This research project focused on a range of polysaccharides, including sodium alginates (with varying mannuronic (M)/guluronic (G) acid ratio), pectin and sodium carboxymethylcellulose (CMC), for wound dressing applications. The samples were prepared as mixed salts such as sodium/calcium salts as Ca2+ ions are known to promote faster healing. The aims of this research were: 1- to provide a greater insight into the nature of binding between various ions (NaT, Ca2+ as well as Zn2+ and Ag+) and the polysaccharide molecules. Interactions between alginate/pectin and alginate/CMC molecules were also studied. This was achieved using a range of analytical techniques such as Fourier transform infrared spectroscopy, Raman spectroscopy and neutron spectroscopy, thermogravimetric analysis, microprobe analysis, X-ray diffraction and atomic absorption spectroscopy. It was found that sodium ions were bound to the carboxyl groups of the alginate molecules, whilst calcium ions attached themselves onto COO- as well as onto the alginate backbone, leading to crosslinked structures. Appearance of OH ... -OOC to the detriment of OH ... OH bonding was also observed. Addition of zinc ions involved greater constraint in the alginate network and the silver ions were believed to produce insoluble alginate salts, due to their larger ionic radius; furthermore hydroxyl-hydroxyl interactions in the silver alginate were rather between the polymer molecules than with the water. The addition of pectin to alginate led to partial binding between the two polysaccharides via hydrogen bonds. By contrast, carboxymethylcellulose molecules were found to act as independent entities in contact with alginate, and therefore suggested incompatibility. 2- to determine the performance of sodium/calcium alginate systems as well as Na/Ca alginate/pectin and Na/Ca alginate/CMC systems, in order to improve properties such as absorbency, gel strength and calcium release (to assess the haemocompatibility) in a simulated serum solution. A greater calcium and guluronic acid content was found to improve the gel strength of alginate samples, but decrease the swelling ability. Calcium release was favoured with a low G and a high calcium content. Addition of a second polysaccharide enhanced these gel properties. For example, the gel strength could be significantly increased with a 25 % pectin addition, while addition of CMC up to 50 % increased both the swelling and the calcium release. 3- to develop a new model of the ion release process for a polysaccharide system brought into contact with a simulated serum solution. It was based on a "hoppingtrapping" mechanism for the calcium ions, whereby different release rates are due to different affinities with the polysaccharide blocks.

No description available.

Diabetes is a growing public health problem that can lead to serious complications for the pa-tient such as foot ulcers and amputations. For affected patients the foot ulcers causes suffer-ing, pain and impaired health. The foot ulcers also contribute to major costs to the society and affects healthcare resources hard. A large part of the district nurse's work consists of wound care. Therefore it is important that the district nurse possess adequate knowledge of wound dressings to promote wound healing and thereby shorten the wound healing time. The aim of the study was to examine the wound healing time due to treatment with antiseptic or non-antiseptic dressings in elderly patients with diabetes and foot ulcers. The method used was a quantitative register study with a retrospective and descriptive design. Patients included in the study were 241 men and women aged ≥ 65 years with diabetes and healed foot ulcers. Men were represented by 68 % (n=164) and women by 32 % (n=77). The results showed no signif-icant difference in wound healing time due to treatment with antiseptic or non-antiseptic dressings. The most common non-antiseptic dressing used was polyurethane foam and the most common antiseptic dressing used was silver dressing. More research to compare wound healing time between non-antiseptic and antiseptic dressings in elderly patients with diabetes and foot ulcers are needed. District nurses need to increase their knowledge within different dressings and its positive and negative effects.

This diploma thesis is focused on the study of bioactive wound dressings. During the thesis, hydrogel, lyophilized and nanofiber wound dressings were prepared. Hydrogel and lyophilized wound dressings were prepared on basis of two polysaccharides – alginate and chitosan. Nanofiber wound dressings were prepared by spinning polyhydroxybutyrate. All prepared wound dressings were enriched with bioactive substances, which represented analgesics (ibuprofen), antibiotics (ampicillin) and enzymes (collagenase). Into hydrogel and lyophilized wound dressings were all the mentioned active substances incorporated, whereas nanofiber wound dressings were only with ibuprofen and ampicillin prepared. The theoretical part deals with the anatomy and function of human skin. There was explained the process of wound healing and also there were introduced available modern wound dressings. The next chapter of the theoretical part deals with materials for preparing wound dressings (alginate, chitosan, polyhydroxybutyrate) and with active substances, which were used during the experimental part of this thesis. In the theoretical part, the methods of preparation of nanofiber wound dressings and also the methods of cytotoxicity testing used in this work were presented. The first part of the experimental part of this thesis was focused on preparing already mentioned wound dressings. Then, their morphological changes over time and also the gradual release of incorporated active substances into the model environment were monitored. The gradual release of ampicillin was monitored not only spectrophotometrically, but also by ultra-high-performance chromatography. In wound dressings, in which collagenase was incorporated, was also the final proteolytic activity of this enzyme monitored. The effect of the active substances was observed on three selected microorganisms: Escherichia coli, Staphylococcus epidermidis and Candida glabrata. The cytotoxic effect of the active substances on the human keratinocyte cell line was monitored by MTT test and LDH test. A test for monitoring the rate of wound healing – a scratch test – was also performed.

