Promising Biopolymer Research Articles

Chitosan/Graphene Oxide Composite Films and Their Biomedical and Drug Delivery Applications: A Review

The healing of wounds is still a challenging clinical problem for which an efficient and fast treatment is needed. Therefore, recent studies have created a new generation of wound dressings that can accelerate the wound healing process with minimal side effects. Chitosan, a natural biopolymer, is an attractive candidate for preparing biocompatible dressings. The biodegradability, non-toxicity, and antibacterial activities of chitosan have made it a promising biopolymer for treating wounds. Graphene oxide has also been considered by researchers as a non-toxic, inexpensive, and biocompatible material for wound healing applications. This review paper discusses the potential use of chitosan/graphene oxide composite films and their application in wound dressing and drug delivery systems.

Thermal and Mechanical Assessment of PLA-SEBS and PLA-SEBS-CNT Biopolymer Blends for 3D Printing

Polylactic acid (PLA) is one of the most promising biopolymers often used as a raw material in 3D printing in many industrial areas. It has good mechanical properties, is characterized by high strength and stiffness, but unfortunately, it has some disadvantages; one is brittleness, and the other is slow crystallization. Amounts of 1–5% SEBS (styrene-ethylene-butylene-styrene) thermoplastic elastomer were blended into the PLA and the thermal and mechanical properties were investigated. DSC (Differential Scanning Calorimetry) measurements on the filaments have shown that SEBS increases the initial temperature of crystallization, thereby acting as a nucleating agent. The cooling rate of 3D printing, on the other hand, is too fast for PLA, so printed specimens behave almost amorphously. The presence of SEBS increases the impact strength, neck formation appears during the tensile test, and in the bending test, the mixture either suffers partial fracture or only bends without fracture. Samples containing 1% SEBS were selected for further analysis, mixed with 0.06 and 0.1% carbon nanotubes (CNTs), and tested for thermal and mechanical properties. As a result of CNTs, another peak appeared on the DSC curve in addition to the original single-peak crystallization, and the specimens previously completely broken in the mechanical tests suffered partial fractures, and the partially fractured pieces almost completely regained their original shape at the end of the test.

Impact of the processing temperature on the crystallization behavior and mechanical properties of poly[R-3-hydroxybutyrate-co-(R-3-hydroxyvalerate)

Poly[R-3-hydroxybutyrate-co-(R-3-hydroxyvalerate)] (PHBVs) are promising biopolymers, which could substitute petro-based plastics for packaging applications. To anticipate the behavior of PHBVs when transformed using conventional thermo-mechanical shaping processes, it is needed to better understand the effect of processing temperature on their crystallization behavior and final properties. The objectives of the present work were thus (1) to better understand the influence of the processing temperature on the PHBV macromolecular and crystalline structures, depending on its HV content, and (2) to define a processing window guaranteeing optimized mechanical properties of PHBV films. An innovative experimental strategy was proposed, enabling the study of melting and crystallization events, crystalline structure changes, and evolution of mechanical properties of PHBV according to processing temperature, using identical thermal cycles. A comprehensive dynamic monitoring of the studied PHBVs was achieved by coupling differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), step scan DSC (SDSC), observations of isothermal crystallization under polarized optical microscopy (POM), thermo-regulated wide angle X-ray analysis (WAXS), Nuclear Magnetic Resonance (NRM), and finally mechanical tests on PHBV films. The combination of these experiments revealed how inappropriate processing temperatures can result in irreversible changes in PHBVs’ macromolecular and crystalline structures, thermal behavior and mechanical performances. When increasing the HV content of the copolymer, adjusting the processing conditions according to these results revealed to be critical to match the functional properties targeted for a specific use.

Nanocomposites Materials of PLA Reinforced with Nanoclays Using a Masterbatch Technology: A Study of the Mechanical Performance and Its Sustainability.

