Biopolymers: Structure-Function Relationship and Application

A special issue of Polymers (ISSN 2073-4360). This special issue belongs to the section "Biomacromolecules, Biobased and Biodegradable Polymers".

Deadline for manuscript submissions: closed (5 February 2023) | Viewed by 57404

Special Issue Editors

Department of Food Science, University of Guelph, 50 Stone Road E., Guelph, ON N1G 2W1, Canada
Interests: biopolymer; food hydrocolloid; dietary fiber; rheology; agricultural byproduct utilization; structure–function correlation; biological hydrolysis; anaerobic digestion; biochemical methane potential; membrane bioreactor; membrane aerated biofilm reactor
Special Issues, Collections and Topics in MDPI journals
College of Food Engineering & Biotechnology, Tianjin University of Science and Technology, Tianjin 300222, China
Interests: carbohydrate polymer; dietary fiber; oligosaccharide; polysaccharide; structural characterization; conformation; computer modeling; physicochemical property; bioactivity; immune-modulatory activity; diabetes and blood sugar control

Special Issue Information

Dear colleagues,

Biopolymer has been widely applied in the food, pharmaceutical, and environmental industries, showing great potential for health benefits, effectiveness, and sustainability.

Structural characterization helps to better understand biopolymer or its hydrolysate/derivative at the molecular level. The in-depth understanding of the structure–function relationship could be the key to help to transfer theoretical studies to industrial applications.

This Special Issue covers the structural characterization (e.g., chemical composition, linkage type, substitution, or conformation), physicochemical properties (e.g., rheology, or emulsifying/biofilm-forming/binding capacities), or bioactivity (e.g., immunomodulation, diabetes and blood sugar control, anticancer, or antibacterial/antivirus) of biopolymers from various sources.

The establishment of the correlations between structural features and functionalities is highly encouraged. Biopolymers used as the carrier or encapsulation matrix to targetedly deliver biologically active components are also included in the scope.

Dr. Huihuang Ding
Prof. Dr. Qingbin Guo
Guest Editors

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Keywords

  • carbohydrate polymers
  • food hydrocolloids
  • dietary fibers
  • protein
  • structure
  • conformation
  • physicochemical properties
  • rheology
  • functionality
  • bioactivity

Published Papers (19 papers)

