High Degree Of Acetylation Research Articles

Anatomical distribution of histone H3 acetylation in human hippocampus

In recent years, the role of histone acetylation in the brain has been studied from different aspects. However, the anatomical distribution of histone H3 acetylation in the human hippocampus and its potential relevance to triple synaptic circuits are unknown. As one of epigenetic remodeling ways, the modification of histones is involved in multiple aspects of neuronal function and development and is a key process in the onset and development of Alzheimer’s disease (AD). In our study, we compared acetylation levels of histone H3 at different regions of the hippocampus in AD and non-AD patients. We found that histone H3 acetylation can be detected in the dentate gyrus (DG), CA4, CA3, CA2, CA1, and lower Toya regions of the human hippocampus. The highest degree of acetylation in the hippocampus is in DG, and the level of acetylation changes gradually and systematically along the triple synaptic circuit. Besides, there were no significant differences in histone acetylation between AD and non-AD groups.

Chitosan-coated liposomal systems for delivery of antibacterial peptide LL17-32 to Porphyromonas gingivalis

Periodontal disease is triggered by surface bacterial biofilms where bacteria are less susceptible to antibiotic treatment. The development of liposome-based delivery mechanisms for the therapeutic use of antimicrobial peptides is an attractive alternative in this regard. The cationic antimicrobial peptide LL-37 (human cathelicidin) is well-known to exert antibacterial activity against Porphyromonasgingivalis, a keystone oral pathogen. However, the antibacterial activity of the 16-amino acid fragment (LL17-32) of LL-37, is unknown. In addition, there are still gaps in studies using liposomal formulations as delivery vehicles of antibacterial peptides against this pathogen. This study was designed to examine the influence of the different types of liposomal formulations to associate and deliver LL17-32 to act against P. gingivalis. Chitosans of varying Mw and degree of acetylation (DA) were adsorbed at the surface of soya lecithin (SL) liposomes. Their bulk (average hydrodynamic size, ζ-potential and membrane fluidity) and ultrastructural (d-spacing, half-bilayer thickness and the water layer thickness) biophysical properties were investigated by a panel of techniques (DLS, SAXS, M3-PALS, fluorescence spectroscopy and TEM imaging). Their association efficiency, in vitro release, stability, and efficacy in killing the periodontal pathogen P. gingivalis were also investigated. All liposomal systems possessed spherical morphologies and good shelf-life stabilities. Under physiological conditions, chitosan formulations with a high DA demonstrated enhanced stability in comparison to low DA-chitosan formulations. Chitosans and LL17-32 both decreased SL-liposomal membrane fluidity. LL17-32 exhibited a high degree of association with SL-liposomes without in vitro release. In biological studies, free LL17-32 or chitosans alone, demonstrated microbicidal activity against P. gingivalis, however this was attenuated when LL17-32 was loaded onto the SL-liposome delivery system, presumably due to the restrained release of the peptide. A property that could be harnessed in future studies (e.g., oral mucoadhesive slow-release formulations).

“MD” method for the precise analysis of the O-acetyl-mannan structure and disclosure of the role in the conformational stability of insulin

Among the diversified glycan modifications, acylation is one of the most abundant. This modification could be responsible for many of the properties of glycans, such as structural stability and specificity for biological activity. To obtain better insight into the effects of acetylation of glycans on the structure and thermostability of insulin, it is critical to investigate glycans with a high degree of acetylation. An in-depth study of three functional glycans named acetyl-mannan from Dendrobium devonianum (DDAM) was conducted herein by efficient enzymatic depolymerization, and the effect of glycosidic bonds on acetylation modification sites was studied through a molecular dynamics (MD) method, as well as its positive effect on insulin secretion, glucose uptake, and the thermal stability of tertiary structures in vitro. Further study indicated that DDAMs play a hypoglycemic role by sparking the thermostability of the insulin conformation. The hypoglycemic activity displayed a positive correlation with the degree of acetylation in DDAMs. In this work, through the MD method, we confirmed the structure characteristics of DDAMs and provided accurate data support for the structure-activity relationship analysis. Thus, these findings demonstrated that DDAMs might be an exceptional leading compound for the stability of insulin drug.

