Natural Polymers

In this work, only N-substituted chitosan derivatives (water-soluble N-carboxymethylchitosan derivatives: N-CMC) with different degrees of substitution were obtained by reaction of a fully deacetylated
chitosan (derived from deacetylation of chitosan using decrystallized method) with monochloroacetic
acid at pH 8 and temperature of 90C. The structure ofN-carboxymethylchitosan and chitosan was characterized by IR,
1
H,
13
C and
1
H–
13
C NMR-HSQC spectra. In the IR spectrum of theN-carboxymethylchitosan, the appearance of peak at 1742 cm
1
was assigned for CO group ofANHACH2ACOOH of substituted
chitosan. In the
1
H NMR spectra, the peaks at about 3.814.06 ppm, assigned forACH2Agroups of
ANHACH2AandAN(CH2)2A, were the major feature, while in the
1
H–
13
C NMR-HSQC spectra, signals
ofACH2Aconfirmed the presence of these two different substitutedACH2Agroups. The degree of substitution (DS) of N-monosubstitution (DSN-mono) decreased from 0.47 to 0.03 meanwhile that of N,Ndisubstitution (DSN,N-di) increased from 0.52 to 0.96 since the mass ratio of chitosan/monochloroacetic
acid changing from 1/1 to 1/4. TheN-carboxymethylchitosan derivatives have been used for adsorption
Cu(II) ion from aqueous solution. The results shown that the optimum conditions for adsorption Cu(II) ion
in nitrate solution were pH 6.5, temperature of 30C, for 60–90 min and the substituted chitosan derivative having DSN-monoof 0.16 and DSN,N-diof 0.81 had maximum adsorption capacity of 192 mg Cu(II) per
gram ofN-CMC

Reactive oxygen species (ROS) (H2O2, OCl−, •OH, O2−) are a family of reactive molecules that are generated intracellularly and are engaged in many
biological processes. In physiological concentrations, ROS act as signaling
molecules to a number of metabolic pathways; however, in excess they can
be harmful to living organisms. Overproduction of ROS has been related
to many pathophysiological conditions and a number of studies have been
reported in elucidating their mechanism in these conditions. With the aim of
harnessing this role, a number of imaging tools and therapeutic compounds
have been developed. Here these imaging and therapeutic tools are reviewed
and particularly those structures with ROS-sensitivity based on their biomedical applications and their functional groups. There is also a brief discussion
about the method of preparation as well as the mechanism of action.

Corn fibers and luffa peels were evaluated for removing toxic heavy metal ions and dissolved organic dyes from water. Fresh peels were pretreated to remove all soluble components before using them for extraction studies. Presence of eOH and eCO 2 H functional groups on the surface of the peels and rough morphologies were characterized using Fourier transform infrared spectroscopy and scanning electron microscopy investigations, respectively. Corn fibers and luffa peels showed maximum extraction effi-ciencies within the pH range of 4e10 and adsorption reached a steady state within 2e3 h. Prewashed corn fibers and luffa peals extracted 159 mg g À1 and 90 mg g À1 of alcian blue, 70 mg g À1 and 124 mg g À1 of methylene blue, 50 mg g À1 and 108 mg g À1 of neutral red as well as 35 mg g À1 and 40 mg g À1 of coomassie brilliant blue from water, respectively. Both materials did not show significant extraction affinity towards heavy metal ions such as Pb 2þ (1 mg g À1), Ni 2þ (4 mg g À1 for corn fiber and 12 mg g À1 for luffa peels), and chromate (3 mg g À1 for corn fibers and 6 mg g À1 for luffa peels) ions from water. The Langmuir and Freundlich isotherms were used to understand the adsorption process on the surface of the adsorbents. Langmuir isotherm model yielded the best fit for the data obtained in the study, indicating a monolayer adsorption of pollutants on the adsorbent surface. Both adsorbents can be regenerated at acidic pH and could be reused for up to five cycles without significant loss of efficiency. Our experimental results suggest that both natural materials are effective towards removing dissolved dyes from water.

