Full life cycle green preparation of collagen-based food packaging films using Halocynthia roretzi as raw material.

The extraction of collagen for packaging films typically requires a time-consuming process and the use of substantial chemicals. Herein, we present a full life cycle green preparation method for rapidly producing collagen-based food packaging films using Halocynthia roretzi (HR), a collagen-rich marine organism, as raw material. We first prepared the micro/nano-sized collagen fibers from HR tissue by utilizing urea and sonication as effective hydrogen-bond breakers. Subsequently, the collagen fiber was rapidly fabricated into a film through vacuum filtration. The resulting collagen fiber film (CFF) exhibited a uniform and dense surface, along with good tensile properties, water resistance, and biodegradability. In addition, the deposition of chitosan (CS) on the surface of CFF resulted in a remarkable preservation effect for both strawberries and pork. This full life cycle preparation method for collagen-based films provides a promising and innovative approach to the sustainable preparation of food packaging films.

Dual green hemostatic sponges constructed by collagen fibers disintegrated from Halocynthia roretzi by a shortcut method.

Recently, biomacromolecules have received considerable attention in hemostatic materials. Collagen, an ideal candidate for hemostatic sponges due to its involvement in the clotting process, has been facing challenges in extraction from raw materials, which is time-consuming, expensive, and limited by cultural and religious restrictions associated with traditional livestock and poultry sources. To address these issues, this study explored a new shortcut method that using wild Halocynthia roretzi (HR), a marine fouling organism, as a raw material for developing HR collagen fiber sponge (HRCFs), which employed urea to disrupt hydrogen bonds between collagen fiber aggregates. This method simplifies traditional complex manufacturing processes while utilized marine waste, thus achieving dual green in terms of raw materials and manufacturing processes. FTIR results confirmed that the natural triple-helical structure of collagen was preserved. HRCFs exhibit a blood absorption ratio of 2000-3500 %, attributed to their microporous structure, as demonstrated by kinetic studies following a capillary model. Remarkably, the cytotoxicity and hemolysis ratio of HRCFs are negligible. Furthermore, during in vivo hemostasis tests using rabbit ear and kidney models, HRCFs significantly reduce blood loss and shorten hemostasis time compared to commercial gelatin sponge and gauze, benefiting from the capillary effect and collagen's coagulation activity. This study provides new insights into the design of collagen-based hemostatic biomaterials, especially in terms of both raw material and green manufacturing processes.

A Review of Advanced Abdominal Wall Hernia Patch Materials.

Tension-free abdominal wall hernia patch materials (AWHPMs) play an important role in the repair of abdominal wall defects (AWDs), which have a recurrence rate of <1%. Nevertheless, there are still significant challenges in the development of tailored, biomimetic, and extracellular matrix (ECM)-like AWHPMs that satisfy the clinical demands of abdominal wall repair (AWR) while effectively handling post-operative complications associated with abdominal hernias, such as intra-abdominal visceral adhesion and abnormal healing. This extensive review presents a comprehensive guide to the high-end fabrication and the precise selection of these advanced AWHPMs. The review begins by briefly introducing the structures, sources, and properties of AWHPMs, and critically evaluates the advantages and disadvantages of different types of AWHPMs for AWR applications. The review subsequently summarizes and elaborates upon state-of-the-art AWHPM fabrication methods and their key characteristics (e.g., mechanical, physicochemical, and biological properties in vitro/vivo). This review uses compelling examples to demonstrate that advanced AWHPMs with multiple functionalities (e.g., anti-deformation, anti-inflammation, anti-adhesion, pro-healing properties, etc.) can meet the fundamental clinical demands required to successfully repair AWDs. In particular, there have been several developments in the enhancement of biomimetic AWHPMs with multiple properties, and additional breakthroughs are expected in the near future.

Formulating ecological sustainability policies for India within the coal energy, biomass energy, and economic globalization framework.