Packaging consumes around 40% of the total plastic production. One of the most important fields with high requirements is food packaging. Food packaging products have been commonly produced with petrol polymers, but due to environmental concerns, the market is being moved to biopolymers. Poly (lactic acid) (PLA) is the most promising biopolymer, as it is bio-based and biodegradable, and it is well established in the market. Nonetheless, its barrier properties need to be enhanced to be competitive with other polymers such as polyethylene terephthalate (PET). Nanoclays improve the barrier properties of polymeric materials if correct dispersion and exfoliation are obtained. Thus, it marks a milestone to obtain an appropriate dispersion. A predispersed methodology is proposed as a compounding process to improve the dispersion of these composites instead of common melt procedures. Afterwards, the effect of the polarity of the matrix was analyzing using polar and surface modified nanoclays with contents ranging from 2 to 8% w/w. The results showed the suitability of the predispersed and concentrated compound, technically named masterbatch, to obtain intercalated structures and the higher dispersion of polar nanoclays. Finally, the mechanical performance and sustainability of the prepared materials were simulated in a food tray, showing the best assessment of these materials and their lower fingerprint.

Effect of plasticizers on physical, thermal, and tensile properties of thermoplastic films based on Dioscorea hispida starch

This study examines the effects of varying the concentrations of sorbitol (S) and glycerol (G) on the physical, morphological, thermal, and mechanical properties of Dioscorea hispida, starch-based films. In this context, the films of Dioscorea hispida starch were developed using solution casting technique with glycerol (G), sorbitol (S), and a mixture of sorbitol-glycerol (SG) as plasticizers at the ratios of 0, 30, 45, and 60 wt%. The films' moisture contents were increased when increasing the plasticizer contents. The tensile strengths were decreased, but elongations at break were increased; 7.38%–11.54% for G-plasticized films, 10.17%–15.76% for S-plasticized films, and 14.41%– 16.10% for SG-plasticized films with increasing plasticizer concentrations of the film samples. Varying plasticizer concentrations exhibited a minor effect on the S-plasticized film's thermal properties. Significant decrement in the glass transition temperatures of Dioscorea hispida starch films was observed when the plasticizer contents were raised from 30% to 60%. Significantly, the present work has shown that plasticized Dioscorea hispida starch can be considered a promising biopolymer for the applications of biodegradable films.

Polyhydroxyalkanoates (PHAs) degradation by the newly isolated marine Bacillus sp. JY14

Polyhydroxyalkanoates (PHAs) are bioplastic substitutes for petroleum-derived plastics that may help to reduce the increasing environmental impact of plastic pollution. Among them, polyhydroxybutyrate (PHB) is a promising biopolymer, incentivizing many researchers to search for PHB-producing and PHB-degrading bacteria for improved PHB utilization. Many novel PHB-producing microorganisms have been discovered; however, relatively few PHB-degrading bacteria have been identified. Six PHB-degrading bacteria were found in marine soil and investigated their PHB-degrading abilities under various temperature and salinity conditions using solid-media based culture. Finally, thermotolerant and halotolerant PHB-degrader Bacillus sp. JY14 was selected. PHB degradation was confirmed by monitoring changes in the physical and chemical properties of PHB films incubated with Bacillus sp. JY14 using scanning electron microscopy, Fourier-transform infrared spectroscopy, and gel permeation chromatography. Further, PHB degradation ability of Bacillus sp. JY14 was measured in liquid culture by gas chromatography. After 14 days of cultivation with PHB film, Bacillus sp. JY14 achieved approximately 98% PHB degradation. Applying various bioplastics to assess the bacteria's biodegradation capabilities, the result showed that Bacillus sp. JY14 could also degrade P(3HB-co-4HB) and P(3HB-co-3HV). Overall, this study identified a thermotolerant and halotolerant bacteria capable of PHB degradation under solid and liquid conditions. These results suggest that this bacteria could be utilized to degrade various PHAs.

Improving the heat deflection temperature of poly(lactic acid) foams by annealing

Poly(lactic acid) is a promising biopolymer but due to its low heat deflection temperature, the usage of PLA-based products is limited. In the case of bulk products, annealing is an effective way to increase the heat deflection temperature. Our aim was to improve the heat deflection temperature of poly(lactic acid) foams by annealing. In this study, we showed that D-lactide content affects the crystallinity of foam structures in the same way it affects the crystallinity of bulk PLA. Lower D-lactide content resulted in a higher degree of crystallinity. Annealing proved to be an effective way to induce cold crystallization. The heat deflection temperatures were calculated with the use of DMA, which produced more accurate results than the HDT device. Outstanding heat deflection temperature results were achieved (from 54°C to 131°C) with the use of annealing of chemically foamed PLA foams (1.4% D-lactide content) containing a nucleating agent. The excellent results can be explained with increased crystallinity, which exceeded 40%. Also, no signs of thermal degradation were found after successful annealing.

