Bacteria have been confirmed as the main etiological factor for root canal infection as well as for root canal treatment failure. Thus the success of endodontic treatment depends on the complete elimination of bacteria and prevention of bacterial recolonization in the root canal system. The major challenge for conventional root canal disinfection strategies is the ability of bacteria to persist as biofilms within the anatomical complexities of the root canal system. In addition, the alterations in the ultrastructure of dentin tissue results in compromised structural integrity of root dentin leading to higher risk of fracture in root-filled teeth. The objectives of this study are twofold: 1) develop and test functionalized nanoparticles to eliminate biofilm bacteria and, 2) to stabilize and strengthen the dentin organic matrix by crosslinking collagen fibrils in the presence of biopolymeric nanoparticles. A bioactive polymeric nanoparticle functionalized with a photosensitizer may present as a single step treatment to achieve both the objectives. Chitosan a bioactive polymer was used owing to their inherent antibacterial and biocompatible characteristics. Chitosan micro-/nanoparticles were synthesized as well as functionalized with photosensitizer (rose bengal) for photodynamic activation. Bioactive chitosan nanoparticle functionalized with a rose bengal is expected to combine the properties of chitosan i.e., polycationic with higher affinity to bacterial cell wall and alter membrane integrity; that of a photosensitizer i.e., to generate singlet oxygen when photoactivated; and the nano-form further potentiate these specific properties. These photodynamically activable chitosan nanoparticles showed the distinct characteristics of chitosan and rose bengal. The synergistic effect of the chitosan conjugated nanoparticles was able to eliminate monospecies and multi-species bacterial biofilms with complete disruption of the biofilm structure. The singlet oxygen generated during photoactivation produced photochemical crosslinking of dentin collagen and infiltration of chitosan nanoparticles. Following crosslinking the dentin collagen showed significantly improved mechanical properties (ultimate tensile strength and toughness) and improved resistance to degradation by bacterial collagenase. In conclusion, this study presents a potential photosensitizer functionalized chitosan nanoparticles based treatment strategy to improve the success of endodontic treatment to achieve complete disinfection of the root canal system and enhanced the mechanical/ structural integrity of the root-filled teeth.

This thesis examined the economics of producing high value bio-ingredients such as chitin and carotenoprotein from shrimp processing waste in Newfoundland. The shrimp waste in the province was estimated to be at least 37000 tons annually. A survey of shrimp processing plants in the province revealed that the waste generated was relatively pure with little or no foreign material. The economic engineering approach was employed to estimate the production cost of chitin and carotenoprotein at the laboratory and pilot scale levels. At the laboratory scale where 480 kg/year of raw material (shrimp waste) was processed, the cost of chitin and carotenoprotein was found to be $159/kg and $315/kg, respectively. At the pilot scale level, the cost of chitin and carotenoprotem was estimated to be $125/kg and $244/kg, respectively based on volume of 4800 kg/year. Sensitivity analysis was carried out to establish the cost variations due to changes in the quantity of starting raw material, labor cost and cost of laboratory supplies (chemicals and enzymes). The cost of chitin and caroteinoprotein showed a decreasing trend with increasing scale of production. An expert opinion survey was conducted with a selected panel of 9 experts from the shrimp processing industry, chitin related industry, and the academic/research community to determine the potential market of the high-grade chitin/chitosan in Canada. The results showed that the health and nutraceutical industry is the most promising niche for high-grade chit in/chitosan. The survey also indicated that potential market would be high in Ontario and Quebec due to the presence of large health and nutraceutical companies in the big metropolitan areas of these regions.

Chemical treatment of contaminated soils (in-situ or ex-situ) is the current most practical option for remediation. The degree of metal complexation by organic acids depends on the type, concentration, metal type, pH and temperature. The influence of pH, temperature on the extraction efficiency of lead, zinc and copper was evaluated using Sodium citrate and sodium acetate buffers. Sodium citrate buffer was selected for the soil treatment. The soil was characterized for its pH, total metal content and the distribution of target heavy metals in soil fractions. Optimal conditions for Pb extraction with 0.5M citrate buffer was used to treat soil in batches and in columns, to evaluate their extraction efficiency and possible use for in-situ remediation. / Chitosan, a derivative of chitin is a versatile biopolymer with metal uptake capabilities. Due to the large amounts of chitosan required to treat heavily contaminated leachates, magnesium (Mg) and iron (Fe) metals granules were evaluated for stripping the heavy metals from solution before the use of chitosan at optimized conditions to effectively polish the soil washing. (Abstract shortened by UMI.)

