Studies on Chitosan Extraction and Its Biomedical Properties

2020 ◽  
Vol 3 (2) ◽  
pp. 69
Author(s):  
Alef Mustafa ◽  
Rodica Sîrbu

Chitin and chitosan are natural biopolymers that are included in the novel families of biological macromolecules. Chitosan its the main derivative of chitin, and research upon the characteristics and properties of these molecules has become increasingly evident and important. It was reported that the main and potential applications of these polymers as well as their derivatives are more than 200. These applications include biomedicine, pharmacy, agriculture, biotechnology, cosmetics. In the last years, especially in the pharmaceutical and medical fields chitosan has received considerable attentions as a functional, renewable, nontoxic and biodegradable biopolymer for diverse applications. The recent efforts of the scientists concentrated on the methods of preparation of chitin from raw material, on processing chitosan, as well as on the chemical and biological properties that help increase solubility in aqueous solutions.

2021 ◽  
Vol 22 (9) ◽  
pp. 4308
Author(s):  
Chayanaphat Chokradjaroen ◽  
Jiangqi Niu ◽  
Gasidit Panomsuwan ◽  
Nagahiro Saito

Sustainability and environmental concerns have persuaded researchers to explore renewable materials, such as nature-derived polysaccharides, and add value by changing chemical structures with the aim to possess specific properties, like biological properties. Meanwhile, finding methods and strategies that can lower hazardous chemicals, simplify production steps, reduce time consumption, and acquire high-purified products is an important task that requires attention. To break through these issues, electrical discharging in aqueous solutions at atmospheric pressure and room temperature, referred to as the “solution plasma process”, has been introduced as a novel process for modification of nature-derived polysaccharides like chitin and chitosan. This review reveals insight into the electrical discharge in aqueous solutions and scientific progress on their application in a modification of chitin and chitosan, including degradation and deacetylation. The influencing parameters in the plasma process are intensively explained in order to provide a guideline for the modification of not only chitin and chitosan but also other nature-derived polysaccharides, aiming to address economic aspects and environmental concerns.


Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2304
Author(s):  
César Burgos-Díaz ◽  
Mauricio Opazo-Navarrete ◽  
José Luis Palacios ◽  
Tamara Barahona ◽  
Yohanna Mosi-Roa ◽  
...  

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 terms of the protein content, solubility, degree of deacetylation, viscosity, molecular weight, FTIR, SEM, XRD, antimicrobial, and antioxidant activity. The results showed that the obtained chitosan had a high degree of deacetylation (91.55%) and a medium molecular weight (589.43 kDa). The antibacterial activity of the chitosan was tested against bacterial strains relevant for the food industry and the lowest minimum inhibitory concentration (MIC) values were evidenced with Salmonella tiphymurium (S. typhimurium), Staphylococcus aureus (S. aureus), Enterococcus faecalis (E. faecalis) and Listeria. Monocytogenes (L. monocytogenes). Moreover, the Chitosan-CGNA showed an effect on DPPH radical scavenging activity, and its antioxidant activity was dependent on concentration and deacetylation degree. These results suggest that P. pugnax exoskeleton could be an excellent natural source for the production of chitosan with potential applications in the health system, and to prevent infections associated with pathogens strains.


2019 ◽  
Vol 70 (6) ◽  
pp. 1897-1902
Author(s):  
Claudia Maria Simonescu ◽  
Alina Melinescu ◽  
Maria Ciuca ◽  
Bianca Zarnescu

The experimental study aimed to establish the potential applications of the nano- and micrometric powders of hydroxyapatite in the removal processes of Cu(II) ions from synthetic aqueous solutions. For this purpose, hydroxyapatite (HAP) was used in the form of: 1) nanometric powder (labeled nano-HAP), and 2) calcium alginate hydroxyapatite composite microparticles (nicro-HAP-CaAlg). Eggshells have been used as a raw material to obtain HAP. The contact time, pH and Cu(II) concentration in the initial solution have been the main process variables with influence on the Cu(II) ions removal by HAP samples. For both HAP based materials, an optimal pH value of 5 has been established. The nano-HAP powder has a higher Cu(II) adsorption capacity than micro-HAP-CaAlg based on the specific surface area values of nano- and micrometric powders. The adsorption isotherm experiments showed that this process can be described using Langmuir model according to which the adsorption takes place as a monolayer process on an homogeneous surface. The kinetic study revealed that the sorption process of Cu(II) from synthetic aqueous solutions can be described using the pseudo-second order kinetics model according to which the rate-determining step is chemisorption. The values of the retention capacity recommends both powders tested (nano-HAP and micro-HAP-CaAlg) to be used in the Cu(II) loaded water treatment process.


Author(s):  
Marcin Kalek ◽  
Jacek Jemielity ◽  
Ewa Grudzien ◽  
Joanna Zuberek ◽  
Zbigniew M. Darzynkiewicz ◽  
...  

2020 ◽  
Vol 154 (2) ◽  
pp. 135-153 ◽  
Author(s):  
Gabriel García Caballero ◽  
Donella Beckwith ◽  
Nadezhda V. Shilova ◽  
Adele Gabba ◽  
Tanja J. Kutzner ◽  
...  