Insights into the enhanced mechanism of electron beam pretreatment on application performance for poly (butylene adipate-co-terephthalate)/acetylated cellulose composite plastics

In this work, we developed a strategy to construct poly (butylene adipate-co-terephthalate) (PBAT) composite plastics with excellent mechanical properties, superior thermal stability and enhanced biodegradability by combining acetylated celluloses (ECs) mediated by electron beam irradiation (EBI), which works as a toughening agent. With findings, the EBI pretreatment assisted with acetylation was applied to develop ECs materials with a higher degree of acetylation than acetylation alone. The pretreated ECs with increased hydrophobicity tended to decrease the chance of self-aggregation and enhanced the interfacial compatibility and adhesion with PBAT in PBAT/ECs composite plastics. Thus, PBAT/ECs composite plastics exhibited a smoother and more uniform surface structure during preparation and offered higher tensile strength, water vapor transmission rate, water absorption rate, thermal stability and degradation rate, and lower elongation at a break during application. On top of that, the PBAT/ECs composite plastics were characterized by a series of methods containing Fourier transform infrared spectroscopy and X-ray diffraction, indicating that these properties are mainly caused by the acetylation of hydroxyl groups from cellulose and carboxyl groups of PBAT. The work is expected to expand the application scope of PBAT and cellulose and provide an attainable solution for a biodegradable substitute for traditional plastics.

Structure and properties of sulfopropyl chitins prepared in NaOH/urea aqueous solutions

A series of sulfopropyl chitins (SCs) with the degree of substitution (DS) ranging from 0.11 to 0.40 and high degree of acetylation (DA ≥ 0.82) were homogeneously synthesized by reacting chitin with sodium 3-chloro-2-hydroxypropanesulfonate (SCHPS) in NaOH/urea aqueous solutions under mild conditions. The structure and properties of SCs were characterized with 1H NMR, CP/MAS 13C NMR, FT-IR, XPS, XRD, elemental analysis, GPC, AFM, ζ-potential and rheological measurements. The mild reaction conditions resulted in less N-deacetylation and uniform structures with substitution occurring predominantly at the hydroxyl groups at C6 of the chitin backbone. The DS value for SC soluble in dilute alkali solution is as low as 0.16. SC exhibited good solubility in distilled water when its DS value reached 0.28. Water-soluble SCs self-assembled in water into micelles by the attractive hydrophobic and hydrogen-bonding interactions between polymer chains. The water-insoluble SC-2 with lower DS could thermally form smart hydrogels at body temperature (37 °C) in physiological condition. Moreover, the SCs exhibited good biocompatibility, making them suitable for biomedical applications.

Comparative Lysine Acetylome Analysis of Y. pestis YfiQ/CobB Mutants Reveals that Acetylation of SlyA Lys73 Significantly Promotes Biofilm Formation of Y. pestis.

Increasing evidence shows that protein lysine acetylation is involved in almost every aspect of cellular physiology in bacteria. Yersinia pestis is a flea-borne pathogen responsible for millions of human deaths in three global pandemics. However, the functional role of lysine acetylation in this pathogen remains unclear. Here, we found more acetylated proteins and a higher degree of acetylation in Y. pestis grown under mammalian host (Mh) conditions than under flea vector (Fv) conditions, suggesting that protein acetylation could significantly change during fleabite transmission. Comparative acetylome analysis of mutants of YfiQ and CobB, the major acetyltransferase and deacetylase of Y. pestis, respectively, identified 23 YfiQ-dependent and 315 CobB-dependent acetylated proteins. Further results demonstrated that acetylation of Lys73 of the SlyA protein, a MarR-family transcriptional regulator, inhibits its binding to the promoter of target genes, including hmsT that encodes diguanylate cyclase responsible for the synthesis of c-di-GMP, and significantly enhances biofilm formation of Y. pestis. Our study presents the first extensive acetylome data of Y. pestis and a critical resource for the functional study of lysine acetylation in this pathogen. IMPORTANCE Yersinia pestis is the etiological agent of plague, historically responsible for three global pandemics. The 2017 plague epidemic in Madagascar was a reminder that Y. pestis remains a real threat in many parts of the world. Plague is a zoonotic disease that primarily infects rodents via fleabite, and transmission of Y. pestis from infected fleas to mammals requires rapid adaptive responses to adverse host environments to establish infection. Our study provides the first global profiling of lysine acetylation derived from mass spectrometry analysis in Y. pestis. Our data set can serve as a critical resource for the functional study of lysine acetylation in Y. pestis and provides new molecular insight into the physiological role of lysine acetylation in proteins. More importantly, we found that acetylation of Lys73 of SlyA significantly promotes biofilm formation of Y. pestis, indicating that bacteria can use lysine acetylation to fine-tune the expression of genes to improve adaptation.