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21 pages, 2387 KiB  
Article
Measuring Structural Changes in Cytochrome c under Crowded Conditions Using In Vitro and In Silico Approaches
by Zahoor Ahmad Parray, Ahmad Abu Turab Naqvi, Ishfaq Ahmad Ahanger, Mohammad Shahid, Faizan Ahmad, Md. Imtaiyaz Hassan and Asimul Islam
Polymers 2022, 14(22), 4808; https://0-doi-org.brum.beds.ac.uk/10.3390/polym14224808 - 09 Nov 2022
Cited by 5 | Viewed by 1737
Abstract
It is known from in vitro studies that macromolecular crowding in the cell effects protein structure, stability and function; but predictive studies are relatively unexplored. There are few reports where the effect of various crowder mixtures has been exploited to discern their combined [...] Read more.
It is known from in vitro studies that macromolecular crowding in the cell effects protein structure, stability and function; but predictive studies are relatively unexplored. There are few reports where the effect of various crowder mixtures has been exploited to discern their combined effect on the structural stability of proteins. These studies are more significant because their effect can mimicked with in vivo conditions, where the environment is heterogeneous. Effects of two crowders, polyethylene glycol (PEG 400 Da), and its monomer ethylene glycol (EG) alone and in mixture on the structural stability of cytochrome c (cyt c) were determined using various spectroscopic and bioinformatics tools. The main conclusions of our study are (i) the monomer EG has a kosmotropic effect on the protein (stabilizes the protein), and has no significant effect on the tertiary structure; (ii) PEG 400 destabilizes the structure as well as the stability of the protein; and (iii) EG counteracts the destabilizing effect of PEG 400. From this investigation, it seems evident that proteins may fold or unfold in the crowded environment of the cell where various interactions assist them to maintain their structure for their functions. Bioinformatics approaches were also used to support all of the in vitro observations. Cyt c is functional protein; if the structure of the protein is modulated due to change in the environment its nature of function will also change. Our research addresses the question by modulating the environment around the protein, and the macromolecule (protein) conformation dynamics and interaction study via in vitro and in silico approaches which indirectly compares with that of the environment in-cellular milieu, which is highly crowded. Full article
(This article belongs to the Special Issue Biopolymers: Structure-Function Relationship and Application)
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14 pages, 4474 KiB  
Article
Effects of the Combined Application of Trimethylated Chitosan and Carbodiimide on the Biostability and Antibacterial Activity of Dentin Collagen Matrix
by Xiangyao Wang, Qilin Li, Haibo Lu, Zhuo Liu, Yaxin Wu, Jing Mao and Shiqiang Gong
Polymers 2022, 14(15), 3166; https://0-doi-org.brum.beds.ac.uk/10.3390/polym14153166 - 03 Aug 2022
Cited by 6 | Viewed by 1691
Abstract
The structural integrity of a dentin matrix that has been demineralized by the clinical use of etchants or calcium-depleting endodontic irrigants, such as endodontic ethylenediaminetetraacetic acid (EDTA), is often deteriorated due to the collagenolytic activities of reactivated endogenous enzymes as well as the [...] Read more.
The structural integrity of a dentin matrix that has been demineralized by the clinical use of etchants or calcium-depleting endodontic irrigants, such as endodontic ethylenediaminetetraacetic acid (EDTA), is often deteriorated due to the collagenolytic activities of reactivated endogenous enzymes as well as the infiltration of extrinsic bacteria. Therefore, the biomodification of dentin collagen with improved stability and antibacterial activity holds great promise in conservative dentistry. The purpose of this study was to evaluate the effects of the combined application of trimethylated chitosan (TMC) and 1-ethyl-3-[3-dimethylaminopropyl]carbodiimide hydrochloride (EDC) on the biostability and antibacterial activity of the demineralized dentin collagen matrix. The morphological changes in the collagen matrix were observed by scanning electron microscopy (SEM), the amount of TMC adsorbed on the collagen surface was detected by X-ray photoelectron spectroscopy, and the elastic modulus was measured by a three-point bending device. Dry weight loss and amino acid release were detected to evaluate its anti-collagenase degradation performance. The antibacterial performance was detected by confocal microscopy. The TMC-treated group had less collagen space and a more compact collagen arrangement, while the untreated group had a looser collagen arrangement. The combined application of TMC and EDC can increase the elastic modulus, reduce the loss of elastic modulus, and result in good antibacterial performance. The current study proved that a dentin collagen matrix biomodified by TMC and EDC showed improved biodegradation resistance and antibacterial activities. Full article
(This article belongs to the Special Issue Biopolymers: Structure-Function Relationship and Application)
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9 pages, 20713 KiB  
Article
Electrospray Deposition of Polyvinylidene Fluoride (PVDF) Microparticles: Impact of Solvents and Flow Rate
by Akinwunmi Joaquim, Omari Paul, Michael Ibezim, Dewayne Johnson, April Falconer, Ying Wu, Frances Williams and Richard Mu
Polymers 2022, 14(13), 2702; https://0-doi-org.brum.beds.ac.uk/10.3390/polym14132702 - 01 Jul 2022
Cited by 4 | Viewed by 1578
Abstract
Polymeric microparticles have been shown to have great impacts in the area of drug delivery, biosensing, and tissue engineering. Electrospray technology, which provides a simple yet effective technique in the creation of microparticles, was utilized in this work. In addition, altering the electrospray [...] Read more.
Polymeric microparticles have been shown to have great impacts in the area of drug delivery, biosensing, and tissue engineering. Electrospray technology, which provides a simple yet effective technique in the creation of microparticles, was utilized in this work. In addition, altering the electrospray experimental parameters such as applied voltage, flow rate, collector distance, solvents, and the polymer-solvent mixtures can result in differences in the size and morphology of the produced microparticles. The effects of the flow rate at (0.15, 0.3, 0.45, 0.6, 0.8, and 1 mL/h) and N, N-Dimethylformamide (DMF)/acetone solvent ratios (20:80, 40:60, 60:40, 80:20, 100:0 v/v) in the production of polyvinylidene fluoride (PVDF) microparticles were studied. Scanning electron microscopy (SEM) was used to observe changes in the morphology of the microparticles, and this revealed that a higher acetone to DMF ratio produces deformed particles, while flow rates at (0.3 and 0.45 mL/h) and a more optimized DMF to acetone solvent ratio (60:40 v/v) produced uniform spherical particles. We discovered from the Raman spectroscopy results that the electrosprayed PVDF microparticles had an increase in piezoelectric β phase compared to the PVDF pellet used in making the microparticles, which in its original form is α phase dominant and non-piezoelectric. Full article