The betterment of environmental conditions is widely recognized as a significant priority for India, which is a critical aspect of the Sustainable Development Goals (SDGs). As an emerging economy, pursuing economic expansion is paramount, requiring significant amount of energy and a degree of openness to other nations. Meanwhile, the nation's energy demands are heavily met by the usage of biomass and coal energy sources. Furthermore, the nation is part of the top consumer of biomass and coal energy globally. However, over the last 50 years, the level of ecological footprint in India has surged by about 82%, despite the country's commitment to achieving environmental sustainability, which tends to raise concerns such as: What is the role of India's major energy sources, biomass, and coal energy, towards ecological sustainability? Does economic globalization promote and hinder India's environmental sustainability goals? As a result, this current study offers answers to these concerns by investigating the effect of economic globalization, coal energy, and biomass energy on the ecological footprint in India while controlling economic growth. Using the dynamic ARDL to analyze the dataset from 1970 to 2018, the result suggests that biomass energy and economic globalization improve ecological quality. However, economic growth and coal energy impede ecological quality in India. Furthermore, we adopted the time-varying causality test solely to understand the causality analysis, which established that economic globalization, biomass energy, economic growth, and coal energy could forecast the future direction of the ecological footprint.

Governing the aggregation of type I collagen mediated through ß-cyclodextrin.

The effect of carbohydrates on collagen self-assembly behavior has been widely investigated because of their regulation on collagen fibrogenesis in vivo. In this paper, ß-cyclodextrin (ß-CD) was selected as an external disturbance to explore its intrinsic regulating mechanism on collagen self-assembly. The results of fibrogenesis kinetics indicated that ß-CD had a bilateral regulation on collagen self-aggregation process, which was closely related to the content of ß-CD: collagen protofibrils with low ß-CD content were less aggregated compared to collagen protofibrils with high ß-CD content. However, typical periodic stripes of ~67 nm on collagen fibrils were observed from transmission electron microscope (TEM), indicating that ß-CD did not disturb the lateral arrangement of collagen molecules to form a 1/4 staggered structure. Correspondingly, the degree of aggregation of collagen self-assembled fibrils was closely correlated with the addition of ß-CD content, as confirmed by field emission scanning electron microscopy (FESEM) and atomic force microscope (AFM). In addition, collagen/ß-CD fibrillar hydrogel had good thermal stability and cytocompatibility. These results provide a better understanding of how to construct a structurally reliable collagen/ß-CD fibrillar hydrogel as a biomedical material in a ß-CD-regulated environment.

Unveiling the nexus between marine energy consumption, seaborne trade, and greenhouse gases emissions from international shipping.

As a result of the globalization of production processes and the expansion of international trade, both water-based trade and the use of marine energy are expanding quickly. Marine energy consumption is rapidly increasing as a result of globalization. Despite being ignored for many decades, reducing marine emissions is today a top priority among European nations. Thus, the present study contributes to the existing literature by investigating the nexus between marine energy consumption, seaborne trade, and GHG emissions by employing time series data for eight Northern European nations from 2005 to 2017. The extended EKC model and three proxy variables for seaborne trade (i.e., container throughput, liner shipping connectivity index, and trade openness) are used to investigate the nexus between these variables. FMOLS and DOLS methods have been employed to control the problems of endogeneity and serial correlation. Only in Denmark, Norway, and Sweden did the data corroborate an inverted U-shaped relationship (the EKC curve) between maritime GHG emissions and economic development. The increase in energy utilization across all nations directly increased marine GHG emissions; however, the adverse effect of energy consumption on the environment is severe in Denmark, Norway, and Sweden. Container throughput, linear shipping connectivity index, and trade openness exhibit a positive impact on marine GHG emissions. The impact of seaborne proxy variables is severe in Denmark and Sweden. In order to have a robust assessment and to confirm the validity and uniformity of the results, Driscoll-Kraay standard errors (DKSE) and robust standard error (RSE) regression techniques are being employed.

An empirical analysis of the nexus between digital financial inclusion, industrial structure distortion, and China's energy intensity.

Stimulating the shift to low-carbon energy and decreasing energy intensity are crucial strategies for green growth. Reducing energy intensity is an important measure to achieve the goal of "double carbon" and building a beautiful new China. Based on the provincial panel data of China from 2011 to 2020, this paper empirically tests the relationship among digital financial inclusion, industrial structure distortion, and energy intensity by using the spatial Durbin model and the intermediary effect method. The results show that the development of digital financial inclusion can promote the decline of energy intensity, and industrial structure distortion has a partial intermediary effect in the relationship between digital financial inclusion and energy intensity. Because of this, it is important to speed up the development of digital financial inclusion, increase the innovation of digital financial inclusion products and services, strengthen the supervision of digital financial inclusion, and reduce the distortion of the industrial structure so that digital finance can play its full role in reducing energy intensity.