Fragrance compounds have been used since antiquity to freshen the air or to mask the odours. Different types of air fresheners are known such as electric air fresheners with 30% market share, sprays, including aerosol air fresheners with 27%, car air fresheners with 16%, gel air fresheners with 9%, candle air fresheners and wax melts with 7 %, liquid air fresheners with 6% and others. According to research studies, in the United States, 34.7% of the population reported health problems, such as migraine headaches and respiratory problems, when exposed to fragranced products. Thus, there are numerous studies with strong evidence that fragmented products can trigger adverse health effects in the general population. Considering that air fresheners have been associated with adverse negative health effects that was the motive for proposing an alternative way of synthesis of gel air fresheners that is more green and more healthy. In this paper the gel air fresheners were synthesized by a simple and green sol-gel reaction using natural biodegradable polymer gelatin and lavender essential oil, as well as with natural banana aroma. The 3D structures of gel air fresheners of desired shapes and odours were obtained. The change in the 3D structure at room temperature was evident, probably as a result of thermal degradation and water evaporation. Anyway, the gel air freshener obtained with lavender essential oil is more acceptable to human health than commercially available ones. The results obtained in this study suggest that further improvement in stability should take place.

The properties of a composite material depend on its constituent materials such as natural biopolymers or synthetic biodegradable polymers and inorganic or organic nanomaterials or nano-scale minerals. The significance of bio-based and synthetic polymers and their drawbacks on coating film application is currently being discussed in research papers and articles. Properties and applications vary for each novel synthetic bio-based material, and a number of such materials have been fabricated in recent years. This review provides an in-depth discussion on the properties and applications of biopolymer-based nanocomposite coating films. Recent works and articles are cited in this paper. These citations are ubiquitous in the development of novel bionanocomposites and their applications.

One of the concerning challenges for engineering and regenerating tissues is providing a suitable condition for development of a utilitarian vascular matrix. Natural polymers such as collagen, gelatin, chitosan, silk fibroin and fibrin are used as bio-compatible scaffolds to prepare appropriate biological and mechanical conditions for regenerative medicine and tissue engineering approaches. A wide range of studies demonstrated that using these biomaterials as scaffolds or engineered constructions such as hydrogels can provide a microenvironment to improve regeneration and repair of target tissues and organs through enhancing angiogenesis. They can be used single or in composition with each other. This review focused on some different natural polymeric constructs that have been incorporated in tissue engineering.

Agro-wastes are derived from diverse sources including grape pomace, tomato pomace, pineapple, orange, and lemon peels, sugarcane bagasse, rice husks, wheat straw, and palm oil fibers, among other affordable and commonly available materials. The carbon-rich precursors are used in the production bio-based polymers through microbial, biopolymer blending, and chemical methods. The Food and Agriculture Organization (FAO) estimates that 20%-30% of fruits and vegetables are discarded as waste during post-harvest handling. The development of bio-based polymers is essential, considering the scale of global environmental pollution that is directly linked to the production of synthetic plastics such as polypropylene (PP) and polyethylene (PET). Globally, 400 million tons of synthetic plastics are produced each year, and less than 9% are recycled. The optical, mechanical, and chemical properties such as ultraviolet (UV) absorbance, tensile strength, and water permeability are influenced by the synthetic route. The production of bio-based polymers from renewable sources and microbial synthesis are scalable, facile, and pose a minimal impact on the environment compared to chemical synthesis methods that rely on alkali and acid treatment or co-polymer blending. Despite the development of advanced synthetic methods and the application of biofilms in smart/intelligent food packaging, construction, exclusion nets, and medicine, commercial production is limited by cost, the economics of production, useful life, and biodegradation concerns, and the availability of adequate agro-wastes. New and cost-effective production techniques are critical to facilitate the commercial production of bio-based polymers and the replacement of synthetic polymers.

