Onome Obodo-Ovie, Mohammad Alyassin, Alan M. Smith, Gordon A. Morris
Green peppers are massively produced all over the world; however, substantial quantities of peppers are wasted. Functional polysaccharides can be produced from pepper waste. A conventional acid extraction method was used to obtain pectin-like materials from green bell pepper (GBP). A 23 experimental design (two-level factorials with three factors: temperature, pH, and time) was used to study the relationship between the extraction conditions and the measured physicochemical properties. The extracted polysaccharides were further analysed regarding their physicochemical and functional properties. The yields were in the range of (11.6–20.7%) and the highest yield value was extracted at pH 1. The polysaccharides were classified as “pectin-like”, as the galacturonic acid content was lower than 65%. Glucose and galactose were the major neutral sugars, and their relative amounts were dependent on the extraction conditions. The degree of esterification (DE) of the pectin-like extracts was greater than 50% and they were therefore classified as high methoxyl regardless of the extraction conditions. Also, important levels of phenolic materials (32.3–52.9 mg GAE/g) and proteins (1.5–5.4%) were present in the extract and their amounts varied depending on the extraction conditions. The green bell pepper polysaccharides demonstrated antioxidant and emulsifying activities and could also be used adequately to stabilise oil/water emulsion systems. This finding shows that green bell pepper could be used as an alternative source of antioxidants and an emulsifier/stabilising agent, and furthermore, the extraction conditions could be fine-tunned to produce polysaccharides with the desired quality depending on their application.
{"title":"The Effect of Different Extraction Conditions on the Physicochemical Properties of Novel High Methoxyl Pectin-like Polysaccharides from Green Bell Pepper (GBP)","authors":"Onome Obodo-Ovie, Mohammad Alyassin, Alan M. Smith, Gordon A. Morris","doi":"10.3390/macromol4020024","DOIUrl":"https://doi.org/10.3390/macromol4020024","url":null,"abstract":"Green peppers are massively produced all over the world; however, substantial quantities of peppers are wasted. Functional polysaccharides can be produced from pepper waste. A conventional acid extraction method was used to obtain pectin-like materials from green bell pepper (GBP). A 23 experimental design (two-level factorials with three factors: temperature, pH, and time) was used to study the relationship between the extraction conditions and the measured physicochemical properties. The extracted polysaccharides were further analysed regarding their physicochemical and functional properties. The yields were in the range of (11.6–20.7%) and the highest yield value was extracted at pH 1. The polysaccharides were classified as “pectin-like”, as the galacturonic acid content was lower than 65%. Glucose and galactose were the major neutral sugars, and their relative amounts were dependent on the extraction conditions. The degree of esterification (DE) of the pectin-like extracts was greater than 50% and they were therefore classified as high methoxyl regardless of the extraction conditions. Also, important levels of phenolic materials (32.3–52.9 mg GAE/g) and proteins (1.5–5.4%) were present in the extract and their amounts varied depending on the extraction conditions. The green bell pepper polysaccharides demonstrated antioxidant and emulsifying activities and could also be used adequately to stabilise oil/water emulsion systems. This finding shows that green bell pepper could be used as an alternative source of antioxidants and an emulsifier/stabilising agent, and furthermore, the extraction conditions could be fine-tunned to produce polysaccharides with the desired quality depending on their application.","PeriodicalId":18139,"journal":{"name":"Macromol","volume":" 15","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141368456","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Coltelli, V. Gigante, Laura Aliotta, Andrea Lazzeri
The present chapter focuses on the recyclability of both renewable and biodegradable plastics, considering the recovery of matter (mechanical or chemical recycling) from the polymeric materials currently most diffused on the market. Biobased and compostable plastics are carbon neutral; thus, they do not contribute significantly to greenhouse gas (GHG) emissions. Nevertheless, recycling can be beneficial because it allows a prolongation of the material life cycle so that carbon is stored for a longer time up to the final composting. The chemical or mechanical recycling option is linked both to the possibility of reprocessing bioplastics without detrimental loss of properties as well as to the capability of selecting homogenous fractions of bioplastics after waste collection. Moreover, the different structural features of biodegradable bioplastics have resulted in different chemical recycling opportunities and also in different behaviors during the reprocessing operations necessary for recycling. All these aspects are discussed systematically in this review, considering biodegradable bioplastics, their blends and composites with natural fibers.