Naturally-derived protein extract from Gryllus bimaculatus improves antioxidant properties and promotes osteogenic differentiation of hBMSCs.

Naturally-derived proteins or peptides are promising biopolymers for tissue engineering applications owing to their health-promoting activity. Herein, we extracted proteins (~90%) from two-spotted cricket (Gryllus bimaculatus) and evaluated their osteoinductive potential in human bone marrow-derived mesenchymal stem cells (hBMSCs) under in vitro conditions. The extracted protein isolate was analyzed for the amino acid composition and the mass distribution of the constituent peptide fraction. Fourier transform infrared (FTIR) spectroscopy was used to determine the presence of biologically significant functional groups. The cricket protein isolate (CPI) exhibited characteristic protein peaks in the FTIR spectrum. Notably, an enhanced cell viability was observed in the presence of the extracted proteins, showing their biocompatibility. The CPI also exhibited antioxidant properties in a concentration-dependent manner. More significant mineralization was observed in the CPI-treated cells than in the control, suggesting their osteoinductive potential. The upregulation of the osteogenic marker genes (Runx2, ALP, OCN, and BSP) in CPI treated media compared with the control supports their osteoinductive nature. Therefore, cricket-derived protein isolates could be used as functional protein isolate for tissue engineering applications, especially for bone regeneration.

Extraction, characterization and rheological behavior of galactomannans in high salinity and temperature conditions

Galactomannans can be extracted from various plant species, including those of the Cassia grandis Linn. f. (Fam. Caesalpiniaceae), a native Brazilian tree. The objective of this work was to obtain galactomannans by three different extraction methods and to characterize them owing to structure and rheological behavior in aqueous saline fluids that are typically applied for enhanced oil recovery. The largest yield obtained was 23.4 wt% and the mannose/galactose ratios were between 1.1 and 1.5. All the gums extracted were characterized by Proton nuclear magnetic resonance, Fourier transform infrared spectroscopy, Elementary Analysis (CHN) and X-Ray Diffraction demonstrating their galactomannan structures. Thermogravimetric analyses allowed determining the real concentration of organic matter present in the final extraction product, which was near 70 wt%. The greatest molar mass of the Cassia gum was Mw = 1.01 × 106 g/mol, determined by Size-exclusion chromatography and since it is a nonionic biopolymer, it was not influenced by the salinity of the prepared synthetic aqueous solutions with high salt concentrations (TDS = 29,711 mg/L and 68,317 mg/L), including the solutions containing divalent cations. Under a shear rate of 7.3 s−1, Cassia gum from method A showed the highest apparent viscosity values that were approximately 158, 78 and 55 mPa s, at concentration of 5,000 ppm and temperatures of 25, 60 and 80 °C, respectively. Thus, Cassia gum stood as a promising biopolymer for enhanced oil recovery application.

Hemostatic and Tissue Regeneration Performance of Novel Electrospun Chitosan-Based Materials.

The application of chitosan (Ch) as a promising biopolymer with hemostatic properties and high biocompatibility is limited due to its prolonged degradation time, which, in turn, slows the repair process. In the present research, we aimed to develop new technologies to reduce the biodegradation time of Ch-based materials for hemostatic application. This study was undertaken to assess the biocompatibility and hemostatic and tissue-regeneration performance of Ch-PEO-copolymer prepared by electrospinning technique. Chitosan electrospinning membranes (ChEsM) were made from Ch and polyethylene oxide (PEO) powders for rich high-porous material with sufficient hemostatic parameters. The structure, porosity, density, antibacterial properties, in vitro degradation and biocompatibility of ChEsM were evaluated and compared to the conventional Ch sponge (ChSp). In addition, the hemostatic and bioactive performance of both materials were examined in vivo, using the liver-bleeding model in rats. A penetrating punch biopsy of the left liver lobe was performed to simulate bleeding from a non-compressible irregular wound. Appropriately shaped ChSp or ChEsM were applied to tissue lesions. Electrospinning allows us to produce high-porous membranes with relevant ChSp degradation and swelling properties. Both materials demonstrated high biocompatibility and hemostatic effectiveness in vitro. However, the antibacterial properties of ChEsM were not as good when compared to the ChSp. In vivo studies confirmed superior ChEsM biocompatibility and sufficient hemostatic performance, with tight interplay with host cells and tissues. The in vivo model showed a higher biodegradation rate of ChEsM and advanced liver repair.