(This article belongs to the Special Issue Biopolymers: Structure-Function Relationship and Application)
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19 pages, 2943 KiB  
Article
Conformational Properties of Flaxseed Rhamnogalacturonan-I and Correlation between Primary Structure and Conformation
by Qingbin Guo, Zhengxin Shan, Yanhui Shao, Nifei Wang, Keying Qian, H. Douglas Goff, Qi Wang, Steve W. Cui and Huihuang H. Ding
Polymers 2022, 14(13), 2667; https://0-doi-org.brum.beds.ac.uk/10.3390/polym14132667 - 30 Jun 2022
Cited by 2 | Viewed by 1320
Abstract
The pectic polysaccharides extracted from flaxseed (Linum usitatissiumum L.) mucilage and kernel were characterized as rhamnogalacturonan-I (RG-I). In this study, the conformational characteristics of RG-I fractions from flaxseed mucilage and kernel were investigated, using a Brookhaven multi-angle light scattering instrument (batch mode) [...] Read more.
The pectic polysaccharides extracted from flaxseed (Linum usitatissiumum L.) mucilage and kernel were characterized as rhamnogalacturonan-I (RG-I). In this study, the conformational characteristics of RG-I fractions from flaxseed mucilage and kernel were investigated, using a Brookhaven multi-angle light scattering instrument (batch mode) and a high-performance size exclusion chromatography (HPSEC) system coupled with Viscotek tetra-detectors (flow mode). The Mw of flaxseed mucilage RG-I (FM-R) was 285 kDa, and the structure-sensitive parameter (ρ) value of FM-R was calculated as 1.3, suggesting that the FM-R molecule had a star-like conformation. The Mw of flaxseed kernel RG-I (FK-R) was 550 kDa, and the structure-sensitive parameter (ρ) values ranged from 0.90 to 1.21, suggesting a sphere to star-like conformation with relatively higher segment density. The correlation between the primary structure and conformation of RG-I was further discussed to better understand the structure–function relationship, which helps the scale-up applications of pectins in food, pharmaceutical, or cosmetic industries. Full article
(This article belongs to the Special Issue Biopolymers: Structure-Function Relationship and Application)
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12 pages, 2438 KiB  
Article
Effect of Transglutaminase Pre-Crosslinking Treatment Incorporated with Glucono-δ-lactone on the Physicochemical and Digestive Properties of Tofu
by Tianran Hui and Guangliang Xing
Polymers 2022, 14(12), 2364; https://0-doi-org.brum.beds.ac.uk/10.3390/polym14122364 - 11 Jun 2022
Cited by 5 | Viewed by 2007
Abstract
This study evaluated the effect of transglutaminase (TGase) pre-crosslinking treatment on the physicochemical and digestive characteristics of tofu coagulated by glucono-δ-lactone (GDL). Results showed that certain TGase pre-crosslinking times (0.5, 1, 2 and 3 h) could promote the colloidal stability of soymilk with [...] Read more.
This study evaluated the effect of transglutaminase (TGase) pre-crosslinking treatment on the physicochemical and digestive characteristics of tofu coagulated by glucono-δ-lactone (GDL). Results showed that certain TGase pre-crosslinking times (0.5, 1, 2 and 3 h) could promote the colloidal stability of soymilk with increased particle average sizes and absolute values of zeta potential. Particularly, the water holding capacity and gel strength of tofu pre-crosslinked by TGase for 2 h were 6.8% and 47.7% enhancement, respectively, compared to the control, and exhibited the highest score of overall acceptability. However, extensive pre-crosslinking by TGase for 3 h had an adverse impact on the sensory of tofu with poor firmness, rough structure and whey separation. Hence, the tofu gel pre-crosslinked by TGase for 2 h and then coagulated by GDL was recommended which showed a “slow release” mode of soluble proteins during the in vitro digestion phase, and had more chances to release bioactive peptides than soymilk. Full article
(This article belongs to the Special Issue Biopolymers: Structure-Function Relationship and Application)
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15 pages, 2064 KiB  
Article
Gelling Characteristics of Emulsions Prepared with Modified Whey Protein by Multiple-Frequency Divergent Ultrasound at Different Ultrasonic Power and Frequency Mode
by Yu Cheng, Georgina Benewaa Yeboah, Xinyi Guo, Prince Ofori Donkor and Juan Wu
Polymers 2022, 14(10), 2054; https://0-doi-org.brum.beds.ac.uk/10.3390/polym14102054 - 18 May 2022
Cited by 3 | Viewed by 2228
Abstract
The effect of ultrasonic frequency mode (mono, dual and tri-frequency) and ultrasonic power (0–300 W) on structural properties (intrinsic fluorescence and sulfhydryl content) of whey protein was studied. Emulsions prepared with modified whey protein were used to form the heat-set gels, and the [...] Read more.
The effect of ultrasonic frequency mode (mono, dual and tri-frequency) and ultrasonic power (0–300 W) on structural properties (intrinsic fluorescence and sulfhydryl content) of whey protein was studied. Emulsions prepared with modified whey protein were used to form the heat-set gels, and the properties of whey protein emulsion gels (WPEG) and their digestion were investigated. The textural and rheological properties of WPEG prepared using whey protein pretreated by mono and dual-frequency ultrasound at the power between 180–240 W were enhanced, while those of WPEG prepared with whey protein pretreated by triple-frequency above the power of 180 W were declined. WPEG prepared using whey protein pretreated by dual-frequency ultrasound (DFU) with the power of 240 W had the highest hardness and storage modulus which were 3.07 and 1.41 times higher than the control. The microstructure of WPEG prepared using DFU pretreated whey protein showed homogeneous and denser networks than those of the control according to the results of confocal laser scanning microscope (CLSM). The modification in the microstructure and properties of the WPEG prepared using DFU pretreated whey protein delayed the protein disintegration during the first 30 min of gastric digestion when compared with control. Whereas the release rate of free amino group of the WPEG prepared using whey protein modified by ultrasonic pretreatment increased during the intestinal phase when compared with that of control. The results indicated that using dual-frequency ultrasound to modify whey protein is more efficient in improving the properties of WPEG, and ultrasonic power should be considered during the application of ultrasound pretreatment in producing protein gels. The fine network of WPEG prepared with whey protein pretreated by ultrasound resulted in better hardness and storage modulus. Partially unfolding of the protein induced by ultrasound pretreatment might make the whey protein more susceptible to the digestive enzyme. Our results could provide new insights for using ultrasound as the potential processing tool on designing specific protein emulsion gels as the delivery system for nutrients. Full article
