Natural Polymer Derivatives Research Articles

Natural Polymer-Based Hydrogels: From Polymer to Biomedical Applications.

Hydrogels prepared from natural polymer have attracted extensive attention in biomedical fields such as drug delivery, wound healing, and regenerative medicine due to their good biocompatibility, degradability, and flexibility. This review outlines the commonly used natural polymer in hydrogel preparation, including cellulose, chitosan, collagen/gelatin, alginate, hyaluronic acid, starch, guar gum, agarose, and dextran. The polymeric structure and process/synthesis of natural polymers are illustrated, and natural polymer-based hydrogels including the hydrogel formation and properties are elaborated. Subsequently, the biomedical applications of hydrogels based on natural polymer in drug delivery, tissue regeneration, wound healing, and other biomedical fields are summarized. Finally, the future perspectives of natural polymers and hydrogels based on them are discussed. For natural polymers, novel technologies such as enzymatic and biological methods have been developed to improve their structural properties, and the development of new natural-based polymers or natural polymer derivatives with high performance is still very important and challenging. For natural polymer-based hydrogels, novel hydrogel materials, like double-network hydrogel, multifunctional composite hydrogels, and hydrogel microrobots have been designed to meet the advanced requirements in biomedical applications, and new strategies such as dual-cross-linking, microfluidic chip, micropatterning, and 3D/4D bioprinting have been explored to fabricate advanced hydrogel materials with designed properties for biomedical applications. Overall, natural polymeric hydrogels have attracted increasing interest in biomedical applications, and the development of novel natural polymer-based materials and new strategies/methods for hydrogel fabrication are highly desirable and still challenging.

Convergence of 3D Bioprinting and Nanotechnology in Tissue Engineering Scaffolds.

Three-dimensional (3D) bioprinting has emerged as a promising scaffold fabrication strategy for tissue engineering with excellent control over scaffold geometry and microstructure. Nanobiomaterials as bioinks play a key role in manipulating the cellular microenvironment to alter its growth and development. This review first introduces the commonly used nanomaterials in tissue engineering scaffolds, including natural polymers, synthetic polymers, and polymer derivatives, and reveals the improvement of nanomaterials on scaffold performance. Second, the 3D bioprinting technologies of inkjet-based bioprinting, extrusion-based bioprinting, laser-assisted bioprinting, and stereolithography bioprinting are comprehensively itemized, and the advantages and underlying mechanisms are revealed. Then the convergence of 3D bioprinting and nanotechnology applications in tissue engineering scaffolds, such as bone, nerve, blood vessel, tendon, and internal organs, are discussed. Finally, the challenges and perspectives of convergence of 3D bioprinting and nanotechnology are proposed. This review will provide scientific guidance to develop 3D bioprinting tissue engineering scaffolds by nanotechnology.

Metal Ion and Dye Adsorption Potential of Grafted Co-polymer of Polysaccharides for the Treatment of Wastewater

Abstract: This review explains the importance of polysaccharide derivatives in removing heavy metals and dyes from contaminated materials. With rising urbanization and industrialization, the availability of heavy metals and dyes in the environment is increasing. Heavy metals can cause a variety of health problems in individuals and offer major environmental dangers. This paper uses diverse techniques to discuss the most recent improvements in metal ion and dye adsorption from wastewater. Various derivatives of natural polymers can be used as good adsorbents for removing heavy metals and dyes from industrial wastewater and treated water released into the environment, lowering the risk of human disease and environmental problems. According to literature reviews, removing heavy metal ions from industrial effluent benefits both people and the environment. Graft copolymers are the most effective heavy metal ion and dye removal adsorbents, and the majority of them obey the pseudo-first and pseudo-second-order models. Also, an overview of each grafted copolymers of polysaccharides for the adsorption of metal ions and dyes is mentioned in this review.

