Antibacterial Biopolymer Research Articles

Eco-Friendly Food Preserviour

Abstract: Chitosan (CS), an antibacterial biopolymer with the ability to form films, has been used topically to preserve foods like fruits, vegetables, and even seafood. We must look for more materials with these qualities if we are to have a variety of options for preservation. Sapindus mukorossi, often known as soap nut (SN), is a plant with similar characteristics. The main substance in soap nuts, known as saponin, is what gives them their antibacterial and film-forming properties. There are numerous reports that suggest saponin can be utilised for culinary purposes up to a point.2This study assessed the synergistic preservation effect of soap nut and chitosan aqueous solutions on fruits and vegetables. The antibacterial effects of CS, SN, and [CS+SN] are initially seen. Staphylococcus aureus and Escherichia coli were the first microorganisms against which the antibacterial effects of CS, SN, and [CS+SN] in film form were investigated. As anticipated, the film CS+SN demonstrated greater antibacterial action, with zones of inhibition against Staphylococcus aureus and Escherichia coli of 25 mm and 23 mm, respectively. Spraying different regional fruits like lemons, bananas, tomatoes, and oranges with a known concentration of CS+SN allowed researchers to assess the substance's potential as a preservative. The control was water. Different concentrations of [CS+SN] -250ppm and 125ppm, together with CS-500ppm, SN-500ppm, and water, were compared. In comparison to control fruits, fruits sprayed with [CS+SN]-250ppm solution displayed a considerable delay in the change in weight loss, decay percentage, and pH. Additionally, it kept its visual quality better than CS, SN, and control samples.

Microstructural, physico-chemical, antibacterial and antibiofilm efficacy of imipenem loaded chitosan nano-carrier systems to eradicate multidrug resistant Acinetobacter baumannii

Acinetobacter baumannii, being labelled as “critical priority pathogen” is a major threat faced by humanity nowadays as it is responsible for numerous life-threatening nosocomial infections. A. baumannii is a highly resistant microbe that forms biofilms at infection site thus interfering with the permeability of antibiotics. Therefore, intrinsically antibacterial biopolymer, chitosan, is utilized to synthesize imipenem (IPM) encapsulated chitosan nano-carrier system (CS-IPM-NCS) against multidrug resistant A. baumannii (MDRAB). CS-IPM-NCS were fabricated using ionic gelation method. The developed CS-IPM-NCSs were characterized using scanning electron microscopy (SEM), atomic force microscopy (AFM), zeta potential, average size and Fourier transform infrared (FTIR) spectroscopy. It was observed that SEM and AFM analyses revealed smooth, regular and homogeneously distributed nano-carrier systems. The mean size of CS-IPM-NCS was found to be < 100 nm and the zeta potential was 38.9 ± 5.52 mV that indicated the stability of the nano-carrier systems. Encapsulation efficiency was optimized to ensure high encapsulation (87 ± 3%) of IPM in 0.3% (w/v) CS-NCS. Changes in characteristic peaks in FTIR spectra demonstrated the successful encapsulation of IPM inside the CS-NCS. The antibacterial activity of CS-IPM-NCS was evaluated by growth kinetics assay and the results exhibited potent (100%) inhibition of MDRAB. The outcome of CS-IPM-NCS on the pre-formed biofilms by MDRAB strains were ∼90%, due to the cationic-anionic interaction between NCS and biofilm structures. Thus, the present study findings suggest that CS-IPM-NCS might be an alternative strategy to conventional (failing) antibiotics to eradicate MDRAB.

Antibacterial Biopolymer Gel Coating on Meshes Used for Abdominal Hernia Repair Promotes Effective Wound Repair in the Presence of Infection.

Prosthetic mesh infection is a devastating complication of abdominal hernia repair which impairs natural healing in the implant area, leading to increased rates of patient morbidity, mortality, and prolonged hospitalization. This preclinical study was designed to assess the effects on abdominal wall tissue repair of coating meshes with a chlorhexidine or rifampicin-carboxymethylcellulose biopolymer gel in a Staphylococcus aureus (S. aureus) infection model. Partial abdominal wall defects were created in New Zealand white rabbits (n = 20). Four study groups were established according to whether the meshes were coated or not with each of the antibacterial gels. Three groups were inoculated with S. aureus and finally repaired with lightweight polypropylene mesh. Fourteen days after surgery, implanted meshes were recovered for analysis of the gene and protein expression of collagens, macrophage phenotypes, and mRNA expression of vascular endothelial growth factor (VEGF) and matrix metalloproteinases (MMPs). Compared to uncoated meshes, those coated with either biopolymer gel showed higher collagen 1/3 messenger RNA and collagen I protein expression, relatively increased VEGF mRNA expression, a significantly reduced macrophage response, and lower relative amounts of MMPs mRNAs. Our findings suggest that following mesh implant these coatings may help improving abdominal wall tissue repair in the presence of infection.

