Luminescent semiconductor quantum dots (QDs) are extensively researched for use in biological applications. They have unique optical and physical properties that make them excellent candidates to replace conventional organic dyes for cellular labeling, multiplexing, nucleic acid detection, and as generalized probes. The primary focus of this dissertation was to utilize quantum dots for improvement in immunoassays. Specifically, atherosclerosis biomarkers were detected simultaneously in an effort to demonstrate advances in early detection diagnostics. Quantum dot-antibody bioconjugates were prepared by encapsulation into mesoporous silica and functionalized with thiol and amine groups to enable bioconjugation. Functionalization of the mesoporous silica quantum dot composites facilitated biocompatibility for use with biological buffers in immunoassays. These bioconjugates were used in a sandwich immunoassay to detect atherosclerosis biomarkers IL-15 and MCP-1. Sandwich assays employ capture antibodies immobilized onto a well plate to bind as much of the antigen as possible. The capture antibodies increased binding by at least 4 times the amount of antigen bound to the surface of a direct detection assay. The sandwich immunoassay was able to detect 1 pg/mL of IL-15 and 50 pg/mL of MCP-1 biomarkers. Human serum albumin nanoparticles (HSAPs) were synthesized via a desolvation and crosslinking method. Human serum albumin is a versatile protein being used in a variety of applications. Quantum dots were loaded into HSAPs as potential detection probes for immunoassays. Efficient loading was not achieved, and the assay was unable to improve current detection limits. Controlled release studies were explored using HSAPs loaded with superparamagnetic iron oxide nanoparticles and a fluorescent drug analog. Exposure to a magnetic field resulted in degradation of the HSAPs. The fluorophore was released and measured to examine how cancer drugs might be controlled through a magnetic field. Gold nanorods and an anticancer drug, Sorafenib, were also encapsulated into HSAPs for treatment of renal cell carcinoma in vivo. Laser irradiation treatment combined with Sorafenib resulted in 100% tumor necrosis and total elimination of any viable tumor present. HSAPs have demonstrated remarkable potential as drug delivery nanocarriers.

Characterization of in vitro and in vivo drug release profiles constitutes an important step in developing and optimizing an effective, long acting delivery system for naltrexone. Accelerated in vitro methods are also important for quality assurance of manufactured dosage forms. For drug release testing of sustained release parenteral dosage forms, the modified USP Apparatus 4 (flow-through cell) has been recommended by the The Fédération Internationale Pharmaceutique/American Association of Pharmaceutical Scientists (FIP/AAPS) Guidelines. Details on such studies however, are generally not found in the literature. To incorporate 'biorelevance' to implant drug release studies, this research investigated an approach to apparatus design and media selection that is significantly different from conventional dissolution studies involving oral dosage forms.Biodegradable implants of naltrexone were obtained from Durect Corporation, USA. A modified Hanks' Balanced Salts Solution was characterized as a 'biorelevant' medium for in vitro drug release studies. Naltrexone was found to be sufficiently stable in the medium, as determined by a stability-indicating High Performance Liquid Chromatography (HPLC) assay. A miniature, cell-culture, capillary system was modified and tested as a 'biorelevant' alternative to the modified flow-through apparatus, to mimic significant barriers to drug release that would be expected in vivo. The in vitro release profiles generated up to 3 months using both devices indicated considerable (2-fold) variation in rates, as expected from the difference in media flow characteristics. An implantation study in a dog was conducted to determine which of the two devices could provide a better simulation of the in vivo conditions. Analysis of in vivo samples was carried out by a Liquid Chromatography-Tandem Mass Spectrometry (LC-MS-MS) method that also employed a molecular model approach to demonstrate the absence of Internal Standard Deuterium Isotope Effects. A good In vitro-In vivo Correlation (IVIVC) resulted from both devices; however, the capillary device provided a superior simulation for the lag-time in absorption. The accelerated study at 45°C and 55°C established a predictable increase in release rates (2-fold and 4-fold increases, respectively). The approach described in this work could provide the basis for future method modification of in vitro drug release tests of subcutaneous implants.

