Antimicrobial Activities Of Chitosan Research Articles

Pharmaceutical applications of chitosan on medical implants: A viable alternative for construction of new biomaterials?

The cytocompatibility, good degradability and antimicrobial action of chitosan (CS) makes this polysaccharide a highly sought after candidate for applications in medical devices. Thus, development of biofunctional implants associated with CS has been proposed in regenerative medicine as these biomaterials can improve and accelerate the osseointegration process on the implants’ surface. The antimicrobial potential of CS has also been investigated in experiments performed on implantable materials associated with CS in different forms, since the incidence of implant-associated infections (IAIs) is increasing worldwide. Biodegradable scaffolds based on CS, and commonly developed as hydrogels, have received lots of attention as implants for controlled release and delivery of drugs. Given this scenario, the present review will focus on methodologies used to coat implant surfaces with CS as well as pharmaceutical applications of these functionalized implants, focusing on cellular, immunological, and antimicrobial responses as well as controlled drug release.

Antimicrobial Application of Chitosan Derivatives and their Nanocomposites.

Chitosan is derived from chitin polysaccharide, the main component of crustacean shells. Chitosan is a biocompatible, nontoxic, and biodegradable polymer soluble in acidic solutions. It is widely used in the medical and pharmaceutical fields. Antimicrobial activities of chitosan against different bacterial, fungal, and viral pathogens have been considered one of its attractive properties, making chitosan valuable for biological applications, including textile, food, tissue engineering, agriculture, and environmental protection. Additionally, chitosan has beneficial effects on livestock, poultry, fish, and crustaceans, which can enhance immunity, improve feed conversion, and promote growth. However, the water solubility of chitosan influences antimicrobial capabilities, limiting its application. In the present work, we reviewed the preparation, factors affecting antimicrobial activity, morphological structure, antimicrobial mechanism, and application of chitosan derivatives, and the problems and prospects were pointed out. Collectively, this review provided an update on the application of chitosan derivatives and their potential for further advanced applications in the antimicrobial field.

New Zinc-Based Active Chitosan Films: Physicochemical Characterization, Antioxidant, and Antimicrobial Properties.

The improvement of the antioxidant and antimicrobial activities of chitosan (CS) films can be realized by incorporating transition metal complexes as active components. In this context, bioactive films were prepared by embedding a newly synthesized acylpyrazolonate Zn(II) complex, [Zn(QPhtBu)2(MeOH)2], into the eco-friendly biopolymer CS matrix. Homogeneous, amorphous, flexible, and transparent CS@Znn films were obtained through the solvent casting method in dilute acidic solution, using different weight ratios of the Zn(II) complex to CS and characterized by powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), Fourier transform infrared (FT-IR), Raman, and scanning electron microscopy (SEM) techniques. The X-ray single-crystal analysis of [Zn(QPhtBu)2(MeOH)2] and the evaluation of its intermolecular interactions with a protonated glucosamine fragment through hydrogen bond propensity (HBP) calculations are reported. The effects of the different contents of the [Zn(QPhtBu)2(MeOH)2] complex on the CS biological proprieties have been evaluated, proving that the new CS@Znn films show an improved antioxidant activity, tested according to the DPPH method, with respect to pure CS, related to the concentration of the incorporated Zn(II) complex. Finally, the CS@Znn films were tried out as antimicrobial agents, showing an increase in antimicrobial activity against Gram-positive bacteria (Staphylococcus aureus) with respect to pure CS, when detected by the agar disk-diffusion method.