{"title":"Recyclability Perspectives of the Most Diffused Biobased and Biodegradable Plastic Materials","authors":"M. Coltelli, V. Gigante, Laura Aliotta, Andrea Lazzeri","doi":"10.3390/macromol4020023","DOIUrl":"https://doi.org/10.3390/macromol4020023","url":null,"abstract":"The present chapter focuses on the recyclability of both renewable and biodegradable plastics, considering the recovery of matter (mechanical or chemical recycling) from the polymeric materials currently most diffused on the market. Biobased and compostable plastics are carbon neutral; thus, they do not contribute significantly to greenhouse gas (GHG) emissions. Nevertheless, recycling can be beneficial because it allows a prolongation of the material life cycle so that carbon is stored for a longer time up to the final composting. The chemical or mechanical recycling option is linked both to the possibility of reprocessing bioplastics without detrimental loss of properties as well as to the capability of selecting homogenous fractions of bioplastics after waste collection. Moreover, the different structural features of biodegradable bioplastics have resulted in different chemical recycling opportunities and also in different behaviors during the reprocessing operations necessary for recycling. All these aspects are discussed systematically in this review, considering biodegradable bioplastics, their blends and composites with natural fibers.","PeriodicalId":18139,"journal":{"name":"Macromol","volume":" 12","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141373228","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yusuke Yamashita, Yoshihiro Ohzuno, Masahiro Yoshida, T. Takei
Conventionally, chitosan hydrogels are acidic and contain toxic chemicals because chitosan is soluble only in acidic solvents and requires toxic additives such as chemical crosslinkers and polymerization agents to fabricate chitosan hydrogels. These properties prevent chitosan hydrogels from being used for medical applications. In this study, chitosan hydrogels were prepared by a simple and versatile process using urea hydrolysis by autoclaving (steam sterilization, 121 °C, 20 min). When autoclaved, urea hydrolyzes in an acidic chitosan aqueous solution, and ammonia is produced, which increases the pH of the solution, and chitosan becomes insoluble, leading to the formation of a chitosan hydrogel. The pH and osmotic concentration of chitosan hydrogels could be adjusted to be suitable for physiological conditions (pH: 7.0–7.5, and osmotic concentration: 276–329 mOsm/L) by changing the amount of urea added to chitosan solutions (chitosan: 2.5% (w/v), urea: 0.75–1.0% (w/v), pH: 5.5). The hydrogels had extremely low cytotoxicity without the washing process. In addition, not only pure chitosan hydrogels, but also chitosan derivative hydrogels were prepared using this method. The autoclaving technique for preparing low-toxic and wash-free sterilized chitosan hydrogels in a single step is practical for medical applications.
{"title":"Autoclaving Achieves pH-Neutralization, Hydrogelation, and Sterilization of Chitosan Hydrogels in One Step","authors":"Yusuke Yamashita, Yoshihiro Ohzuno, Masahiro Yoshida, T. Takei","doi":"10.3390/macromol4020021","DOIUrl":"https://doi.org/10.3390/macromol4020021","url":null,"abstract":"Conventionally, chitosan hydrogels are acidic and contain toxic chemicals because chitosan is soluble only in acidic solvents and requires toxic additives such as chemical crosslinkers and polymerization agents to fabricate chitosan hydrogels. These properties prevent chitosan hydrogels from being used for medical applications. In this study, chitosan hydrogels were prepared by a simple and versatile process using urea hydrolysis by autoclaving (steam sterilization, 121 °C, 20 min). When autoclaved, urea hydrolyzes in an acidic chitosan aqueous solution, and ammonia is produced, which increases the pH of the solution, and chitosan becomes insoluble, leading to the formation of a chitosan hydrogel. The pH and osmotic concentration of chitosan hydrogels could be adjusted to be suitable for physiological conditions (pH: 7.0–7.5, and osmotic concentration: 276–329 mOsm/L) by changing the amount of urea added to chitosan solutions (chitosan: 2.5% (w/v), urea: 0.75–1.0% (w/v), pH: 5.5). The hydrogels had extremely low cytotoxicity without the washing process. In addition, not only pure chitosan hydrogels, but also chitosan derivative hydrogels were prepared using this method. The autoclaving technique for preparing low-toxic and wash-free sterilized chitosan hydrogels in a single step is practical for medical applications.","PeriodicalId":18139,"journal":{"name":"Macromol","volume":"75 