Stability improvement of carboxymethyl cellulose/chitosan complex beads by thermal treatment

Carboxymethyl cellulose (CMC) and chitosan (CHI) are two well-known natural polymer derivatives, as such the CMC@CHI complex beads fulfill many requirements for bio-related and safety-required applications. However, poor mechanical properties of CMC@CHI beads hinder their applications. We managed to improve the beads stability by a simple thermal treatment during the bead preparation. The effects of temperature, changing from 25 °C to 75 °C, on the stability of the formed beads were investigated. The morphology, diameter, shell thickness and structure of the beads treated at different temperature were analyzed using SEM, XPS and FTIR. The mechanical test and swelling experiments showed that the thermal treatment enhanced the bead's ability to withstand pressure and swelling. The beads treated at 75 °C showed the best pressure resistance, while the beads treated at 55 °C exhibited the highest swelling capability without losing integrity. This method is convenient to implement, not only improves the stability, but also controls the swelling capacity and mechanical properties of the beads, which are important for their potential applications in adsorption and controlled release. More importantly, this work offered insights on the effects of thermal treatment on the complexation process of the two polysaccharide molecular chains.

Synthesis and Study of Antifungal Properties of New Cationic Beta-Glucan Derivatives.

The interaction of positively charged polymers (polycations) with a biological membrane is considered to be the cause of the frequently observed toxicity of these macromolecules. If it is possible to obtain polymers with a predominantly negative effect on bacterial and fungal cells, such systems would have great potential in the treatment of infectious diseases, especially now when reports indicate the growing risk of fungal co-infections in COVID-19 patients. We describe in this article cationic derivatives of natural beta-glucan polymers obtained by reacting the polysaccharide isolated from Saccharomyces boulardii (SB) and Cetraria islandica (CI) with glycidyl trimethyl ammonium chloride (GTMAC). Two synthesis strategies were applied to optimize the product yield. Fungal diseases particularly affect low-income countries, hence the emphasis on the simplicity of the synthesis of such drugs so they can be produced without outside help. The three structures obtained showed selective anti-mycotic properties (against, i.e., Scopulariopsis brevicaulis, Aspergillus brasiliensis, and Fusarium solani), and their toxicity established using fibroblast 3T3-L1 cell line was negligible in a wide range of concentrations. For one of the polymers (SB derivative), using in vivo model of Aspergillus brasiliensis infection in Galleria mellonella insect model, we confirmed the promising results obtained in the preliminary study.

The source of conductivity and proton dynamics study in TEMPO-oxidized cellulose doped with various heterocyclic molecules

Our manuscript focuses on the study of proton conductivity phenomena caused by a high degree of mobility and dynamic movement of protons that occur in some hybrid composites obtained from TEMPO oxidized cellulose doped with three heterocyclic compounds. The first stage consists in the preparation of the organic matrix, the reaction conditions being chosen so as to allow the incorporation of as many carboxyl groups as possible. The numerous COOH groups, introduced after oxidation in the cellulose backbone, allow the successful attachment of N-base molecules, such as: 1-hydroxybenzotriazole (HBT), imidazole (IM), and 7-azaindole (AI). The as prepared cellulose-based powder composites (OxC-HBT, OxC-IM, OxC-AI) were firstly analyzed using extensive FTIR study. Different explanations regarding the nature and the source of the proton conductivity were proposed based on the FTIR experiments. A good thermal stability of the prepared samples has been revealed by thermal analyses. Moreover, the composites showed good values of proton conductivity both at lower and higher temperatures, for example, under anhydrous conditions, the proton conductivity has been found equal to 1.2 × 10−1 S/m for the composite containing IM and 2.3 × 10−2 S/m for the hybrid material containing HBT. The activation energies were also calculated and discussed for each heterocyclic dopant. The use of derivatives of natural polymers, i.e. TEMPO oxidized cellulose, create the prerequisite conditions for cheap, non-hazardous and environmentally safety approaches to find new biopolymer composites materials with proton conductive properties with potential application in fuel cell technology.

Antibacterial nano cerium oxide/chitosan/cellulose acetate composite films as potential wound dressing

Novel chitosan and cellulose acetate polymer composites with nanosized cerium oxide were prepared as potential wound dressing materials. Chitosan and cellulose acetate are natural polymer derivatives with biocompatible properties. Both polymers can be dissolved in formic acid. The polymer composite was formed by solvent-casting method. The formed films were not soluble in water. In order to improve antibacterial, thermal, and mechanical properties of the composite material, films were loaded with nanosized cerium oxide. Films were characterized with thermogravimetric, scanning electron microscopy with energy-dispersive X-ray spectroscopy, mechanical, ultraviolet-visible light transmittance, water solubility, pH, moisture content, water vapor transmission rate, swelling, and antibacterial tests. The physical properties and antibacterial characteristics of the films are promising for further research as a potential wound covering material.