(This article belongs to the Special Issue Biopolymers: Structure-Function Relationship and Application)
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16 pages, 3524 KiB  
Article
In Vitro Fermentability of Soybean Oligosaccharides from Wastewater of Tofu Production
by Yuling Wang, Chunrong Li, Zhengxin Shan, Sijia Yin, Yue Wang, Congcong Wang, Tianhui Liu, Nifei Wang and Qingbin Guo
Polymers 2022, 14(9), 1704; https://0-doi-org.brum.beds.ac.uk/10.3390/polym14091704 - 22 Apr 2022
Cited by 6 | Viewed by 3032
Abstract
Soybean oligosaccharides (SBOS) isolated from wastewater of tofu production were studied in terms of their structural characteristics and in vitro fermentation by human fecal inocula. Three sub-fractions named Z1 (14%), Z2 (13%), and Z3 (17%) were obtained by Sephadex G-15 column separation. Z1 [...] Read more.
Soybean oligosaccharides (SBOS) isolated from wastewater of tofu production were studied in terms of their structural characteristics and in vitro fermentation by human fecal inocula. Three sub-fractions named Z1 (14%), Z2 (13%), and Z3 (17%) were obtained by Sephadex G-15 column separation. Z1 contained mainly stachyose; Z2 and Z3 contained stachyose, raffinose, and sucrose with different relative percentages. The in vitro batch fermentation model of human intestinal bacteria including 0, 12, 24, and 48 h was used to investigate the fermentation characteristics of SBOS. According to the results, during the fermentation process, the molecular weight of oligosaccharides decreased significantly with increasing fermentation time, indicating that oligosaccharides could be utilized and degraded by the colonic microbiota. Furthermore, SBOS could significantly promote the production of short-chain fatty acids (SCFAs), especially acetic, propionic, and butyric acids. SBOS increased the abundance of Firmicutes, while that of Proteobacteria was decreased. Additionally, SBOS could promote the proliferation of Dialister, Bacteroides, and Akkermansia at the genus level. Therefore, SBOS can be potentially used as prebiotic promoting gut health. Full article
(This article belongs to the Special Issue Biopolymers: Structure-Function Relationship and Application)
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16 pages, 3772 KiB  
Article
Research on Extraction, Structure Characterization and Immunostimulatory Activity of Cell Wall Polysaccharides from Sparassis latifolia
by Jing Liu, Xuemeng Zhang, Jingsong Zhang, Mengqiu Yan, Deshun Li, Shuai Zhou, Jie Feng and Yanfang Liu
Polymers 2022, 14(3), 549; https://0-doi-org.brum.beds.ac.uk/10.3390/polym14030549 - 28 Jan 2022
Cited by 5 | Viewed by 2405
Abstract
The cell wall polysaccharides were extracted from Sparassis latifolia fruit bodies by acid–alkali and superfine-grinding assisted methods, and the chemical characterization and in vitro immunity activities of these polysaccharide fractions were studied and compared. Results showed that superfine-grinding assisted extraction exhibited the highest [...] Read more.
The cell wall polysaccharides were extracted from Sparassis latifolia fruit bodies by acid–alkali and superfine-grinding assisted methods, and the chemical characterization and in vitro immunity activities of these polysaccharide fractions were studied and compared. Results showed that superfine-grinding assisted extraction exhibited the highest yield of polysaccharides (SP, 20.80%) and low β-glucan content (19.35%) compared with alkaline extracts. The results revealed that the 20% ethanol precipitated fraction (20E) from SP was mainly composed of β-(1→3)-glucan and α-(1→4)-glucan. With the increase of ethanol precipitation, the fractions (30E, 40E, 50E) were identified as α-(1→4)-glucan with different molecular weights and conformations. Cell wall polysaccharides extracted through NaOH (NSP) and KOH (KSP) extraction had similar yields with 8.90% and 8.83%, respectively. Structural analysis indicated that the purified fraction from KSP (KSP-30E) was a β-(1→3)-glucan backbone branched with β-(1→6)-Glcp, while the purified fraction from NSP (NSP-30E) mainly contained β-(1→3)-glucan with a small number of α-linked-Glcp. The two fractions both exhibited rigid chain conformation in aqueous solutions. All polysaccharide fractions exerted the activity of activating Dectin-1 receptor in vitro, and the KSP-30E mainly identified as β-(1→3)-glucan with the terminal group via 1→6-linkage attached at every third residue exhibited a stronger enhancing effect than other fractions. Results suggested that KOH extraction could be efficient for the preparation of bioactive β-(1→3, 1→6)-glucan as a food ingredient. Full article
(This article belongs to the Special Issue Biopolymers: Structure-Function Relationship and Application)
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16 pages, 2795 KiB  
Article
High Retention and Purification of Bromelain Enzyme (Ananas comosus L. Merrill) from Pineapple Juice Using Plain and Hollow Polymeric Membranes Techniques
by Felix M. Carbajal Gamarra, José C. C. Santana, Segundo A. V. Llanos, Jorge A. Heredia Pérez, Fábio Richard Flausino, Ada P. B. Quispe, Pedro Córdova Mendoza, Rosangela M. Vanalle, Carmen Carreño-Farfan, Fernando T. Berssaneti, Roberto R. de Souza and Elias B. Tambourgi
Polymers 2022, 14(2), 264; https://0-doi-org.brum.beds.ac.uk/10.3390/polym14020264 - 10 Jan 2022
Cited by 4 | Viewed by 3502
Abstract
The demand for bromelian and pineapple fruit has been increasing substantially in the world because of their benefits for the human health and use in diverse areas. In this context, this work aimed to study the capacity of higher retention (concentration); bromelain activity [...] Read more.
The demand for bromelian and pineapple fruit has been increasing substantially in the world because of their benefits for the human health and use in diverse areas. In this context, this work aimed to study the capacity of higher retention (concentration); bromelain activity underwent ultrafiltration from pineapple juice (Ananas comusus L. Merrill). All assays were carried out at pH 7.0 and 7.5, and at 0.05 and 0.40 bar of transmembrane pressures. Results have shown that at the best operating conditions, between 85 and 87% of bromelain activity was recovered using the plain membrane separation process at 0.05 bar. The ultrafiltration has shown the capacity to retain 100% of proteolytic activity of the bromelain extracted. The samples have kept the same physics properties after ultrafiltration, and the result was verified via electrophoresis. The bromelain enzyme obtained was characterized, and pH 7 and between 30 and 40 °C were the best conditions. Therefore, this work shows that the use of both polymeric membranes has shown high efficiency, and can be used in the purification of bromelain enzymes. Full article
(This article belongs to the Special Issue Biopolymers: Structure-Function Relationship and Application)
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14 pages, 937 KiB  
Article