24","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141101611","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This research was devoted to study the effect of the tacticity on the surface physicochemical properties of PMMA. (1) Background: The determination of the surface free energy of polymers is generally carried out by inverse gas chromatography (IGC) at infinite dilution. The dispersive, polar and surface acid-base properties of PMMA at different tacticities were obtained via IGC technique with the help of the net retention time and volume of adsorbed. (2) Methods: The London dispersion equation was used to quantify the polar free energy of adsorption, while the London dispersive surface energy γsd(T) of PMMAs was determined using the thermal model. (3) Results: The results showed non-linear variations of γsd(T) of atactic, isotactic, and syndiotactic PMMAs with three maxima characterizing the three transition temperatures of PMMAs. The obtained values of the enthalpic and entropic Lewis’s acid-base parameters showed that the basicity of the atactic PMMA was about four times larger than its acidity. (4) Conclusions: A large difference in the behavior of the various PMMAs was proven in the different values of the polar acid and base surface energies of the three PMMAs with an important effect of the tacticity of PMMA on its acid-base surface energies.
{"title":"Effect of Tacticity on London Dispersive Surface Energy, Polar Free Energy and Lewis Acid-Base Surface Energies of Poly Methyl Methacrylate by Inverse Gas Chromatography","authors":"T. Hamieh","doi":"10.3390/macromol4020020","DOIUrl":"https://doi.org/10.3390/macromol4020020","url":null,"abstract":"This research was devoted to study the effect of the tacticity on the surface physicochemical properties of PMMA. (1) Background: The determination of the surface free energy of polymers is generally carried out by inverse gas chromatography (IGC) at infinite dilution. The dispersive, polar and surface acid-base properties of PMMA at different tacticities were obtained via IGC technique with the help of the net retention time and volume of adsorbed. (2) Methods: The London dispersion equation was used to quantify the polar free energy of adsorption, while the London dispersive surface energy γsd(T) of PMMAs was determined using the thermal model. (3) Results: The results showed non-linear variations of γsd(T) of atactic, isotactic, and syndiotactic PMMAs with three maxima characterizing the three transition temperatures of PMMAs. The obtained values of the enthalpic and entropic Lewis’s acid-base parameters showed that the basicity of the atactic PMMA was about four times larger than its acidity. (4) Conclusions: A large difference in the behavior of the various PMMAs was proven in the different values of the polar acid and base surface energies of the three PMMAs with an important effect of the tacticity of PMMA on its acid-base surface energies.","PeriodicalId":18139,"journal":{"name":"Macromol","volume":"121 15","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141124093","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Elaine Halligan, Billy Shu Hieng Tie, D. M. Colbert, M. Alsaadi, Shuo Zhuo, Gavin Keane, Luke M. Geever
The design and manufacturing of objects in various industries have been fundamentally altered by the introduction of D-dimensional (3D) and four-dimensional (4D) printing technologies. Four-dimensional printing, a relatively new technique, has emerged as a result of the ongoing development and advancements in 3D printing. In this study, a stimulus-responsive material, N-Vinylcaprolactam-co-DEGDA (NVCL-co-DEGDA) resin, was synthesised by Stereolithography (SLA) 3D printing technique. The N-Vinylcaprolactam-co-DEGDA resins were initiated by the Diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide (TPO) photoinitiator. A range of Di(ethylene glycol) diacrylate (DEGDA) concentrations in the NVCL-co-DEGDA resin was explored, ranging from 5 wt% to 40 wt%. The structural properties of the 3D printed objects were investigated by conducting Attenuated Total Reflectance–Fourier Transform Infrared Spectroscopy (ATR-FTIR). Additionally, the 3D printed samples underwent further characterisation through differential scanning calorimetry (DSC) and swelling analysis. The results revealed an inverse relationship between DEGDA concentration and Tg values, indicating that higher concentrations of DEGDA resulted in lower Tg values. Additionally, the pulsatile swelling studies demonstrated that increasing DEGDA concentration prolonged the time required to reach the maximum swelling ratio. These findings highlight the influence of DEGDA concentration on both the thermal properties and swelling behaviour of 3D printed samples.