CHARLES UNIVERSITY IN PRAGUE Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical technology Name of the student: Hana Jakubíková Title of diploma thesis: Aciclovir release from mucoadhesive polyester matrices Consultant: PharmDr. Eva Šnejdrová, Ph.D. The aim of this diploma thesis was to investigate aciclovir release from polyesters of lactic acid and glycolic acid branched with mannitol, pentaerythritol, dipentaerythritol and tripentaerythritol, and plasticized using ethyl pyruvate or methyl salicylate. Theoretical part sums up the application possibilities of mucoadhesive preparations. Experimental part of thesis deals with aciclovir release from polyester matrices applied on mucous substrate. Short term dissolution experiments of aciclovir were carried out in phosphate citrate buffer of pH 7, 4 at 37 řC. Mucus from porcine stomach was used as model substrate. The amount of aciclovir released was determined spectrophotometrically at 256 nm contrary to a blank sample, and also using HPLC method. Dissolution of aciclovir was affected by molar mass of polyester, and by the type and concentration of plasticizer. Polyester branched with 3 % of tripentaerythritol, and plasticizes by 40 % of methyl salicylate was found to be most suitable carrier of aciclovir for topical application on...

L’objectif de ce travail de thèse est d’étudier la relation entre la méthode de préparation des nanoparticules, les propriétés colloïdales et l’encapsulation d’un principe actif à usage pédiatrique. Dans ce but, le diclofenac a été utilisé comme molécule modèle et les nanoparticules ont été préparées via la nanoprécipitation et l’émulsification-diffusion. Des études fondamentales et systématiques ont permis de mettre en évidence l'existence de différences notables entre les propriétés électrocinétiques et l'efficacité d’encapsulation en fonction du procédé utilisé pour la préparation des particules. Ces propriétés colloïdales et physico-chimiques sont primordiales pour la bonne stabilité des dispersions de nanosphères et des nanocapsules et pour le comportement de ces vecteurs lors d’utilisation in vivo. Cette étude a permis de proposer et de discuter le mécanisme de formation des nanoparticules en se basant sur le comportement des variables critiques du procédé et de la formulation, les propriétés de surface et l'efficacité d’encapsulation de l’actif modèle / The objective of this PhD thesis is to point out the relationship between the preparation method of the nanoparticles, the colloidal properties and the encapsulation efficiency of a given active molecule for paediatric purpose. In this direction, diclofenac was used as model molecule and the nanoparticles were prepared via the nanoprecipitation and the emulsification-diffusion processes. The conducted fundamental and systematic studies rend evident notable differences between the two processes, particularly in the electrokinetic properties of the particles and the effectiveness of the drug encapsulation. These colloidal and physicochemical properties are paramount for the good stability of the nanoparticles and their in vivo use. This research work made it possible to propose and to discuss the mechanism of nanoparticle formation from the behavior of key variables of the process and the recipe used, the surface properties of the particles and the effectiveness of encapsulation of the model drug

A liberação controlada de fármacos é um tópico importante para várias iniciativas em nanotecnologia devido ao possível impacto para a sociedade, com a criação de sistemas otimizados que garantam a liberação num sítio específico e a uma taxa controlada. Dentre os vários paradigmas de liberação controlada destaca-se o uso de lipossomos, uma vez que muitos fármacos e drogas podem ser transportados. Este trabalho descreve a fabricação de filmes automontados de lipossomos que incorporam o fármaco ibuprofeno. Os lipossomos foram preparados de dipalmitoil fosfatidil colina (DPPC), dipalmitoil fosfatidil glicerol (DPPG) e palmitoil-oleoil fosfatidil glicerol (POPG), cujas camadas foram alternadas por interações eletrostáticas com camadas do dendrímero PAMAM geração 4. Medidas de espalhamento dinâmico de luz indicaram que a incorporação do ibuprofeno tornou os lipossomos de DPPC e DPPG mais estáveis, com uma diminuição no diâmetro médio de 140 para 74 nm e 132 para 63nm, respectivamente. Ao contrário, os lipossomos de POPG ficaram menos estáveis, com aumento do diâmetro de 110 para 160 nm. A influência na estabilidade foi confirmada em medidas de microscopia de força atômica nos filmes automontados, que mostraram grande tendência à ruptura nos lipossomos de POPG com a incorporação de ibuprofeno. O crescimento dos filmes automontados foi investigado com espectroscopia de fluorescência e uma balança de cristal de quartzo. A intensidade da fluorescência devida ao ibuprofeno aumentou exponencialmente com o número de camadas depositadas, mas não por causa de uma crescente adsorção de ibuprofeno. Ao