Synthesis, characterization, pH‐sensitive swelling and antimicrobial activities of chitosan–graft‐poly(hydroxyethyl methacrylate) hydrogel composites for biomedical applications

AbstractIn this paper, 2‐hydroxyethyl methacrylate (HEMA) was graft copolymerized onto chitosan (CHI) at different ratios using a radical initiator. The grafted hydrogel composites were then characterized by attenuated total reflection Fourier transform ınfrared spectroscopy (ATR‐FTIR) and thermo‐gravimetric analysis (TGA). Swelling behavior of the hydrogels was investigated at different pH and different times. The antimicrobial activity of the chitosan‐graft‐HEMA (CHI‐HEMA) against gram‐negative bacteria and gram‐positive bacteria was studied by the standard agar well diffusion assay method. The CHI‐HEMA 1:1 and CHI‐HEMA 1:2 showed an obvious antimicrobial effect against six test strains. The CHI‐HEMA 1:1 and CHI‐HEMA 1:2 exhibited a highly significant increase (p < 0.01) in diameter of the inhibition zones compared with the standard antibiotics. Furthermore, CHI‐HEMA 1:1 presented the highest antimicrobial activity against all test strains with a significant difference (p < 0.01) compared with CHI‐HEMA 1:2. Meanwhile, the decreasing order of the average sensitivity to CHI‐HEMA 1:1 and CHI‐HEMA 1:2 was observed to be S. marcescens > E. coli > S. aureus subsp. aureus > S. enteritidis > E. faecalis > E. aerogenes. These results indicate potential application of CHI‐HEMA 1:1 and CHI‐HEMA 1:2 graft hydrogels as a novel and efficient antimicrobial agent in biomedical fields.

Design of heat sealable starch-chitosan bioplastics reinforced with reduced graphene oxide for active food packaging

Interest in producing films from renewable and biodegradable polymers, such as polysaccharides, has increased in recent years with the aim of reducing the environmental pollution caused by petroleum-based plastics. Additionally, combining the thermoplastic property of starch with the antioxidant and antimicrobial activities of chitosan is of great interest to develop active materials for food packaging. This study aims the preparation of thermoplastic blended starch-chitosan films mechanically reinforced with reduced graphene oxide (rGO). Blending the starch with chitosan and rGO showed that films had a hydrophobic surface (>100°), low water solubility (weight loss less than 10%), and improved antioxidant activity. Furthermore, blended film prepared with 75% starch and 25% chitosan with rGO achieved the maximum value of electrical conductivity (6.51 × 10−3 S/m) while maintaining the heat sealing properties of starch. The functional properties and heat sealability of starch-chitosan blended films with rGO enhance their application for active food packaging.

Antibacterial and antifungal activity of chitosan against Bacillus cereus and Aspergillus niger isolated from some Egyptian canned and fast food

A total of (213) canned food samples comprising of Tuna &Sardines,Juices, Tomatoes pasts, Jam and Beef were randomly collected fromsuper stores and local markets in Tanta city from Awlad Ragab,Fatthallah, Munshwi, Casion. Also 24 fast food samples collected fromlocal cafeterias and restaurants in Tanta city from Al Gaan, Abu Deshish,Al Baraka, Abu Owaf. All canned food samples were within expiry date,none of which is bloated, leaking and/or physically damaged. Sampleswere investigated for some bacteria and fungi using specific media andincubated for suitable incubation period. The results revealed thatspecies of microbes isolated in this study namely Bacillus subtilis,Bacillus cereus, Bacillus atrophaeus., Staphylococcus saprophyticus,Enterococcus faecalis, Staphylococcus epidermides, E. coli, Klebsiella,Salmonella , Aspergillus niger, Penicillium notatum, Candida tropicalisand Saccharomyces cerevisiae. Biochemical tests were performed for allisolates to know the most common isolates (Bacillus cereus andAspergillus niger). Antimicrobial activities of chitosan were investigatedagainst the most common isolates B. cereus and A. niger. Resultsrevealed that chitosan has antibacterial activity towards Bacillus cereus.The minimum inhibition concentration (MIC) for chitosan was 6.25μg/ml with mean diameter of inhibition zone 8 mm. Also chitosan hasantifungal activity toward Aspergillus.niger with minimum inhibitionconcentration (MIC) 30mg/ml and percent of fungal growth inhibition16.7%.

