Role Of Chitosan Research Articles

Development of a microemulsion for encapsulation and delivery of gallic acid. The role of chitosan

A novel water-in-oil (W/O) microemulsion based on natural oils, namely extra virgin olive oil (EVOO) and sunflower oil (SO), in the presence of non-ionic surfactants was successfully formulated. The novel microemulsion was used as a carrier for gallic acid (GA) to assure its protection and efficacy upon nasal administration. The work presents evidence that this microemulsion can be used as a nasal formulation for the delivery of polar antioxidants, especially, after incorporation of chitosan (CH) in its aqueous phase. The structure of the system was studied by Small Angle X-ray Scattering (SAXS), Dynamic Light Scattering (DLS) and Electron Paramagnetic Resonance (EPR) spectroscopy techniques. By the addition of CH, the diameter of the microemulsion remained unaltered at 47 nm whereas after the incorporation of GA, micelles with 51 nm diameter were detected. The dynamic properties of the surfactant monolayer were affected by both the incorporation of CH and GA. Moreover, the antioxidant activity of the latter remained unaltered (99 %). RPMI 2650 cell line was used as the in vitro model for cell viability and for GA nasal epithelial transport studies after microemulsion administration. The results suggested that the nasal epithelial permeation of GA was enhanced, 3 h post administration, by the presence of 0.2 % v/v microemulsion in the culture medium. However, the concentration of the transported antioxidant in the presence of CH was higher indicating the polymer’s effect on the transport of the GA. The study revealed that nasal administration of hydrophilic antioxidants could be used as an alternative route besides oral administration.

Role of Chitosan In Lymphoedema

Lymphoedema is a chronic problem with various skin changes that lead to impaired care for the affected limb. These skin changes also lead to recurrent infections. The difficulty in care and the subsequent neglect leads to further spread of the infection and increased risk of future infections. Prevention of infections and prevention of progress of the skin changes is one of the main components of the treatment of the lymphoedema. There are various materials available to enhance the healing of the knobs and fissures secondary to lymphoedema. We would like to present our case report on the usage of chitosan in a patient with stage 7 skin changes of lymphedema.

What Are the Functions of Chitin Deacetylases in Aspergillus fumigatus?

Deacetylation of chitin by chitin deacetylases (Cda) results in the formation of chitosan. Chitosan, a polymer of β1,4 linked glucosamine, plays multiple roles in the function of the fungal cell wall, including virulence and evasion of host immune responses. In this study, the roles of chitosan and putative CDAs in cell wall structure and virulence of Aspergillus fumigatus were investigated. Low levels of chitosan were found in the conidial and cell wall of A. fumigatus. Seven putative CDA genes were identified, disrupted and the phenotype of the single mutants and the septuple mutants were investigated. No alterations in fungal cell wall chitosan levels, changes in fungal growth or alterations in virulence were detected in the single or septuple Δcda1-7 mutant strains. Collectively, these results suggest that chitosan is a minority component of the A. fumigatus cell wall, and that the seven candidate Cda proteins do not play major roles in fungal cell wall synthesis or virulence. However, Cda2 is involved in conidiation, suggesting that this enzyme may play a role in N-acetyl-glucosamine metabolism.

Role of chitosan and some plant parts wraps as alternative interior edible coat surrounding semi-hard cheese in inhibiting fungal growth and mycotoxins migration

Food packaging is a part of food preservation concept. Exposed surfaces of cheese are vulnerable to mold contamination from several sources. Thus, cheese spoilage is generally confined to molds. Two mycotoxigenic fungal isolates were used in this study Penicillium citrinum and Penicillium verrocosum, a new method was applied in this study as a safe alternative composite coat to conventional internal coat (EVOH) in semi-hard cheese (Gouda). The new chitosan composite coat is based on chitosan/potato starch and/or thyme and safflower powders. These new coats are adjusted for thickness homogeneity, using the standard methods of ASTM with certain modification. This study aimed at investigating the effects of these wraps and the conventional coat on fungal growth and mycotoxins migration to cheese. Our results illustrated that the use of chitosan coat alone or enriched with HPPs succeeded in controlling the growth of the tested fungi invading cheese and significantly reducing the mycotoxins migrated amounts to cheese. The addition of this plant material (HPPs) ameliorated the capability of EVOH to reduce fungal growth and the majority of the tested mycotoxins migration amounts. Our results may achieve a significant impact on shelf-life extension and cheese safety during transport and trade when the addition of HPPs is applied.