Synthesis and Antibacterial Activity of Chitin Tetrazole Derivatives

New tetrazole derivatives of natural chitin polymers of high, medium, and low molecular masses with high, medium, and low degrees of substitution were synthesized and tested in vitro for antibacterial activity. The obtained tetrazole derivatives were characterized by pronounced antibacterial activity in vitro against S. aureus and E. coli. The chitin derivative of medium molecular mass with a medium degree of substitution had the highest antibacterial activity among all obtained derivatives. The antibacterial activity of this derivative as measured by bacterial growth inhibition zones was comparable to those of the antibiotics ampicillin and gentamycin.

Impacts of natural polymer derivative neutral polysaccharide Jag S and cationic hydroxypropyl polysaccharide Jag C162 on rainfall infiltration on an experimental loess hillslope

ABSTRACT Developing effective measures to improve soil structure and increase soil infiltration in the Loess Plateau located in arid and semiarid areas is important for soil and water conservation. Simulated rainfall experiments were conducted to determine the effects of two new natural polymer derivatives, namely neutral polysaccharide (Jag S) and cationic hydroxypropyl polysaccharide (Jag C162), on rainfall infiltration and their underlying mechanisms. The proportions of different sizes of water-stable soil aggregates were analyzed after spraying four different concentrations (0, 1, 3, and 5 g m−2) of Jag S and Jag C162 under rainfall intensities of 1, 1.5, and 2 mm min−1 and a slope gradient of 15°. Treatments with Jag S and Jag C162 significantly improved the rainfall infiltration rates (IRs) compared with the control. Moreover, applying 1 and 3 g m−2 Jag S effectively increased the IRs by 22.81% and 13.69%, respectively. Treatment with Jag C162 also increased the rainfall IRs by 39.47%, 46.59%, and 46.50%. Furthermore, the content of >0.25 mm water-stable soil aggregates increased from 27.19% to 90.42% before rainfall and from 9% to 50% after rainfall. Compared with Jag C 162, treatment with Jag S was less effective on improving rainfall infiltration and aggregate content. In particularly, application of 5 g m−2 Jag S improved the soil aggregate content but weakened rainfall infiltration because of the higher viscidity and consistency of the Jag S solution. Overall, spraying appropriate amounts of Jag C162 and Jag S on the loess slope surface can increase the water-stable soil aggregate content, resulting in improved rainfall infiltration and reduced soil erosion. Thus, application of two new natural polymer derivatives is a possible alternative conservation practice in the Loess Plateau.

Efficacy of Natural Polymer Derivatives on Soil Physical Properties and Erosion on an Experimental Loess Hillslope.

Raindrops disperse large soil aggregates into smaller particles, which can clog soil pores, cause soil crusting, reduce rainfall infiltration and increase soil loss. It was found that natural polymer derivatives were effective in improving soil physical properties and decreasing soil erosion on an experimental loess hillslope. This study investigated the effect of new natural polymer derivatives (Jag S and Jag C162) on soil properties, rainfall infiltration and sediment yield at four rates of sprayed polymers (0, 1, 3 and 5 g/m2), three rainfall intensities (1, 1.5 and 2 mm/min) and a slope gradient of 15° with a silt loam soil through simulated rain. The results showed that both Jag S and Jag C162 significantly increased the shear strength and improved the aggregates composition of the soil surface. The water-stable soil aggregates >0.25 mm increased from 9% to 50% with increasing rates of Jag S and Jag C162. Jag S and Jag C162 also effectively increased rainfall infiltration and final infiltration rate, and reduced erosion compared to controls without natural polymer derivatives added. However, higher rates of Jag S produced lower infiltration rates. Although both Jag S and Jag C162 effectively influenced soil physical properties and erosion, the effect of Jag C162 was more significant than that of Jag S.

Photo-reactive natural polymer derivatives for medical application

Abstract Biomaterials should be biocompatible and biodegradable. Many researches had been studied to upgrade biomaterials to deliver various types of drugs. In this respect, natural polymers have been catching on as a biomaterial. To immobilize drugs using natural polymer, photo-immobilization method has been designed. This method has several advantages. For photo-immobilization, photo-reactive functional group should be introduced to natural polymer. According to purpose of application, you could choice one of the photo-reactive functional group. Finally, many types of chemically modified natural polymers, which are photo-reactive natural polymer derivatives, have been prepared and studied to apply in medical field.