Agro-wastes are derived from diverse sources including grape pomace, tomato pomace, pineapple, orange, and lemon peels, sugarcane bagasse, rice husks, wheat straw, and palm oil fibers, among other affordable and commonly available materials. The carbon-rich precursors are used in the production bio-based polymers through microbial, biopolymer blending, and chemical methods. The Food and Agriculture Organization (FAO) estimates that 20–30% of fruits and vegetables are discarded as waste during post-harvest handling. The development of bio-based polymers is essential, considering the scale of global environmental pollution that is directly linked to the production of synthetic plastics such as polypropylene (PP) and polyethylene (PET). Globally, 400 million tons of synthetic plastics are produced each year, and less than 9% are recycled. The optical, mechanical, and chemical properties such as ultraviolet (UV) absorbance, tensile strength, and water permeability are influenced by the ...

Gelatine is derived from collagen,which  is broadly used in the  food, pharmaceutical, cosmetic and  photography industries. Due to its great demand, there is a need for an alternative source of gelatine due to health, supply and religious issues. This study presents the development of lightweight and spongy gelatine which is pure in appearance, derived from avian waste material (chicken shank and toes) by modified acid extraction and lyophilisation. The physical and chemical characteristics of the gelatine, such as physical identification, proximate analysis, pH, gel strength, clarity, viscosity, thermal analysis, scanning electron  microscope, SDS-PAGE, and  MALDI-TOF,  were analysed. The results show that the average yield of gelatine obtained was 5.18%, with a pH of 3.8, moisture content of
7.17%, total protein content of 93.77%, total fat content of
0.93% and total ash content of 1.57%. The bloom strength was found to be higher than that of commercially available bovine gelatine. All test results for the gelatine comply with pharmaceutical standards as stated in standard pharmacopoeias.

Agro-wastes are derived from diverse sources including grape pomace, tomato pomace, pineapple, orange, and lemon peels, sugarcane bagasse, rice husks, wheat straw, and palm oil fibers, among other affordable and commonly available materials. The carbon-rich precursors are used in the production bio-based polymers through microbial, biopolymer blending, and chemical methods. The Food and Agriculture Organization (FAO) estimates that 20–30% of fruits and vegetables are discarded as waste during post-harvest handling. The development of bio-based polymers is essential, considering the scale of global environmental pollution that is directly linked to the production of synthetic plastics such as polypropylene (PP) and polyethylene (PET). Globally, 400 million tons of synthetic plastics are produced each year, and less than 9% are recycled. The optical, mechanical, and chemical properties such as ultraviolet (UV) absorbance, tensile strength, and water permeability are influenced by the ...

This article investigates the environmental sustainability of plastic nets in agricultural environments based on published experimental data. This article focuses on biodegradable and synthetic plastics used in farms as mulching materials and shade materials/greenhouse covering materials (shade nets and plastic films) to protect plants from pests and extreme weather. The sustainability was determined by three factors, carbon footprint from cradle to the end of life (LCA), durability (resistance to photo-oxidation and high tensile strength), and affordability. The LCA analyses showed that the production of polyethylene (PE) requires less energy and generates low quantities of greenhouse gas equivalents. Beyond the LCA data, biodegradable polymers are sustainable based on biodegradability and compostability, ability to suppress weeds, control soil temperatures, and moisture, and augment fertigation and drip irrigation. However, existing technologies are a limiting factor because lab-based innovations have not been commercialized. In addition, industrial production of shade nets, plastic greenhouse covers, and mulching materials are limited to synthetic plastics. The bio-based plastic materials are sustainable based on biodegradability, and resistant to photo-oxidation. The resistance to UV degradation is an essential property because solar radiation cleaves CC bonds, which in turn impact the mechanical strength of the materials. In brief, the sustainability of plastics in farms is influenced by LCA data, mechanical and optical properties, and performance relative to other materials.