{"title":"Synthesis and Characterisation of 4D-Printed NVCL-co-DEGDA Resin Using Stereolithography 3D Printing","authors":"Elaine Halligan, Billy Shu Hieng Tie, D. M. Colbert, M. Alsaadi, Shuo Zhuo, Gavin Keane, Luke M. Geever","doi":"10.3390/macromol4010008","DOIUrl":"https://doi.org/10.3390/macromol4010008","url":null,"abstract":"The design and manufacturing of objects in various industries have been fundamentally altered by the introduction of D-dimensional (3D) and four-dimensional (4D) printing technologies. Four-dimensional printing, a relatively new technique, has emerged as a result of the ongoing development and advancements in 3D printing. In this study, a stimulus-responsive material, N-Vinylcaprolactam-co-DEGDA (NVCL-co-DEGDA) resin, was synthesised by Stereolithography (SLA) 3D printing technique. The N-Vinylcaprolactam-co-DEGDA resins were initiated by the Diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide (TPO) photoinitiator. A range of Di(ethylene glycol) diacrylate (DEGDA) concentrations in the NVCL-co-DEGDA resin was explored, ranging from 5 wt% to 40 wt%. The structural properties of the 3D printed objects were investigated by conducting Attenuated Total Reflectance–Fourier Transform Infrared Spectroscopy (ATR-FTIR). Additionally, the 3D printed samples underwent further characterisation through differential scanning calorimetry (DSC) and swelling analysis. The results revealed an inverse relationship between DEGDA concentration and Tg values, indicating that higher concentrations of DEGDA resulted in lower Tg values. Additionally, the pulsatile swelling studies demonstrated that increasing DEGDA concentration prolonged the time required to reach the maximum swelling ratio. These findings highlight the influence of DEGDA concentration on both the thermal properties and swelling behaviour of 3D printed samples.","PeriodicalId":18139,"journal":{"name":"Macromol","volume":"41 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140230206","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
G. Leni, Lorenzo Del Vecchio, Claudia Dellapina, Vita Maria Cristiana Moliterni, A. Caligiani, Martina Cirlini
Black soldier fly larvae (BSFL) represent a way of converting organic substrates into valuable biomolecules, and are potentially exploitable as feed and food. In the present work, BSFL grown on retted hemp fiber were chemically analyzed to evaluate their nutritional profile. Chemical analysis revealed BSFL biomass to be an interesting source of proteins (40% on dry matter) rich in essential amino acids. In addition, larval biomass contained 12% fat, mainly composed of saturated fatty acids, and β-sitosterol and campesterol were found to be the most abundant among sterols. A total of 9% of the larval biomass was composed of chitin. The investigation extended to the enzymatic hydrolysis of proteins, leading to the identification of potential bioactive peptides. Peptidomics analysis coupled with in silico tools unveiled promising antioxidant, ACE-inhibitory, and DPP-IV-inhibitory properties within the protein hydrolysates. These findings revealed the potential of BSFL grown on retted hemp fiber as a source of dietary compounds as well as bioactive molecules which can be exploited as functional ingredients in the feed and food sectors.