Thiol-ol Chemistry for Grafting of Natural Polymers to Form Highly Stable and Efficacious Antibacterial Coatings.

Bacterial contamination of surfaces and the associated infection risk is a significant threat to human health. Some natural antibacterial polymers with low toxicity are promising coating materials for alleviating pathogenic colonization on surfaces. However, widespread application of these polymers as antibacterial coatings is constrained by coating techniques which are not easily scalable due to stringent reaction conditions. Herein, thiol-ol reaction involving oxidative conjugation between thiol and hydroxyl groups is demonstrated as a facile technique to graft two natural polymer derivatives, agarose (AG) and quaternized chitosan (QCS), as antibacterial coatings on polymer and metal substrates. The substrate surfaces are first treated with oxygen plasma followed by UV-induced grafting of the polymers under atmospheric conditions. Dimercaprol, a FDA-approved drug, is used as both surface anchor and cross-linker of the polymer chains during grafting. The AG coating achieves >2 log reduction in Pseudomonas aeruginosa and Staphylococcus aureus biofilm formation, while the QCS coating reduces bacterial count from contaminated droplets on its surface by >95%. The coatings are noncytotoxic and exhibits a high degree of stability under conditions expected in their potential applications as antibacterial coating for biomedical devices (for AG), and for preventing pathogen transmission in the environment (for QCS).

The impact of natural polymer derivatives on sheet erosion on experimental loess hillslope

Macromolecular polymers can effectively improve soil structure, increase soil penetration and control runoff and erosion on hillslopes. Simulated rainfall experiments on a bare soil investigated the impact of natural polymer derivatives (NPD) on soil properties and the characteristics of runoff and sediment yield of sheet erosion on experimental loessial hillslopes. A control (without NPD) and three concentrations of polymers (1, 3 and 5g/m2) were tested at rainfall intensities of 1, 1.5 and 2mm/min and a slope gradient of 15°. NPD effectively altered the onset, volume and sediment content of the runoff. Higher concentrations of NPD provided earlier onsets, lower depth and lower sediment contents of the runoff. Compared with control, cumulative runoffs decreased by 49–68%, 61–70% and 69–79% at concentrations of 1, 3 and 5g/m2 NPD, respectively, while cumulative erosion modulus decreased by 31–37%, 39–47%, 56–61%, respectively. Additionally, NPDs significantly increased the shear strength and the composition of aggregates from soil surface. Shear strength was 2.71, 3.24 and 4.01 times higher at 1, 3 and 5g/m2, respectively, than in the controls. The percent mass of aggregates >0.25mm increased to 52.5%, 62.65% and 73.0% from 8.9% in the control at the three respective concentrations. More research is needed to confirm the utility of NPDs in helping to control sheet erosion.

Preparation of an Humidity Control Paper Board by Simple Physical Blending and its Properties

Humidity control paper board comprising natural polymer derivatives, porous natural minerals, inorganic salts, natural moisturizing material and paper was prepared by simple physical blending and its humidity control properties were tested. The moisture adsorption and desorption rate are 0.82 g/7h.g-1 and 0.71 g/7h.g-1, respectively. The adsorbed moisture amount is 0.85 g/g. It can maintain the relative humidity (RH) range between 50% and 60% within 20 min at 25 °C. Above all, the prepared paper board shows pronounced humidity control properties and the preparation technology is simple, which is feasible for production in large scale.

Patents Review on Lignocellulosic Biomass Processing Using Ionic Liquids

With the depletion of resources, biomass becomes a promising source of chemicals and fuels, currently obtained from petroleum. Cellulose is the most abundant material produced in earth, but it is difficult to dissolve which makes its transformation limited. Dissolution of cellulose requires severe temperature, non-conventional solvents and/or extreme acid or basic conditions. Thus, its processing is very pollutant. Ionic liquids are presented as clean solvents for cellulose. These are substances composed entirely of ions that are liquid at room temperature. Among other interesting properties, ionic liquids are non volatile and they are good solvents for a number of substances. Processes for cellulose processing in ionic liquids have been patented for several applications, the most important being: pre-treatment for biomass prior to fermentation for bio-ethanol production, hydrolysis for obtaining chemicals from biomass and substitution reaction for obtaining derivatives of cellulose and other natural polymers.