Chitosan is a potential inhibitor of ovarian cancer: Molecular aspects.

Although ovarian cancer has a lower prevalence than breast cancer, its mortality rate is three times higher, which is reported to increase in the coming years. As the early stages of ovarian cancer do not have any obvious symptoms, in most of the cases, this cancer is diagnosed at advanced stages with a poor prognosis. Moreover, in many patients who are diagnosed with advanced stage, relapse of the disease and drug resistance are observed. Over the past years, these women have been treated with chemotherapy and cytoreductive surgeries. However, the chemotherapy could affect the healthy tissues in addition to the malignancies. Therefore, discovering new diagnostic and therapeutic options seems to be a crucial need. Unlike the common invasive and/or nonspecific treatments, nanomedicine is trying to find a new way for cancer imaging, diagnosis, and drug delivery method. Nanoparticles (NPs), which has recently drawn attention, can be used in order to reduce the toxicity and frequent dosing of drugs, tumor-specific delivery, and early diagnosis for malignancies. Chitosan as an NP and product of chitin deacetylation has multiple characteristics, including biocompatibility, biodegradability, and safety. In this review, we cover the studies concerned with the role of chitosan in finding solutions to overcome the problems faced in ovarian cancer treatments. Furthermore, we highlight how chitosan is being used in delivering chemotherapy drugs, gene therapy, and imaging methods for both detection and image-guided therapies.

Role of chitosan and transglutaminase on the elaboration of gluten-free bread.

The increasing sensitivity to gluten has aroused interest in gluten-free products like bread. However, one of the biggest challenges of producing gluten-free bread is to get a good quality structure. We hypothesize that using chitosan along with transglutaminase, a network of crosslinks would be generated, guaranteeing a better structure. Thus, in the present work, we produced gluten-free bread using red rice flour and cassava flour, transglutaminase, and chitosan at concentrations of 0%, 1%, and 2%. Loaves of bread were characterized, and the instrumental texture properties during five days were determined. Bread produced with chitosan and transglutaminase presented lighter brown coloration due to incomplete Maillard reaction and low specific volumes varying from 1.64 to 1.48cm3/g, possibly due to chitosan interfering with yeast fermentation. Rheological tests revealed increases in viscosity before and after fermentation when chitosan was used. Bread with chitosan presented high initial firmness but a lower rate of staling, possibly due to water retention. According to results, a possible network involving chitosan and other proteins promoted by transglutaminase was formed and after optimization could yield better gluten-free bread.

The Role of Chitosan as a Possible Agent for Enteric Methane Mitigation in Ruminants

Simple SummaryRuminant husbandry is one the largest contributors to greenhouse gas emissions from the agriculture sector, particularly of methane gas, which is a byproduct of the anaerobic fermentation of structural and non-structural carbohydrates in the rumen. Increasing the efficiency of production systems and decreasing its environmental burden is a global commitment, thus methane mitigation is a strategy in which to reach these goals by rechanneling metabolic hydrogen (H2) into volatile fatty acids (VFA) to reduce the loss of energy as methane in the rumen, which ranges from 2% (grain rations) to 12% (poor-quality forage rations) of gross energy intake. A strategy to achieve that goal may be through the manipulation of rumen fermentation with natural compounds such as chitosan. In this review, we describe the effects of chitosan on feed intake and rumen fermentation, and present some results on methanogenesis. The main compounds with antimethanogenic properties are the secondary metabolites, which are generally classified into five main groups: saponins, tannins, essential oils, organosulfurized compounds, and flavonoids. Novel compounds of interest include chitosan obtained by the deacetylation of chitin, with beneficial properties such as biocompatibility, biodegradability, non-toxicity, and chelation of metal ions. This compound has shown its potential to modify the rumen microbiome, improve nitrogen (N) metabolism, and mitigate enteric methane (CH4) under some circumstances. Further evaluations in vivo are necessary at different doses in ruminant species as well as the economic evaluation of its incorporation in practical rations.Livestock production is a main source of anthropogenic greenhouse gases (GHG). The main gases are CH4 with a global warming potential (GWP) 25 times and nitrous oxide (N2O) with a GWP 298 times, that of carbon dioxide (CO2) arising from enteric fermentation or from manure management, respectively. In fact, CH4 is the second most important GHG emitted globally. This current scenario has increased the concerns about global warming and encouraged the development of intensive research on different natural compounds to be used as feed additives in ruminant rations and modify the rumen ecosystem, fermentation pattern, and mitigate enteric CH4. The compounds most studied are the secondary metabolites of plants, which include a vast array of chemical substances like polyphenols and saponins that are present in plant tissues of different species, but the results are not consistent, and the extraction cost has constrained their utilization in practical animal feeding. Other new compounds of interest include polysaccharide biopolymers such as chitosan, mainly obtained as a marine co-product. As with other compounds, the effect of chitosan on the rumen microbial population depends on the source, purity, dose, process of extraction, and storage. In addition, it is important to identify compounds without adverse effects on rumen fermentation. The present review is aimed at providing information about chitosan for dietary manipulation to be considered for future studies to mitigate enteric methane and reduce the environmental impact of GHGs arising from livestock production systems. Chitosan is a promising agent with methane mitigating effects, but further research is required with in vivo models to establish effective daily doses without any detrimental effect to the animal and consider its addition in practical rations as well as the economic cost of methane mitigation.