Silk fibroin/chitosan/alginate multilayer membranes as a system for controlled drug release in wound healing

In this study, we proposed the use of the biopolymers silk fibroin, chitosan and alginate, which are recognized for their biocompatibility and biodegradability, for the preparation of multilayer membranes aiming at high performance wound dressings with controlled drug delivery. The rationale was to combine in one material the mechanical properties of fibroin, the antimicrobial action of chitosan and the ideal exudate absorption of alginate, reaching a synergic effect of each biopolymer, without losing their individual intrinsic properties. The membranes were prepared by casting and diclofenac sodium was incorporated as model drug into the chitosan solution before the solvent evaporation, being retained in the middle layer of the membrane. Morphological, thermal, mechanical, solubility and barrier properties of the membranes were evaluated, as well as cytotoxicity and microbiological permeation. Results show that the incorporation of the drug did not affect mechanical and barrier properties, as well as microbiological permeation. Drug release was evaluated in vitro using simulated solution of wound exudate at 37 °C and diclofenac sodium was released from the multilayer membrane in 7 h, in which Fickian diffusion was the main mechanism associated. The results show the potential application of the biopolymer multilayer membranes as high-performance wound dressings.

Penicillium citrinum and Penicillium mallochii: New phytopathogens of orange fruit and their control using chitosan

The antimicrobial action of chitosan against several phytopathogens in agriculture has been tested, including Penicillium digitatum, which is the major pathogen that causes postharvest decay of oranges. However, the biopolymer action has not been tested against other fungi that are capable of developing molds in orange fruit. This study have demonstrated that chitosan is able to inhibit the growth in vitro and in vivo of two Penicillium species, which were isolated from decay oranges fruit and identified as Penicillium citrinum and Penicillium mallochii, using molecular methods. This is the first report of P. mallochii acting as an orange phytopathogen. The commercial chitosan with higher molecular weight demonstrated a reduction in the disease incidence of 50–70 % for the inoculum P. citrinum and of 40 % for the inoculum P. mallochii for the in vivo experiments. The data obtained opens interesting alternative options to synthetic fungicide to prevent orange decay caused by the potential phytopathogenic species of Penicillium here identified.

In-vitro Evaluation of the Antimicrobial Activities of Chitosan and Chitosan-PVP Linked Nanocomposite Films against Some Multidrug Resistant Bacteria

In-vitro Evaluation of the Antimicrobial Activities of Chitosan and Chitosan-PVP Linked Nanocomposite Films against Some Multidrug Resistant Bacteria

Chitosan Inhibits the Rehabilitation of Damaged Microbes Induced by Photodynamic Inactivation.

Previously, we showed that chitosan could augment the biocidal efficacy mediated by photodynamic treatment against Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans. In this study, we showed that the antimicrobial action of chitosan in augmenting photodynamic inactivation (PDI) is related to the increase in cell surface destruction. The microbial cell surfaces exhibit severe irregular shapes after PDI in the presence of chitosan as demonstrated by transmitted electron microscopy. Furthermore, increases in the concentration or incubation time of chitosan significantly reduced the amounts of photosensitizer toluidine blue O required, indicating that chitosan could be an augmenting agent used in conjunction with PDI against S. aureus, P. aeruginosa, and C. albicans. A prolonged lag phase was found in microbial cells that survived to PDI, in which chitosan acted to completely eradicate the cells. Once the exponential log stage and cell rebuild began, their cellular functions from PDI-induced damage returned and the increased cytotoxic effect of chitosan disappeared. Together, our results suggest that chitosan can prevent the rehabilitation of PDI-surviving microbial cells, leading to increased biocidal efficacy.