To date, a number of researchers are seeking for and/or designing novel molecules which function as arithmetic molecular engines. Biomolecules such as deoxyribonucleic acid (DNA) and proteins are examples of promising candidate molecules. In the present article, we showed our view that DNA-based molecules could be used as a novel class of platforms for discrete mathematical operations or tools for natural computation. Here, we report on a novel molecular logic circuit combining exclusive disjunction (XOR) gate and conjunction (AND) gate implemented on a single DNA molecule performing arithmetic operations with simple binary numbers through polymerase chain reactions (PCR); which was inspired by previously developed protein-based computing model allowing simple polynomial algebra over fields through algebraic representation of cyclic inter-conversions in the catalytic modes of a plant enzyme as a cyclic additive group. In addition, we showed that DNA can be used as the platform for image coding and processing leading to DNA-coded animation by using novel PCR-based protocols. Lastly, we discussed the significance of recent attempts in the stream of natural computing and synthetic biological research, by handling DNA and related biomolecules as the media for discrete mathematical operations.

The removal of water from archaeological wooden objects for display or storage is of great importance to their long-term conservation. Any mechanical instability caused during drying can induce warping or cracking of the wood cells, leading to irreparable damage of the object.
Drying of an object is commonly carried out in one of three ways: (i) air-drying with controlled temperature and relative humidity, (ii) drying-out of a non-aqueous solvent or (iii) freeze-drying.
Recently, there has been great interest in the replacement of the standard, but limited, polyethylene glycol with biopolymers for wood conservation; however, their behaviour and action within the wood is not completely understood. Three polysaccharides—low-molar-mass (Mw) chitosan (Mw
ca. 60,000 g/mol), medium-molar-mass alginate (Mw ca. 100,000 g/mol) and cellulose nanocrystals (CNCs)-are investigated in relation to their drying behaviour. The method of drying reveals a significant difference in the morphology of these biopolymers both ex situ and within the wood
cells. Here, the effect these differences in structuration have on the coating of the wood cells and the biological and thermal stability of the wood are examined, as well as the role of the environment in the formation of specific structures. The role these factors play in the selection of appropriate consolidants and drying methods for the conservation of waterlogged archaeological wooden objects is also investigated. The results show that both alginate and chitosan are promising wood consolidants from a structural perspective and both improve the thermal stability of the lignin component of archaeological wood. However, further modification would be necessary to improve the biocidal activity of alginate before it could be introduced into wooden objects. CNCs did not prove to be sufficiently suitable for wood conservation as a result of the analyses performed here.

In today's world, no one can stand without plastic. These ingredients are enormously dependent on several industries including aerospace, food packaging, automotive, plastic shopping bags, and many more. Landfills are full of plastic waste and the accumulation of plastic waste in the environment caused many problems. Plastic shopping bags are made from polyethylene, which causes environmental problems as they are resistant to degradation so they stay in the environment for a long time. In the meantime, there are various options to reduce the environmental problems by increasing the use of biopolymers. In the present study, a mixture of organic compounds of polyethylene and bio-based fillers (sago starch, SS) was prepared. SS was modified with starch cross-linker. Samples with different levels of unmodified starch and the same amount of modified SS was mixed with polyethylene using different additives were fabricated by melt blending method tracked by injection molded to form composites. The loss of tensile strength of the modified composite was less but more elongation at break than unmodified composite, which indicates a good interfacial bond between polyethylene and SS. The biodegradation behavior of these composites was observed in terms of weight loss, morphology, and tensile features during water environment and soil burial.

Due to their small structure and large number of micropores, nanofibers can be employed effectively in a variety of applications, including drug delivery, wound dressing, tissue engineering, filtration, and in cosmetic products. Several fabrication techniques have recently been developed to produce nanofibers. Electrospinning has been widely used owing to its high-degree of flexibility in fabrication and its suitability for use in industrial-scale production. Both synthetic and natural polymers have been employed in the process of electrospinning nanofibers. Natural polymers appear to be particularly attractive materials for use in this process because their structures are similar to those found in extracellular matrices prevalent in the human body, resulting in a compatible interaction with this biological environment. This review summarizes the current development of nanofibers produced from natural polymers and their application in various fields. Fabrication limitations and future application are also considered.