Improved mechanical, physical and biological properties of chitosan films using Aloe vera and electrospun PVA nanofibers for wound dressing applications

Natural polymers such as chitosan and Aloe vera are widely used in novel wound dressings due to their biocompatibility and biodegradability. A problem associated with these polymers is their poor mechanical behavior. Efforts have been made to improve the mechanical properties by mixing synthetic polymers such as PVA, but the role of chitosan and Aloe vera in the final dressing is dimmed. The techniques are also time-consuming and costly and there is still a need for an acceptable and affordable wound dressing which can be made through easily accessible techniques. A new but very simple method is introduced in this work for incorporating PVA nanofibers with Aloe vera-containing chitosan films. Using this method the levels of Aloe vera and chitosan in the system can be optimized at higher scales while benefiting from PVA best mechanical properties as a composite layer. Higher amounts of Aloe vera and chitosan in the system lead to lower product costs and more biocompability. The biological properties of films were examined through cell cytotoxicity and antibacterial tests and compared with Atomic force microscopy results. Physical and mechanical properties of films containing PVA nanofibers were characterized by water vapor permeability, swelling ratio, and tensile tests. The morphology of fibers before and after applying on the films was also observed by scanning electron microscopy. According to the results, this combination of natural and synthetic polymers has led to an affordable, biocompatible, and flexible film for wound dressing applications.

The role of chitosan as coating material for nanostructured lipid carriers for skin delivery of fucoxanthin.

Fucoxanthin (FUCO) is a marine carotenoid characterized by antiproliferative properties against hyperproliferative cells. The aim of this work was to design and develop nanostructured lipidic carriers (NLCs) based on bacuri butter and tucumã oil and loaded with FUCO, intended for skin application to prevent skin hyperproliferative diseases and in particular psoriasis. The presence of FUCO should control the hyperproliferation of skin diseased cells and the lipids forming the NLC core, rich in antioxidants and characterized by wound healing properties, should favor the restoring of skin integrity. NLCs were coated with chitosan (CS) to improve their biopharmaceutical properties (bio/mucoadhesion and wound healing) and to combine the advantages of lipidic nanoparticles with the biological properties of CS. Chitosan coated and non-coated NLC were prepared by means of high shear homogenization and characterized for chemico-physical and biopharmaceutical properties (in vitro biocompatibility and cell uptake towards normal dermal human fibroblasts). Moreover, the pharmacological activity of FUCO loaded in NLCs was assessed in psoriatic-like cellular model. NLCs were characterized by dimensions ranging from about 250 to 400 nm. Moreover, the CS coating and FUCO loading determined an increase of size. Moreover, TEM and zeta potential analysis confirmed the presence of CS coating on nanoparticle surface, thus conferring to nanoparticle good bioadhesion properties. NLCs uptake in fibroblasts was observed and NLC-FUCO-CS caused a reduction of cell viability with a less marked effect in fibroblasts rather than in psoriatic cells, highlighting the capability of this system to control skin hyperproliferation and inflammation. The loading of NLC-FUCO-CS in pullulan film should render NLCs application easy, without impair prompt interaction of the drug with the skin. Considering the overall results skin application of CS coated NLCs loaded with FUCO seems a promising approach to control skin hyperproliferation and to preserve skin integrity in psoriatic skin.