Grafted chitosan thin films of various degrees of acetylation as a reusable platform for the investigation of biological interactions

Surface treatment by adhesive polymers is a promising solution to immobilize and study bacteria cells through microscopic assays and, for example, control their growth or determine their susceptibility to antibiotic treatment. The stability of such functional films in wet conditions is crucial, as the film degradation would compromise a persistent use of the coated devices. In this work, low roughness chitosan thin films of degrees of acetylation (DA) ranging from 0.5 % to 49 % were chemically grafted onto silicon and glass substrates and we have demonstrated how the physicochemical properties of the surfaces and the bacterial response were DA-dependent. A fully deacetylated chitosan film presented an anhydrous crystalline structure while the hydrated crystalline allomorph was the preferred structure at higher DA. Moreover, their hydrophilicity increased at higher DA, leading to higher film swelling. Low DA chitosan-grafted substrate favored bacterial growth away from the surface and could be envisioned as bacteriostatic surfaces. Contrarily, an optimum of Escherichia coli adhesion was found for substrates modified with chitosan of DA = 35 %: these surfaces are adapted for the study of bacterial growth and antibiotic testing, with the possibility of reusing the substrates without affecting the grafted film – ideal for limiting single-use devices.

Synthesis and characterization of reversible thermosensitive methylated chitin and its application in zinc‐ion battery thermal runaway

AbstractNovel water‐soluble methylated chitins (MCHs) were synthesized homogeneously in aqueous alkaline solution. The relatively mild reaction conditions resulted in the MCH with high degree of acetylation (DA >0.76). The chemical structure of the obtained MCHs was analyzed and the degree of methylation substitution (DS) and DA were determined by proton NMR in both D2O and 20% DCl/D2O. The MCH aqueous solutions (DS = 0.46 ~ 0.71) showed a reversible thermosensitive sol–gel–sol transition upon heating and cooling. The gel transition temperature of these MCHs (in the range of 15–85 °C) increased with increasing DS and decreasing polymer concentration. Thermal runaway has been an important safety issue impeding the development of high‐energy‐density zinc‐ion batteries. A smart thermosensitive reversible electrolyte was prepared based on this MCH for the aqueous zinc‐ion battery to prevent thermal runaway. When the temperature of zinc‐ion battery rises or even gets out of control, the thermosensitive electrolyte can quickly gel and inhibit the migration of zinc ions, resulting in increase of the internal resistance and realizing intelligent and efficient thermal self‐protection. Thus the novel thermosensitive methylated chitin shows promise for safe aqueous zinc‐ion batteries.

Comparison and the lipid-lowering ability evaluation method discussion of Dendrobium officinale polysaccharides from different origins based on principal component analysis

As typical acetylated glucomannans, Dendrobium officinale polysaccharides (DOPs) from different origins differ in their structural characteristics and some of their physicochemical properties. To rapidly select D. officinale plants, we systematically investigate the differences among DOPs from different origins and analyzed the structural characteristics, such as the degree of acetylation and monosaccharide composition; the physicochemical properties, such as solubility, water absorption and apparent viscosity; and the lipid-lowering activity of the obtained DOPs. Principal component analysis (PCA), a method for analyzing multiple variables, was used to analyze the relationship between the physicochemical and structural properties, and lipid-lowering activity. It was found that the structural and physicochemical characteristics had significant effects on lipid-lowering activity, and DOPs with a high degree of acetylation, high apparent viscosity and large D-mannose-to-d-glucose ratio were associated with greater lipid-lowering activity. Therefore, this study provides a reference for the selection and application of D. officinale.

A New Functional Food Ingredient Obtained from Aloe ferox by Spray Drying.

Aloe mucilages of Aloe ferox (A. ferox) and Aloe vera (A. vera) were spray-dried (SD) at 150, 160 and 170 °C. Polysaccharide composition, total phenolic compounds (TPC), antioxidant capacity and functional properties (FP) were determined. A. ferox polysaccharides were comprised mainly of mannose, accounting for >70% of SD aloe mucilages; similar results were observed for A. vera. Further, an acetylated mannan with a degree of acetylation >90% was detected in A. ferox by 1H NMR and FTIR. SD increased the TPC as well as the antioxidant capacity of A. ferox measured by both ABTS and DPPH methods, in particular by ~30%, ~28% and ~35%, respectively, whereas in A. vera, the antioxidant capacity measured by ABTS was reduced (>20%) as a consequence of SD. Further, FP, such as swelling, increased around 25% when A. ferox was spray-dried at 160 °C, while water retention and fat adsorption capacities exhibited lower values when the drying temperature increased. The occurrence of an acetylated mannan with a high degree of acetylation, together with the enhanced antioxidant capacity, suggests that SD A. ferox could be a valuable alternative raw material for the development of new functional food ingredients based on Aloe plants.