Over 30 million tons of banana peels are thrown away annually worldwide, leading to disposal by burning which is environmentally unfriendly. Strong governments support for environmental conservation and increasing dangers of incineration emissions have directed research into eco-friendly materials. The aim of this research therefore, was to study the utilization of banana peels, a case study of factors affecting viscosity of locally made bio-resin from raw banana peels. The peels were washed, boiled and pureed. Effect of temperature, time, resin, glycerin, and water ratios on bio-resin viscosity were studied through use of the universal rotatable design and multiple regression analysis. Second order polynomial regression equation for viscosity was fitted and exhibited a coefficient of determination (R 2) of 0.95. According to the results obtained in this research paper, resin quantity was the most influential factor towards the desired viscosity of the bio-resin contributing 41% to the regression model. Other factors included water ratio (20%), glycerin ratio (18.6%) among others. The developed bio-resin had an optimized viscosity response value of 242.01 mPa.s within confidence interval limits of 229.6 mPa.s to 254.5 mPa.s. This viscosity value was in a close range to existing commercial resins including maize cornstarch bio-resin and synthetic urea formaldehyde used in reinforced bio-composites development.

Hyaluronic acid (HA)/chitosan (CHI) films were assembled by LbL using different conditions of pH and ionic strength (IS) in order to obtain stable surfaces to avoid the adhesion and proliferation of Pseudomonas aeruginosa and Staphylococcus aureus. The results showed that pH and IS were key synthesis variables for obtaining different features, such as wettability, thickness and the availability of functional groups. The antibacterial effect was more effective against S. aureus with a reduction of approximately 3, 4, and 1.5 log reduction after 4, 8 and 24 h of culture time, respectively. In the case of P. aeruginosa, the films presented a lower bacterial reduction: 1 log reduction in times evaluated. In conclusion, the results of the antibacterial effect against S. aureus after 24 h, suggest that the HA/CHI films assembled by LbL can protect several substrates, such as biomedical devices, against bacterial proliferation.

The aim of this study was to identify and compare the effect of ultrasound (US) and microwave (MW) irradiation on the assisted synthesis reaction to obtain cationic corn and potato starch derivatives, with cationizing agent (3-chloro-2-hydroxypropyl)-trimethylammonium chloride in solution and in limited solvent conditions, known as a paste process. The starch derivatives were characterized by techniques, such as Fourier Transformed
Infrared Spectroscopy, Thermo Gravimetric Analysis, Differential Scanning Calorimetry, Scanning Electron Microscopy and Atomic Force Microscopy.
The application of both (MW) and (US) irradiation as energy sources permitted the shortening of the etherification time to minutes from the
previously reported 18 hours of traditional heating. The results show the high potential of alternative energy sources to innovate and increase the efficiency of a technological starch derivatization process.

The enhancement of the PLA thermomechanical properties is significant due to its suitability as a replacement for primary synthetic polymer use in diverse industrial production. The amphiphilic chitin was used as a compatibilizer in PLA/starch biocomposite. The properties of plasticised polylactic acid blended with starch, and amphiphilic chitin was studied for enhanced thermomechanical and viscoelastic properties. Chitin was modified using acetylated substitution reaction and blended with plasticised PLA/starch biocomposite. The biocomposite was prepared with combined compression and melt extrusion techniques. The biocomposite’s thermomechanical, thermal, mechanical, and morphological properties were studied using dynamic mechanical analysis, TGA-DSC, tensile test, and scanning electron microscopy. The storage and loss modulus were significantly enhanced with increased amphiphilic chitin content. Similarly, the single peak of tan delta showed good miscibility of the polymeric blend. Additionally, the modulus increases with frequency change from 1 Hz to 10 Hz. The thermal stability of the biocomposite was observed to be lower than the neat PLA. The tensile properties of the biocomposite increased significantly more than the neat PLA, with P4S4C having the highest tensile strength and modulus of 87 MPa and 7600 MPa. The SEM images show good miscibility with no significant void in the fractured surface. The viscoelastic properties of PLA were enhanced considerably with plasticizer and amphiphilic chitin with improved biodegradability. The properties of the biocomposite can be adapted for various industrial applications.

