A COMPLEX SURFACE FORMATION MODEL ON CHITOSAN ADSORPTION TO METALS

The aim of the first year research is: to predict a complex surface formation between chitosan and metal ions. This prediction is according to the plot adsorptive capacity and the bonding tendency between chitosan and some metals. Chitosan as adsorbent isolated from Green Crab’s shell. Metal ions used in this research are Cr(III), Cu(II), Ni(II), Zn(II), Fe(II) and Pb(II). The subject of this research is green crab’s shell (Scylla serata) and the object is the adsorptive capacity chitosan to some metal ions. Chitosan was prepared in three steps: deproteination, demineralization and deacetylation. This chitosan are impurities by 20 %- 30%kitin. The adsorption experiment was carried out at room temperature for 24 hours. A half gram of chitosan was added into 50 mL of various metals solution at pH system 5. This experiment was performed in two methods. An each ion metal was adsorbed by chitosan and some metal ions i.e: Cr(III), Cu(II), and Ni(II) (1:1:1) were adsorbed simultaneous. Chitosan was characterized by FTIR. Metal ions concentration before and after adsorption was measured by by AAS. Adsorptive capacity is defined as differences of metal ion concentration due to the adsorption per gram chitosan. Then the obtained data was plotted through Langmuir isotherm and Freundlich isotherm equations. The result of this work concludes that adsorptive capacity of chitosan in order for some metals ion are Cr(III) > Fe(II)> pb(II) = Zn(II)> Ni(II) = Cu(II). The interaction chitosan with metal ions is indicated complex surface formation by -NH2 groups or –OH groups. A multilayer are formatted by active site chitosan and metal ion interactions, but the interaction of chitosan to copper(II) is prefer a monolayer formation. Key words: chitosan, adsorption, multilay FMIPA, 2006 (PEND. KIMIA

Pemanfaatan Chitosan darimLimbah Udang (Penaneusmerquensis) sebagai Adsorben Ion Logam Krom.

Di Indonesia udang diekspor dalam bentuk bekuannya melalui proses "cold storage". Akibat proses tersebut akan diperoleh hasil sainping berupa kepala, kulit, dan kaki yang merupakan iimbah. Kulit dan kepala udang (Penaneus merguensis) mengandung chitin yang dapat ditrasformasi menjadi chitosan. Chitosan dimanfaatkan sebagai adsorben ion logam dengan membentuk kompleks chitosan-ion logam. Pada penelitian ini ditentukan daya adsorbsi chitosan terhadap krom (VI) dengan metode AAS. Hasil penelitian menunjukkan bahwa chitosan yang diperoleh mempunyai kadar air 4,58 %, kadar abu 1,35 %, dan titik leleh 204-205 °C. Daya adsorbsi chitosan terhadap krom (VI) ditentukan dengan variasi waktu 20, 40, 60, 80, dan 100 menit pada pH = 5 dan pH = 4, dan 10, 20, 30, dan 40 menit pada pH = 3. Dari hasil pengukuran diketahui bahwa pada waktu 40 menit pada pH = 4, chitosan memberikan daya adsorbsi terbesar yaitu 69,4445 mg/g atau 29,83 %. Dari hasil penelitian dapat disimpulkan bahwa chitosan dari limbah udang dapat digunakan sebagai adsorben ion logam horn (VI). In Indonesia shrimp is exported in the frozen form by cold storage process. This process produces waste head, shell, and Legs of shirimps as by-products. Shell and head of shrimp (Penaneus merguensis) contain chitin that can be transformed to, chitosan. Chitosan is used as metal ion adsorben by forming a chitosan-metal complex. This research was conducted to measure adsorption capacity of chitosan on chrome hexavalence by using AAS method. The results showed that chitosan obtained contained 4.58 % water, 1.35 % ash, and possesed melting point at 264-265 °C. Adsorption capacity of chitosan on hexavalence chrome was measured with time variation at 20, 40, 60, 80, dan 100 minutes at pH = 5 and pH = 4, and 10, 20, 30, and 40 minutes at pH = 3. From the measurement, it is know that at 40 minutes and pH = 4, chitosan exhibited the maximum adsorption capacity namely 69A445 mg/g or 29.83 %. From the research it can be concluded that chitosan from shrimp shell can be used as chrome (VI) ion adsorbent. i

Global Requirements of Chitosan for Medical and Food Applications

Chitosan is a biopolymer obtained by deacetylation of chitin which widely distribute in nature and biologically safe. This polymer exhibits several favor properties such as biodegradability, low toxicity and ability to form film hydrogel. Chitosan offers a wide range of unique application such as in medical application for hypocholesterolemic, antimicrobial and wound-healing properties, drug delivery and biologically active agent. For food application, chitosan is used for dietary ingredient, food preservative, edible film and coatings. The fulfill the requirement of medical and food application, it is necessary to prepare several tests, grouped in preliminary, confirmatory and other tests. The characterization of chitosan used for the application tests, viscosity and molecular weight determination. The main limitations in the use of chitosan in several applications are its high viscosity and low solubility at neutral pH. Low molecular weight (Mw) chitosans and oligomers can he prepared by degradation of chitosan such as chemical hydrolysis, oxidative degradation, irradiation of chitosan and enzymatic hydrolysis. For medical application, high degrees of deacetylation of chitosan is the important parameter of chitosan for medical and food applications. For some specific applications, these smaller molecules have been found to he much more usefu

