Abstract In the present research, nutrient broth (NB) medium was identified to be able to neutralize the antibacterial activity of chitosan and its derivatives. Therefore, an improved test method independent of NB medium was proposed to precisely quantify the antibacterial effectiveness and efficiency of chitosan. The minimum bactericidal concentration (MBC) of chitosan was 60 μg mL−1 against S. aureus and E. coli, and 0.01 % (w/v) chitosan could kill 100 % of bacteria within 3 min. From another point of view, the neutralizing efficiency of NB could be tripled by adding 25 g L−1 of sodium chloride. Then the neutralizing mechanism of NB medium was ascribed to flocculation between chitosan and protein. Adding extra sodium chloride could significantly reduce the size of floccules, and smaller floccules would lose the ability of binding with bacteria directly, showing higher neutralizing rate on the macro scale.
Last. Xiguang Chen(Ocean University of China)H-Index: 61
view all 9 authors...
Abstract The aim of this study was to evaluate the antibacterial activity and cytocompatibility of novel pH-activated nanoparticles (NPs) in vitro and in vivo. The NPs were synthesized from a quaternary ammonium chitosan, i.e., N,N,N-trimethyl chitosan, a liposome, and doxycycline (TMC-Lip-DOX NPs). The cytocompatibility of the NPs was evaluated. The TMC-Lip-DOX NPs achieved superb inhibition of free mixed bacteria and biofilm formation. They also showed excellent biocompatibility with human per...
Last. Shaoyun Wang(FZU: Fuzhou University)H-Index: 20
view all 4 authors...
Abstract The interaction between polysaccharides and proteins has attracted great interests and the phase behavior and colloidal properties of complexes between chitosan, a positively charged polysaccharide, and proteins still need careful investigation. Here, we use chitosan/casein as model system and monitor their complex size, zeta-potential, light scattering intensity and phase behavior as functions of chitosan deacetylation degree, pH and ionic strength. Chitosan flocculates casein at low p...
The present article reviews several approaches for inducing flocculation of Escherichia coli cells. The common industrially used bacterium E. coli does not naturally have floc-forming ability. However, there are several approaches to induce flocculation of E. coli cells. One is induction by flocculants—polyvalent inorganic salts, synthetic polymeric flocculants, or bio-based polymeric materials, including polysaccharide derivatives. Another method is the induction of spontaneous flocculation by ...
#1Kejian Wei(BNU: Beijing Normal University)H-Index: 7
#2Lin Chen(BNU: Beijing Normal University)H-Index: 9
Last. Jinlong Zhang(SHU: Shanghai University)H-Index: 9
view all 7 authors...
Abstract Zeta potentials of the bare Zirlo alloy and its microarc oxidation (MAO) film in KCl, NaCl, H 3 BO 3 and LiOH solutions were measured. Their corrosion behavior in different solutions were evaluated by electrochemical impedance spectroscopy (EIS). The correlation between zeta potential and corrosion behavior was also analyzed. The MAO treatment shifted the iso-electric point (IEP) to a higher pH value in 1500 ppm B 3+ and 2.3 ppm Li + mixed aqueous solution for simulating normal water ch...
Plant leaves (phyllosphere) have a great potential for colonization and microbial growth, consisting of a dynamic environment in which several factors can interfere with the microbial population structure. The use of genetically modified (GM) plants has introduced several traits in agriculture, such as the improvement of plant drought tolerance, as observed in the AtAREB1 transcription factor overexpression in soybean (Glycine max L. Merrill). The present study aimed at investigating the taxonom...
Last. Xiguang Chen(Ocean University of China)H-Index: 61
view all 7 authors...
Abstract In this work, a composite sponge was produced by physically mixing hydroxybutyl chitosan with chitosan to form a porous spongy material through vacuum freeze-drying. Hydrophilic and macroporous composite hydroxybutyl chitosan sponge was developed via the incorporation of chitosan into hydroxybutyl chitosan. The composite sponge showed higher porosity (about 85%), greater water absorption (about 25 times), better softness and lower blood-clotting index (BCI) than those of chitosan sponge...
This review gives an updated overview of the current state-of-the-art for antimicrobial chitosan and chitosan derivatives and the effects of structural modifications on activity and toxicity. The various synthetic routes introduced for chemical modification of chitosan are discussed, and the most common functional groups are highlighted. Different analytical techniques used for structural characterization of the synthesized chitosan derivatives are discussed and critically evaluated. For the pur...
Last. Ira Bhatnagar(CCMB: Centre for Cellular and Molecular Biology)H-Index: 16
view all 6 authors...
Abstract Chitin is one of the most abundant polysaccharide found on earth. The deacetylated form of chitin viz. chitosan has been reported for its various important pharmacological properties and its role in tissue engineering and regenerative medicine is also well documented. Chitosan based bone graft substitutes are biocompatible, biodegradable, osteoconductive, osteoinductive and structurally similar to bone, with excellent mechanical strength and cost effectiveness. Chitosan based hydrogels ...
Abstract Chitosan is the deacetylated form of chitin, a biopolymer that can be obtained from various waste streams and shows antimicrobial activity against different fungi, gram positive and gram negative bacteria. Although chitosan has been studied for years, many aspects remain unclear. This review gives an overview of the antimicrobial activity of chitosan and novel chitosan derivatives of the last 15 years. The most important parameters (molecular weight, degree of deacetylation, etc.) are d...
Abstract Crosslinked chitosan was prepared by Schiff base formation between the aldehyde groups of dialdehyde cellulose (DAC) and the amino groups of chitosan and a subsequent reduction. DAC was obtained through periodate oxidation of cellulose and solubilization in hot water at 100 °C for 1 h. Three grades of DAC-crosslinked chitosan were prepared by adding various amounts DAC. The degrees of crosslinking as determined by amino group content were 3.8, 8.3, and 12.1%, respectively. DAC-crosslink...
Last. Xiguang Chen(Ocean University of China)H-Index: 61
view all 6 authors...
Abstract In the present research, an optimized liquid medium which had no neutralizing effect to chitosan was developed. Moreover, magnesium chloride (MgCl2) was identified to be able to absolutely neutralize the antibacterial activity of chitosan and its derivatives. Took the two results together, the minimum bactericidal concentration (MBC) and minimum inhibitory concentration (MIC) of chitosan were precisely quantified through a further improved method based on the optimized medium and the re...
Chitin is one of the most abundant natural polysaccharides in the world and it is mainly used to produce chitosan by a deacetylation process. In the present study, the extraction of chitin and chitosan from the Parastacus pugnax (P. pugnax) crayfish exoskeleton was studied for the first time. Thus, the P. pugnax crayfish exoskeleton was converted to chitosan following the steps of depigmentation, deproteinization, and deacetylation. The produced chitosan (Chitosan-CGNA) was characterized in term...