contrário, a quantidade de material adsorvido nas primeiras camadas aumentou inicialmente, mas depois diminuiu drasticamente após a 6ª. bicamada, e o filme praticamente pára de crescer a partir da 10ª. bicamada. Portanto, a grande fluorescência para filmes espessos deve ser associada a um ambiente favorável, que aumenta a emissão quântica do ibuprofeno. A liberação do ibuprofeno, estudada com medidas de fluorescência, é mais lenta quando incorporado em lipossomos. Em experimentos com uma membrana de diálise, notamos que o tempo de decaimento do ibuprofeno puro é 5,2 h, enquanto este tempo aumentou para 9,2 e 8 h para ibuprofeno encapsulado em lipossomos de DPPG e POPG, respectivamente. O ibuprofeno também foi liberado de filmes automontados contendo lipossomos de DPPG e POPG, o que é promissor para o uso em bandagens (patches). / Controlled drug delivery is a key issue in a number of nanotechnology endeavors owing to the large impact on society that may achieved if improved systems are created which allows for delivery at a specific target and with a controlled rate. Among the various paradigms employed in drug delivery, the use of liposomes is prominent because a variety of drug molecules can be carried. This work describes the fabrication of layer-by-layer (LbL) films made with liposomes incorporating ibuprofen. The liposomes were made with dipalmitoyl phosphatidyl choline (DPPC), dipalmitoyl phosphatidyl glycerol (DPPG) and palmitoyl-oleoyl-phosphatidyl glycerol (POPG), whose layers were alternated with layers of the dendrimer PAMAM generation 4 via electrostatic interactions. According to dynamic light scattering measurements, the incorporation of ibuprofen caused DPPC and DPPG liposomes to become more stable, with a decrease in diameter from 140 to 74 nm and from 132 to 63 nm, respectively. In contrast, liposomes from POPG became less stable, with an increase in size from 110 to 160 nm. These results were confirmed with atomic force microscopy images of LbL films, which showed a large tendency to rupture for POPG liposomes. The film growth was monitored with fluorescence spectroscopy and a quartz crystal microbalance (QCM). The fluorescence intensity arising from ibuprofen increased exponentially with the number of layers, but this was not caused by an increased adsorption of ibuprofen. Instead, the QCM measurements showed that the amount of material adsorbed increases initially with the number of PAMAM/liposome(ibuprofen) layers, but after the 6th bilayer it decreases sharply and film growth practically stops after the 10th layer. Therefore, the inevitable conclusion is that the increased fluorescence is due to a favorable environment for the ibuprofen, whose quantum emission efficiency increases with the number of layers deposited. Also using fluorescence measurements, we noted that release of ibuprofen was delayed when incorporated in liposomes. For instance, in a membrane dialysis experiment, the characteristic decay time was 3.5 h for ibuprofen in solution, whereas this time increased to 9.2 and 8 h for ibuprofen encapsulated into DPPG and POPG liposomes, respectively. Ibuprofen could also be released from the LbL films made with DPPG and POPG liposomes, which is promising for further use in patches.

A evolução das resinas compostas fez com que esses materiais passassem a ter uma durabilidade maior e características estéticas muito boas, mas o risco de cárie recorrente é ainda um problema a ser resolvido. Na tentativa de solucionar esse problema, estudos vêm sendo conduzidos na tentativa de se formularem resinas compostas contendo agentes antibacterianos, como é o caso da incorporação de clorexidina (CHX). Outro fato que impede a longevidade deste material é a degradação de matriz de colágeno por proteases ativadas por pH ácido. Para tentar contornar esse problema, a adição de clorexidina, assim como Epigallocatechin gallate (EGCg), clássicos antibacterianos e inibidores de proteases da matriz , como as metaloproteinases da matriz (MMP) a resinas, poderia melhorar a eficácia destes materiais como substitutos de dentina em procedimentos restauradores, aumentando a longevidade do tratamento restaurador, mediante preservação das propriedades mecânicas do material. Assim, o objetivo desse estudo é avaliar o poder de inibição de resinas experimentais contendo inibidores conhecidos de proteases da matriz sobre gelatinases e colagenase. Para isso, copolímeros experimentais foram preparados combinando Bis-GMA com o diluente TEGDMA (70/30 mol%). Com exceção do copolímero placebo (sem drogas), EGCg ou CHX foram incorporados a 1% em peso isoladamente ou em combinação, a 0,5% em peso cada. Amostras contendo EGCg, CHX ou EGCg e CHX concentradas 10X foram obtidas do armazenamento de espécimes polimerizados da resina experimental em água deionizada (1 mL) após o período de 24h a 37°C e sua posterior concentração. O efeito da ação dos inibidores foi checado por zimografia e confirmado por um ensaio enzimático específico para colagenases