Controlled release formulations deliver an active ingredient over an extended period of time. It is an ideal dosage form for an active ingredient with a short elimination half-life. An active ingredient with a short elimination half-life would be released in small portions over an extended period of time and thus less frequent administration is necessary and this improve patient compliance. Other advantages of these formulations include: decreased side effects, constant drug levels in the blood, improvement in treatment efficiency and reduction in cost of administration. Controlled release beads are formulated in such a way that the active ingredient is embedded in a matrix of insoluble substance like chitosan; the dissolving drug then has to find its way through the pores of the matrix into the surrounding medium. The chitosan matrix swells to form a gel, the drug then has to first dissolve in the matrix and diffuse through the outer surface into the surrounding medium. Chitosan is a biocompatible, biodegradable polymer of natural origin. It has mucoadhesive properties as well as the ability to manipulate the tight junctions in the epithelium membrane and these properties have qualified chitosan as an effective drug carrier in controlled release dosage forms. The effect of a modern controlled release polymer namely Kollidon® SR in combination with chitosan on drug release was investigated. Ketoprofen was chosen as model drug. Ketoprofen is an anti-inflammatory drug that causes gastrointestinal side effects in conventional dosage forms. Ketoprofen has a short elimination half-life of 2.05 ± 0.58 h and this characteristic makes it an ideal candidate for use in a controlled release formulation. The aim of this study was to achieve controlled release and minimize gastrointestinal effects of ketoprofen with chitosan particles. Kollidon® SR was used as polymer because it exhibits pH independent release characteristics and previous studies have shown potential for this combination. Chitosan beads and chitosan-Kollidon® SR beads, as well as chitosan granules and chitosan-Kollidon® SR granules, were prepared and investigated as potential controlled release formulations. Chitosan beads were prepared through the inotropic gelation method using tripolyphosphate as a cross linking agent. Granules were prepared through wet granulation using 2% v/v acetic acid as the granulating fluid or by dissolving ketoprofen in ethanol and Kollidon® SR in 2-pyrrolidinone and using the solution as granulating fluid. Kollidon® SR was added in concentrations of 0.25, 0.5 and 1% (w/v) in the bead formulations and concentrations of 1, 5 and 10% (w/w) in the granule formulations. The beads and granules were characterised by evaluating the following properties: morphology, drug loading and drug release. Additionally swelling and friability tests were also conducted on the bead formulations. The cross linking times of the bead formulations were varied to investigate the effect of cross linking time on the characteristics of the beads. Chitosan-Kollidon® SR beads showed promising results for controlled release formulations and ketoprofen were released over an extended period of time. Drug loading of the plain chitosan beads was 74.65 ± 0.71% and it was noted that the inclusion of Kollidon® SR in the beads resulted in an increase in drug loading and the formulation containing 1% (w/v) Kollidon® SR, cross linked for 30 minutes had a drug loading of 77.38 ± 0.01%. Drug loading of the beads that were cross linked for a longer time were slightly lower which is an indication that some of the drug might have leached out during cross linking. The degree of swelling was promising with some beads swelling to a degree of 2.5 in phosphate buffer solution pH 5.6. Granules had a drug loading between 81.73 ± 1.53% and 93.30 ± 0.50%. Ketoprofen release from the beads and the granules in PBS pH 7.40 at 37 °C over a period of 6 hours were investigated. The bead formulations were more effective in achieving controlled release and it was noted that the bead formulations that was cross linked for a longer period was more efficient in achieving controlled release. The granules did not form a matrix and were not effective in achieving controlled release. Controlled release of ketoprofen were achieved and the results show potential for chitosan-Kollidon® SR formulations in the future. / Thesis (M.Sc. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2008.

