Ground type-I collagen—a focused study on its fibrillogenesis behavior and bioactivity in vitro

Yuling Xu,Lei Dai,Ke Li,Jialin Liu,Haibo Wang,Lang He,Chengzhi Xu,Benmei Wei,Juntao Zhang 한국고분자학회 2023 Macromolecular Research Vol.31 No.1

Take bovine tendon type-I collagen as the raw material, we pretreated it by freezing and then grinding the macromolecule at a low temperature (4–10 °C). Effects of the grinding process on the molecular structure, water solubility, fibrillogenesis behavior in vitro and biological activity of collagen were systematically prospected. Sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS–PAGE) results revealed that the collagen had typical structural characteristics of type-I collagen; moreover, grinding treatment gave rise to partially degraded collagen molecules which took on continuous bands with lower molecular weights different from α1 and α2. More strikingly, the degradation degree positively corresponded to the grinding duration. Circular dichroism (CD) analysis manifested that with extended grinding, intensities of both the positive and negative peaks for collagen samples shrunk. Interestingly, grinding also contributed to improved water solubility of collagen. The water solubility of the sample ground for 20 min (COL20) was 1.91 mg/mL, which is about 6 times higher than that of the natural collagen sample (0.28 mg/mL). Amid the study concerning the fibrillogenesis behavior, turbidity and rheological data collaboratively demonstrated that with prolonged grinding time, the assembly rate and degree of the sample plunged. Assembled gel from the ground collagen with finer fibrils was also observed in scanning electron microscope (SEM), which further embraced the conclusion aforementioned in fibrillogenesis kinetics. Cell experiments corroborated that the grinding process can be harnessed to manipulate the cell proliferation promoting ability of collagen. Simultaneously, further dissection of COL20 with the best biological activity clarified that the water-soluble part and water-insoluble part of COL20 had distinct aptitudes as to promoting cell proliferation as well as inhibiting the growth of liver cancer cells.

Silk Nonwoven: Recycling and Upcycling of Waste Silk into Bio-based Materials with High Value-Added Properties

Hongchang Wang,Liyao Cao,Yuling Li,Run Wen,Guangbiao Xu 한국섬유공학회 2023 Fibers and polymers Vol.24 No.10

With the increasing awareness of human environmental protection, the development of biodegradable bio-based materials has received more attention. As the off-cuts of silk, a natural protein fiber, waste silk still retains excellent properties such as biodegradability and biocompatibility, recycling and utilization of waste silk is currently very limited. To find a possible method to recycle low-cost waste silk and process it into high-value-added products, in this work, the waste silk from the silk spinning process was prepared into silk nonwoven (SN) with excellent air permeability, softness, water–oil amphiphilicity, biodegradability, and ultraviolet resistance by the wet laid process. The results showed that the uniform SN could be prepared when the alkali concentration was higher than 0.6%. The permeability of SN is higher than 80 mm/s, and the bending stiffness is lower than 0.085gf·cm2/cm. Notably, SN possesses entanglement at both fiber and fibril levels, enabling it to achieve a base strength of 0.58 MPa without additional reinforcement. The water contact angle and oil contact angle of SN were below 40° and 50°, respectively. The ultraviolet protection of SN-0.6 was classified as very good, with a degradation rate of 4.31% of SN-0.6 after 30 days of burial. The present research shows that silk nonwoven is a potential bio-based material with promising applications in the field of packaging and cleaning.

A New Method of Gelatin Modified Collagen and Viscoelastic Study of Gelatin-Collagen Composite Hydrogel

Lang He,Sheng Li,Chengzhi Xu,Benmei Wei,Juntao Zhang,Yuling Xu,Beirong Zhu,Yang Cao,Xilin Wu,Zhijin Xiong,Rongrui Huang,Jian Yang,Haibo Wang 한국고분자학회 2020 Macromolecular Research Vol.28 No.9