Comparison of the Degree of Acetylation of Chitin Nanocrystals Measured by Various Analysis Methods.

Chitin and its derivate chitosan have versatile properties and have been used in various applications. One key parameter determining the functionality of chitin-based materials is the degree of acetylation (DA). For DA determination, NMR and FTIR spectroscopy are often considered to be the gold standard, but these techniques may not always be available and are rather time-consuming and costly. The first derivative UV method has been suggested, although accurate measurements can be challenging for materials with high degrees of acetylation, due to hydroxymethylfurfural (HMF) formation and other side reactions occurring. In this paper, we re-evaluated the first derivate UV method for chitin and chitosan powder, chitin nanocrystals, and deacetylated chitin nanocrystals. Our results showed that the first derivative UV method is capable of measuring DA with high accuracy (>0.9), leading to values comparable to those obtained by 1H NMR, 13C NMR, and FTIR. Moreover, by-product formation could either be suppressed by selecting the proper experimental conditions, or be compensated. For chitin nanocrystals, DA calculation deviations up to 20% due to by-product formation can be avoided with the correction that we propose. We conclude that the first derivative UV method is an accessible method for DA quantification, provided that sample solubility is warranted.

Spheronized drug microcarrier system from canola straw lignin

ABSTRACT Inhomogeneous lignin from a canola (rapeseed) straw was isolated and valorized as regularly shaped spherical microparticles for drug delivery formulations. Lignin with a purity of 83% and broad molecular weight distribution (Ð > 5.0) was extracted by alkali pulping and acetylated to increase spheronization ability. Lignins with high degrees of acetylation (0.76 and 0.89) were successfully assembled into microparticles with uniform sizes (approximately 2 μm) and smooth spherical surfaces via solvent–antisolvent precipitation. Hydrophobic coumarin 153 and positively charged ciprofloxacin were used as model drugs to assess the encapsulation and release performance of lignin microparticles. Highly acetylated lignin microparticles displayed encapsulation efficiencies of 89.6% for coumarin 153% and 90.6% for ciprofloxacin. Scanning electron microscope images showed that coumarin 153 was encapsulated in the hydrophobic core, while ciprofloxacin was adsorbed on the less hydrophobic shell. The synthesis of lignin microcarriers not only provides a facile approach to utilizing waste canola straw lignin for drug delivery matrices but also has the potential to serve as an alternative lignin powder feedstock for bio-based materials.

Facile nanofibrillation of strong bamboo holocellulose via mild acid-assisted DES treatment

A facile and sustainable strategy for preparing bamboo holocellulose nanofibrils (HCNFs) via zinc acetate/ choline chloride deep eutectic solvents treatment assisted with mild acetic acid (HAc) was developed in the present work. The treatment was performed under fast microwave irradiation and followed by mechanical homogenization , resulting in HCNFs with considerable amounts of xylan hemicellulose (15 %−19 %) remained. Less HAc consumption was achieved, which is beneficial for fabricating nanofibrils with higher aspect ratios (>800). More xylan contents and higher degrees of acetylation on cellulose were investigated, resulting in greater charge repulsion and steric hindrance between HCNFs and favoring the fibrils dissociation. Moreover, the HCNFs maintained high crystallinity of 70 %− 80 % and good thermal stability, confirming the intact hydrogen bonding linkages between cellulose and xylan hemicellulose. Transparent films prepared from the HCNFs suspensions by vacuum drying approach displayed better mechanical strength (>40 MPa) and well-mimicked the complex of polysaccharides interactions in plant cell walls. • Bamboo HCNFs were prepared by ZnAc/ChCl DES with mild HAc and microwave assistance. • Acetylation and charge repulsion favored the holocellulose nanofibrillated. • Higher DES ratios fabricated HCNFs with greater aspect ratios and xylan content. • HCNFs films present high transparency and improved mechanical strength.