The peak and valley problems caused by oral administration, injection or other conventional methods, call for developing systems that can deliver therapeutics more effectively. As one of the techniques, diffusion-controlled drug release membranes have significant interest due to great ease with which they can be designed to achieve near-zeroth-order release kinetics. Since diffusion is the rate-limiting step in these systems, determining the permeability and diffusivity of drug molecules in the membrane is therefore important in evaluating drug release performance. This study focuses on the Membrane Permeation Controlled Release (MPC) system, which involves a non-porous (dense) membrane, comprising of two biopolymers, sericin and chitosan. Ciprofloxacin hydrochloride and (+)-cis-diltiazem hydrochloride were used as hydrophilic model drugs, and nitro-2-furaldehyde semicarbazone (Nitrofurazon) was used as a hydrophobic model drug. Permeation experiments were carried out in a semi-infinite reservoir/receptor system to simulate in-vitro drug release. The intrinsic permeability and diffusivity (P, D) of the drugs through the membranes were determined using a modified time-lag method based on short time permeation and mass balance method based on long time permeation. The partition coefficients Kd of the drugs in the membranes and the swelling degree of the membranes were determined by sorption/desorption experiments. The diffusivities of the drugs were also determined from the sorption/desorption kinetics. Over the experimental ranges tested, the drug concentration and membrane cross-linking did not have significant effects on these parameters presumably due to the relatively low drug concentrations and mild crosslinkings of the membranes. The diffusivity coefficients of ciprofloxacin hydrochloride, (+)-cis-diltiazem hydrochloride and nitrofurazon in the membranes were found to be in the range of (2.0-2.6)×〖10〗^(-9)±2.6×〖10〗^(-10) cm2/s, (2.5-2.6) ×〖10〗^(-9)±1.1×〖10〗^(-10) and (38-134) ×〖10〗^(-9)±33.1×〖10〗^(-9) (cm2/s), respectively, and their permeability coefficients were in the range of (24-29)×〖10〗^(-8),(51-52) ×〖10〗^(-8) and (131-169) ×〖10〗^(-8) (cm2/s), respectively. The partition coefficients were determined to be around 0.91±0.21, 25±0.12 and 26±0.31, respectively. The diffusivity coefficients determined from sorption experiments for ciprofloxacin hydrochloride, diltiazem hydrochloride and nitrofurazon were found to be in the range of (3.2-7.6) ×〖10〗^(-9)±6.3×〖10〗^(-8), (6-10) ×〖10〗^(-9)±2.6×〖10〗^(-8) and (15-18) ×〖10〗^(-9)±2.7×〖10〗^(-7) (cm2/s), respectively. Also the diffusivity coefficients determined from sorption experiments for ciprofloxacin hydrochloride, diltiazem hydrochloride and nitrofurazon were in the range of (20-47) ×〖10〗^(-9), (12-24) ×〖10〗^(-9) and (11-20) ×〖10〗^(-9) (cm2/s), respectively. Nonetheless the differences in the diffusivities calculated from permeation and sorption/desorption experiments are considered to be acceptable, in view of the different experimental techniques used in this work, for the purpose of comparison of the membrane diffusivity and permeability.

Thesis (M.S.)--University of Delaware, 2008. / Principal faculty advisor: Haiqiang Chen, Animal & Food Sciences. Includes bibliographical references.

Thesis (M.Sc.)--Memorial University of Newfoundland, 2004. / Restricted until October 2005. Bibliography: leaves 135-154.