Influence of Commonly Used Endodontic Irrigants on the Setting Time and Metal Composition of Various Base Endodontic Sealers
by Jerry Jose, Kavalipurapu Venkata Teja, Manish Ranjan, Roshan Noor Mohamed, Mohammad Khursheed Alam, Deepti Shrivastava, Valentino Natoli, Anil Kumar Nagarajappa, Krishnamachari Janani and Kumar Chandan Srivastava
Polymers 2022, 14(1), 27; https://0-doi-org.brum.beds.ac.uk/10.3390/polym14010027 - 22 Dec 2021
Cited by 2 | Viewed by 3007
Abstract
The present study aimed to evaluate if commonly used endodontic irrigants such as 3% sodium hypochlorite (NaOCl, Prime Dental, Thane, India), 2% chlorhexidine (CHX, Sigma-Aldrich Co., St. Louis, MO, USA), and 17% ethylenediaminetetraacetic acid (EDTA, Meta-Biomed Co. Ltd., Cheongju-si, South Korea) influenced the [...] Read more.
The present study aimed to evaluate if commonly used endodontic irrigants such as 3% sodium hypochlorite (NaOCl, Prime Dental, Thane, India), 2% chlorhexidine (CHX, Sigma-Aldrich Co., St. Louis, MO, USA), and 17% ethylenediaminetetraacetic acid (EDTA, Meta-Biomed Co. Ltd., Cheongju-si, South Korea) influenced the setting time and metal composition of different base endodontic sealers on exposure. AH Plus (Dentsply De Trey GmbH, Konstanz, Germany), Sealapex (SybronEndo, Orange, CA, USA), mineral trioxide aggregate (MTA) Fillapex (Angelus Soluções Odontológicas, Londrina, Brazil), and Tubli-Seal (Kerr Dental, Orange, CA, USA) were selected as the different base representatives of endodontic sealers. These sealers were exposed to 3% NaOCl, 2% CHX, and 17% EDTA, and the individual setting time of the sealers was analyzed. The samples were analyzed for heavy metal elements such as chromium (Cr), nickel (Ni), cobalt (Co), cadmium (Cd), arsenic (As), mercury (Hg), lead (Pb), and beryllium (Be) by using inductively coupled plasma mass spectrometry (ICP-MS) analysis. For statistical analysis, one-way ANOVA and post hoc Tukey’s tests were used. All selected sealers showed variation in setting time post-exposure to different irrigants. MTA Fillapex had the shortest mean setting time (215.7 min, post-exposure at 187.3 min) (p < 0.05). Mean setting time was also affected for AH Plus (479.6 min, post-exposure at 423.9 min) (p < 0.05) and Tubli-Seal (514.7 min, post-exposure at 465.2 min) (p < 0.05). Sealapex showed the maximum reduction of setting time (864.8 min, post-exposure at 673.4 min) (p < 0.05). All tested sealers showed heavy metals (Cr, Ni, Co, Cd, As, Hg, and Pb) in their composition, and the quantities were influenced by interaction with different irrigants. The heavy metal Be was not seen in any of the samples. Sealapex showed the longest setting time in comparison to other test sealers. Heavy metals were most present in Sealapex, followed by AH Plus, Tubli-Seal, and MTA Fillapex. MTA Fillapex was seen to have the shortest setting time, and heavy metal composition was least affected on interaction with different commonly used endodontic irrigants. Further, this study provides significant insight into the influence of different endodontic irrigants on interaction with different base endodontic sealers, which has not been reported previously, and future studies should emphasize endodontic irrigant-sealer interactions and their possible effects in the long run. Full article
(This article belongs to the Special Issue Biopolymers: Structure-Function Relationship and Application)
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16 pages, 1772 KiB  
Article
Physical, Mechanical, and Water Vapor Barrier Properties of Starch/Cellulose Nanofiber/Thymol Bionanocomposite Films
by Siti Hajar Othman, Bilguisse Mamadou Wane, Norhazirah Nordin, Noor Zafira Noor Hasnan, Rosnita A. Talib and Joko Nugroho Wahyu Karyadi
Polymers 2021, 13(23), 4060; https://0-doi-org.brum.beds.ac.uk/10.3390/polym13234060 - 23 Nov 2021
Cited by 19 | Viewed by 2596
Abstract
The application of starch films, such as food packaging materials, has been restricted due to poor mechanical and barrier properties. However, the addition of a reinforcing agent, cellulose nanofibers (CNF) and also thymol, into the films, may improve the properties of films. This [...] Read more.
The application of starch films, such as food packaging materials, has been restricted due to poor mechanical and barrier properties. However, the addition of a reinforcing agent, cellulose nanofibers (CNF) and also thymol, into the films, may improve the properties of films. This work investigates the effects of incorporating different concentrations of thymol (3, 5, 7, and 10 wt.%) on physical, mechanical, water vapor barrier, and antibacterial properties of corn starch films, containing 1.5 wt.% CNF produced using the solvent casting method. The addition of thymol does not significantly affect the color and opacity of the films. It is found that the tensile strength and Young’s modulus of the films decreases from 10.6 to 6.3 MPa and from 436.9 to 209.8 MPa, respectively, and the elongation at break increased from 110.6% to 123.5% with the incorporation of 10 wt.% thymol into the films. Furthermore, the addition of thymol at higher concentrations (7 and 10 wt.%) improved the water vapor barrier of the films by approximately 60.0%, from 4.98 × 10—9 to 2.01 × 10—9 g/d.m.Pa. Starch/CNF/thymol bionanocomposite films are also found to exhibit antibacterial activity against Escherichia coli. In conclusion, the produced starch/CNF/thymol bionanocomposite films have the potential to be used as antibacterial food packaging materials. Full article
(This article belongs to the Special Issue Biopolymers: Structure-Function Relationship and Application)
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10 pages, 1945 KiB  
Article
Electrospun Ultrafine Cationic Cellulose Fibers Produced from Sugarcane Bagasse for Potential Textile Applications
by Andrés Felipe Ochica Larrota, Ricardo Vera-Graziano, Alex López-Córdoba and Edwin Yesid Gómez-Pachón
Polymers 2021, 13(22), 3927; https://0-doi-org.brum.beds.ac.uk/10.3390/polym13223927 - 13 Nov 2021
Cited by 2 | Viewed by 1702
Abstract
Sugarcane bagasse (SCB) is an abundant by-product of sugar refining that can be utilized as a raw material for cellulose isolation for several industrial applications. Electrospinning has garnered attention in recent years because it allows the preparation of cellulosic materials with unique properties. [...] Read more.
Sugarcane bagasse (SCB) is an abundant by-product of sugar refining that can be utilized as a raw material for cellulose isolation for several industrial applications. Electrospinning has garnered attention in recent years because it allows the preparation of cellulosic materials with unique properties. In this study, cellulose was isolated from sugarcane bagasse and acetylated to fabricate fine acetate cellulose fibers through electrospinning. Subsequently, the electrospun fibers were deacetylated and cationized in order to produce functionalized materials with potential textile applications. The functional fibers were colored with an anionic dye (vinyl sulfone) with and without the presence of salt and were evaluated according to dye fixation, color attributes, morphological characteristics, and thermal stability. Cationic cellulose fibers that were dyed without added salt were found to be brighter and demonstrated better color fixation than those with added salt. In addition, morphological analysis performed using scanning electron microscopy demonstrated that cationized fibers dyed without added salt were better preserved at this stage. The cationic fiber also evidenced a high-temperature resistance, exhibiting a degradation temperature above 236 °C. The results suggest that cellulose fibers dyed in this manner can potentially be considered for use in textile applications due to their suitable dye fixation and tunable porosity (i.e., breathability). Full article
