Chitosan is a biopolymer that has been widely used in medical, pharmaceutical, agricultural, cosmetics, food as well as textile, and paper industries due to its biocompatibility, biodegradability, non-toxic, and less allergenic nature. In recent times, chitosan has gained much attention for its application in the form of nanofibres. Nanofibres have diameters in the range of 1 to 100 nanometers. Various processing techniques like drawing, template synthesis, phase separation, melt-blown technology, bicomponent extrusion, self-assembly and electro-spinning are involved in the fabrication of nanofibres. Among these techniques, electro-spinning is the most widely and commonly used technique as it generates ultra-thin nanofibres and has the capacity for mass production. This article reviews the process of electro-spinning and applications of the nanofibres containing chitosan in the areas of enzyme immobilization, filtration, wound dressing, tissue engineering, drug delivery, catalysis, and as an analytical system, biosensor, and diagnostic aid in detail.
Background: Chitosan is a cationic biopolymer obtained from deacetylating chitin, a natural compound present in crustacean shell, fungi and exoskeleton of insects. Chitosan involves various applications, including as drug and gene delivery systems, as wound dressing material and scaffolds for tissue engineering, agriculture, textile, food and feed nanotechnology, and in wastewater treatments. Chitosan-TPP particle has been figured out as the most important and stable nanoparticle for chitosan application in various fields.
Objective: In this study, chitosan was chemically modified by sodium tripolyphosphate (TPP). Afterward, TPP-chitosan was radiolabeled with the gallium-67 radionuclide. The effect of several factors on labeling yield, such as chitosan solubility, acidity and concentration of TPPchitosan solution, and incubation time with gallium-67, were investigated.
Methods: To prepare [67Ga] gallium-chitosan complex, chitosan (0.5 ml) was dissolved in 2.2 mCi of [67Ga] gallium chloride solution. The obtained solution was stirred for 5 min and then kept for 30 min at room temperature. The radiochemical purity and radiolabeling yield were measured via radiochromatography, which was performed by using a radio thin-layer chromatography (TLC) scanner instrument. To investigate the effect of chitosan kind and concentration on the labeling yield, two kinds of chitosan (acid-soluble chitosan and water-soluble chitosan) at two different concentrations (1% and 0.5%) and different pH were used. In addition, labeling efficiency and stability of the 67Ga-TPP-chitosan complex (acidic/water soluble chitosan) at both concentrations (0.5 and 1%) and at room temperature were assessed for 30, 45 and 60 min.
Results: The incubation time did not have any significant effect on labeling yield. The acidic soluble chitosan exhibited the highest radiolabeling yield at pH=9.3-10.4, while water-soluble chitosan showed the highest radiolabeling yield at pH > 5. Also, the prepared complex was stable in the final solution at room temperature and could even be used 24 hours after preparation for further application.
Conclusion: Taken together, the TPP-modified water-soluble chitosan at the concentration of 0.5 % depicted the highest radiochemical yield (>95 %) in the optimized condition (pH= 6.2– 7.6). Therefore, TPP modified water-soluble chitosan can prove to be an effective carrier for therapeutic radionuclides in tumor treatment.
Author(s): Ahmed A. Haroun*, Hala A. Amin, Sameh H. Abd El-Alim.
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Background: Using Multi-Walled Carbon Nanotubes (MWCNTs) as a drug delivery system, can avoid the need for solvents and preventing drug precipitation in aqueous solution. Soyasapogenol B (SSB) acts as an important therapeutic agent owing to its numerous reported biological activities. Hence, this work deals with preparation and characterization of SBB loaded onto functionalized MWCNTs with tetraethyl orthosilicate (TEOS) and/or chitosan.
Method: SSB was immobilized onto functionalized MWCNTs using miniemulsion technique. Moreover, niosomes were utilized to encapsulate the prepared systems. The formulations were analyzed by Fourier Transform Infrared Spectroscopy (FTIR), Transmission Electron Microscope (TEM) and particle size distribution analysis. In vitro release profiles of loaded SSB particles were carried out and kinetics of release were also studied. In vitro cytotoxicity of the prepared materials was examined and evaluated by SRB assay using different human cell lines such as normal melanocytes (HFB4), and carcinoma breast and liver (MCF7 and HepG2, respectively) in comparison with the standard doxorubicin.
Results: SSB loaded materials exhibited successful encapsulation in niosomes, resulting in sustainable in drug release. Study of kinetics of release revealed presence of several complex factors affecting SSB release. Mathematical processing of the in vitro release data showed that the release of SSB from niosomal formulations obeyed more than one model. The second order and Higuchi’s models were the most fitting models in case of presence of chitosan or TEOS, respectively. While, all formulations exhibited low cytotoxic properties on all tested cell lines.