{"title":"Black Soldier Fly Larvae Grown on Hemp Fiber: Nutritional Composition and Production of Potential Bioactive Peptides","authors":"G. Leni, Lorenzo Del Vecchio, Claudia Dellapina, Vita Maria Cristiana Moliterni, A. Caligiani, Martina Cirlini","doi":"10.3390/macromol4010007","DOIUrl":"https://doi.org/10.3390/macromol4010007","url":null,"abstract":"Black soldier fly larvae (BSFL) represent a way of converting organic substrates into valuable biomolecules, and are potentially exploitable as feed and food. In the present work, BSFL grown on retted hemp fiber were chemically analyzed to evaluate their nutritional profile. Chemical analysis revealed BSFL biomass to be an interesting source of proteins (40% on dry matter) rich in essential amino acids. In addition, larval biomass contained 12% fat, mainly composed of saturated fatty acids, and β-sitosterol and campesterol were found to be the most abundant among sterols. A total of 9% of the larval biomass was composed of chitin. The investigation extended to the enzymatic hydrolysis of proteins, leading to the identification of potential bioactive peptides. Peptidomics analysis coupled with in silico tools unveiled promising antioxidant, ACE-inhibitory, and DPP-IV-inhibitory properties within the protein hydrolysates. These findings revealed the potential of BSFL grown on retted hemp fiber as a source of dietary compounds as well as bioactive molecules which can be exploited as functional ingredients in the feed and food sectors.","PeriodicalId":18139,"journal":{"name":"Macromol","volume":"100 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140236036","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Plant-based proteins are important macronutrients in the human diet, crucial for cell development in our bodies and for supporting the immune system. Given their nutritional and functional properties, plant-based proteins are excellent candidates for the development of plant-based food. Among other things, plant-based cheese has been identified as a potential enabler for future innovation through improvements in ingredient technology. Unlike traditional dairy cheeses, plant-based cheeses are made from a variety of ingredients such as nuts and legumes that can be fortified with nutrients also found in traditional cheese. Of course, plant-based cheeses still have some nutritional drawbacks, and most of them are processed, which means they contain preservatives, colour additives and high sodium content. Nevertheless, the physicochemical and functional properties of plant-based proteins are of great interest to the food industry and the initial interest in natural sources of plant proteins has recently shifted to the field of modification and processing. This review discusses the natural sources and classification of plant-based proteins and summarises recent studies on processing methods in the production of plant-based cheese.
{"title":"Plant-Based Proteins and Their Modification and Processing for Vegan Cheese Production","authors":"Jelica Kovačević, Thomas Bechtold, Tung Pham","doi":"10.3390/macromol4010002","DOIUrl":"https://doi.org/10.3390/macromol4010002","url":null,"abstract":"Plant-based proteins are important macronutrients in the human diet, crucial for cell development in our bodies and for supporting the immune system. Given their nutritional and functional properties, plant-based proteins are excellent candidates for the development of plant-based food. Among other things, plant-based cheese has been identified as a potential enabler for future innovation through improvements in ingredient technology. Unlike traditional dairy cheeses, plant-based cheeses are made from a variety of ingredients such as nuts and legumes that can be fortified with nutrients also found in traditional cheese. Of course, plant-based cheeses still have some nutritional drawbacks, and most of them are processed, which means they contain preservatives, colour additives and high sodium content. Nevertheless, the physicochemical and functional properties of plant-based proteins are of great interest to the food industry and the initial interest in natural sources of plant proteins has recently shifted to the field of modification and processing. This review discusses the natural sources and classification of plant-based proteins and summarises recent studies on processing methods in the production of plant-based cheese.","PeriodicalId":18139,"journal":{"name":"Macromol","volume":"13 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140494284","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The disruption of cell membranes by tau and amylin oligomers is linked to amyloid diseases such as Alzheimer’s and diabetes, respectively. The recent studies suggest that misfolded tau and amylin can form neurotoxic hetero-oligomers that are structurally different from homo-oligomers. However, the molecular interactions of these hetero-oligomers with the neuronal membranes remain unclear. Using MD simulations, we have investigated the binding behaviors, membrane disruption, and protein folding of hetero-oligomers on a raft membrane containing phase-separated lipid nanodomains like those found in neurons. We discovered that the hetero-oligomers bind to the liquid-order and liquid-disorder phase boundaries of the raft membrane. The major lipid-binding sites of these interactions include the L16 and I26 residues of amylin and the N-terminal of tau. Strong disruptions of the raft domain size by the hetero-tetramer were detected. Furthermore, the hetero-dimer disrupted the saturated phospholipid orientational order to a greater extent than the individual tau or amylin monomer. In addition, the constituent tau more strongly promoted the alpha-helix to the beta-sheet transition of the constituent amylin within the hetero-dimer when compared with the amylin monomer alone. Our results provide new molecular insights into understanding the neurotoxicity of the hetero-oligomers associated with the cross-talk between amyloid diseases.