Thermal and biological studies of Schiff bases of chitosan derived from heteroaryl aldehydes

The synthesis of Schiff bases of chitosan is performed by the reaction of chitosan with different heteroaryl aldehydes, i.e., furfuraldehyde, thiophene-2-carboxylaldehyde, pyrrole-2-carboxylaldehyde, pyridine-2-carboxylaldehyde, pyridine-3-carboxylaldehyde and pyridine-4-carboxylaldehyde. The structural characterizations of the biopolymeric Schiff bases are executed by 1H NMR spectroscopy, Fourier transform infrared spectroscopy and elemental analysis (C, H, N). The 1H NMR spectroscopy is also used to determine the degree of deacetylation of chitosan as well as the degree of substitution (DS) of Schiff bases and DS found to be varying from 58 to 74%. Thermogravimetry studies of chitosan and its Schiff base polymers show that they have nearly the same decomposition temperature and hence equally thermally stable. The model-free multiple heating rate method Kissinger–Akahira–Sunose has been employed for the thermal degradation kinetics of the most potent antimicrobial compound ChSB-6. The antimicrobial activities of chitosan and its Schiff bases are tested against different pathogenic bacteria: Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Aspergillus niger, and results shows that the activities of the Schiff bases of chitosan are found to be stronger than that of chitosan.

Synthesis, thermal and antimicrobial studies of some Schiff bases of chitosan

The Schiff bases of chitosan are synthesized by the reaction of chitosan with different aromatic aldehydes. The structures of the biopolymeric Schiff bases are characterized by Fourier transform infrared spectroscopy, 1H-NMR spectroscopy and elemental analysis (C, H, N). The 1H NMR spectroscopy is used to determine degree of deacetylation of chitosan and degree of substitution of Schiff bases. The Schiff base polymers have greater degrees of substitution varying from 65 to 88.5 %. Thermogravimetry of Schiff base polymers shows that they have nearly the same decomposition temperature as the chitosan, indicating that Schiff bases are thermally stable. The antimicrobial activities of chitosan and its Schiff bases are tested against Staphylococcus aureus, Bacillus subtilis, Escherichia coli and Aspergillus niger and found that the antimicrobial activities of the Schiff bases of chitosan were stronger than those of chitosan.

Preparation and characterization of N-benzoyl-O-acetyl-chitosan

A novel amphipathic chitosan derivative, N-benzoyl-O-acetyl-chitosan (BACS), was prepared by using the selective partial acylation of chitosan (CS), benzoyl chloride, and acetic acid under high-intensity ultrasound. The chemical structure and physical properties of BACS were characterized by FTIR, 1H NMR, TGA, and XRD techniques. The degrees of substitution of benzoyl and acetyl for the chitosan derivatives were 0.26 and 1.15, respectively, which were calculated from the peak areas in NMR spectra by using the combined integral methods. The foaming properties of CS and BACS were determined and the results suggested BACS had better foam capacity and stability than those of chitosan. In addition, the antimicrobial activities of CS and BACS were also investigated against two species of bacteria (Escherichia coli and Staphylococcus aureus) and a fungus (Aspergillus niger), the results indicated that the antibacterial and antifungal activities of BACS were much stronger than those of the parent chitosan. These findings suggested that BACS was preferable for use as a food additive with a dual role of both foaming agent and food preservative.

Synthesis and characterization of chitosan derivatives with dual-antibacterial functional groups

With the aim to discover chitosan derivatives with enhanced antibacterial activity and good water solubility compared with natural chitosan, a novel O-quaternary ammonium N-acyl thiourea chitosan (OQCATUCS) bearing double antibacterial groups with different degrees of substitution has been synthesized. The derivative was characterized by FTIR, 13C NMR, elemental analysis, XRD, TGA and zeta potential analysis. Water solubility was also investigated. The antimicrobial activities of chitosan and its derivatives were investigated by assessing the mortality rates of Staphyloccocus aureus, Escherichia coli, Aspergillus niger, Pseudomonas aeruginosa and Bacillus subtilis. The order of antibacterial activities was O-quaternary ammonium N-acyl thiourea chitosan (OQCATUCS)>O-quaternary ammonium chitosan (OQCS)>chitosan (CS). The zeta potential and antibacterial results indicated that the introduced quaternary ammonium and thiourea groups increased the positive charge of chitosan derivative, thereby enhanced its antibacterial activity. The mechanism of chitosan derivatives against E. coli and S. aureus was evaluated via analyzing integrity of cell membranes and transmission electron microscopy data. These results demonstrated that OQCATUCS killed the bacteria via disrupting the cell membrane.