e gelatinases. Os dados passaram por teste de homogeneidade (Bartlett) e normalidade (Kolmogorov-Smirnov) e foram avaliados por ANOVA a 2 critérios, seguido pelo teste de Bonferroni para comparações individuais (p<0,05). Os resultados do presente estudo, mostraram que, in vitro, a liberação de EGCg e CHX incorporados em resinas é capaz de reduzir a atividade gelatinolítica das MMPs -2 e -9, bem como a atividade da colagenase bacteriana, sugerindo um efeito potencial no aumento da longevidade de restaurações de resinas. Com isso, podemos afirmar que a liberação de ativos de resinas experimentais é possível e que esses ativos são capazes de inibir as MMPs, assim sugerindo um novo substituto para dentina em procedimentos restauradores. / The evolution of composite resins made these materials to have a greater durability and very good esthetics characteristics, but the risk of recurrent caries is still a problem to be solved. In the attempt to solve this problem, studies are being conducted with the purpose to formulate composite resins containing antibacterial agents, such as chlorhexidine (CHX). Another fact that prevents the longevity of this material is the degradation of the collagen matrix by the proteases activated by acidic pH. In order to solve this problem, the addition of chlorhexidine and/or Epigallocatechin gallate (EGCg), classical antibacterial agents and inhibitors of matrix proteases, such as matrix metalloproteinases (MMP) in resins, could improve the efficacy of these materials as dentin substitutes in restorative procedures, increasing the longevity of the restorative treatment, while preserving the mechanical properties of the material. Thus, the aim of this study is to evaluate the ability of experimental resins containing known matrix protease inhibitors on the inhibition of gelatinases and collagenase. For this purpose, experimental copolymers were prepared combining Bis-GMA with the diluent TEGDMA (70/30 mol%). Except for the placebo copolymer (drug free), EGCg or CHX were incorporated at 1% in weight, isolated or in combination (0.5% in weight each). Samples containing EGCg, CHX or EGCg and CHX concentrated 10X were obtained after storage of polymerized specimens of the experimental resin in deionized water (1 mL) after the period of 24 h, at 37°C and after that were concentra. The effect of the action of the inhibitors was checked by zymography and confirmed by an enzymatic test specific for collagenases and gelatinases. The data passed in the tests of homogeneity (Bartlett test) and normality (Kolmogorov-Smirnov test), and were evaluated by 2-way ANOVA, followed by Bonferroni test for individual comparisons (p<0.05). The results of this study showed that the in vitro release of EGCG and CHX incorporated in resins was able to reduce the gelatinolytic activity of MMPs-2 and -9 and bacterial collagenase activity, suggesting a potential effect in increasing the longevity of resin restorations. It can be concluded that the release of drugs from experimental resins is possible and that these drugs are able to inhibit MMPs, thereby suggesting a new substitute for dentin in restorative procedures.

This thesis focuses on improved processing methods for enhanced mechanical properties in polymer nanocomposites, and controlled drug release in polymer based delivery systems. Supercritical carbon dioxide assisted mixing was successfully used in preparation of polypropylene/sepiolite and polypropylene/multiwall carbon nanotube nanocomposites. Relatively homogeneous dispersed and well separated nanofillers were obtained throughout the PP matrix. A better preservation of nanofiller lengths was observed in the scCO 2 assisted mixing. Mechanical property studies showed a marked increase in Young's modulus and tensile strength with the addition of nanofillers. More interestingly, techniques usually designed to achieve high quality PP nanocomposites, such as the use of masterbatches, maleic anhydride grafted polypropylene compatibilizers or polymer coated MWNTs are not needed to achieve equivalent mechanical properties with scCO2 assisted mixing. ScCO2 was also used as a foaming technique to modify the traditional cured poly(ethyl methacrylate/tetrahydrofurfuryl methacrylate) system for a controlled release of chlorhexidine. Highly porous structures were produced and chlorhexidine released from scCO2 foamed samples was more than 3 times higher than traditionally cured samples. By altering the processing conditions, such as CO2 saturation time and depressurization time the CX release rate was altered. Finally, the electrospinning method was combined with the layering encapsulation technique in order to enable the incorporation of water-soluble drugs in poly(lactic-co-glycolic acid) fibres for biomedical applications. Water-soluble drug, Rhodamine 6G or protein bovine serum albumin, loaded calcium carbonate microparticles were successfully incorporated in PLGA fibres and a bead and string structured composite fibres.