The synthesis and application of chitosan coated ZnO nanorods for multifunctional cotton fabrics

It is of great interest in the interaction of fabrics with various biopolymers to improve their properties. Chitosan (CHT) is a promising biopolymer due to its abundance and challenging functions for many industries including textiles. CHT can be modified by metal and metal oxide nanoparticles to obtain new functional materials. In this study, binary chitosan-zinc oxide (CHT-ZnO) nanocomposite was successfully prepared by precipitation method. The cotton fabrics were treated by obtained bionanocomposites (BNC) using pad-dry-cure and sol-gel methods to increase their washing durability against multiple cycles. Moreover, (3-Glycidyloxypropyl) trimethoxysilane (GPTMS) was used to improve washing durability of BNC. BNC coated fabrics were tested for the antibacterial and UV protection performances. A ternary chitosan-zinc oxide-titanium dioxide (CHT-ZnO-TiO2) nanocomposite was also synthesized to observe the changes in UV properties for the first time. The results revealed that CHT-ZnO binary complex provided very good antibacterial and UV protective properties. The results also proved that sol-gel application by GPTMS enhanced these effects against multi washing cycles of BNC treated cotton fabrics in comparison to CHT treated fabrics. The application of the ternary system changed the UV protection factor (UPF) rating of fabrics from the “very good protection” category to the “excellent protection” category.

New insights into the biodegradation of polylactic acid: from degradation to upcycling

Owing to its biosynthetic and biodegradable properties, polylactic acid (PLA) is considered to be a most promising biopolymer that could play a crucial role as a potentially environmentally friendly material for a sustainable bioeconomy. However, its long-life cycle indicates that it cannot be easily degraded in nature. Therefore, understanding the biodegradation mechanism of PLA is important for reducing the impacts of waste plastic and waste disposal. With the recent development of molecular biology techniques, some studies have confirmed that specific groups of microorganisms can facilitate the biodegradation of PLA. Here, recent advances in the biodegradation of PLA (i.e., microbial and enzymatic degradation) and key factors affecting the degradation efficiency were reviewed. In addition, compared with complete degradation through mineralization, upcycling is also proposed as a more recyclable strategy for disposing of waste plastics.

PHB/CHIT Scaffold as a Promising Biopolymer in the Treatment of Osteochondral Defects-An Experimental Animal Study.

Biopolymer composites allow the creation of an optimal environment for the regeneration of chondral and osteochondral defects of articular cartilage, where natural regeneration potential is limited. In this experimental study, we used the sheep animal model for the creation of knee cartilage defects. In the medial part of the trochlea and on the medial condyle of the femur, we created artificial defects (6 × 3 mm2) with microfractures. In four experimental sheep, both defects were subsequently filled with the porous acellular polyhydroxybutyrate/chitosan (PHB/CHIT)-based implant. Two sheep had untreated defects. We evaluated the quality of the newly formed tissue in the femoral trochlea defect site using imaging (X-ray, Computer Tomography (CT), Magnetic Resonance Imaging (MRI)), macroscopic, and histological methods. Macroscopically, the surface of the treated regenerate corresponded to the niveau of the surrounding cartilage. X-ray examination 6 months after the implantation confirmed the restoration of the contour in the subchondral calcified layer and the advanced rate of bone tissue integration. The CT scan revealed a low regenerative potential in the bone zone of the defect compared to the cartilage zone. The percentage change in cartilage density at the defect site was not significantly different to the reference area (0.06–6.4%). MRI examination revealed that the healing osteochondral defect was comparable to the intact cartilage signal on the surface of the defect. Hyaline-like cartilage was observed in most of the treated animals, except for one, where the defect was repaired with fibrocartilage. Thus, the acellular, chitosan-based biomaterial is a promising biopolymer composite for the treatment of chondral and osteochondral defects of traumatic character. It has potential for further clinical testing in the orthopedic field, primarily with the combination of supporting factors.