(This article belongs to the Special Issue Biopolymers: Structure-Function Relationship and Application)
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29 pages, 15530 KiB  
Article
Comparative Study of Crystallization, Mechanical Properties, and In Vitro Cytotoxicity of Nanocomposites at Low Filler Loadings of Hydroxyapatite for Bone-Tissue Engineering Based on Poly(l-lactic acid)/Cyclo Olefin Copolymer
by Farzana Nazir and Mudassir Iqbal
Polymers 2021, 13(22), 3865; https://0-doi-org.brum.beds.ac.uk/10.3390/polym13223865 - 09 Nov 2021
Cited by 4 | Viewed by 1972
Abstract
A poly(l-lactic acid)/nanohydroxyapatite (PLLA/nHA) scaffold works as a bioactive, osteoconductive scaffold for bone-tissue engineering, but its low degradation rate limits embedded HA in PLLA to efficiently interact with body fluids. In this work, nano-hydroxyapatite (nHA) was added in lower filler loadings [...] Read more.
A poly(l-lactic acid)/nanohydroxyapatite (PLLA/nHA) scaffold works as a bioactive, osteoconductive scaffold for bone-tissue engineering, but its low degradation rate limits embedded HA in PLLA to efficiently interact with body fluids. In this work, nano-hydroxyapatite (nHA) was added in lower filler loadings (1, 5, 10, and 20 wt%) in a poly(l-lactic acid)/cyclo olefin copolymer10 wt% (PLLA/COC10) blend to obtain novel poly(l-lactic acid)/cyclo olefin copolymer/nanohydroxyapatite (PLLA/COC10-nHA) scaffolds for bone-tissue regeneration and repair. Furthermore, the structure-activity relationship of PLLA/COC10-nHA (ternary system) nanocomposites in comparison with PLLA/nHA (binary system) nanocomposites was systematically studied. Nanocomposites were evaluated for structural (morphology, crystallization), thermomechanical properties, antibacterial potential, and cytocompatibility for bone-tissue engineering applications. Scanning electron microscope images revealed that PLLA/COC10-nHA had uniform morphology and dispersion of nanoparticles up to 10% of HA, and the overall nHA dispersion in matrix was better in PLLA/COC10-nHA as compared to PLLA/nHA. Fourier transformation infrared spectroscopy (FTIR), powder X-ray diffraction (XRD), and differential scanning calorimetry (DSC) studies confirmed miscibility and transformation of the α-crystal form of PLLA to the ά-crystal form by the addition of nHA in all nanocomposites. The degree of crystallinity (%) in the case of PLLA/COC10-nHA 10 wt% was 114% higher than pure PLLA/COC10 and 128% higher than pristine PLLA, indicating COC and nHA are acting as nucleating agents in the PLLA/COC10-nHA nanocomposites, causing an increase in the degree of crystallinity (%). Moreover, PLLA/COC10-nHA exhibited 140 to 240% (1–20 wt% HA) enhanced mechanical properties in terms of ductility as compared to PLLA/nHA. Antibacterial activity results showed that 10 wt% HA in PLLA/COC10-nHA showed substantial activity against P. aeruginosa, S. aureus, and L. monocytogenes. In vitro cytocompatibility of PLLA/COC10 and PLLA nanocomposites with nHA osteoprogenitor cells (MC3T3-E1) and bone mesenchymal stem cells (BMSC) was evaluated. Both cell lines showed two- to three-fold enhancement in cell viability and 10- to 30-fold in proliferation upon culture on PLLA/COC10-nHA as compared to PLLA/nHA composites. It was observed that the ternary system PLLA/COC10-nHA had good dispersion and interfacial interaction resulting in improved thermomechanical and enhanced osteoconductive properties as compared to PLLA/nHA. Full article
(This article belongs to the Special Issue Biopolymers: Structure-Function Relationship and Application)
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12 pages, 2041 KiB  
Article
Wear Resistance, Color Stability and Displacement Resistance of Milled PEEK Crowns Compared to Zirconia Crowns under Stimulated Chewing and High-Performance Aging
by Simone Shah Abhay, Dhanraj Ganapathy, Deepak Nallaswamy Veeraiyan, Padma Ariga, Artak Heboyan, Pokpong Amornvit, Dinesh Rokaya and Viritpon Srimaneepong
Polymers 2021, 13(21), 3761; https://0-doi-org.brum.beds.ac.uk/10.3390/polym13213761 - 30 Oct 2021
Cited by 34 | Viewed by 4518
Abstract
Recently, polyetheretherketone (PEEK) has been introduced to the dental market as a high-performance and chemically inert biomaterial. This study aimed to compare the wear resistance, abrasiveness, color stability, and displacement resistance of zirconia and PEEK milled crowns. An ideal tooth preparation of a [...] Read more.
Recently, polyetheretherketone (PEEK) has been introduced to the dental market as a high-performance and chemically inert biomaterial. This study aimed to compare the wear resistance, abrasiveness, color stability, and displacement resistance of zirconia and PEEK milled crowns. An ideal tooth preparation of a first maxillary molar was done and scanned by an intraoral scanner to make a digital model. Then, the prosthetic crown was digitally designed on the CAD software, and the STL file was milled in zirconia (CaroZiir S, Carol Zircolite Pvt. Ltd., Gujarat, India) and PEEK (BioHpp, Bredent GmbH, Senden, Germany) crowns using five-axis CNC milling machines. The wear resistance, color stability, and displacement resistance of the milled monolithic zirconia with unfilled PEEK crowns using a chewing simulator with thermocyclic aging (120,000 cycles) were compared. The antagonist wear, material wear, color stability, and displacement were evaluated and compared among the groups using the Wilcoxon–Mann–Whitney U-test. Zirconia was shown to be three times more abrasive than PEEK (p value < 0.05). Zirconia had twice the wear resistance of PEEK (p value < 0.05). Zirconia was more color stable than PEEK (p value < 0.05). PEEK had more displacement resistance than zirconia (p value < 0.05). PEEK offers minimal abrasion, better stress modulation through plastic deformation, and good color stability, which make it a promising alternative to zirconia crown. Full article
(This article belongs to the Special Issue Biopolymers: Structure-Function Relationship and Application)
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8 pages, 928 KiB  
Communication
Effect of Solvent on the Hydrodynamic Properties of Collagen
by Katarzyna Lewandowska, Marta Szulc and Alina Sionkowska
Polymers 2021, 13(21), 3626; https://0-doi-org.brum.beds.ac.uk/10.3390/polym13213626 - 21 Oct 2021
Cited by 5 | Viewed by 1831
Abstract