The spatial impact of digital economy on energy intensity in China in the context of double carbon to achieve the sustainable development goals.

Using the provincial panel data of China during 2012-2019, the present study employed spatial Durbin error model to explore the spatial effect of the digital economy on energy intensity. The results show that both digital economy and energy intensity have spatial autocorrelation, showing the distribution characteristics of spatial aggregation. The digital economy has a significant negative influence on energy intensity. The result shows a significant spatial spillover effect of digital economy on energy intensity, and the development of the digital economy in neighboring regions reduces energy intensity in the central region. Additionally, industrial structure, urbanization, energy price, and foreign direct investment have a heterogenous impact on energy intensity. Thus, it is crucial to give importance to the development of the energy intensity, plan the spatial layout of the digital industry as a whole, drive the coordinated growth of the regional digital economy, quicken the upgrading of industrial structure, promote urbanization, perfect the energy price formation mechanism, raise the entry threshold for foreign direct investment, to effectively reduce the energy intensity, and facilitate the smooth realization of the "double carbon" goal.

Interaction dynamics of optical dark bound solitons for a defocusing Lakshmanan-Porsezian-Daniel equation.

We investigate the propagation and interaction dynamics of the optical dark bound solitons for the defocusing Lakshmanan-Porsezian-Daniel equation, which is a physically relevant generalization of the nonlinear Schrödinger equation involving the higher-order effects. Explicit N-dark soliton solutions in the compact determinant form are constructed via the binary Darboux transformation method. Bound states of the dark solitons are discussed when the incoherent solitons have the same velocity. We find an interesting phenomenon that dark soliton molecules and double-valley dark solitons (DVDSs) can be obtained by controlling the interval of the bound state dark solitons, and abundant interaction modalities between them can be formed. Moreover, dark soliton molecules always undergo elastic interactions with other solitons, while interactions for the DVDSs are usually inelastic, and special parameter conditions for elastic interaction of DVDSs through asymptotic analysis are obtained. Numerical simulations are employed to verify the stability of the bound state dark solitons. Analytical results obtained in this paper are expected to be useful for the experimental realization of bound-state dark solitons in optical fibers with higher-order effects and a further understanding of their optical transmission properties..

Rapid fabrication of bionic pyrogallol-based self-adhesive hydrogel with mechanically tunable, self-healing, antibacterial, wound healing, and hemostatic properties.

Hydrogels are functional materials that are similar to human skin and have received much attention in recent years for biomedical applications. However, the preparation of nontoxic, highly adhesive, and antimicrobial hydrogels in an efficient way remains a great challenge. Inspired by adhesive mussel foot proteins (mfps) which consist of abundant catecholic amino acids and lysine (Lys) residues, gallic acid-modified ε-poly-L-lysine (EPL/GA) was synthesized, and an active functional monomer (AA-EPL/GA) was then created through a reaction with acrylic acid (AA). The polymerization of AA-EPL/GA occurred rapidly (30-160 s) under blue light (λ = 405 nm) irradiation to produce a biomimetic PAA-EPL/GA hydrogel under mild conditions. The biomimetic pyrogallol-Lys distribution endowed the PAA-EPL/GA hydrogels with superior adhesion in humid environments (with an adhesive strength of 50.02 kPa toward wet porcine skin) and tunable mechanical and self-healing properties. Additionally, the PAA-EPL/GA hydrogels exhibited outstanding antibacterial ability due to the inherent characteristics of GA and EPL. In a mouse model, PAA-EPL/GA adhered firmly around the wound tissues. Photographs of the wound and the histological results demonstrated the ability of the hydrogel to promote wound healing, control wound infection, and suppress scar formation. Moreover, the hydrogel had a good hemostatic effect on liver bleeding. Our results highlighted the promising application potential of GA-based hydrogels, which were easily, harmlessly, and efficiently fabricated by blue light irradiation.

Adhesive, Antibacterial, Conductive, Anti-UV, Self-Healing, and Tough Collagen-Based Hydrogels from a Pyrogallol-Ag Self-Catalysis System.