Chitin extraction from shrimp shell using enzymatic treatment. Antitumor, antioxidant and antimicrobial activities of chitosan

Chitin was recovered through enzymatic deproteinization of the shrimp processing by-products. Different microbial and fish viscera proteases were tested for their deproteinization efficiency. High levels of protein removal of about 77±3% and 78±2% were recorded using Bacillus mojavensis A21 and Balistes capriscus proteases, respectively, after 3h of hydrolysis at 45°C using an enzyme/substrate ratio of 20U/mg. Therefore, these two crude proteases were used separately for chitin extraction and then chitosan preparation by N-deacetylation.Chitin and chitosan samples were then characterized by 13 Cross polarization magic angle spinning nuclear magnetic resonance (CP/MAS)-NMR spectroscopy and compared to samples prepared through chemical deproteinization. All chitins and chitosans showed identical spectra. Chitosans prepared through enzymatic deproteinization have practically the same acetylation degree but higher molecular weights compared to that obtained through chemical process. Antimicobial, antioxidant and antitumoral activitities of chitosan-M obtained by treatment with A21 proteases and chitosan-C obtained by alkaline treatment were investigated. Results showed that both chitosans inhibited the growth of most Gram-negative, Gram-positive bacteria and fungi tested. Furthermore, both chitosans exhibited antioxidant and antitumor activities which was dependent on the molecular weight.

APLIKASI KITOSAN DENGAN PENAMBAHAN EKSTRAK BAWANG PUTIH SEBAGAI PENGAWET DAN PELAPIS EDIBEL BAKSO SAPI (Chitosan Application with Addition of Garlic Extract as a Preservative and Meatballs Edibel Coating)

The main objective of this research was to to prolong the shelf life of beef meatball by using chitosan with the addition of garlic extract. Two methods of application, i.e. as preservative agent by mixing chitosan with meatball ingredients and as coating of meatball have been conducted. Prior to application, antimicrobial activities of chitosan and chitosan enriched with garlic extract were assessed by diffusion agar methods. It showed that chitosan solution of 1% (w/v) enriched with garlic extract 2% (v/v) could inhibit Pseudomonas aureginosa and Bacillus cereus.The application of chitosan enriched with garlic extract as preservative agent could extend the shelf-life of meatball only for 12 hours while its application as edible coating could extend the shelf life of beef meatball until 24 hours when stored at room temperature. This result revealed that the application of chitosan with garlic extract as edible coating were more effective in controlling microbiological growth in meatball than as preservative agent. The micrograph obtained by SEM showed that the surfaces of meatball coated with chitosan were more smooth and compact than those of meatball without coatings.Keywords: chitosan, antimicrobial film, preservative, meatball, edible coating

Preparation of O-Carboxymethyl Chitosan by Schiff Base and Antibacterial Activity

A novel method of preparation O-Carboxymethyl chitosan (OCMC) was studied that the product was prepared by reaction of Schiff's base of chitosan. Schiff base of chitosan (BCTS) was synthesized by the reaction of chitosan with aromatic aldehyde, then BCTS reacted with chloroacetic acid and removed the group of amino protection to get the target product. The chitosan derivative was characterized by FT-IR spectroscopy, 1HNMR and elemental analysis. Elemental analysis results confirmed that the degree of substitution(DS) of OCMC was 0.83. Solubility of OCMC in water and organic solvents was demonstrated to be better than that of chitosan. The antimicrobial activities of chitosan and OCMC were investigated against Aspergillus niger and Staphylococcus aureus. The results indicate that the antimicrobial activity of OCMC was superior to chitosan.