Adsorption of sodium dodecylsulfate on modified carbon adsorbents

The adsorption of anionic surfactants on carbon adsorbents modified with water-soluble derivatives of natural polymers, cellulose and chitin, is considered with sodium dodecylsulfate taken as an example. It is shown that such modification leads to changes in the adsorption structural characteristics and the particle size distribution of carbon-water suspensions of the original adsorbent, and to the emergence of new functional groups on its surface that are able to interact selectively with adsorbate molecules. It is assumed that adsorption of anionic surfactant on carbon adsorbents under equilibrium conditions proceeds via stepwise filling of the carbon’s porous structure: we first observe volume filling of micropores according to their sizes, and then the formation of a surfactant’s monolayer in mesopores and on the outer surface of the adsorbate. It is established by thermal analysis that the thermal stability of carbon adsorbents is enhanced through the preferential localization of anionic surfactants in micropores. The filling of mesopores and the outer carbon surface by surfactant molecules leads to a regular decrease in thermal stability and an increase in the adsorbent surface’s hydrophilicity.

Autoassociative natural polymer derivatives: the alkylchitosans. Rheological behaviour and temperature stability

Chitosan may be chemically modified by reductive amination leading to the grafting of hydrophobic alkyl chains along the hydrophilic macromolecular chain. This allows to obtain amphiphilic polymers whose the hydrophobicity (or the hydrophile–lipophile balance, HLB) may be adjusted according to the length of the grafted alkyl chain or the degree of substitution of the amine functions. The existence of hydrophobic interactions between the alkyl chains will change the physico-chemical properties of the solutions of the modified chitosans. These properties are studied and the study is particularly focused on the influence of the polymer concentration and temperature on them and applications as rheology modifiers. Threshold concentrations, over which the polymer solutions have peculiar temperature behaviour, were defined. According to their structure it is possible to prepare solutions with constant viscosity or increasing one with temperature.

Recognition and Selective Transport of Nucleic Acid Components through Molecularly Imprinted Polymeric Membranes

To induce “molecular memory” in a membrane substrate at the same time that the membrane was prepared from its polymer solution, an alternative molecular imprinting technique was applied. Upon membrane formation, a “molecular memory” of the imprint molecule is retained by the formed membrane that recognizes or favors interaction with print molecule analogues. In the present study, polystyrene resin bearing a tetrapeptide derivative, a derivative of natural polymer, and an entirely non-chiral synthetic polymer were adopted as candidate materials to form molecular recognition sites. 9-Ethyladenine was adopted as a print molecule. These molecularly imprinted polymeric membranes recognized and adsorbed adenosine (As), which is an analogue of the print molecule, in preference to guanosine (Gs) from As/Gs mixtures. However Gs was permeated in preference to As contrary to adsorption selectivity, possibly because of the relatively high affinity between As and the membrane.

Recognition and Selective Transport of Nucleic Acid Components through Molecularly Imprinted Polymeric Membranes

To induce “molecular memory” in a membrane substrate at the same time that the membrane was prepared from its polymer solution, an alternative molecular imprinting technique was applied. Upon membrane formation, a “molecular memory” of the imprint molecule is retained by the formed membrane that recognizes or favors interaction with print molecule analogues. In the present study, polystyrene resin bearing a tetrapeptide derivative, a derivative of natural polymer, and an entirely non-chiral synthetic polymer were adopted as candidate materials to form molecular recognition sites. 9-Ethyladenine was adopted as a print molecule. These molecularly imprinted polymeric membranes recognized and adsorbed adenosine (As), which is an analogue of the print molecule, in preference to guanosine (Gs) from As/Gs mixtures. However Gs was permeated in preference to As contrary to adsorption selectivity, possibly because of the relatively high affinity between As and the membrane.

光学分割膜 分子インプリント膜による光学分割

An alternative molecular imprinting technique is applied to the preparation of polymeric membranes for optical resolution. In this technique, the “molecular memory” of the print molecule is introduced in the membrane during the membrane preparation process. It was found that a membrane which contains an oligopeptide residue from a D-amino acid and is imprinted by D-isomer recognizes the D-isomer in preference to L-isomer, and vice versa. As for the membranes from a derivative of natural polymer or non-chiral synthetic polymers, the D-isomer imprinted polymeric membranes recognize D-isomer in preference to L-isomer, and vice versa. Enantioselective electrodialysis is attained with the present membranes reflecting their adsorption selectivity.