Optimizing yield and chemical compositions of dimethylsulfoxide-extracted birchwood xylan

Dimethylsulfoxide (DMSO) extraction is commonly used to study the chemical structures of original xylan in the plant cell wall, since the DMSO can preserve the original structure of the xylan as much as possible during the extracting process. In addition, the DMSO-extracted xylans have unique properties allowing their potential applications in emulsifying or filming materials. However, the yield of DMSO-extracted xylan is always low and the effects of different DMSO extraction conditions on the chemical compositions of xylan have not been fully studied, which greatly hinders its researches and applications. In this study, we have found that extensive delignification before DMSO extraction results in destruction of lignin-carbohydrate complex (LCC), leading to xylan yield and xylose unit content increased by up to 220% and 20%, respectively. Tert-butanol washing of the holocellulose can further increase the DMSO extracted xylan yield by ∼10%. The yield of xylan extracted by the DMSO at 80 °C for 7 h was obviously higher than that at room temperature for 3 d by 30%–40%. Thermal analysis showed that the xylans extracted at different conditions had thermal stability without obvious differences. The results indicate that the DMSO-extracted xylan with a high yield, a high purity and a high degree of acetylation can be extracted at a high delignification level, a high reaction temperature and a short reaction time. This study is of great significance for studying xylan structure-property relationships and promoting the applications of DMSO-extracted xylan.

Raman Study of Pathogenic Candida auris: Imaging Metabolic Machineries in Reaction to Antifungal Drugs

The multidrug-resistant Candida auris often defies treatments and presently represents a worldwide public health threat. Currently, the ergosterol-targeting Amphotericin B (AmB) and the DNA/RNA-synthesis inhibitor 5-flucytosine (5-FC) are the two main drugs available for first-line defense against life-threatening Candida auris infections. However, important aspects of their mechanisms of action require further clarification, especially regarding metabolic reactions of yeast cells. Here, we applied Raman spectroscopy empowered with specifically tailored machine-learning algorithms to monitor and to image in situ the susceptibility of two Candida auris clades to different antifungal drugs (LSEM 0643 or JCM15448T, belonging to the East Asian Clade II; and, LSEM 3673 belonging to the South African Clade III). Raman characterizations provided new details on the mechanisms of action against Candida auris Clades II and III, while also unfolding differences in their metabolic reactions to different drugs. AmB treatment induced biofilm formation in both clades, but the formed biofilms showed different structures: a dense and continuous biofilm structure in Clade II, and an extra-cellular matrix with a “fluffy” and discontinuous structure in Clade III. Treatment with 5-FC caused no biofilm formation but yeast-to-hyphal or pseudo-hyphal morphogenesis in both clades. Clade III showed a superior capacity in reducing membrane permeability to the drug through chemically tailoring chitin structure with a high degree of acetylation and fatty acids networks with significantly elongated chains. This study shows the suitability of the in situ Raman method in characterizing susceptibility and stress response of different C. auris clades to antifungal drugs, thus opening a path to identifying novel clinical solutions counteracting the spread of these alarming pathogens.

Microwave-Assisted Synthesis of Lactose Acetates with Antimicrobial, Cytotoxic, and Antiviral Properties

The task of this study was to perform the "green" synthesis of lactose octaacetate through microwave irradiation and to establish their biological activities. Lactose ester was prepared after microwave-assisted esterification of lactose with acetic anhydride (yield 85-90 %). Lactose octaacetate was characterized by a high degree of acetylation (DS 3.2-3.7). The lactose esters' structure was elucidated by infrared spectroscopy and nuclear magnetic resonance spectroscopy. Lactose octaacetate showed better antifungal activities than antibacterial activities. It possessed slight to moderate antifungal activities against Aspergillus niger ATCC 1015, Penicillium sp., Rhizopus sp., Fusarium moniliforme ATCC 38932. Lactose acetates demonstrated low cytotoxicity against three cell lines: Madin-Darby bovine kidney (MDBK) cells, human epithelial type 2 (HEp-2), and Madin-Darby canine kidney (MDCK) cells. This is the first report for antiviral activity of lactose acetates against herpes simplex virus type 1 (HSV-1), influenza virus A/Panama/2007/99/H3N2 - (IAV/H3N2), PV-1 and Coxsackievirus B1. It was found that this compound showed activity with SI = 2.4 only against PV-1, but against HSV-1, IAV/H3N2, and Coxsackievirus B1 was inactive. The current study demonstrated the applications of lactose acetates as antimicrobial and antiviral substances in food, pharmaceutical, agricultural and cosmetic preparations.