The Effect of Fermentation Bran and Chitosan in Ration to Percentage of Tegal Duck Digestive Tract Weight

Duck productivity is largely determined by the optimization of bodily functions. The food consumed greatly determines the development of digestive organs and internal organs of livestock. Digestive organs that are well developed and function optimally will be very decisive in turning feed into meat and eggs. Chitosan is a crustacean waste product known as animal fiber and is antimicrobial. Whereas fermented bran contains natural fiber rich in nutrients and is hypocholesterol. The aim of the study was to look at the role of chitosan and bran fermented on the weight percentage of digestive organs of ducks. The study used a completely randomized design (CRD) with 4 treatments and 5 replications. Each test consists of 2 ducks as a unit of experiment. The treatment is R0 = 45% corn + 35% concentrate + 20% bran without fermentation, R1 = 45% corn + 35% concentrate + 20% fermented bran, R2 = 45% corn + 35% concentrate + 19.5% fermented bran + 0.5% chitosan and R3 = 45% corn + 35% concentrate + 17.5% fermented + 2.5% chitosan bran. The variable measured is the weight percentage of the digestive organs (gizzard, small intestine and pancreas) in ducks. Data was processed using SAS Windows 16. The results showed that the administration of fermented chitosan and bran gave an average percentage of gizzard weight (ventriculus) and pancreatic weight percentage was not significantly different between treatments (P> 0.05), while treatment R1 (20% fermented bran) It was shown that the percentage of small intestine weight was higher (31.85%) than control R0.

Role of Chitosan in the Regulation of the Growth, Antioxidant System and Photosynthetic Characteristics of Maize Seedlings under Cadmium Stress

Cadmium (Cd) pollution was becoming more and more serious; there is an urgent need for an effective solution to inhibit the harm of cadmium stress. Chitosan (CTS) is a biologically active polysaccharide that plays a unique role under abiotic stress. So it was of much improtance to explore the effects of CTS on maize resistance ability. The results showed that maize (Zea mays L.) seedling growth was significantly inhibited, root system was the first organ that contact with cadmium stress, so the roots accumulated a lot of cadmium content, reducing the root activity, root growth was blocked, which led a reduction in nutrients to the leaves, and the chlorophyll content and photosynthetic enzyme activity were decreased. Additionally, the antioxidant enzyme activity was reduced. Under cadmium stress, CTS treatments significantly increased the growth rate and compensated for the function of root system, and which increased SOD, POD, CAT, APX and GR activities and AsA, GSH contents of leaves, but reduced $${\text{O}}_{2}^{{\centerdot \, - }}$$ , H2O2 and MDA contents. CTS increased chlorophyll content, Pn, Gs, Tr, Fv/Fm, ΦPSII, qP and NPQ, reduced Ci, avoided excessive light damage and maintained higher PSII activity. CTS alleviated the destruction of antioxidant enzymes and inhibited the production of reactive oxygen species, which improved the chlorophyll content and photosynthesis of plants. Our results showed that CTS could be used in cadmium-contaminated areas to reduce the toxicity of cadmium stress. The study results provide a theoretical and experimental basis for the safe production of maize in cadmium-contaminated areas.

A renoprotective role of chitosan against lithium-induced renal toxicity in rats

BackgroundLithium (Li) is considered as the first therapeutic line for treatment of bipolar affective disorders and manic-depressive illness. Renal toxicity can be categorized as the most common undesirable side effect of Li therapy. Therefore, the present study aimed to reveal efficiency of chitosan (CS) as a natural chelator against renal toxicity induced as a result of Li injection. During current experiment, the renal functions (urea, creatinine, blood urea nitrogen (BUN), uric acid and total protein) were determined in serum samples. The urinary excretion of N-acetyl-β-D-glucosaminidase (NAG) was assayed through measuring its level in urine samples. Moreover, markers of the oxidative stress (superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), reduced glutathione (GSH) and lipid peroxidation product (LPO)) were assessed in renal tissues. In addition, histopathological and ultrastructural examinations were carried out in that tissue.ResultsIt was found that Li injection caused significant (P < 0.05) elevation in serum urea, creatinin and BUN levels associated with decline in uric acid and T. protein. Moreover, Li increased the urinary excretion of NAG significantly (P < 0.05). Administration of CS orally restored levels of these measurements to normalcy in CS pre-treated group through lowering urea, creatinin, BNU levels and urinary excretion of NAG with enhancing uric acid and T. protein levels.On the other hand, it was found that Li caused significant (P < 0.05) elevation in the LPO level associated with decline in activity of the antioxidant system in the renal tissues. Likewise, it caused severe alterations in the renal levels at histopathological and ultrastructural levels. The treatment with CS reduced the renal LPO associated with stimulating the antioxidant system through increasing levels of SOD, CAT, GPx and GSH in addition to its beneficial role against the histopathological abnormalities.ConclusionsThe CS exhibited promising role in the protection against the oxidative stress and renal toxicity induced as a result of Li injection.