Recently, versatile hydrogels with multifunctionality have been widely developed with emerging applications as wearable and implantable devices. In this work, we reported novel versatile hydrogels by self-catalyzing the gelation of an interpenetrating polymer network consisting of acrylic acid (AA) monomers and GA-modified collagen (GCOL) in situ decorated silver nanoparticles (AgNPs). The resultant hydrogel, namely AgNP@GCOL/PAA, has many desirable features, including good mechanical properties (such as 123 kPa, 916%, and 1961 J m-2 for the fracture stress, strain and tearing energy) that match with those of animal skin, excellent self-healing performance, favorable conductivity and strain sensitivity as a flexible biosensor, and excellent antibacterial and anti-UV properties, as well as the strong adhesiveness on skin. Moreover, AgNP@GCOL/PAA showed excellent biocompatibility via in vitro cell culture. Remarkably, AgNP@GCOL/PAA displayed superior hemostatic properties with sharply decreasing blood loss for a mouse liver incision, closely related to its strong self-adhesion which produced anchoring strength to the bleeding site and thus formed a network barrier with liver tissue. This study provides new opportunities for the facile preparation of widely used multifunctional collagen-based hydrogels based on a simple pyrogallol-Ag system.

Tendon-inspired fibers from liquid crystalline collagen as the pre-oriented bioink.

Nature provides rich bionic resources for the construction of advanced materials with excellent mechanical properties. In this work, inspired by animal tendons, a bionic collagen fiber was developed using collagen liquid crystals as the pre-oriented bioink. The texture of liquid crystalline collagen observed from polarized optical microscopy (POM) showed the specific molecular pre-orientation. Meanwhile, the collagen spinning liquids exhibited a minimal rise in viscosity upon increasing concentration from 60 to 120 mg/mL, indicating the feasible processability. The collagen fiber, which was prepared via wet spinning without being denatured, exhibited the favorable orientation of fibrils along its axis as observed with FESEM and AFM. Thanks to the synergistic effects between pre-orientation and shearing orientation, the maximum tensile strength and Young's modulus of collagen fibers reached 9.98 cN/tex (219.29 ± 22.92 MPa) and 43.95 ± 1.11 cN/tex (966.20 ± 24.30 MPa), respectively, which were also analogous to those of tendon. In addition, the collagen fiber possessed a desirable wet strength. Benefiting from the natural tissue affinity of collagen, the as-prepared bionic collagen fiber possessed excellent wound suture performance and biodegradability in vivo, which offers a new perspective for the potential of widespread applications of collagen fibers in biomedical fields.

Novel Modification of Collagen: Realizing Desired Water Solubility and Thermostability in a Conflict-Free Way.

Because of poor water solubility and low thermostability, the application of collagen is limited seriously in fields such as injectable biomaterials and cosmetics. In order to overcome the two drawbacks simultaneously, a novel bifunctional modifier based on the esterification of polyacrylic acid (PAA) with N-hydroxysuccinimide (NHS) was prepared. The esterification degree of PAA-NHS esters was increased upon increasing the NHS dose, which was confirmed by Fourier-transform infrared (FTIR) and nuclear magnetic resonance spectrascopy. FTIR results indicated that the triple helix of the modified collagens remained integrated, whereas the molecular weight became larger, as reflected by the sodium dodecyl sulfate-polyacrylamide gel electrophoresis pattern. The modified collagens displayed excellent water solubility under neutral condition, owing to lower isoelectric point (3.1-4.3) than that of native collagen (7.1). Meanwhile, denaturation temperatures of the modified collagens were increased by 4.8-5.9 °C after modification. The modified collagen displayed hierarchical microstructures, as reflected by field-emission scanning electron microscopy, while atomic force microscopy further revealed a "fishing net-like" network in the nanoscale, reflecting a unique aggregation behavior of collagen macromolecules after modification. As a whole, the PAA-NHS ester as a bifunctional modifier endowed collagen with desired water solubility and thermostability in a conflict-free manner, which was beneficial to the process and application of the water-soluble collagen.

Novel Self-Healing Hydrogel with Injectable, pH-Responsive, Strain-Sensitive, Promoting Wound-Healing, and Hemostatic Properties Based on Collagen and Chitosan.