SYNTHESIS AND CHARACTERIZATION OF STARCH-CHITOSAN COMPOSITES

In this experiment, the composites based on chitosan-starch were synthesized at different weight ratios (3/7, 4/6, 5/5, 6/4, 7/3, 8/2, 9/1) by using 4 %v of glycerol as plasticizer. The influence of composition and the degree of deacetylation of chitosan on the properties of starch-chitosan composites film were studied. The films were observed on the aspect of mechanical characteristic, and % swelling, and biodegradability. Tensile strength of the composite films first increased and then decreased with chitosan addition. Otherwise, the addition of chitosan increased the elasticity of film and decreased % swelling. Films made of chitosan with the higher degree of deacetylation were found to have higher tensile strength and elongation in a tensile test

pH-Sensitive Chitosan–Heparin Nanoparticles for Effective Delivery of Genetic Drugs into Epithelial Cells

Chitosan has been extensively studied as a genetic drug delivery platform. However, its efficiency is limited by the strength of DNA and RNA binding. Expecting a reduced binding strength of cargo with chitosan, we proposed including heparin as a competing polyanion in the polyplexes. We developed chitosan–heparin nanoparticles by a one-step process for the local delivery of oligonucleotides. The size of the polyplexes was dependent on the mass ratio of polycation to polyanion. The mechanism of oligonucleotide release was pH-dependent and associated with polyplex swelling and collapse of the polysaccharide network. Inclusion of heparin enhanced the oligonucleotide release from the chitosan-based polyplexes. Furthermore, heparin reduced the toxicity of polyplexes in the cultured cells. The cell uptake of chitosan–heparin polyplexes was equal to that of chitosan polyplexes, but heparin increased the transfection efficiency of the polyplexes two-fold. The application of chitosan–heparin small interfering RNA (siRNA) targeted to vascular endothelial growth factor (VEGF) silencing of ARPE-19 cells was 25% higher. Overall, chitosan–heparin polyplexes showed a significant improvement of gene release inside the cells, transfection, and gene silencing efficiency in vitro, suggesting that this fundamental strategy can further improve the transfection efficiency with application of non-viral vectors

Development Of Ecologically Safe Technology Of Waste Mycelia Recycling

Chitosan is a cationic polymer derived by deacetylation of chitin obtained from crustaceans. Biodegradable and mucoadhesion properties of chitosan have recently led to increasing the interest. Chitosan can be used as raw material for the manufacture of films, membranes and fibers, in such branches as medicine, agriculture, veterinary medicine, biotechnology, cosmetics and pulp, and paper industry. Previously it was investigated that in Aspergillus Niger cell wall constituents, chitin comprises of 42 % and also researchers confirmed that the chitosan content of fungi depends on fungal strains, mycelial age, cultivation medium and conditions [1]. In the paper the results of the study of physical and chemical properties of obtained samples of chitosan are shown. The influence of initial parameters of the process on the quality of chitosan is investigated. Use of the biomass to produce chitosan on the basis of the developed methodology is shown. It is found that the resulting chitosan is characterized by low values of ash content, moisture content and the value is within 75–82 %. A further development of the scientific basis for the creation of an efficient, competitive and environmentally safe technologies for utilization mycelial biomass of the fungus Aspergillus Niger with the production of a valuable product is chitosan, which is in contrast to the known allows to reduce production costs by 10–80 % (by using not concentrated solutions of chemicals and low temperature process. This leads to reducing the cost of reagents and electricity. The calculation was performed on indicators such as net present value, internal rate of return and payback period.) The use of the developed technological schemes in practice allows utilization of mycelial waste with the aim of obtaining from them valuable product of chitosan, and to ensure the improvement of ecological situation in the region

Biocompatible chitosan-functionalized upconverting nanocomposites

Simultaneous integration of photon emission and biocompatibility into nanoparticles is an interesting strategy to develop applications of advanced optical materials. In this work, we present the synthesis of biocompatible optical nanocomposites from the combination of near-infrared luminescent lanthanide nanoparticles and water-soluble chitosan. NaYF4:Yb,Er upconverting nanocrystal guests and water-soluble chitosan hosts are prepared and integrated together into biofunctional optical composites. The control of aqueous dissolution, gelation, assembly, and drying of NaYF4:Yb,Er nanocolloids and chitosan liquids allowed us to design novel optical structures of spongelike aerogels and beadlike microspheres. Well-defined shape and near-infrared response lead upconverting nanocrystals to serve as photon converters to couple with plasmonic gold (Au) nanoparticles. Biocompatible chitosan-stabilized Au/NaYF4:Yb,Er nanocomposites are prepared to show their potential use in biomedicine as we find them exhibiting a half-maximal effective concentration (EC50) of 0.58 mg mL–1 for chitosan-stabilized Au/NaYF4:Yb,Er nanorods versus 0.24 mg mL–1 for chitosan-stabilized NaYF4:Yb,Er after 24 h. As a result of their low cytotoxicity and upconverting response, these novel materials hold promise to be interesting for biomedicine, analytical sensing, and other applications