Vegetable oil is readily available and inexpensive,  can be used to synthesize various types of polymers. In our present study, epoxidized punnal oil has been synthesized from punnal oil via peroxyacetic acid generated ‘in situ by treating acetic acid with hydrogen peroxide as an oxygen donor. The epoxidation is catalyzed by using sulphuric acid. The epoxidation is confirmed by iodine value, oxirane oxygen analysis, Fourier transform infrared spectroscopy  (FT-IR),  nuclear magnetic resonance  (NMR), and thin-layer chromatography  (TLC)  analysis. Natural fibers such as jute,  sisal,  banana,  rice husk, etc are locally available in abundance and have excellent physical and mechanical properties, and can be used more effectively in the development of composite materials for various applications.  Epoxy composite samples are prepared from the natural fiber with different ratios using triethylamine hardener and phthalic anhydride. The mechanical properties viz. tensile strength and the physical properties observed are discussed in detail.

Patient compliance and safety is of prime importance in case of any drug delivery system. As safety is concern, natural polymers are always better than synthetic and semisynthetic polymers. The reason behind this fact is that all natural polymers are either biodegradable or biocompatible. Unlike synthetic polymers, they are nontoxic, noncarcinogenic and most admiringly ecofriendly. Tamarind Seed Polysaccharide (TSP) is one of such natural polymer which is obtained from seeds of Tamarindus indica. Isolation and characterization of TSP involves simple techniques resulting in lucrative yield in its production. In order to improve the physicochemical properties like heat stability TSP is modified either by physical or chemical method. High drug holding capacity, high swelling index, high thermal stability and improved shelf life are some valuable properties of modified TSP. Due to these remarkable properties TSP has wide range of application from food industry to pharma industry.

The polyelectrolyte complexes (PECs) are versatile formulations formed by electrostatic interactions
between oppositely charged biopolymers. PECs have been investigated widely by the researchers
to explore the virtues of this formulation viz. high biocompatibility, excellent biodegradability, low
toxicity, cost-effective, environment-friendly, and energy-efficient production. The prime object of
the present review is to present the prominent features of PECs including mechanism of PEC
formation, structural models of PECs, interactions involved in PEC formation, steps involved in PEC
fabrication, factors affecting the formation of PECs and applications of PECs. The patents pertaining
to PECs have briefly been tabulated as well.

Natural polymer-based scaffolds can increase cell affinity to biomaterials and improve cell responses. Silk fibroin, chitosan and gelatin that mimic the properties of natural extra-cellular matrix (ECM) were chosen due to their biocompatibility, biodegradability and less immunogenic reactions. We prepared composite scaffolds with different blending ratios of silk fibroin-chitosan-gelatin by freeze-drying technique. Silk fibroin was extracted from the Bombyx mori silkworm. The scaffolds were characterized by scanning electron microscopy (SEM), surface wet-tability, swelling measurements, In Vitro enzymatic degradation measurements and tensile test. The composite scaffolds showed pore sizes from 125 μm to 175 μm, good interconnectivity between pores and suitable porosity which are desirable for cell growth. The addition of chitosan-gelatin to silk fibroin increased water uptake and degradation rate and reduced mechanical strength but silk fibroin affect reversely on the degradation and mechanical strength of composite scaffolds. Biocompatibility of scaffolds was demonstrated by MTT-assay and hematoxylin-eosin (H&E) staining which lead to the growth and adhesion of endothelial cells. In this study, the fabricated composite scaffolds have the potential for tissue engineering applications.