In this study, the effect of solvent on the hydrodynamic properties of collagen extracted from tail tendons of young rats was researched. Collagen was dissolved in various aqueous carboxylic acid solutions, including acetic acid (AA), acetic acid with the addition of sodium chloride [...] Read more.
In this study, the effect of solvent on the hydrodynamic properties of collagen extracted from tail tendons of young rats was researched. Collagen was dissolved in various aqueous carboxylic acid solutions, including acetic acid (AA), acetic acid with the addition of sodium chloride (AA/NaCl), formic acid (FA), lactic acid (LA), citric acid (CA), and also citrate buffer at pH = 3.7 (CB). The properties of collagen solutions at a concentration of 0.45 mg/mL were characterized based on the viscometric method. The reduced viscosity, intrinsic viscosity, and Huggins coefficient of collagen solutions and effect of solvent, temperature, and UV irradiation on these properties were investigated. Collagen solutions in acetic acid, acetic acid/NaCl, and citrate buffer were irradiated with UV light up to 1 h, and the viscosity of collagen solutions was measured. It was found that the organic acids used as solvent affected viscosity behavior, denaturation temperature, and stability of collagen solutions. The lowest values of studied parameters were obtained for the collagen solutions in acetic acid with the addition of sodium chloride. Thus, the effect of various aqueous carboxylic acid solutions on collagen solutions properties and denaturation temperature can also be affected by the sodium chloride addition. The results of this research can be crucial for the preparation of collagen solutions for both cosmetic and biomedical applications. Full article
(This article belongs to the Special Issue Biopolymers: Structure-Function Relationship and Application)
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34 pages, 66473 KiB  
Article
Rubber Degrading Strains: Microtetraspora and Dactylosporangium
by Ann Anni Basik, Jayaram Nanthini, Tiong Chia Yeo and Kumar Sudesh
Polymers 2021, 13(20), 3524; https://0-doi-org.brum.beds.ac.uk/10.3390/polym13203524 - 13 Oct 2021
Cited by 6 | Viewed by 2617
Abstract
Rubber composed of highly unsaturated hydrocarbons, modified through addition of chemicals and vulcanization are widely used to date. However, the usage of rubber, faces many obstacles. These elastomeric materials are difficult to be re-used and recovered, leading to high post-consumer waste and vast [...] Read more.
Rubber composed of highly unsaturated hydrocarbons, modified through addition of chemicals and vulcanization are widely used to date. However, the usage of rubber, faces many obstacles. These elastomeric materials are difficult to be re-used and recovered, leading to high post-consumer waste and vast environmental problems. Tyres, the major rubber waste source can take up to 80 years to naturally degrade. Experiments show that the latex clearing proteins (Lcp) found in Actinobacteria were reportedly critical for the initial oxidative cleavage of poly(cis-1,4-isoprene), the major polymeric unit of rubber. Although, more than 100 rubber degrading strains have been reported, only 8 Lcp proteins isolated from Nocardia (3), Gordonia (2), Streptomyces (1), Rhodococcus (1), and Solimonas (1) have been purified and biochemically characterized. Previous studies on rubber degrading strains and Lcp enzymes, implied that they are distinct. Following this, we aim to discover additional rubber degrading strains by randomly screening 940 Actinobacterial strains isolated from various locations in Sarawak on natural rubber (NR) latex agar. A total of 18 strains from 5 genera produced clearing zones on NR latex agar, and genes encoding Lcp were identified. We report here lcp genes from Microtetraspora sp. AC03309 (lcp1 and lcp2) and Dactylosporangium sp. AC04546 (lcp1, lcp2, lcp3), together with the predicted genes related to rubber degradation. In silico analysis suggested that Microtetraspora sp. AC03309 is a distinct species closely related to Microtetraspora glauca while Dactylosporangium sp. AC04546 is a species closely related to Dactylosporangium sucinum. Genome-based characterization allowed the establishment of the strains taxonomic position and provided insights into their metabolic potential especially in biodegradation of rubber. Morphological changes and the spectrophotometric detection of aldehyde and keto groups indicated the degradation of the original material in rubber samples incubated with the strains. This confirms the strains’ ability to utilize different rubber materials (fresh latex, NR product and vulcanized rubber) as the sole carbon source. Both strains exhibited different levels of biodegradation ability. Findings on tyre utilization capability by Dactylosporangium sp. AC04546 is of interest. The final aim is to find sustainable rubber treatment methods to treat rubber wastes. Full article
(This article belongs to the Special Issue Biopolymers: Structure-Function Relationship and Application)
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13 pages, 4083 KiB  
Article
Effect of Molecular Weight and Degree of Substitution on the Physical-Chemical Properties of Methylcellulose-Starch Nanocrystal Nanocomposite Films
by Qian Xiao, Min Huang, Xiaolan Zhou, Miaoqi Dai, Zhengtao Zhao and Hui Zhou
Polymers 2021, 13(19), 3291; https://0-doi-org.brum.beds.ac.uk/10.3390/polym13193291 - 27 Sep 2021
Cited by 4 | Viewed by 1641
Abstract
This research studied the effect of molecular weight (Mw) and degree of substitution (DS) on the microstructure and physicochemical characteristics of methylcellulose (MC) films with or without SNC. The Mw and DS of three types of commercial MC (trade name [...] Read more.
This research studied the effect of molecular weight (Mw) and degree of substitution (DS) on the microstructure and physicochemical characteristics of methylcellulose (MC) films with or without SNC. The Mw and DS of three types of commercial MC (trade name of M20, A4C, and A4M, respectively) were in the range of 0.826 to 3.404 × 105 Da and 1.70 to 1.83, respectively. Mw significantly affected the viscosity of methylcellulose solutions as well as the microstructure and tensile strength of methylcellulose films, while DS had a pronounced effect on their oxygen permeability properties. The incorporation of 15% (w/w) SNC resulted in the efficient improvement of tensile strength, water, and oxygen barrier properties of films, particularly for the A4C nanocomposite films. The results from SEM and FTIR illustrated that relatively homogenous dispersion of SNC was distinguished in A4C-15% (w/w) SNC films. Furthermore, microstructures of MC-SNC nanocomposite films were strongly dependent on both Mw and DS of MC. This work offers a convenient and green method to fabricate MC-based nanocomposite films with desirable mechanical, light, oxygen, and water vapor barrier properties. Full article
(This article belongs to the Special Issue Biopolymers: Structure-Function Relationship and Application)
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Review