tau和淀粉样蛋白寡聚体对细胞膜的破坏分别与阿尔茨海默氏症和糖尿病等淀粉样疾病有关。最近的研究表明，折叠错误的 tau 和淀粉样蛋白可形成具有神经毒性的杂合低聚物，其结构与同源低聚物不同。然而，这些异质高分子与神经元膜的分子相互作用仍不清楚。通过 MD 模拟，我们研究了异质高聚物在含有相分离脂质纳米域（如神经元中的纳米域）的筏膜上的结合行为、膜破坏和蛋白质折叠。我们发现，异构体与筏膜的液相阶和液相阶相界结合。这些相互作用的主要脂质结合位点包括淀粉蛋白的 L16 和 I26 残基以及 tau 的 N-末端。检测到异源四聚体对筏域大小的强烈破坏。此外，与单个 tau 或淀粉样蛋白单体相比，异源二聚体对饱和磷脂定向秩序的破坏程度更大。此外，与单独的淀粉样蛋白单体相比，异源二聚体中的组成 tau 能更有力地促进组成淀粉样蛋白的α-螺旋向β-片转变。我们的研究结果为了解与淀粉样蛋白疾病之间的交叉作用有关的异二聚体的神经毒性提供了新的分子见解。
{"title":"Molecular Mechanisms of Protein–Lipid Interactions and Protein Folding of Heterogeneous Amylin and Tau Oligomers on Lipid Nanodomains That Link to Alzheimer’s","authors":"Natalia Santos, Luthary Segura, Amber Lewis, Thuong Pham, Kwan H. Cheng","doi":"10.3390/macromol3040046","DOIUrl":"https://doi.org/10.3390/macromol3040046","url":null,"abstract":"The disruption of cell membranes by tau and amylin oligomers is linked to amyloid diseases such as Alzheimer’s and diabetes, respectively. The recent studies suggest that misfolded tau and amylin can form neurotoxic hetero-oligomers that are structurally different from homo-oligomers. However, the molecular interactions of these hetero-oligomers with the neuronal membranes remain unclear. Using MD simulations, we have investigated the binding behaviors, membrane disruption, and protein folding of hetero-oligomers on a raft membrane containing phase-separated lipid nanodomains like those found in neurons. We discovered that the hetero-oligomers bind to the liquid-order and liquid-disorder phase boundaries of the raft membrane. The major lipid-binding sites of these interactions include the L16 and I26 residues of amylin and the N-terminal of tau. Strong disruptions of the raft domain size by the hetero-tetramer were detected. Furthermore, the hetero-dimer disrupted the saturated phospholipid orientational order to a greater extent than the individual tau or amylin monomer. In addition, the constituent tau more strongly promoted the alpha-helix to the beta-sheet transition of the constituent amylin within the hetero-dimer when compared with the amylin monomer alone. Our results provide new molecular insights into understanding the neurotoxicity of the hetero-oligomers associated with the cross-talk between amyloid diseases.","PeriodicalId":18139,"journal":{"name":"Macromol","volume":"40 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138998669","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mohsen Sadeghi-Shapourabadi, S. Elkoun, Mathieu Robert
Nanofibrillated cellulose was extracted from potato peel waste using a fast and green method with a simple process. To extract cellulose and eliminate non-cellulosic constituents, alkaline and hydrogen peroxide treatments were performed under microwave irradiation. The nanofibrillated cellulose was extracted from purified cellulose via TEMPO oxidation followed by ultrasonication. The TEM, FTIR, XRD, and TGA experiments were used to evaluate the structural, crystalline, and thermal properties of cellulose fiber and nanofiber. The chemical and FTIR analysis of bleached fibers indicates that almost all non-cellulosic components of biomass have been eliminated. The diameter of the extracted nanofibers is in the range of 4 to 22 nm. In terms of crystallinity, extracted nanocellulose had 70% crystallinity, compared to 17% for unprocessed lignocellulose fibers, which makes it an excellent choice for use as a reinforcement phase in biobased composites. Thermogravimetric analysis reveals that cellulose nanofibers are less thermally stable than potato peel pure cellulose, but it has a higher char content (28%) than pure cellulose (6%), which signifies that the carboxylate functionality acts as a flame retardant. The comparison between cellulose derived from microwave and conventional extraction methods confirmed that their impact on the removal of non-cellulosic materials is nearly identical.