An attempt has been made for the study of some electrical properties of chemically treated coir fiber-reinforced epoxy composites in a systematic way. The hand molding method with chemically treated coir fiber has been adopted to make the epoxy composites reinforced. The electrical properties, such as dielectric constant (e0), and AC conductivity (σac), at different temperatures and frequencies have been reported here and the findings of such properties have been also compared with the predictions of artificial neural networking (ANN) model. We have found from the present study that the obtained results are in good agreement with the simulation of ANN model. Finally, the XRD analysis suggested the crystalline nature of coir fiber-reinforced epoxy composites.

Spider silk is considered as the basis of a new family of high performance fibers that would reproduce the excellent mechanical properties of the silk, in particular its extreme toughness. However, it has been observed that the mechanical properties of spider silk are severely influenced by humid environments that give rise to significant decreases in its length and elastic modulus. The change from stiff to compliant tensile properties is associated with the glass transition from a glassy to a rubbery state; here, we have found that it depends on both temperature and relative humidity. The glass transition was identified at different temperatures and relative humidities by monitoring the variation of the elastic modulus and observing the emergence of supercontraction. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 994–999, 2006

This article investigates the environmental sustainability of plastic nets in agricultural environments based on published experimental data. This article focuses on biodegradable and synthetic plastics used in farms as mulching materials and shade materials/greenhouse covering materials (shade nets and plastic films) to protect plants from pests and extreme weather. The sustainability was determined by three factors, carbon footprint from cradle to the end of life (LCA), durability (resistance to photo-oxidation and high tensile strength), and affordability. The LCA analyses showed that the production of polyethylene (PE) requires less energy and generates low quantities of greenhouse gas equivalents. Beyond the LCA data, biodegradable polymers are sustainable based on biodegradability and compostability, ability to suppress weeds, control soil temperatures, and moisture, and augment fertigation and drip irrigation. However, existing technologies are a limiting factor because lab-b...

We studied the effects of mono-, di-, tri-, and hexamers of glucosamine (GlcN) and N-acetylglucosamine (GlcNAc) on oxidative and calcium signals in transgenic tobacco suspension culture (Nicotiana tabacum L. cv. Bright Yellow-2, cell line CST-1) expressing aequorin. Addition of (GlcN)n to the cells induced an immediate oxidative burst monitored by superoxide-specific chemiluminescence of CLA (CLA-CL). The superoxide generated by (GlcN)n was converted to hydrogen peroxide, causing a transient increase in cytosolic Ca2+ concentration ([Ca2+]c) which was monitored by ([Ca2+]c-dependent luminescence of aequorin. The longer the polymer of (GlcN)n the greater the effect. The (GlcN)n-dependent CLA-CL in the culture was inhibited by a peroxidase inhibitor, but not by a NADPH oxidase inhibitor. The (GlcN)n-dependent CLA-CL was also observed in the extracellularly excreted peroxidase preparation and also in horseradish peroxidase reaction mixture. We have previously obtained similar results using salicylic acid and aromatic amines. Addition of (GlcNAc)n also resulted in an elevation of [Ca2+]c. No superoxide generation preseding [Ca2+]c elevation was detected using CLA, but gradual accumulation of superoxide signal was detected with electron spin resonance spectroscopy using Tiron as a spin trapper. No effect of GlcNAc monomer and oligomers shorter than hexamer on [Ca2+]c elevation or superoxide generation was observed.
In various plants, generation of reactive oxygen species (ROS) is one of the important early events in the active defense against pathogens. ROS can be induced by pathogen invation or treatment with elicitors....

Edible biopolymer (pullulan/carrageenan) based functional composite films were fabricated by the addition of copper sulfide nanoparticles (CuSNP) and D-limonene (DL). The DL and CuSNP were compatible with the pullulan/carrageenan biopolymer matrix. The addition of CuSNP significantly increased the UV-blocking properties without substantially reducing the transparency of the film. The addition of CuSNP improved the film's tensile strength by 10%; however, the DL addition did not significantly influence the strength, while the combined addition of CuSNP and DL increased the strength by 15%. The addition of the fillers did not significantly affect the thermal stability of the film, but the water vapor barrier property was slightly improved. There was no significant change in the moisture content and hydrophobicity of the composite film. Besides, the composite film showed some antimicrobial activity against food-borne pathogenic bacteria. The fabricated pullulan/carrageenan-based film with antimicrobial and UV-barrier properties is likely to be used in active food packaging applications.