Collagen (COL)-chitosan (CS) composite hydrogels are attracting increasing attention because of their great potential for application as biomaterials. However, conventional COL-CS hydrogels were easily disabled for lack of fully reversible linking in their networks. In this work, we developed a kind of self-healing hydrogel for wound dressing, composed of COL, CS, and dibenzaldehyde-modified PEG2000 via dynamic imine bonds, and the COL/CS hydrogels showed good thermal stability, injectability, and pH sensitivity, ideally promoting wound-healing performance and hemostatic ability. Furthermore, the hydrogel could monitor multiple human motions, especially the facial expression via strain sensitivity. This work offers a new perspective for the biomass-based hydrogels applied in medical field as wound dressing.

Insight into the rheological behaviors of a polyanionic collagen fabricated with poly(γ-glutamic acid)-NHS ester.

The rheological behaviors of a polyanionic collagen, fabricated using poly(γ-glutamic acid)-N-hydroxysuccinimide (γ-PGA-NHS) as a novel modifier, were investigated in this study. It was found that both of the native and modified collagen solutions were pseudoplastic fluids, as shown from the steady-shear tests. While the storage modulus and loss modulus of collagen increased with increasing the amount of γ-PGA-NHS, or with increasing the degree of esterification of γ-PGA-NHS; meanwhile, the dynamic denaturation temperature determined by dynamic temperature sweep was also increased, indicating an improved thermal stability of collagen solution modified by γ-PGA-NHS. The creep-recovery measurements showed that the resistance to deformation was enhanced for modified collagen, probably due to the cross-linking occurred between the ε-amino groups of collagen molecules and α-COOH groups of γ-PGA-NHS, as well as the electrostatic interaction and hydrogen-bond interactions between the two molecules. Furthermore, the aggregation of collagen fibers was promoted due to these interactions between collagen and γ-PGA-NHS as observed by atomic force morphology. In addition, the modified collagen exhibited good cytocompatibility as demonstrated by cell growth culturing. The obtained information was expected to give valuable clues to the design and fabrication of controlled stable collagen-based products for applications in various biomedical fields.

Dual-functionalized hyaluronic acid as a facile modifier to prepare polyanionic collagen.

Hyaluronic acid (HA) is a natural polysaccharide possesses outstanding physiological activities. In this work, HA was activated as a novel collagen modifier via the esterification reaction between N-hydroxysuccinimide (NHS) and the carboxyl groups of HA. Both of Fourier transform infrared spectroscopy (FTIR) and 1H- nuclear magnetic resonance (NMR) spectra indicated the successful synthesis of HA-NHS esters. As reflected by FTIR, circular dichroism (CD) and sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE), collagens modified with HA-NHS ester maintained its intact triplex structure with larger molecular weight. The resultant polyanionic collagen displayed an excellent dissolubility in the neutral water to form a clear solution, due to the significantly lower isoelectric point values (3.8-4.4) compared with that of the native collagen (7.1). In addition, the thermal transition temperature of collagen was significantly increased (16 °C) after modifying with HA-NHS esters. Both of the aggregation morphology and rheological property exhibited high dependence on the NHS/COOH ratio of HA-NHS esters, as reflected by field-emission scanning electron microscopy (FESEM) and rheological test, respectively. The present study offered a novel dual-functional modifier based on the design of HA-NHS ester to obtain water-soluble collagen with desired thermal stability and rheological property, which will significantly widen the application range of collagen, especially in the fields of injectable biodegradable materials and cosmetics.

Fluorescence studies on the aggregation behaviors of collagen modified with NHS-activated poly(γ-glutamic acid).

The poly(γ-glutamic acid)-NHS (γ-PGA-NHS) esters were used to endow collagen with both of excellent water-solubility and thermal stability via cross-linking reaction between γ-PGA-NHS and collagen. In the present work, the effect of γ-PGA-NHS on the aggregation of collagen molecules was studied by fluorescence techniques. The fluorescence emission spectra of pyrene in collagen solutions and the intrinsic fluorescence emission spectra of collagen suggested different effects of γ-PGA-NHS on collagen molecules: inhibiting aggregation below critical aggregation concentration (CAC) and promoting aggregation above CAC. The two-dimensional (2D) fluorescence correlation spectra indicated that the intermolecular hydrogen bonding and cross-linking between γ-PGA-NHS and collagen would influence the aggregation of collagen molecules. By the ultra-sensitive differential scanning calorimeter (VP-DSC), it was found that the main denaturational transition temperature (Tm2) of modified collagen increased, while its calorimetric enthalpy changes (ΔH2) decreased compared to those of native collagen, further indicating that the modification of γ-PGA-NHS influenced the aggregation of collagen molecules. The study provide useful information for the utilizing and or the processing of water-soluble collagen in aqueous solution in the fields such as cosmetics, health care products, tissue engineering and biomedical materials, etc.