Jump to: Research

35 pages, 6389 KiB  
Review
Cellulose-Based Nanofibers Processing Techniques and Methods Based on Bottom-Up Approach—A Review
by Ana Kramar and Francisco Javier González-Benito
Polymers 2022, 14(2), 286; https://0-doi-org.brum.beds.ac.uk/10.3390/polym14020286 - 11 Jan 2022
Cited by 16 | Viewed by 4718
Abstract
In the past decades, cellulose (one of the most important natural polymers), in the form of nanofibers, has received special attention. The nanofibrous morphology may provide exceptional properties to materials due to the high aspect ratio and dimensions in the nanometer range of [...] Read more.
In the past decades, cellulose (one of the most important natural polymers), in the form of nanofibers, has received special attention. The nanofibrous morphology may provide exceptional properties to materials due to the high aspect ratio and dimensions in the nanometer range of the nanofibers. The first feature may lead to important consequences in mechanical behavior if there exists a particular orientation of fibers. On the other hand, nano-sizes provide a high surface-to-volume ratio, which can have important consequences on many properties, such as the wettability. There are two basic approaches for cellulose nanofibers preparation. The top-down approach implies the isolation/extraction of cellulose nanofibrils (CNFs) and nanocrystals (CNCs) from a variety of natural resources, whereby dimensions of isolates are limited by the source of cellulose and extraction procedures. The bottom-up approach can be considered in this context as the production of nanofibers using various spinning techniques, resulting in nonwoven mats or filaments. During the spinning, depending on the method and processing conditions, good control of the resulting nanofibers dimensions and, consequently, the properties of the produced materials, is possible. Pulp, cotton, and already isolated CNFs/CNCs may be used as precursors for spinning, alongside cellulose derivatives, namely esters and ethers. This review focuses on various spinning techniques to produce submicrometric fibers comprised of cellulose and cellulose derivatives. The spinning of cellulose requires the preparation of spinning solutions; therefore, an overview of various solvents is presented showing their influence on spinnability and resulting properties of nanofibers. In addition, it is shown how bottom-up spinning techniques can be used for recycling cellulose waste into new materials with added value. The application of produced cellulose fibers in various fields is also highlighted, ranging from drug delivery systems, high-strength nonwovens and filaments, filtration membranes, to biomedical scaffolds. Full article
(This article belongs to the Special Issue Biopolymers: Structure-Function Relationship and Application)
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16 pages, 1656 KiB  
Review
Mango Peel Pectin: Recovery, Functionality and Sustainable Uses
by Malaiporn Wongkaew, Pikulthong Chaimongkol, Noppol Leksawasdi, Kittisak Jantanasakulwong, Pornchai Rachtanapun, Phisit Seesuriyachan, Yuthana Phimolsiripol, Thanongsak Chaiyaso, Warintorn Ruksiriwanich, Pensak Jantrawut and Sarana Rose Sommano
Polymers 2021, 13(22), 3898; https://0-doi-org.brum.beds.ac.uk/10.3390/polym13223898 - 11 Nov 2021
Cited by 13 | Viewed by 10793
Abstract
Concerns regarding the overconsumption of natural resources has provoked the recovery of biopolymers from food processing biomass. Furthermore, the current market opportunity for pectin in other areas has increased, necessitating the search for alternative pectin resources. This is also a step towards the [...] Read more.
Concerns regarding the overconsumption of natural resources has provoked the recovery of biopolymers from food processing biomass. Furthermore, the current market opportunity for pectin in other areas has increased, necessitating the search for alternative pectin resources. This is also a step towards the sustainable and circular green economy. Mango peel is the byproduct of agro-processing and has been used for high value-added components such as polysaccharide biopolymers. Pectin derived from the peel is yet to be exploited to its greatest extent, particularly in terms of its separation and physiochemical properties, which limit its applicability to dietary fiber in culinary applications. The functionality of the mango peel pectin (MPP) strongly depends on the molecular size and degree of esterification which highlight the importance of isolation and characterisation of pectin from this novel resource. This article therefore provides a useful overview of mango peel as a potential biomaterial for the recovery of MPP. Different extraction techniques and the integrated recovery were also discussed. The utilisation of MPP in different industrial schemes are also detailed out from different perspectives such as the pharmaceutical and biotechnology industries. This review convincingly expresses the significance of MPP, providing a sustainable opportunity for food and pharmaceutical development. Full article
(This article belongs to the Special Issue Biopolymers: Structure-Function Relationship and Application)
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