Pure collagen materials are expensive with poor mechanical properties, which need modifications in most cases. As the degradation product of collagen, gelatin is cheap, degradable and biocompatible, but few literatures have reported the research about gelatin-collagen composite materials. This is because gelatin and collagen have different soluble temperatures—gelatin is soluble in hot water (≥30 oC) and swells in cold water. However, a low temperature (2-10 oC) is required to prepare and store collagen solution, and neutral collagen solution denatures quickly above the room temperature. In this study, gelatin was ground into powders and swelled in neutral bovine tendon pepsin-soluble collagen solution (BPSC) to form a homogeneous gelatin-collagen mixture, in light of the swelling characteristics of gelatin in cold water. The assembly properties and gel properties of this composite material were further studied. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) test results showed that the bovine tendon collagen had typical type-I collagen structural characterizations with two α chains of about 100 kDa and one β chain of about 200 kDa; while the SDS-PAGE pattern of gelatin displayed bands continuously distributed from 30 to 200 kDa. Amino acid composition analysis test indicated that the content of polar amino acids and the sum of acidic and base amino acids for gelatin were higher than that of BPSC. Studies on gel properties demonstrated that gelatin-collagen mixed solution had collagenlike assembly characteristics and assembly kinetics. The moduli of the assembled gel at 35 oC were equivalent to that of pure bovine tendon collagen system; moreover, the system moduli didn’t change with time with elastic moduli (G') of about 40 Pa. However, at 25 oC, the moduli of gelatin-collagen composite hydrogel increased with the extension of time, its G' increased about 18 times within 8 h, and the ratio of elastic modulus to viscous modulus (G'') increased 4.6 times, showing a significant aging effect of structural strength. Meanwhile, the mechanical strength of the composite hydrogel was also regulated by temperature—the gel was highly elastic (G'≈3,000 Pa, G'>>G'') at a low temperature (5 oC); as the temperature rose, the system moduli gradually decreased and the elastic gel transformed into waterlike fluid at 50 oC little by little. What’s more, gelatin-collagen composite hydrogel also had reversible sol-gel performances and self-healing capability similar to the gelatin hydrogel. This novel preparation method for preparing composite materials and the resultant composite hydrogel are expected to be used in the fields of natural food gels, injectable hydrogels, cell scaffolds, drug sustained-release materials and so on, and improve and promote the processing performances, price and large-scale production of collagen-based materials.

Reconstituted Fibril from Heterogenic Collagens-A New Method to Regulate Properties of Collagen Gels

Jian Yang,Haibo Wang,Lang He,Benmei Wei,Chengzhi Xu,Yuling Xu,Juntao Zhang,Sheng Li 한국고분자학회 2019 Macromolecular Research Vol.27 No.11

Heterotypic collagen fibril has long been found in the tissues of organisms, which plays an important role in the formation and function of complex structures of organisms. Inspiring by the phenomenon, scholars tried to incubate collagens from different sources into novel collagen materials in vitro, and the forming of heterogenic reconstituted collagen fibrils (RF) was often demonstrated by differential scanning calorimetry (DSC) and fluorescence quenching analysis. In this work, we used two type-I collagens from different species (bovine tendon and grasscarp fish skin) to coassemble in vitro, and verified the formation of RF from a new rheological perspective. In addition, we also investigated the assembly behavior, surface hydrophilicity and hydrophobicity, microscopic morphology and cell proliferation ability of the RF. The results showed that the assembly rate, surface properties, fibril size, viscoelastic properties of RF can be delicately regulated by the method of heterogenic collagen reconstitution. This study provides new experimental evidence for the reconstitution of heterogenic collagens, and also offers a new means for the regulation of collagen gel performance, which would help to expand the application range of collagen gel materials.

Enhanced Strength-Ductility Synergy in Mg-0.5 wt%Ce Alloy by hot Extrusion

Hui Yu,Yu Liu,Ya Liu,Dongliang Wang,Yuling Xu,Binan Jiang,Weili Cheng,Lixin Huang,Weineng Tang,Wei Yu 대한금속·재료학회 2023 METALS AND MATERIALS International Vol.29 No.7

The microstructure and mechanical properties of micro-alloyed Mg-0.5 wt%Ce alloys are investigated systemically in this study. It shows that Mg-Ce binary system is very sensitive to extrusion temperature. On the one hand, the high tensile yield strength (TYS) of 343 MPa was obtained by extrusion at 250 °C mainly due to the combined effects of profuse nano-precipitation phase, grain refinement, texture strengthening and high-density dislocation; On the other hand, the excellent elongation of 30% was acquired by extrusion at 300 °C resulting from the elimination of dislocations as well as the modification of texture.