Effect of carboxymethylcellulose on fibril formation of collagen in vitro.

The effect of carboxymethylcellulose (CMC) on the fibril formation of collagen in vitro was studied by turbidity measurements and atomic force microscopy (AFM). The kinetics curves of fibril formation indicated that the rate of collagen fibrillogenesis was decreased with the addition of CMC, meanwhile the final turbidity was obviously increased as the CMC/collagen ratio reached 30%. The AFM images of collagen-CMC solutions showed that the number of nucleation sites of collagen fibrillogenesis was significantly increased with the presence of CMC, while the diameter of immature collagen fibrils was obviously decreased. Moreover, the thermal stability of collagen fibril hydrogels was obviously improved with the presence of CMC. In addition, the morphologies of collagen fibrils observed by AFM revealed that the adjacent fibril segments or fibrils were intertwisted and even tightly merged, probably due to the hydrogen bonding and molecular entanglement interactions between CMC and collagen molecules.

The Preparation of Nano-SiO2/Dialdehyde Cellulose Hybrid Materials as a Novel Cross-Linking Agent for Collagen Solutions.

Nano-SiO2 was immobilized onto dialdehyde cellulose (DAC) to prepare SiO2/DAC hybrid materials. Fourier transform infrared spectra (FTIR), thermogravimetric analysis and field emission scanning electron microscopy of SiO2/DAC indicated that nano-SiO2 had been successfully hybridized with DAC. X-ray diffraction suggested that the structure of DAC was influenced by the nano-SiO2. SiO2/DAC was then used as the cross-linker of collagen solutions. Gel electrophoresis patterns and FTIR reflected that cross-linking occurred between DAC and collagen, but that collagen retained the native triple-helix, respectively. Differential scanning calorimetry indicated that the thermal stability of collagen could be effectively improved by SiO2/DAC. Dynamic rheology tests revealed that the flowability of collagens cross-linked by SiO2/DAC was superior to that of those cross-linked by DAC; meanwhile, collagens cross-linked by SiO2/DAC possessed a more homogeneous morphology compared to those cross-linked by DAC. The hybridization of SiO2/DAC as a cross-linker for collagen could effectively prevent the gelation caused by excessive cross-linking, and significantly improve the thermostability of collagen, which could be helpful for collagen being applied in fields including biomaterials, cosmetics, etc.

The preparation of poly(γ-glutamic acid)-NHS ester as a natural cross-linking agent of collagen.

γ-PGA-NHS ester, which was prepared using poly(γ-glutamic acid) (γ-PGA) and N-hydroxysuccinimide (NHS) as the raw materials, was synthesized to be a novel cross-linker of collagen. Fourier transform infrared spectra analysis suggested that the products displayed the characteristic absorption peak of ester. Results from nuclear magnetic resonance analysis indicated that the esterification degree of γ-PGA-NHS ester was increased with the increase of NHS. Modified collagen was prepared and characterized. The results of circular dichroism analysis indicated modified collagen retained the triple helix structure of natural collagen. Sodium dodecyl sulphate polyacrylamide gel electrophoresis revealed that the molecular weight of collagen was increased after cross-linking. Peptide mapping of collagen suggested that cross-linked collagen possessed an enhanced resistance to trypsin degradation. Differential scanning calorimeter results showed that the denaturation temperature of collagen was improved from 68.1±0.4 to 91.2±0.5°C (p<0.05). Dynamic viscoelastic measurements demonstrated the improvement of thermal stability and reflected the exponential increase in η*. The cross-linked collagen retained porous structure and the pore size became larger as observed by scanning electron microscopy. The investigation results provided useful information to produce collagen with improved physicochemical properties, particularly the thermal stability via the use of γ-PGA-NHS ester as a biomacromolecule-based cross-linker.