Biomaterials for tissue engineering include natural and synthetic polymers, but their clinical application is still limited due to various disadvantages associated with the use of these polymers. This uncertainty of the polymeric approach in tissue engineering launches an opportunity to address a key question: can we eliminate the disadvantages of both natural and synthetic polymers by combining them to form a synergistic relationship? To answer this question, we fabricated scaffolds from elastin, collagen, fibrin, and electrospun polycaprolactone (PCL) with different ratios. The material characterization of these scaffolds investigated degradation, water contact angle, angiogenesis by an ex ovo chorion allantoic membrane (CAM) assay, and mechanical and structural properties. Biological activity and specific differentiation pathways (MSC, adipogenic, osteogenic, myogenic, and chondrogenic) were studied by using human adipose-derived stem cells. Results indicated that all composite polymers degraded at a different rate, thus affecting their mechanical integrity. Cell-based assays demonstrated continual proliferative and viable properties of the cells on all seeded scaffolds with the particular initiation of a differentiation pathway among which the PCL/collagen/fibrin composite was the most angiogenic material with maximum vasculature. We were able to tailor the physical and biological properties of PCL-based composites to form a synergistic relationship for various tissue regeneration applications.

Paliperidone is a well known dopamine antagonist of the atypical antipsychotic class. In present study Paliperidone was formulated as matrix type sustained release tablets using natural polymers. Gum exudates are among the oldest natural polymers. They are already being used as thickening and stabilizing agent from last several years. The plant derived polymers comply with many requirements of pharmaceutical excipients.  The aim of sustained release formulation is to reduce the frequency of dosing. Tablets were prepared by direct compression method. The optimized formulations contain Paliperidone as active ingredient and Guar gum, xanthum gum and Acacia gum are used as polymers. The evaluation parameters include the thickness, weight variation test, drug content, hardness, friability and in vitro release studies. Based on the results of in-vitro studies it was concluded that the natural polymers can be used as an efficient matrix former to provide sustained release of Paliperidone. The release of Paliperidone was prolonged for 20 hrs, indicating the usefulness of the formulations for once daily dosage forms. Thus the reducing frequency of dosing increases patient compliance.

The aim of this study was to identify and compare the effect of ultrasound (US) and microwave (MW) irradiation on the assisted synthesis reaction to obtain cationic corn and potato starch derivatives, with cationizing agent (3-chloro-2-hydroxypropyl)-trimethylammonium chloride in solution and in limited solvent conditions, known as a paste process. The starch derivatives were characterized by techniques, such as Fourier Transformed Infrared Spectroscopy, Thermo Gravimetric Analysis, Differential Scanning Calorimetry, Scanning Electron Microscopy and Atomic Force Microscopy. The application of both (MW) and (US) irradiation as energy sources permitted the shortening of the etherification time to minutes from the previously reported 18 hours of traditional heating. The results show the high potential of alternative energy sources to innovate and increase the efficiency of a technological starch derivatization process.

Biomaterials for Skin Repair and Regeneration examines a range of materials and technologies used for regenerating or repairing skin. With a strong focus on biomaterials and scaffolds, the book also examines the testing and evaluation pathway for human clinical trials.

Beginning by introducing the fundamentals on skin tissue, the book goes on to describe contemporary technology used in skin repair as well as currently available biomaterials suitable for skin tissue repair and regeneration. Skin tissue engineering and the ideal requirements to take into account when developing skin biomaterials are discussed, followed by information on the individual materials used for skin repair and regeneration. As evaluation of biomaterials in animal models is mandatory before proceeding into human clinical trials, the book also examines the different animal models available.

With a strong focus on materials, engineering, and application, this book is a valuable resource for materials scientists, skin biologists, and bioengineers with an interest in tissue engineering, regeneration, and repair of skin.