Antibacterial Activity of Sugarcane Bagasse Nanocellulose Biocomposite with Chitosan Against Escherichia coli

Antibacterials have been used to treat infectious diseases in both humans and animals since 1929. Along with their use, there is resistance to some antibacterials. 43% of Escherichia coli is resistant to various types of antibiotics. Therefore, research on the development of antibacterial ingredients is always being developed. Nanocellulose has received a lot of attention on its application of antibacterial material support. Meanwhile, chitosan is an antibacterial biopolymer with a brittle structure, hence nanocellulose is added to chitosan film to increase its structural stability. In this study, nanocellulose was extracted from sugarcane bagasse through a combination method of sulfuric acid hydrolysis with ultrasonic waves. The effect of addition of nanocellulose to chitosan mechanical properties was investigated. Scanning Electron Microscopy (SEM) characterization showed that there were differences in morphology between nanocellulose, chitosan, and nanocellulose-chitosan biocomposites. The result of X-Ray Diffraction and Fourier-transformed infrared spectroscopy analysis showed that biocomposites was successfully formed. The average size of nanocellulose particle was 132.67 nm. Nanocellulose-chitosan biocomposites with a ratio of 10:2 have the best antibacterial activity against Escherichia coli than other biocomposite ratios.

Antibacterial Activity of Sugarcane Bagasse Nanocellulose Biocomposite with Chitosan Against Escherichia coli

Antibacterials have been used to treat infectious diseases in both humans and animals since 1929. Along with their use, there is resistance to some antibacterials. 43% of Escherichia coli is resistant to various types of antibiotics. Therefore, research on the development of antibacterial ingredients is always being developed. Nanocellulose has received a lot of attention on its application of antibacterial material support. Meanwhile, chitosan is an antibacterial biopolymer with a brittle structure, hence nanocellulose is added to chitosan film to increase its structural stability. In this study, nanocellulose was extracted from sugarcane bagasse through a combination method of sulfuric acid hydrolysis with ultrasonic waves. The effect of addition of nanocellulose to chitosan mechanical properties was investigated. Scanning Electron Microscopy (SEM) characterization showed that there were differences in morphology between nanocellulose, chitosan, and nanocellulose-chitosan biocomposites. The result of X-Ray Diffraction and Fourier-transformed infrared spectroscopy analysis showed that biocomposites was successfully formed. The average size of nanocellulose particle was 132.67 nm. Nanocellulose-chitosan biocomposites with a ratio of 10:2 have the best antibacterial activity against Escherichia coli than other biocomposite ratios.

Design, preparation, and characterization of CS/PVA/SA hydrogels modified with mesoporous Ag2O/SiO2 and curcumin nanoparticles for green, biocompatible, and antibacterial biopolymer film.

One of the most significant factors affecting the rapid and effective healing of wounds is the application of appropriate wound dressings. In the present study, novel antibacterial wound dressings are fabricated that consist of Chitosan (CS)/Polyvinyl alcohol (PVA)/Sodium Alginate (SA), which are all biocompatible, functionalized with mesoporous Ag2O/SiO2 and curcumin nanoparticles as reinforcements. In this research nanocomposites are fabricated (0 wt%, 5 wt%, 10 wt%, 15 wt%, and 20 wt% of Ag2O/SiO2). After the composition of nanocomposites using the cross-linked technique, Fourier Transform Infrared (FT-IR) spectroscopy is performed to confirm the functional groups that are added to the polymer at each step. X-ray diffraction (XRD) is done to show the crystallinity of Ag2O/SiO2. Field emission scanning electron microscopy (FE-SEM) studies are performed to demonstrate the morphology of the structure, Energy-dispersive X-ray spectroscopy (EDS) is done to examine the elements in the wound dressing and atomic force microscopy (AFM) study is performed to show surface roughness and pores. Then the nanocomposites with different weight percentages are cultured in three bacteria called Acinetobacter baumannii, Staphylococcus epidermidis, and Proteus mirabilis, all three of which cause skin infections. Finally, by performing the tensile test, the results related to the tensile strength of the wound dressings are examined. The results show that with the increase of Ag2O/SiO2, the mechanical properties, as well as the healing properties of the wound dressing, have increased significantly. Fabricating these nanocomposites helps a lot in treating skin infections.

The Effects of Silver Nanoparticles Compositions on the Mechanical, Physiochemical, Antibacterial, and Morphology Properties of Sugar Palm Starch Biocomposites for Antibacterial Coating.