Combining hyaluronic acid with chitosan enhances gene delivery

The low gene transfer efficiency of chitosan-DNA polyplexes is a consequence of their high stability and consequent slow DNA release. The incorporation of an anionic polymer is believed to loosen chitosan interactions with DNA and thus promote higher transfection efficiencies. In this work, several formulations of chitosan-DNA polyplexes incorporating hyaluronic acid were prepared and characterized for their gene transfection efficiency on both HEK293 and retinal pigment epithelial cells. The different polyplex formulations showed morphology, size, and charge compatible with a role in gene delivery. The incorporation of hyaluronic acid rendered the formulations less stable, as was the goal, but it did not affect the loading and protection of the DNA. Compared with chitosan alone, the transfection efficiency had a 4-fold improvement, which was attributed to the presence of hyaluronic acid. Overall, our hybrid chitosan-hyaluronic acid polyplexes showed a significant improvement of the efficiency of chitosan-based nonviral vectors in vitro, suggesting that this strategy can further improve the transfection efficiency of nonviral vectors.Fundacao para a Ciencia e Tecnologia [SFRH/BD/52424/2013]; Marie Curie Reintegration Grant [PIRG-GA-2009-249314

Prawn Shell Chitosan Has Anti-Obesogenic Properties, Influencing Both Nutrient Digestibility and Microbial Populations in a Pig Model

This study was supported financially (Grant-Aid Agreement No. MFFRI/07/01) under the Sea Change Strategy with the support of the Marine Institute and the Department of Agriculture, Food and the Marine, funded under the National Development Plan 2007–2013.peer-reviewedThe potential of natural products to prevent obesity have been investigated, with evidence to suggest that chitosan has anti-obesity effects. The current experiment investigated the anti-obesity potential of prawn shell derived chitosan on a range of variables relevant to obesity in a pig model. The two dietary treatment groups included in this 63 day study were: T1) basal diet and T2) basal diet plus 1000 ppm chitosan (n = 20 gilts per group (70 ± 0.90 kg). The parameter categories which were assessed included: performance, nutrient digestibility, serum leptin concentrations, nutrient transporter and digestive enzyme gene expression and gut microbial populations. Pigs offered chitosan had reduced feed intake and final body weight (P< 0.001), lower ileal digestibility of dry matter (DM), gross energy (GE) (P< 0.05) and reduced coefficient of apparent total tract digestibility (CATTD) of gross energy and nitrogen (P<0.05) when compared to the basal group. Fatty acid binding protein 2 (FABP2) gene expression was down-regulated in pigs offered chitosan (P = 0.05) relative to the basal diet. Serum leptin concentrations increased (P< 0.05) in animals offered the chitosan diet compared to pigs offered the basal diet. Fatness traits, back-fat depth (mm), fat content (kg), were significantly reduced while lean meat (%) was increased (P<0.05) in chitosan supplemented pigs. Pigs offered chitosan had decreased numbers of Firmicutes in the colon (P <0.05), and Lactobacillus spp. in both the caecum (P <0.05) and colon (P <0.001). Bifidobacteria populations were increased in the caecum of animals offered the chitosan diet (P <0.05). In conclusion, these findings suggest that prawn shell chitosan has potent anti-obesity/body weight control effects which are mediated through multiple biological systems in vivo.This study was supported financially (Grant-Aid Agreement No. MFFRI/07/01) under the Sea Change Strategy with the support of the Marine Institute and the Department of Agriculture, Food and the Marine, funded under the National Development Plan 2007–2013

The Effect of Configuration to Interaction Energy Between The Segments of Chitosan and Ascorbic Acid Molecule: Theoretical Study of Drug Release Control

Polymer systems plays an important role in drug delivery, which can control the time release of the drug, reduce the rate of degradation of the drug, and can reduce the toxic properties of the drug. Chitosan is a polymer of N-acetyl glucosamine that is biocompatible, biodegradable, and have active groups that can be used as a drug carrier matrix to control the release rate of the drug in the human body. The related research has been conducted experimentally by applying chitosan as a matrix to control the release rate of ascorbic acid by in vitro in an aqueous medium. So that, this study aimed to describe the interactions that occur between segments of chitosan and ascorbic acid theoretically using ab initio computational methods. Software used is Gaussian03, while the level of theory and basis set calculations determined is HF-SCF / 6-31G (d, p). The results for the nine configuration interaction calculations indicate hydrogen bonds between ascorbic acid molecules and chitosan segment. The interaction energy obtained is different for each configuration. It can be used as a basis for explaining the gradual release of ascorbic acid molecule from chitosan matrix. Ascorbic acid molecules that bound to the matrix of chitosan with lower energy will be easier to release on the medium that used