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Item The effect of changing the oil concentration on oil content, encapsulation efficiency and release rate of cinnamon leaf oil encapsulated chitosan microcapsules.(International Research Symposium on Pure and Applied Sciences, 2017 Faculty of Science, University of Kelaniya, Sri Lanka., 2017) Muthumali, A.M.T.; Wickramarachchi, P.A.S.R.Antibiosis, insect repelling and stress reducing properties of essential oils have been widely studied and well established. However, the release speeds of these compounds are usually high. Encapsulation is one of the effective methods commonly used to control the release and to increase the bioavailability of these compounds. In this research, cinnamon leaf oil was incorporated into chitosan microcapsules (MCs) to achieve the above mentioned goals. Here, we investigated the effect of changing the oil concentration on oil load, oil content, encapsulation efficiency and release rate of MCs. MCs were prepared by decreasing the solubility of chitosan. Briefly, NaOH was dripped into pre-prepared oil-chitosan emulsion, with slow stirring. Glutaraldehyde (10 mmol/g of polymer) was used for further crosslinking of chitosan wall of MCs. The average particle size was determined using the stage micrometer. Oil release was studied by UV-visible spectrophotometry. Oil release, encapsulation efficiency, oil content and oil load in MCs were calculated. All the parameters were dependent on the amount of oil. The particle size, encapsulation efficiency, oil content and release rate of cinnamon oil increased with the increase in oil loading. Scanning electron microscopy study showed a change in surface characteristics of the microcapsules due to cinnamon oil loading.Item Synthesis of Chitosan Stabilized Silver Nanoparticles using Gamma Ray Irradiation and Characterization(University of Kelaniya, 2011) Hettiarachchi, M.A.; Wickramarachchi, P.A.S.R.Chitosan stabilized silver nanoparticles (AgNPs) were synthesized using gamma ray irradiation. Four different sample solutions were prepared [1 mM AgNO3 in 0.1% (w/v) chitosan, 1 mM AgNO3 in 0.5% (w/v) chitosan, 2 mM AgNO3 in 0.1% (w/v) chitosan 2 mM AgNO3 in 0.5% (w/v) chitosan] with controls maintaining dose of radiation at 20±2 kGy. The formation of AgNPs were determined by the appearance of the characteristic colour of the AgNPs, using the surface plasmon resonance band (SPR) at 400-432 nm range and the N-H band of the FT-IR spectrum. Stability of the maximum absorption wave lengths of the samples was monitored for three months by UV-visible spectroscopy. The particle size distribution of the stabilized sample, showed a wide distribution of 28-1106 nm. The sample, 2 mM AgNO3 in 0.5% (w/v) chitosan was stable for three months. FT-IR spectroscopic analysis revealed a shifting of N-H stretching vibration band from 3367-3228 cm-1 with the introduction of nanoparticles.