Antibacterial sugar palm starch biopolymer composite films were developed and derived from renewable sources and inorganic silver nanoparticles (AgNPs) as main ingredients for antibacterial coatings. The composite films were produced by solution casting method and the mechanical and physicochemical properties were determined by tensile test, Fourier Transform Infrared (FTIR) analysis, thermal gravimetric analysis (TGA), antibacterial screening test and field emission scanning electron microscopy (FESEM) images. It was found that mechanical and antibacterial properties of biocomposite films were improved after the addition of AgNPs compared with the film without active metals. The weakness of neat biocomposite films was improved by incorporating inorganic AgNPs as a nanofiller in the films’ matrix to avoid bacterial growth. The results showed that the tensile strength ranged between 8 kPa and 408 kPa and the elasticity modulus was between 5.72 kPa and 9.86 kPa. The addition of AgNPs in FTIR analysis decreased the transmittance value, caused small changes in the chemical structure, caused small differences in the intensity peaks, and produced longer wavelengths. These active films increased the degradation weight and decomposition temperature due to the more heat-stable AgNPs. Meanwhile, the average inhibited areas measured were between 7.66 and 7.83 mm (Escherichia coli), 7.5 and 8.0 mm (Salmonella cholerasuis), and 0.1 and 0.5 mm for Staphylococcus aureus. From the microscopic analysis, it was observed that the average size of all microbes for 1 wt% and 4 wt% AgNPs ranged from 0.57 to 2.90 mm. Overall, 3 wt% AgNP nanofiller was found to be the best composition that fulfilled all the mechanical properties and had better antimicrobial properties. Thus, the development of an organic-inorganic hybrid of antibacterial biopolymer composite films is suitable for antibacterial coatings.

Modification of chitosan and chitosan nanoparticle by long chain pyridinium compounds: Synthesis, characterization, antibacterial, and antioxidant activities

Chitosan is an antibacterial biopolymer and conjugation of it with other antimicrobial agents can be a valuable method to improve the potential application of the resultant materials in the various industries such as cosmetics, food and packaging materials. In this work, a series of quaternary pyridinium compounds were synthesized; then to achieve developed biological properties, they were attached to the chitosan and chitosan nanoparticles. The formation of chitosan derivatives was evinced by FT-IR, 1H and 13C NMR, UV–vis and EDX spectroscopy. The morphology of samples was detected by FE-SEM, TEM and AFM images. The QAC-chitosan hybrids were investigated for antibacterial activity against two Gram-positive and two Gram-negative bacteria, and they showed a significant effect on the Gram-positive bacteria. DPPH-radical scavenging assay shows mild improvement in antioxidant activity of new chitosan derivatives.

Photoresponsive Multilayer Films of Chitosan and an Azopolymer

The main goal of this work was the development of photoactive multilayer films. Taking into account that chitosan is a biodegradable, biocompatible, nontoxic, and antibacterial biopolymer, the fabrication of chitosanbased multilayer films can be an interesting pathway to obtain biopolymer-based films in which properties can be combined with a light-responsive material, such as an azobenzene-containing polymer. In particular, the layer-by-layer technique was used for the fabrication of the optically active films consisting of alternating layers of chitosan and an azopolymer. The influence of the pH and the number of bilayers on the structure and properties of the films was investigated by different experimental techniques and it was found that the roughness and elastic modulus of the multilayer films increased with the decrease in chitosan solution pH. Besides, induced birefringence measurements revealed that a higher level of photoorientation was attained with the decrease in pH and the increase in bilayer number of the developed films. © 2015 Scrivener Publishing LLC.

Chitin deacetylases: properties and applications.

Chitin deacetylases, occurring in marine bacteria, several fungi and a few insects, catalyze the deacetylation of chitin, a structural biopolymer found in countless forms of marine life, fungal cell and spore walls as well as insect cuticle and peritrophic matrices. The deacetylases recognize a sequence of four GlcNAc units in the substrate, one of which undergoes deacetylation: the resulting chitosan has a more regular deacetylation pattern than a chitosan treated with hot NaOH. Nevertheless plain chitin is a poor substrate, but glycolated, reprecipitated or depolymerized chitins are good ones. The marine Vibrio sp. colonize the chitin particles and decompose the chitin thanks to the concerted action of chitinases and deacetylases, otherwise they could not tolerate chitosan, a recognized antibacterial biopolymer. In fact, chitosan is used to prevent infections in fishes and crustaceans. Considering that chitin deacetylases play very important roles in the biological attack and defense systems, they may find applications for the biological control of fungal plant pathogens or insect pests in agriculture and for the biocontrol of opportunistic fungal human pathogens.