Effect of Ionic Liquids on the Fibril-Formation and Gel Properties of Grass Carp (Ctenopharyngodon idellus) Skin Collagen

Zhongwei Zhai,Haibo Wang,Benmei Wei,Peiwen Yu,Chengzhi Xu,Lang He,Juntao Zhang,Yuling Xu 한국고분자학회 2018 Macromolecular Research Vol.26 No.7

Self-assembled environment of collagen is one of the important factors for improving and regulating the properties of collagen-based biomaterials. This study aimed to investigate the effect of ionic liquids (ILs) on the fibril-formation and gel properties of grass carp (Ctenopharyngodon idellus) skin collagen. Fibrillogenic kinetics analysis showed that the collagen self-assembly can be suppressed by the introduction of ILs, and the inhibitory effect is influenced by concentration and types of ILs. Scanning electron microscopy test indicated that the assembled collagen fibrils in the presence of ILs had bigger diameters than that in the conventional buffer. Differential scanning calorimetry analysis revealed that the thermal stability of collagen fibrils can be significantly increased when self-assembly is performed in the presence of ILs. Moreover, the introduction of ILs enhanced the mechanical strength of collagen gels. Finding from this work provides a new idea for improving the performance of fish-sourced collagen biomaterials.

A Two-Dimensional Risk Assessment Method for Oil and Gas Pipelines Based on “Accident Probability–Reputation Loss”

Chen Xuefeng,Chen Wentao,Zhang Yifu,Peng Bin,Wang Yuling,Xu Mingwei 한국화학공학회 2024 Korean Journal of Chemical Engineering Vol.41 No.1

Oil and gas pipeline accidents not only caused personnel casualties, economic losses and environmental pollution but also brought great panic to the public. To provide accurate accident prevention strategies, risk assessment (RA) has been widely used in the oil and gas pipeline industry. It aims to quantify the potential risk due to unexpected eventualities. However, the current RA methods mainly pay attention to the tangible risk (such as the human safety risk, economic risk and environmental risk), and the intangible risk (such as reputation loss risk) is often neglected. This cannot refl ect the real risk for the oil and gas pipeline. To settle existing research limitation, a two-dimensional risk assessment method for oil and gas pipelines based on “accident probability–reputation loss” is proposed. The method mainly involves four steps, namely, risk identifi cation, probability calculation, consequence assessment and risk assessment. The proposed method is used to quantitatively assess a natural gas pipeline in central China. Its results indicate that pipeline risk is unacceptable due to the unacceptability of accident probability and various dimensions of risk. Therefore, this study can enrich and develop the current oil and gas pipeline RA method to refl ect the real risk of oil and gas pipeline accidents.

Modulation of the Self-Assembly of Collagen by Phytic Acid: An In Vitro Study

Xiao Tu,Xincheng Chen,Ying Peng,Jie Nan,Benmei Wei,Lang He,Chengzhi Xu,Yuling Xu,Dong Xie,Juntao Zhang,Haibo Wang 한국고분자학회 2018 Macromolecular Research Vol.26 No.13

Phytic acid, containing a myoinositol ring coupled with six phosphate groups, can react with the amino groups of collagen to regulate their self-assembly behavior. The aim of this research is to evaluate the effects of phytic acid on the selfassembly behavior of collagen, the structures and properties of the resulting fibrils and hydrogels. Turbidity and chloramine T assay suggested that phytic acid could improve the self-assembly kinetics and degree of collagen, and the optimal ratio of phytic acid/collagen was 1/1 (w/w). Scanning electron microscopy (SEM) analysis indicated that co-fibrils of collagen with phytic acid are more slender than that of pure collagen, and transmission electron microscopy (TEM) reveals that the characteristic D-periodicity of collagen fibrils is not affected by phytic acid. Besides, differential scanning calorimetry (DSC) and rheology revealed that the thermal stability of collagen fibrils and the viscoelasticity of collagen hydrogels could be improved by phytic acid and the optimal ratio of phytic acid/collagen is 1/1 (w/w).