Role of chitosan on the growth, physiological parameters and enzymatic activity of milk thistle (Silybum marianum (L.) Gaertn.) in a pot experiment

Salt stress is the destructive factor in plant growth and physiological activities. Using biobased stimulants, such as chitosan, is important to reduce the adverse effects of salinity. This study was carried out in a greenhouse located at the University of Tehran, in 2016. The goal of this study was to evaluate the effect of chitosan application on modification of adverse effects of soil salinity on growth and physiological characteristics of milk thistle (Silybum marianum (L.) Gaertn.). A pot experiment with a factorial arrangement of treatments was conducted based on a randomized complete block design (RCB) with three replications Four irrigation water salinity levels were control (tap water 0.8), 4, 8 and 12 dS/m and four levels of chitosan were mixed with dry soil to yield 0, 0.01, 0.05 and 0.1% chitosan (DW/DW). The results showed that salinity reduced root dry weight; shoot dry weight, total plant biomass, and increased soluble sugars, proline content, CAT spell out first use and POD spell out first use enzyme activity and H2O2 concentration in leaves. The use of chitosan led to a reduction of salinity adverse effects and increased plant growth and improved physiological traits. Chitosan application at 0.01% increased chlorophyll a and total chlorophyll and at 0.05% level increased chlorophyll b compared to other chitosan treatments. The highest concentration of soluble sugars and proline was achieved by chitosan application across all salinity levels. Chitosan application under 0.01 and 0.05% enhanced the enzymatic activity and decreased H2O2 concentration in leaves. The results illustrated that chitosan could protect plants from salt stress damage by modulating intracellular ion concentration and by enhancing the capacity of antioxidant enzyme activities. It seems that the average concentration of chitosan as a bio-stimulant (0.01 and 0.05%) plays a positive role in reducing salinity and enhancing growth in milk thistle.

Role of chitosan on controlling the characteristics and antifungal activity of bioadhesive fluconazole vaginal tablets

Vaginal fluconazole (FLZ) prolonged release tablets containing chitosan in physical blends with other bioadhesive polymers were designed. Chitosan was mixed with hydroxypropyl methylcellulose (HPMC), guar gum or sodium carboxymethyl cellulose (NaCMC) at different ratios and directly compressed into tablets. In-vitro release profiles of FLZ were monitored at pH 4.8. Compressing chitosan with HPMC at different ratios slowed FLZ release, however, time for 80% drug release (T80) did not exceed 4.3 h for the slowest formulation (F11). Adding of chitosan to guar gum at 1:2 ratio (F3) showed delayed release with T80 17.4 h while, in presence of PVP at 1:2:1 ratio (F5), T80 was 8.8 h. A blend of chitosan and NaCMC at 1:2 ratio (F15) showed prolonged drug release with T80 11.16 h. Formulations F5 and F15 showed fair physical characteristics for the powder and tablets and were subjected to further studies. Fast swelling was observed for F15 that reached 1160.53 ± 13.02% in 4 h with 2 h bioadhesion time to mouse peritoneum membrane compared with 458.83 ± 7.09% swelling with bioadhesion time exceeding 24 h for F5. Extensive swelling of F15 could indicate possible dehydration effect on vaginal mucosa. Meanwhile, antifungal activity against C. albicans was significantly high for F5.