Relationship Between Crystallization, Mechanical and Gas Barrier Properties of Poly(ethylene furanoate) (PEF) in Multinanolayered PLA-PEF and PET-PEF Films

Food packaging films must be reinvented in order to answer the new demanding ecological requirements. Biobased and/or biodegradable polymers appear as an interesting alternative to reduce petroleum dependence and carbon dioxide emissions. Poly(ethylene furanoate) (PEF) appears today as a new promising biopolymer thanks to its good gas barrier and mechanical properties, despite its high price that could limit its industrial applications. Its combination with other polymers is thus of great interest and for the first time, film coextrusion process is used to create PLA-PEF and PET-PEF multi-micro/nano layered films. A new PEF grade developed by AVA Biochem in the H2020 Mypack program, has been used and firstly analysed in terms of melt processability, mechanical, thermal and gas barrier properties. Our major results confirmed the good gas barrier as well as mechanical properties of amorphous PEF. Post-extrusion PEF bulk thermal crystallization led to very brittle material making gas barrier measurements impossible. Micro/nanolayered PLA-PEF and PET-PEF films with different PEF layer thicknesses have been processed and post-extrusion annealing treatment was carried out. The relationship between crystallinity, mechanical and gas barrier properties will be investigated.

Multifunctional manganese-based carboxymethyl chitosan hydrogels for pH-triggered pesticide release and enhanced fungicidal activity

Carboxymethyl chitosan (CMCS) has emerged as a promising biopolymer carrier for controlled release formulations of pesticide. In this study, manganese-based carboxymethyl chitosan hydrogel was facilely prepared to encapsulate and release fungicide prothioconazole in a controllable manner. The loading content (LC) and encapsulation efficiency (EE) of prothioconazole were optimized by orthogonal test. When scaled up under the optimal condition, the corresponding LC and EE were 22.17 % and 68.38 %, respectively. The result showed that the pH-triggered release behavior of prothioconazole for the hydrogels was consistent with swelling behavior. The pesticide rapidly released in neutral and slightly alkaline solutions than in acidic conditions. Moreover, the prepared hydrogel showed enhanced fungicidal ability against wheat take-all pathogen (Gaeumannomyces graminis var. tritic) compared to that of prothioconazole technical material. This research seeks to provide a promising approach to develop metal and polysaccharide-based hydrogels to control the pesticide release and reduce pesticide use in sustainable agriculture application.

Biocompatibility of the Biopolymer Cyanoflan for Applications in Skin Wound Healing

There is a great demand for the development of novel wound dressings to overcome the time and costs of wound care performed by a vast number of clinicians, especially in the current overburdened healthcare systems. In this study, Cyanoflan, a biopolymer secreted by a marine unicellular cyanobacterium, was evaluated as a potential biomaterial for wound healing. Cyanoflan effects on cell viability, apoptosis, and migration were assessed in vitro, while the effect on tissue regeneration and biosafety was evaluated in healthy Wistar rats. The cell viability and apoptosis of fibroblasts and endothelial cells was not influenced by the treatment with different concentrations of Cyanoflan, as observed by flow cytometry. Moreover, the presence of Cyanoflan did not affect cell motility and migratory capacity, nor did it induce reactive oxygen species production, even revealing an antioxidant behavior regarding the endothelial cells. Furthermore, the skin wound healing in vivo assay demonstrated that Cyanoflan perfectly adapted to the wound bed without inducing systemic or local oxidative or inflammatory reaction. Altogether, these results suggest that Cyanoflan is a promising biopolymer for the development of innovative applications to overcome the many challenges that still exist in skin wound healing.