Abstract The concept of biomedical significance of the functional pairing between tissue lectins and their glycoconjugate counterreceptors has reached the mainstream of research on the flow of biological information. A major challenge now is to identify the principles of structure–activity relationships that underlie specificity of recognition and the ensuing post-binding processes. Toward this end, we focus on a distinct feature on the side of the lectin, i.e. its architecture to present the carbohydrate recognition domain (CRD). Working with a multifunctional human lectin, i.e. galectin-3, as model, its CRD is used in protein engineering to build variants with different modular assembly. Hereby, it becomes possible to compare activity features of the natural design, i.e. CRD attached to an N-terminal tail, with those of homo- and heterodimers and the tail-free protein. Thermodynamics of binding disaccharides proved full activity of all proteins at very similar affinity. The following glycan array testing revealed maintained preferential contact formation with N-acetyllactosamine oligomers and histo-blood group ABH epitopes irrespective of variant design. The study of carbohydrate-inhibitable binding of the test panel disclosed up to qualitative cell-type-dependent differences in sections of fixed murine epididymis and especially jejunum. By probing topological aspects of binding, the susceptibility to inhibition by a tetravalent glycocluster was markedly different for the wild-type vs the homodimeric variant proteins. The results teach the salient lesson that protein design matters: the type of CRD presentation can have a profound bearing on whether basically suited oligosaccharides, which for example tested positively in an array, will become binding partners in situ. When lectin-glycoconjugate aggregates (lattices) are formed, their structural organization will depend on this parameter. Further testing (ga)lectin variants will thus be instrumental (i) to define the full range of impact of altering protein assembly and (ii) to explain why certain types of design have been favored during the course of evolution, besides opening biomedical perspectives for potential applications of the novel galectin forms.


Author(s):  
Mahima Singh ◽  
Sriramakamal Jonnalagadda

AbstractThis study evaluates the suitability of 3D printed biodegradable mats to load and deliver the topical antibiotic, neomycin, for up to 3 weeks in vitro. A 3D printer equipped with a hot melt extruder was used to print bandage-like wound coverings with porous sizes appropriate for cellular attachment and viability. The semicrystalline polyester, poly-l-lactic acid (PLLA) was used as the base polymer, coated (post-printing) with polyethylene glycols (PEGs) of MWs 400 Da, 6 kDa, or 20 kDa to enable manipulation of physicochemical and biological properties to suit intended applications. The mats were further loaded with a topical antibiotic (neomycin sulfate), and cumulative drug-release monitored for 3 weeks in vitro. Microscopic imaging as well as Scanning Electron Microscopy (SEM) studies showed pore dimensions of 100 × 400 µm. These pore dimensions were achieved without compromising mechanical strength; because of the “tough” individual fibers constituting the mat (Young’s Moduli of 50 ± 20 MPa and Elastic Elongation of 10 ± 5%). The in vitro dissolution study showed first-order release kinetics for neomycin during the first 20 h, followed by diffusion-controlled (Fickian) release for the remaining duration of the study. The release of neomycin suggested that the ability to load neomycin on to PLLA mats increases threefold, as the MW of the applied PEG coating is lowered from 20 kDa to 400 Da. Overall, this study demonstrates a successful approach to using a 3D printer to prepare porous degradable mats for antibiotic delivery with potential applications to dermal regeneration and tissue engineering.


2020 ◽  
Vol 92 (10) ◽  
pp. 1563-1574
Author(s):  
Marie-Claire Bellissent-Funel

AbstractIn many relevant situations, water is not in its bulk form but instead attached to some substrates or filling some cavities. We shall call water in the latter environment confined water as opposed to bulk water. It is known that the confined water is essential for the stability and the function of biological macromolecules. In this paper, we provide a review of the experimental and computational advances over the past decades concerning the understanding of the structure and dynamics of water confined in aqueous solutions of biological relevance. Examples involving water in solution of organic solutes (cryoprotectants such as dimethylsulfoxide (DMSO), sugars such as trehalose) are provided.


2018 ◽  
Vol 294 (5) ◽  
pp. 1602-1608 ◽  
Author(s):  
Xiunan Yi ◽  
Eric J. Verbeke ◽  
Yiran Chang ◽  
Daniel J. Dickinson ◽  
David W. Taylor

Cryo-electron microscopy (cryo-EM) has become an indispensable tool for structural studies of biological macromolecules. Two additional predominant methods are available for studying the architectures of multiprotein complexes: 1) single-particle analysis of purified samples and 2) tomography of whole cells or cell sections. The former can produce high-resolution structures but is limited to highly purified samples, whereas the latter can capture proteins in their native state but has a low signal-to-noise ratio and yields lower-resolution structures. Here, we present a simple, adaptable method combining microfluidic single-cell extraction with single-particle analysis by EM to characterize protein complexes from individual Caenorhabditis elegans embryos. Using this approach, we uncover 3D structures of ribosomes directly from single embryo extracts. Moreover, we investigated structural dynamics during development by counting the number of ribosomes per polysome in early and late embryos. This approach has significant potential applications for counting protein complexes and studying protein architectures from single cells in developmental, evolutionary, and disease contexts.


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