Made available in DSpace on 2014-06-11T19:23:32Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-11-24Bitstream added on 2014-06-13T20:50:29Z : No. of bitstreams: 1 jorge_pcs_me_arafcf.pdf: 737046 bytes, checksum: dec84c3ab28e6bf448b4986f93072480 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Os filmes e revestimentos biodegradáveis são usados para revestir os alimentos, agindo como barreira à umidade e a gases, reduzindo a respiração e as perdas de água por transpiração e desidratação, além do escurecimento enzimático, e mantendo as características do alimento, com aumento da vida de prateleira. Este trabalho teve como objetivos reunir informações sobre o uso da quitosana como revestimento de frutas e vegetais, visando dar suporte ao trabalho experimental; avaliar maçãs revestidas com quitosana comercial, durante o armazenamento à temperatura ambiente, simulando as condições de comercialização das frutas para o mercado interno; avaliar maçãs revestidas com quitosana comercial durante 6 meses de armazenamento sob atmosfera controlada e baixa temperatura, condições de estocagem das frutas para o mercado externo, seguido de armazenamento por 30 dias em atmosfera ambiente e baixa temperatura, visando simular o transporte das frutas para o mercado consumidor no exterior, e posteriormente estocadas à temperatura ambiente, simulando as condições de comercialização; e avaliar maçãs revestidas com quitosana modificada, quando submetidas à temperatura ambiente, visando prolongar a vida de prateleira durante a comercialização, após 6 meses de armazenamento sob atmosfera controlada e baixa temperatura, seguidos de armazenamento por 30 dias em atmosfera ambiente e baixa temperatura. Maçãs ‘Royal Gala’ foram produzidas na safra de 2009, e após a colheita foram separadas em 3 lotes, sendo as frutas do 1o lote revestidas com quitosana comercial; as do 2o lote imersas em solução de ácido acético, que foram usadas como branco e as maçãs do 3o lote não receberam tratamento e foram usadas como controle. Após 6 meses de armazenamento sob atmosfera controlada e baixa temperatura, seguido de mais 30 dias de armazenamento em atmosfera ambiente... / The films and biodegradable coatings are used to coat the food, acting as a barrier to moisture and gases, reducing the respiration and water loss by transpiration and dehydration in addition to the enzymatic browning, maintaining the characteristics of food, with increased of shelf life. This study aimed to gather information about the use of chitosan as a coating for fruits and vegetables, aiming to support the experimental work; evaluate apples coated with commercial chitosan coating during storage at ambient temperature, simulating the real conditions of sale of the fruit for the domestic market; evaluate apples coated with commercial chitosan during 6 months of storage under controlled atmosphere and low temperature, storage conditions of fruit for the export market, followed by 30 days storage under at ambient and low temperature, in order to simulate the transport of fruit to the consumer market abroad, and subsequently stored at ambient temperature, simulating the conditions of marketing; and evaluate apples coated with modified chitosan, at ambient temperature, in order to prolong the shelf life during marketing after six months storaged under controlled atmosphere and low temperature, followed by another 30 days storage under at ambient atmosphere and low temperature. ‘Royal Gala’ apples were produced in 2009 crop and after the harvest they were separated into 3 lots, the first batch of fruit coated with commercial chitosan, those from second lot were immersed in an acetic acid solution and used as blank and the third lot of apples used as controls received no treatment. After 6 storage months under controlled atmosphere and low temperature, followed by another 30 days storage under at ambient atmosphere and low temperature apples without any treatment were separated in 2 lots, being the first batch of fruit coated with modified chitosan, and the second batch used as controls... (Complete abstract click electronic access below)