Antibacterial action of chitosan-arginine against Escherichia coli O157 in chicken juice

The antimicrobial action of chitosan and functionalized chitosan derivatives is well known; however, limited research has been undertaken on its use in meat environments. In this study, the antibacterial activity of a newly-developed arginine-functionalized chitosan was tested against pathogenic Escherichia coli O157 in chicken juice. The chicken juice was representative of the liquid which accumulates in food packaging and which is frequently implicated in food poisoning incidents. Aliquots of chicken juice (50 ml) were inoculated with a lux-marked strain of E. coli O157 to approximately 8.75 log10 CFU ml−1. Samples were subsequently mixed with chitosan-arginine of varying concentrations (0–500 mg l−1) and incubated at 4 or 20 °C to mimic refrigeration and room temperatures, respectively. Pathogen persistence and metabolic activity (indexed by bioluminescence measurements) were subsequently quantified in the liquor at 0 (immediately after mixing), 3, 12, 24, 48, and 72 h post-incubation. The presence of chitosan-arginine significantly reduced both the numbers and metabolic activity of the pathogen in a dose-dependent manner with greater inhibition seen at higher concentration. In addition, it also suppressed the growth of general food spoilage bacteria, reduced malodor and prevented pathogen re-growth up to 72 h. The results imply that incorporating water soluble chitosan-arginine into packaging may help maintain both product shelf life and freshness as well as minimize the risk of food poisoning in both retail outlets and domestic homes.

Review of antimicrobial and antioxidative activities of chitosans in food.

Interest in chitosan, a biodegradable, nontoxic, non-antigenic, and biocompatible biopolymer isolated from shellfish, arises from the fact that chitosans are reported to exhibit numerous health-related beneficial effects, including strong antimicrobial and antioxidative activities in foods. The extraordinary interest in the chemistry and application in agriculture, horticulture, environmental science, industry, microbiology, and medicine is attested by about 17,000 citations on this subject in the Scopus database. A special need exists to develop a better understanding of the role of chitosans in ameliorating foodborne illness. To contribute to this effort, this overview surveys and interprets our present knowledge of the chemistry and antimicrobial activities of chitosan in solution, as powders, and in edible films and coating against foodborne pathogens, spoilage bacteria, and pathogenic viruses and fungi in several food categories. These include produce, fruit juices, eggs and dairy, cereal, meat, and seafood products. Also covered are antimicrobial activities of chemically modified and nanochitosans, therapeutic properties, and possible mechanisms of the antimicrobial, antioxidative, and metal chelating effects. Further research is suggested in each of these categories. The widely scattered data on the multifaceted aspects of chitosan microbiology, summarized in the text and in 10 tables and 8 representative figures, suggest that low-molecular-weight chitosans at a pH below 6.0 presents optimal conditions for achieving desirable antimicrobial and antioxidative-preservative effects in liquid and solid foods. We are very hopeful that the described findings will be a valuable record and resource for further progress to improve microbial food safety and food quality.

Control of Dongchimi Fermentation with Chitosan Deacetylated by Alkali Treatment to Prevent Over‐Ripening

Antimicrobial activities of chitosan against lactic acid bacteria were studied to apply for controlling dongchimi (whole-radish juicy kimchi) fermentation to prevent over-ripening. Antimicrobial activity of chitosan against lactic acid bacteria such as Leuconostoc mesenteroides and Lactobacillus plantarum was assayed at 10, 20, 30, and 40 mg/L concentration in the medium. The addition of 40 mg/L of the chitosan prepared at 140 degrees C for 10 min showed strong inhibitory effect on the growth of L. mesenteroides and L. plantarum. The effects of addition of chitosan to dongchimi have also been studied during fermentation at different temperatures of 4, 10, and 20 degrees C. Addition of chitosan decreased markedly viable cell counts of lactic acid bacteria such as Leuconostoc spp. and Lactobacillus spp. at the initial stage. Subsequently the lactic acid bacteria recovered the growth to the same level as non-chitosan treated dongchimi. During the dongchimi fermentation, the addition of chitosan at larger quantity up to 1000 mg/L (CS1000) prolonged the palatable fermentation period. Addition of chitosan in the dongchimi seemed to inhibit the growth of lactic acid bacteria, thereby lowering the acid content. It, therefore, caused the shelf life to be extended and resulted in a prolonged palatable period for the dongchimi.