{"title":"Microwave-Assisted Chemical Purification and Ultrasonication for Extraction of Nano-Fibrillated Cellulose from Potato Peel Waste","authors":"Mohsen Sadeghi-Shapourabadi, S. Elkoun, Mathieu Robert","doi":"10.3390/macromol3040044","DOIUrl":"https://doi.org/10.3390/macromol3040044","url":null,"abstract":"Nanofibrillated cellulose was extracted from potato peel waste using a fast and green method with a simple process. To extract cellulose and eliminate non-cellulosic constituents, alkaline and hydrogen peroxide treatments were performed under microwave irradiation. The nanofibrillated cellulose was extracted from purified cellulose via TEMPO oxidation followed by ultrasonication. The TEM, FTIR, XRD, and TGA experiments were used to evaluate the structural, crystalline, and thermal properties of cellulose fiber and nanofiber. The chemical and FTIR analysis of bleached fibers indicates that almost all non-cellulosic components of biomass have been eliminated. The diameter of the extracted nanofibers is in the range of 4 to 22 nm. In terms of crystallinity, extracted nanocellulose had 70% crystallinity, compared to 17% for unprocessed lignocellulose fibers, which makes it an excellent choice for use as a reinforcement phase in biobased composites. Thermogravimetric analysis reveals that cellulose nanofibers are less thermally stable than potato peel pure cellulose, but it has a higher char content (28%) than pure cellulose (6%), which signifies that the carboxylate functionality acts as a flame retardant. The comparison between cellulose derived from microwave and conventional extraction methods confirmed that their impact on the removal of non-cellulosic materials is nearly identical.","PeriodicalId":18139,"journal":{"name":"Macromol","volume":"551 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139247560","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Wood–plastic composites, consisting of wood particles and a thermoplastic matrix, are common composites often used in buildings as decking boards or for similar non-load-carrying applications. As these are usually semi-finished products, a certain amount of material is available after cutting these to size, in the factory and also at installation sites. Especially for in-house waste streams in factories, the question remains whether these materials can be reprocessed without any negative influence on the materials’ properties. Therefore, the aim of this work is to investigate the influence of reprocessing on the property profile of polypropylene based wood–plastic composites. Two base formulations with 40 wt% of wood particles and two different polypropylene grades were investigated for their mechanical properties, wood particle size, color, weathering stability and water uptake. We found that most of the wood–plastic composites’ properties were not negatively influenced by the multiple processing steps; the most pronounced effect beside particle size reduction is color degradation, as the composites darken with increasing number of processing steps. In our opinion this shows, that wood–plastic composites can be recycled, especially if these are only reprocessed in smaller shares together with virgin materials.
{"title":"Recycling of Wood–Plastic Composites—A Reprocessing Study","authors":"Christoph Burgstaller, Károly Renner","doi":"10.3390/macromol3040043","DOIUrl":"https://doi.org/10.3390/macromol3040043","url":null,"abstract":"Wood–plastic composites, consisting of wood particles and a thermoplastic matrix, are common composites often used in buildings as decking boards or for similar non-load-carrying applications. As these are usually semi-finished products, a certain amount of material is available after cutting these to size, in the factory and also at installation sites. Especially for in-house waste streams in factories, the question remains whether these materials can be reprocessed without any negative influence on the materials’ properties. Therefore, the aim of this work is to investigate the influence of reprocessing on the property profile of polypropylene based wood–plastic composites. Two base formulations with 40 wt% of wood particles and two different polypropylene grades were investigated for their mechanical properties, wood particle size, color, weathering stability and water uptake. We found that most of the wood–plastic composites’ properties were not negatively influenced by the multiple processing steps; the most pronounced effect beside particle size reduction is color degradation, as the composites darken with increasing number of processing steps. In our opinion this shows, that wood–plastic composites can be recycled, especially if these are only reprocessed in smaller shares together with virgin materials.","PeriodicalId":18139,"journal":{"name":"Macromol","volume":"19 5","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135934412","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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