Submitted by Maria Medeiros (maria.dilva1@ufcg.edu.br) on 2018-06-25T14:25:31Z No. of bitstreams: 1 JACKSON BORBA DA CRUZ - TESE (PPGCEMat) 2015.pdf: 4572910 bytes, checksum: 529c14d2c73d94769063607a9a287e65 (MD5) / Made available in DSpace on 2018-06-25T14:25:31Z (GMT). No. of bitstreams: 1 JACKSON BORBA DA CRUZ - TESE (PPGCEMat) 2015.pdf: 4572910 bytes, checksum: 529c14d2c73d94769063607a9a287e65 (MD5) Previous issue date: 2015-05-22 / As neoplasias constituem um conjunto de doenças que se caracterizam por uma massa anormal de tecido com crescimento descontrolado e excessivo em relação aos demais tecidos normais. De acordo com o comportamento biológico, elas podem ser classificadas em benignas ou malignas (câncer). Segundo o Instituto Nacional de Câncer (INCA), são esperados 576 mil casos novos de câncer para 2014 e 2015 no Brasil. O combate ao câncer é feito com medidas preventivas, diagnóstico precoce e tratamento. O sistema de liberação controlada de fármacos através da utilização de biomateriais poliméricos associados a compostos com ação antineoplásica pode ser empregado como alternativa de tratamento para esta patologia. Desta forma, este trabalho tem como objetivo a síntese e caracterização de arcabouços de quitosana utilizados como carreadores da droga antitumoral (1,4- Naftoquinona), cuja taxa de liberação poderá ser controlada pela utilização de um agente reticulante como o tripolifosfato de sódio (TPP), com a perspectiva da confecção de um sistema de liberação controlada de fármacos antitumorais. O método consiste na solubilização da quitosana em ácido acético, adição do fármaco, congelamento, liofilização e reticulação com TPP. Todas as amostras foram caracterizadas por Difração de Raios X (DRX), Microscopia Eletrônica de Varredura (MEV), Espectroscopia de Energia Dispersiva de Raios X (EDS), Espectroscopia na Região do Infravermelho com Transformada de Fourier (FTIR) e Biodegradação Enzimática, A microscopia (MEV) evidenciou a formação de arcabouços porosos de quitosana (Q), quitosana com TPP (QT), quitosana com 1,4 – Naftoquinona (QN) e quitosana com TPP e 1,4 – Naftoquinona (QNT). Já no EDS foi observada a presença de elementos químicos como sódio, fósforo, nitrogênio, carbono e oxigênio. A reticulação dos arcabouços, comprovada pelo FTIR, DRX, Termogravimetria, Grau de Intumescimento e EDS, aumentou a taxa de degradação dos mesmos demonstrada pelo ensaio de Biodegradação Enzimática. A incorporação do fármaco foi confirmada por DRX, FTIR, Grau de Intumescimento e Termogravimetria. Desta forma, pode-se concluir que houve à formação de arcabouços reticulados e não reticulados porosos, com propriedades morfológicas e físico-químicas que podem contribuir para carrear fármacos antineoplásicos, sendo possível controlar a taxa de degradação dos mesmos e consequentemente a liberação do fármaco. / The neoplasias are a group of disorders characterized by an abnormal mass of tissue which has uncontrolled and excessive growth when compared to normal tissue. According to their biological behavior, they can be classified as benign or malignant (cancer). According to the National Cancer Institute (NCI), it is expected that there will be 576,000 new cancer cases in Brazil during 2014 and 2015. The fight against cancer is done with preventive measures, early diagnosis and treatment. The controlled release system of drugs through the use of polymeric biomaterials associated with the compounds that have an antineoplastic action can be used as an alternative treatment for this disease. Thus, this work has as the objective, the synthesis and characterization of chitosan scaffolds used as carriers for antitumor drugs (1,4 Naftoquinona), whose release rate can be controlled by using a crosslinking agent such as sodium tripolyphosphate (TPP), with the prospect of making a controlled release system for antitumor drugs. The method comprises in the solubility of chitosan in acetic acid, drug addition, freezing the material, lyophilization and crosslinking with TPP. All samples were characterized by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS), Fourier Transform Infrared Spectroscopy (FTIR), and Enzymatic Biodegradation. The Microscopy (SEM) showed the formation of porous scaffolds of chitosan (Q), chitosan with TPP (CT), chitosan with 1.4 - Naftoquinona (QN) and chitosan with TPP and 1.4 - Naftoquinona (QNT). EDS showed the presence of chemical elements such as sodium, phosphorus, nitrogen, carbon and oxygen. The crosslinking of the scaffolds, proven by FTIR, XRD, Thermogravimetry, Degree of Swelling and EDS, increased its rate of degradation thereof, as demonstrated by the Enzymatic Biodegradation test. The incorporation of the drug was confirmed by XRD, FTIR, Degree of Swelling and Thermogravimetry. Thus, it can be concluded that there was the formation of crosslinked and non-crosslinked porous scaffolds, with morphological and physicochemical properties that can contribute to the carrying of antineoplastic drugs, being possible to control their degradation rate and consequently drug release.