Conclusion: FTIR, particle size and TEM analysis confirmed that SSB was successfully loaded onto functionalized MWCNTs. Moreover, the different niosome formulations based on functionalized MWCNTs were prepared with sustainable SSB release in. The cytotoxicity could be minimized in case of chitosan and TEOS functionalization.
Author(s):Kunjan Phukan, Marika Nandy, Rupanjali B. Sharma, Hemanta K. Sharma.
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Background: Drug targeting to brain has always been problematic due to Blood-Brain Barrier (BBB), which, does not allow most of the drugs to pass through it as they are hydrophilic and macromolecular drugs. So, in order to bypass the BBB, alternative modes of administration were searched and nasal to brain delivery route was tried by many workers. Such studies yielded patented nano-formulations with the ability to cross blood brain barrier.
Methods: Nanoparticles being smaller in size and large surface area help in increasing the rate of drug permeation to the brain. In this review work, emphasis has been laid on discussion on various works done in the field of nasal delivery of drugs to brain over the last decade.
Results: The works that are discussed in this paper show better drug targeting of brain when given through nasal route as nanoparticles. Experiments performed in animal models have clearly exhibited that nano-sized formulations are able to facilitate the delivery of drugs to brain through nose in comparison to tantamount drug solutions.
Conclusion: However, it is not yet confirmed whether the drug is freed from the formulation in the nasal cavity and then absorbed or the nanoparticles themselves are absorbed and then the drug is released in the CNS. Furthermore, the toxicity studies were not carried out extensively in suitably designed model, which should be considered before going for further studies and application.
Author(s): Li Lin, Xiaoda Li, Yongbo Yang, Lijia Jing, Xiuli Yue, Xuzhu Chen, Zhifei Dai
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Background: The lack of smart and controllable gene vectors with high safety and efficiency is still a main obstruction for clinical applications of gene therapy. Recently, the external physical stimuli, such as near infrared light induced temperature elevation, have been applied to enhance the gene transfection efficiency and specificity. The aim of this paper is to fabricate chitosan functionalized CuS nanoparticles (CuS@CS NPs) with small size and higher biocompatibility for enhanced gene delivery by photothermal effect.
Methods: CuS@CS NPs were successfully prepared by simple hydrothermal method. The biocompatibility was detected by MTT method and hymolytic analysis. pEGFP-C1was used as gene model, and its expression efficiency was detected by fluorescence microscopy and flow cytometry to investigate the effect of photothermal effect on the transfection efficiency.
Results: The CuS@CS NPs around 15 nm were successfully engineered. The modification of CuS nanoparticles with chitosan conduced to higher physiological stability and biocompatibility. The utilization of CuS@CS NPs in combination with external near infrared (NIR) laser irradiation could enhance gene transfection efficiency due to photothermal effect. The gene transfection efficiency of CuS@CS NPs found to increase from 5.05±0.54% (0 min) to 23.47±1.27% (10 min), significantly higher than the free polyethylenimine (18.15±1.03%).
Conclusion: CuS@CS NPs showed great capability to control gene delivery by an external NIR laser irradiation and enhance the gene transfection efficiency and specificity because of convenient preparation, stabilized optical properties, excellent photothermal effect and good biocompatibility. It encourages further exploration of the CuS@CS NPs as a photocontrollable nanovector for combined photothermal and gene therapy, as well as image guided therapy.
Background: Gut microbiota has a significant role in the pathogenesis of diabetes. Colonic microflora modulation using an antibiotic might have an emerging role to treat the metabolic disorders. The present study was aimed to optimize the Moxifloxacin loaded chitosan microspheres (MCMs) by emulsion cross linking method for colon targeted delivery to alter the microflora.
Methods: Preliminary optimization of MCMs was carried out using Placket-Burman design (PBD) following by final optimization with Box-Behnken design (BBD). Optimized MCMs were evaluated for yield, particle size, entrapment efficiency and in vitro/ in vivo antimicrobial activities.
Results: FTIR spectroscopy of MCMs confirms the absence of chemical interactions during the formulation. MCMs were found to be smooth, spherical with particle size around 20μm. An enteric coating of MCMs prevented the drug release in the acidic environment of the stomach and ileum with complete release at the colon. MCMs had followed the korsmeyer – peppas model of drug release, indicating the drug release by non-fickian diffusion pattern. MCMs showed significant in vitro antimicrobial activity against Lactobacillus casei and Escherichia coli. In vivo results of MCMs exhibited prolonged antimicrobial effect of drug in the cecal content of rats. Significant protective activity observed in the ileum and colon histology in rats treated with MCMs compared to the pure drug.
Conclusion: MCMs were formulated by emulsion cross linking method using QBD approach. An enteric coating around the microspheres prevented the premature drug release at upper gastrointestinal tract, while chitosan cross linking has provided the sustain release of the drug in the colonic region over the time.
Bentham Science 
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