Integrative analysis of multiomics data identified acetylation as key variable of excessive energy metabolism in hyperthyroidism-induced osteoporosis rats

BackgroundResults from the previous experiment have demonstrated bone loss and excess metabolism in Hyperthyroidism-induced rats. Thus, an underlying relationship between metabolism and bone loss was speculated. In addition, previous studies have shown the influence of acetylation on metabolism in tissues and diseases. The hypothesis from this case study suggests that excessive metabolism is induced by acetylation of vital metabolism enzymes. ResultsIn the case study, a HYP-induced osteoporosis rat model was used and the glucose metabolite was tested through the acetylation of proteins by the mass spectrometer. The results showed that pivotal enzymes of Glycolysis-Tricarboxylic acid cycle-Oxidative phosphorylation were acetylated along with upregulated metabolites. With all acetyly-lysine sites of related enzymes listed, the results in this study showed that bone loss in HYP rats was accompanied by the upregulation of CREB-binding protein (Crebbp, CBP). Furthermore, it is also indicated that CBP has a close relationship with the enhancement of LDHA which promotes glucose metabolism. ConclusionsAcetylation is highly correlated with excessive energy metabolism in HYP-induced osteoporotic rats, where a representation relationship between CBP and LDHA is demonstrated. SignificanceHyperthyroidism may lead to osteoporosis. Our study found an interesting phenomenon of hyperthyroidism induced-osteoporosis is that osteoporosis is accompanied by excessive glucose metabolism. In this process, some molecular mechanisms are still unclear. This study indicates a high degree of acetylation of metabolic enzymes, which may be closely related to excessive glucose metabolism. The relationship between CBP and LDHA was also investigated in this study, which showed that CBP and LDHA had some extent interaction. Glucose metabolism and acetylation maybe all associated with hyperthyroidism induced-osteoporosis. This data provides new insights into the molecular mechanisms of hyperthyroidism induced-osteoporosis.

Macrophage polarization in vitro and in vivo modified by contact with fragmented chitosan hydrogel.

We have previously shown that implantation of a fragmented chitosan hydrogel suspension (chitosan-FPHS) into a traumatic spinal cord lesion in adult rats led to significant axon regrowth and functional recovery, which was associated to a modulation of inflammation. Using an in vitro culture system, we show here that polarization of bone marrow-derived macrophages is indeed modified by direct contact with chitosan-FPHS. Reducing the degree of acetylation (DA) and raising the concentration of chitosan (Cp, from 1.5% to 3%), favors macrophage polarization toward anti-inflammatory subtypes. These latter also migrate and adhere efficiently on low, but not high DA chitosan-FPHS, both in vitro and in vivo, while inflammatory macrophages rarely invade a chitosan-FPHS implant in vivo, no matter the DA. Our in vitro model setup should prove a valuable tool for screening diverse biomaterial formulations and combinations thereof for their inflammatory potential prior to implantation in vivo.

Electrosteric stabilization of oil/water emulsions by adsorption of chitosan oligosaccharides—An electrokinetic study

The present study was focused on investigation of electrokinetic behaviour of lecithin-stabilized oil/water emulsions in the presence of chitosan oligosaccharides (COS). The oligosaccharides give unique opportunity for precisely characterization of the properties of chitosan as a function of the degree of acetylation (DA) and degree of polymerization (DP) of the polymer. For the study were chosen well characterized ultra pure COS molecules with completely acetylated monomers and mixture of COS molecules with acetylated and deacetylated monomers. The obtained results confirmed experimentally for the first time, the suggestion for the predominant contribution of hydrophobic (at high DA) and electrostatic (at low DA) interactions between chitosan monomers and the lecithin-covered droplet surface.

Surface coating of chitosan of different degree of acetylation on non surface sized writing and printing grade paper

Chitosan is a renewable biopolymer which can be applied on the surface of writing and printing (W&P) grade paper to enhance its different properties. A variety of chitosan is available based on degree of acetylation (DA), molecular weight, viscosity, etc. DA has a profound effect on the performance of chitosan in many applications. Present study compared the performance of different DA chitosan for surface application of W&P grade paper. Chitosan samples of 23 %, 16 % and 6% DA were studied for their impact on various physical and surface properties of W&P grade paper. Surface coating of chitosan was done at 1.6 ± 0.2 g/m2 (lower dose) and 2.3 ± 0.3 g/m2 (higher dose) on W&P grade paper. Some properties including air permeance, TEA, showed considerable effect of DA in which high DA chitosan outperformed the low DA. Broadly, chitosan with different DA had varied impact on individual properties of paper.