O presente estudo avaliou, por meio de microscopia eletrônica de varredura (MEV) e análise Fourier Transform Infrared Spectroscopy (FT-IR), a capacidade de limpeza e as alterações da superfície dentinária após diferentes tratamentos. Foram utilizados 32 incisivos bovinos, dos quais obteve-se uma amostra de dentina do terço médio radicular de cada espécime. Inicialmente as 32 amostras foram analisadas em FT-IR após os seguintes tratamentos: dentina normal, sem tratamento (T1); NaOCl 2,5% por 5´ (T2). Os espécimes foram, então, distribuídos em quatro agrupamentos conforme tratamento com soluções (n=8): T3- EDTA 15%; T4- quitosana 1% diluída em ácido acético 1% + genipina 0,06%; T5- quitosana 1% diluída em ácido acético 1% + EDTA 15% + genipina 0,06%; T6- quitosana 1% diluído em EDTA 5% + genipina 0,06%. Os dados referentes a relação amidaIII/fosfato de cada tratamento foi submetida ao teste ANOVA, com dados vinculados seguido do teste de Tukey (p<0,001). Para a avaliação em MEV, após biomecânica de 8 raízes bovinas com limas rotatórias e NaOCl 2,5%, as mesmas foram distribuídas em 4 grupos (n=2), conforme irrigação final. As soluções utilizadas em G1, G2 G3 e G4 foram, respectivamente, as mesmas empregadas em T3, T4, T5 e T6, com volume de 1mL por 5´. Foram obtidas 6 fotomicrografias do terço médio radicular de cada espécime para análise da capacidade de limpeza e da deposição de quitosana/genipina sobre a superfície dentinária. Os resultados mostraram não haver diferença na porcentagem da razão amidaIII/fosfato entre T1 e T2. Houve diferença significante entre a porcentagem da razão amidaIII/fosfato de T3, T4, T5 e T6 em relação à T1. A porcentagem da razão amidaIII/fosfato foi significantemente menor para T4 em relação a T3, T5 e T6. Todos os grupos, com exceção de G2, removeram a camada de smear. Observou-se deposição de quitosana/genipina sobre a dentina do G3 e G4. Dentre os tratamentos propostos, o uso de quitosana solubilizada em EDTA associada à genipina removeu a camada de smear sem erudir o tecido, além de evidenciar a presença de aglomerado de quitosana/genipina sobre a superfície dentinária. / The present study evaluated, by scanning electron microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FT-IR) analysis, the cleaning ability and the changes of the dentin surface after different treatments. Thirty-two bovine incisors were used, from which a dentin sample was obtained from the middle third of each specimen. Initially the 32 samples were analyzed in FT-IR after the following treatments: normal dentin, without treatment (T1); NaOCl 2.5% by 5\' (T2). The specimens were then distributed into four groups according to treatment with solutions (n = 8): T3- EDTA 15%; T4- chitosan 1% diluted in acetic acid 1% + genipine 0.06%; T5- chitosan 1% diluted in acetic acid 1% + EDTA 15% + genipine 0.06%; T6 chitosan 1% diluted in 5% EDTA + 0.06% genipine. The data concerning the amideIII / phosphate ratio of each treatment was submitted to the ANOVA test, with bound data followed by the Tukey test (p <0.001). For evaluation in SEM, after biomechanics of 8 bovine roots with rotating files and 2.5% NaOCl, they were distributed in 4 groups (n = 2), according to final irrigation. The solutions used in G1, G2, G3 and G4 were, respectively, the same as those employed in T3, T4, T5 and T6, with a volume of 1mL per 5\'. Six photomicrographs of the root mean third of each specimen were obtained for analysis of the cleaning capacity and chitosan/genipine deposition on the dentin surface. The results showed no difference in the percentage of the amide III/phosphate ratio between T1 and T2. There was a significant difference between the percentage of amide III/phosphate ratio of T3, T4, T5 and T6 in relation to T1. The percentage of the amide III/phosphate ratio was significantly lower for T4 compared to T3, T5 and T6. All groups, except for G2, removed the smear layer. Chitosan/genipine deposition was observed on G3 and G4 dentin. Among the proposed treatments, the use of chitosan solubilized in EDTA associated to genipine removed the smear layer without erode the tissue, besides evidencing the presence of agglomerate of chitosan/genipine on the dentin surface.