Review article- Role of Chitosan in Wound Healing - a Review of the Recent Advances

During the past decade, much interest has been developed in biopolymer based materials due to their biocompatible, biodegradable, non-toxic and non-allergic nature. Studies have been done on the key features of inherent properties of chitosan, their modification, and its use in biomedical engineering particularly toward anti inflammatory and wound healing. Chitin and chitosan with beneficial biological and antimicrobial properties and high valuable potential for wound healing are attractive for wound care. The chitin nanowhiskers applications are used mainly as reinforcing polymer nanocomposites, but also to prepare scaffolds, hydrogels and wound dressings, as adsorbents in industry, water purification, for protein immobilization, transformation of bacteria by exogenous genes, stabilization of oil-in-water emulsion and nematic gels, formation of CaCO3/chitin-whisker hybrids and as carbon precursors.

Antimicrobials in foods today and the role of chitosan - current hopes and new perspectives

Antimicrobials in foods today and the role of chitosan - current hopes and new perspectives

Synthesis and characterization of chitosan-stabilized gold nanoparticles through a facile and green approach

In the present study, gold nanoparticles (Au NPs) were synthesized through a facile and green approach encompassing chitosan in citric acid as a reducing and stabilizing agent, water as solvent, low reaction time, and temperature. The size and dispersity of the Au NPs were optimized by varying the method of addition of reagents. Addition of the reducing agent to a preheated metal precursor solution results in polydispersed nanoparticles whereas reversing the addition yields small and monodispersed nanoparticles. Au NPs of uniform shape and size with an average size range of 14.5 to 16 nm were obtained by controlling the nucleation and growth steps during the synthesis. The role of chitosan is found to be multifold as a mild reducing, chelating, and stabilizing agent. The as-prepared Au NPs are stable in the aqueous phase without any agglomeration, thus offering ample scope for catalytic and sensor applications.

PSY74 - HTA On Role of Chitosan In Hemostasis

PSY74 - HTA On Role of Chitosan In Hemostasis

Role of chitosan in improving salinity resistance through some morphological and physiological characteristics in fenugreek (Trigonella foenum-graecum L.)

Soil salinity is a serious environmental problem that has negative impacts on growth and production of plants. On the other hand, application of chitosan has recently been increased to enhance the resistance to different stresses, such as salinity. In order to study the effect of chitosan seed-priming on alleviation of salinity stress in fenugreek (Trigonella foenum-graecum L.) a factorial experiment, based on completely randomized design with three replications, was conducted in 2014 in the Research Greenhouse of University of Zabol. Chitosan pretreatment, taken as the first factor, was applied at three levels (0, 0.5 and 1 g/l) and sodium chloride (NaCl) was the second factor at four levels (0, 50, 150 and 250 mM). Before planting, the seeds were soaked for 6 hours in the chitosan solutions. NaCl was applied to the plants by irrigation water (after 2-leaf stage), with 3-day intervals. Results indicated that increasing salinity stress reduced growth characteristics, content of photosynthetic pigments, leaf relative water content, chlorophyll index and increased the amount of anthocyanin and proline. Seed-pretreatment by application of 0.5 mg/L chitosan, under salinity stress, increased plant dry weight, length of stem and roots, and leaf relative water content, as compared to the control treatment. In addition, under the salinity level of 250 mM, application of 1 g/L chitosan increased chlorophyll a, chlorophyll b and carotenoids content by 43.7, 65.4 and 28 percent, respectively, as compared to the control treatment. The highest amount of anthocyanin was found in the 1 g/L chitosan treatment. In general, these results suggested that in salt-affected areas, seed pretreatment by application of chitosan could be utilized efficiently for reducing the salinity stress on leaf relative water content and photosynthetic pigments, and better growth and stablishment of fenugreek plant.

Scanning Electron Microscopy Studies of Root Canal Dentin Irrigated with a Chitosan-Citrate Solution: A Preliminary Report

The success of endodontic treatment depends on thorough cleaning and shaping of the root canal system. In recent years, attention has focused on the role of chitosan instead of ethylenediaminetetraacetic acid (EDTA) as a c omplexing agent in root canal irrigation. In this in vitro study, dentin samples from the root canal were irrigated with varying concentrations of a chitosan-citrate solution. All the samples were analysed using scanning electron microscopy (SEM), and the smear layer covering the dental surfaces at the coronal, middle and apical root canal levels was evaluated. The results demonstrated that a 0.6% solution of chitosan in 1% citric acid was very effective at removing the smear layer.