increase was also observed when a film of MgO was grown on MgO. However, the bandgap energies obtained in this study were well below that of bulk MgO due to the non-stoichiometry of the deposited layers and crystallinity of the samples, as shown by EDX and XRD, respectively.

Transparent, Adhesive Film Formation of Per-O-valeryl-β-cyclodextrin

Abstract Per-O-valeryl-β-cyclodextrin forms a transparent, adhesive sheet-like film on water surface and on backing membrane, without any chemical crosslinkings.