Jusqu'à aujourd'hui, le traitement des maladies oculaires postérieures, telles que la dégénérescence maculaire liée à l'âge, la rétinopathie diabétique et l'uvéite, reste difficile. L'œil avec ses différentes barrières oculaires est bien protégé des agressions extérieures. Ces barrières réduisent également la biodisponibilité des médicaments pour le vitré. Après une administration topique, seule une quantité limitée (0,001 - 0,0004 %) permet d'atteindre le vitreux. Ceci est causé par exemple par une dilution des larmes et une faible perméabilité cornéenne du médicament. Après une administration systémique ou orale, les barrières hémato-oculaires empêchent le médicament d'entrer et seulement environ 2 % du médicament administré se trouve dans le vitré. Afin d'atteindre des concentrations thérapeutiques, une dose élevée doit être administrée, ce qui augmente le risque d'effets secondaires. La façon la plus efficace de traiter les maladies postérieures restent l'injection intravitréenne. Cependant, de petites molécules lipophiles comme la dexaméthasone peuvent facilement se diffuser à travers la rétine et les barrières oculaires et ont donc une demi-vie limitée de quelques heures seulement. Étant donné que de nombreuses maladies postérieures sont chroniques, une injection intravitréenne fréquente serait nécessaire. Chaque injection comporte des risques de décollement de la rétine, d'hémorragie et d'autres effets secondaires. Les implants biodégradables pour administration intravitréenne peuvent prolonger la libération du médicament et en diminuer les effets secondaires. PLGA est un polymère largement utilisé qui est biocompatible et biodégradable. Il peut également soutenir la libération du médicament de quelques jours à plusieurs mois. Dans cette étude, les implants de formation in situ (ISFI) et les implants préformés préparés par extrusion à chaude ont été étudié en profondeur. L'objectif de ce travail était (i) d'étudier l'impact du volume du rejet (ii) évaluer le comportement de libération, de gonflement et de dégradation des implants préformés préparés avec différentes charges de médicament et différents types de polymères, (iii) visualiser la libération de médicament et l'absorption d'eau des implants préformés et de l'ISFI en utilisant des médicaments modèles colorés et (iv) étudier l'effet des quantités variables des différents additifs sur les caractéristiques essentielles de l'ISFI. Ces informations peuvent aider à fabriquer des implants avec différents profils de libération. Nos études montrent que l'ISFI est assez robuste en ce qui concerne les différents volumes de l'humeur vitreuse que l'on peut rencontrer in vivo. Cependant, le poids moléculaire et la concentration du polymère ont une forte influence sur la morphologie et le gonflement de l'implant. Par conséquent, la dégradation et la libération du médicament sont affectées. Pour les implants préformés, le gonflement "orchestre" la libération du médicament. Au début, seule une quantité limitée d'eau peut se diffuser dans les implants. Ainsi, seules des quantités insignifiantes du médicament sont dissoutes et peuvent être libérées. Lorsque le PLGA commence à se dégrader, le polymère devient plus hydrophile et de plus grandes quantités d'eau peuvent pénétrer. Ce gonflement du polymère facilite la dissolution et la diffusion du médicament et déclenche la libération du médicament. Les études utilisant des médicaments modèles colorés corroborent le rôle de la pénétration de l'eau et de la dissolution du médicament pour les implants préformés. En ce qui concerne l'ISFI, il a visualisé l'importance de la concentration du polymère sur la structure interne de l'implant qui en résulte et par conséquent l'absorption d'eau et la libération du médicament. Le comportement de gonflement et la morphologie de l'ISFI pourraient également être modifiés de manière significative en utilisant différents additifs. L'effet global sur la libération du médicament a été limité. / Until today, the treatment of posterior eye diseases, such as age-related macular degeneration, diabetic retinopathy and uveitis, remains challenging. The eye with its different ocular barriers is well protected from external factors. Those barriers also reduce the bioavailability of drugs to the vitreous. After a topical administration, only a limited amount (0.001 – 0.0004 %) reaches the vitreous. This is caused by for example reflexive blinking, tear dilution and a low corneal permeability of the drug. After a systemic or oral administration, the blood-aqueous and the blood-retinal barrier hinder the drug from entering and only around 2 % of the administered drug is found in the vitreous. In order to reach therapeutic concentrations, a high dose has to be given which in turn increases the risk for systemic side effects. The most efficient way to treat posterior diseases remains the intravitreal injection. However, small lipophilic molecules like dexamethasone can easily diffuse through the retina and the blood-ocular barriers and, thus, have a limited half-life of just a few hours. Since many of the posterior diseases are chronic, a frequent intravitreal injection would be necessary. Every intravitreal injection bears the risks for retinal detachment, hemorrhage, and other side effects. Biodegradable implants for