Potential of macroalgae-based biorefinery for lactic acid production from exergy aspect

The increasing production of plastics has raised concerns over the depletion of fossil fuels. In addition, the environmental issues associated with the improper management of plastic waste are increasingly alarming. Therefore, there is a sharp rise of researches conducted on one of the most promising biopolymers for the production of biodegradable plastics, which is known as polylactic acid (PLA). Subsequently, this has led to an increased interest in the production of its monomer, lactic acid (LA). However, the high production cost of LA has been limiting its large-scale manufacturing. The utilization of expensive raw materials and complicated downstream processes have led to the high overall production cost of LA. This review explores the potential of 3G feedstock, specifically macroalgae biomass, as a substrate for LA production. Then, the recent technological advancements for LA production and the challenges currently faced in the LA industry are addressed. Lastly, the sustainability aspect of macroalgae biomass is evaluated economically and environmentally by utilizing engineering tools such as life cycle assessment and exergy analysis, which represent the highlights of this review paper.

Feasibility studies on bio composites using PLA and Epoxy for structural applications.

Biopolymers are eco-friendly substitute materials to synthetic polymers due to their abundant resource, biodegradability, and ease of processing. In recent years biopolymer-based polymers attracted many researchers because of cost, lightweight, and recyclability. One of the most promising biopolymers used in many applications such as food, packaging, and medical and pharmaceutical industries is Polylactic Acid (PLA). Polymer scientists in the last decade widely investigated. Biopolymer is going to replace many synthetic materials. Desired properties of biopolymer can be obtained by blending with various additives. This research aims to reduce the dependence of synthetic polymer by reinforcing PLA in an Epoxy matrix. The Percentage of PLA is varied from 10 to 50% in a step of 10% using Solution Casting Technique. The mechanical, Functional (FTIR), thermal properties are investigated. The Epoxy and PLA composites with 20% PLA has shown improvement in Tensile strength compared to 10 and 30%.

Biosynthesis and prebiotic activity of a linear levan from a new Paenibacillus isolate

Levan, a type of β (2→6)-linked fructan, is a promising biopolymer with distinct properties and extensive applications in the fields of food, pharmaceutical, cosmetics, etc. However, the commercial availability of levan is still limited due to the relatively high production costs. Here, a new Paenibacillus sp. strain FP01 was isolated and identified as an efficient fructan producer with high yield (around 89.5g/L fructan was obtained under 180g/L sucrose) and conversation rate (49.7%). The fructan named Plev was structurally characterized as a linear levan-type fructan with a molecular mass of 3.11 × 106Da. Aqueous solutions of Plev exhibited a non-Newtonian behavior at concentrations 3-5%. Heating and chilling had no obvious effects on apparent viscosities of Plev solutions. Plev also had good rheological stabilities toward pH (3-11) and metal salts (Na+, K+, Ca2+, Mg2+). Microbiome and metabolome analysis showed that Plev intervention increased the abundance of beneficial bacteria and elevated the levels of short-chain fatty acids (SCFAs) in feces of mice. Taken together, Plev could be considered a potential thickener and prebiotic supplement in food industry.Key points• Paenibacillus sp. strain FP01 was identified as a high-efficient levan producer.• The levan Plev from FP01 exhibited good rheological properties and stabilities.• The in vivo prebiotic activities of linear levan were revealed.

Poly(lactic acid)-PLA: An Analysis Based on Literature Text Mining

The most researched and used biodegradable aliphatic polyester worldwide is poly (lactic acid) - PLA. Due to its inherent properties, PLA is a leading biomaterial for several and numerous applications and the most promising biopolymer capable of replacing conventional petroleum-derived polymers. Besides, PLA is also one of the most promising candidates for new developments in the traditional sectors such as packaging and the automotive industry, in the electronics industry, and the biomedical area. To verify the importance of drug release in the various applications of PLA, a text mining of the last ten years was carried out. The text-mining tool was used to identify this polymer's main applications in the last ten years, allowing us to draw a map year by year based on correlation analysis. Firstly, an analysis was made of the main applications of PLA in scientific research, by searching for "PLA", in the ScienceDirect scientific base (https://www.sciencedirect.com/) and using the online tool Voyant Tools. Some words related to drug release were selected, checking how many times they were mentioned over the years. In this way, it was possible to see which years were the most and least used PLA in drug release. It was not possible to observe a gradual increase or decrease in this polymer's use, for this purpose, over time. The text mining presented here proved to be an efficient and fast way to observe the desired theme.