intravi-treal administration can prolong the drug release and in turn decrease the side effects. Poly(lac-tic-co-glycolic acid) (PLGA) is a widely used polymer that is biocompatible and biodegrada-ble. It can also sustain the drug release from a few days up to several months. In this study, in-situ forming implants (ISFI) and pre-formed implants prepared via hot melt extrusion were studied in depth. The aim of this work was (i) to study the impact of the volume of the release medium, polymer type and concentration as well as drug content of different ISFI, (ii) to eval-uate the drug release, swelling and degradation behavior of pre-formed implants prepared with different drug loadings and polymer types, (iii) to visualize the drug release and water uptake of ISFI and pre-formed implants using colored model drugs and (iv) to investigate the effect of varying amounts of different additives on key features of ISFI. This knowledge can help to manufacture implants with different release profiles. Our studies show that ISFI are rather ro-bust regarding different volumes of the vitreous humor that could be encountered in vivo. How-ever, the polymer molecular weight and polymer concentration have a strong influence on the morphology and swelling behavior of the implants. Consequently, the degradation and drug release are affected. For pre-formed implants the swelling “orchestrates” the drug release. In the beginning only limited amounts of water can diffuse into the implants. Thus, only insignif-icant amounts of the drug are dissolved and can be released. When the PLGA starts to degrade, the polymer becomes more hydrophilic and bigger amounts of water can penetrate. This poly-mer swelling facilitates drug dissolution and diffusion and initiates the drug release. The studies using colored model drugs corroborate the role of water penetration and drug dissolution for pre-formed implants. Concerning ISFI, it visualized the importance of the polymer concentra-tion on the resulting inner implant structure and consequently the water uptake and drug release. The swelling behavior and morphology of ISFI could also be significantly altered using differ-ent additives. The overall effect on the drug release was limited.

The breath figure method is a versatile and facile approach of generating ordered micro and nanoporous structures in polymeric materials. When a polymer solution (dissolved in a high vapor pressure organic solvent) is evaporated out in the presence of a moist air stream, the evaporative cooling effect causes the condensation and nucleation of water droplets onto the polymer solution surface. This leads to the formation of an imprinted porous structure upon removal of the residual solvent and water. The facile removal of the water droplet template leaving its structural imprint is a specifically appealing aspect of the breath figure film technology. The first part of the dissertation work involves the fabrication of drug loaded breath figure thin films and its utilization as a controlled drug release carrier and biomaterial scaffold. In a single fabrication step, single layer/multilayer porous thin films were designed and developed by combining the breath figure process and a modified spin or dip coating technique. Using biodegradable polymers such as poly (lactic-co-glycolic acid) (PLGA) and poly (ethylene glycol) (PEG), drug loaded films were fabricated onto FDA approved medical devices (the Glaucoma drainage device and the Surgical hernia mesh). The porosity of the films is in the range of 2-4 µm as characterized by scanning electron microscope. The drug coated medical implants were characterized for their surface and bulk morphology, the degradation rate of the film, drug release rate and cell cytotoxicity. The results suggest that the use of breath figure morphologies in biodegradable polymer films adds an additional level of control to drug release. In comparison to non-porous films, the breath figure films showed an increased degradation and enhanced drug release. Furthermore, the porous nature of the film was investigated as a biomaterial scaffold to construct three dimensional in vitro tissue model systems. The breath figure film with interconnected pores facilitates cell infiltration and tissue remodelling in vitro, suggesting its high potential in regenerative medicine and tissue engineering applications. In the second part of the dissertation, the versatility of breath figure polymers was explored as a reverse template to create micropatterned soft materials. Unlike traditional lithographic masters, the breath figure assembly is a simple and cost-effective approach to create micro/nano sized “bead†like uniform patterns on the surface of hydrogels and biopolymers. By incorporating iron nanoparticles into the pores, this technique was extended to form hydrogels decorated with nanoparticles specifically in the pattern. The morphology features and the functional characteristics were demonstrated through scanning electron microscopy. The potential applications of these micro-fabricated materials in biosensors and cell culture substrates are outlined. / acase@tulane.edu

<p>The focus of this study is to synthesize a novel hinged polymer actuator. The linking molecule (hinge) is phenazine with interconnected dipyrrole units.</p>