Syftet med studien är att genom en litteratursammanställning undersöka evidensen för olika förbandsmaterial vid behandling av sår. Kostnaden för behandling av sårrelaterade åkommor uppgår till flera miljarder kronor för Landstingen i Sverige varje år. Målet för sårbehandling ska vara att minska det individuella lidandet, främja en god hälsa och underlätta det dagliga livet, det är därför viktigt att rätt förband används till rätt typ av sår. Studien undersöker även hur Landstinget i Uppsala län har beställt olika typer av förband. Resultatet visar att det finns för lite underlag för att kunna dra konkreta slutsatser huruvida en viss förbandstyp ska användas för en viss typ av sår. Däremot belyser studien behovet av mer forskning inom området. / The purpose of the study is by a literature review investigate the evidence for different kinds of wound dressings in treating wounds. The cost for treatment of wound related affections amounts several billions SEK each year. The aim for wound treatment is to reduce individual suffering, promote good health and facilitate daily life, thus it is important choosing the right wound dressing for the right kind of wound. In combination the usage of wound dressings in Uppsala County Council will also be addressed. The result shows that there is too little research to be able to draw significant conclusions regarding whether a certain type of wound dressing should be used for a specific kind of wound. However the study highlights the need for more research in the area.

Les pansements dits " hydrocolloïdes " sont très couramment utilisés dans le traitement des plaies à forte exsudation. Ils permettent de réguler l'hygrométrie au sein d'une plaie tout en évitant une accumulation d'eau susceptible d'entrainer la prolifération de bactéries entre le pansement et la peau. Deux propriétés antagonistes apparaissent alors nécessaires : une fonction d'adhésion pour assurer le maintien du pansement sur la peau, et de fortes propriétés d'absorption et de perméabilité à l'eau pour réguler l'humidité et favoriser la cicatrisation de la plaie. Pour satisfaire ces deux fonctions, des systèmes hétérogènes sont utilisés : l’adhésion est apportée par une matrice adhésive hydrophobe, composée d’un élastomère modifié par un plastifiant et des résines tackifiantes, la régulation de l’humidité est assurée par de fines particules hydrophiles sèches de carboxymethylcellulose (CMC), dispersées dans la matrice adhésive. Un enjeu majeur de ces pansements est le maintien de l’adhésion cutanée dans le temps. Or une perte de l’adhésion est souvent observée après un long contact avec l’eau. Ces travaux de thèse visent à mieux comprendre l’origine de cette perte d’adhésion, à travers l’étude des propriétés mécaniques de la matrice hydrophobe, de ses interactions avec les particules hydrophiles et des mécanismes de transport d’eau. La substitution de la CMC par des particules d’hydrogels synthétisés au laboratoire a permis l’étude plus systématique de l’effet des propriétés physico-chimiques de la phase hydrophile sur l’absorption, la perméabilité et l’adhésion des pansements hydrocolloïdes ainsi mis en œuvre. / Hydrocolloid wound dressings are commonly used for the care of highly exuding wounds. They allow to control the wound moisture, while avoiding the water accumulation which could lead to bacterial proliferation between the dressing and the skin. Two antagonist properties appear to be required: an adhesive function to maintain the dressing on the skin, and high water absorption and permeability to control the humidity level and promote healing. To achieve both properties, heterogeneous systems are used : the adhesion is ensured by an hydrophobic adhesive matrix, made of an elastomer modified by plasticizers and tackifying resins, the regulation of the humidity relies on fine dry hydrophilic particles, made of carboxymethylcellulose (CMC), dispersed within the matrix. A major issue of these wound dressings is to maintain a long term skin adhesion. However a loss of adhesion is often observed after a long contact with water. This PhD work aims at a better understanding the origin of this loss of adhesion through the study of the hydrophobic matrix mechanical properties, its interactions with the hydrophilic particles and water transport. Replacing the CMC by tailor-made hydrogel particles allowed to a systematic study of the impact of the physico-chemical properties of the hydrophilic phase on the absorption, the permeability and the adhesion of the hydrocolloid-based adhesives.

Wound care is a difficult process in the healthcare sector, especially the problem with chronic and infected wounds. There are a lot of patients suffering from these wounds and it is both painful and time consuming for nurses and patients. A wound on the verge of slowing down in the healing process has a shift in its pH value from acidic to neutral and alkaline. If healthcare staff could easily identify this change the chances of treating the wound in time increases, which could stop the developing of a chronic wound. This report aims to research the possibilities of textile materials that can respond to pH changes and be used in the healthcare sector as a wound dressing. If this becomes a reality, it can both reduce the number of patients suffering from infected and chronic wounds and facilitate the efficiency of healthcare workers' work. Through interviews and a selective reading into the subjects of: pH, chronic wounds and wound dressings, textile materials and healthcare requirements sketches and ideas were created on how to incorporate a pH indicator into a textile material and through this: into a wound dressing. What was found was that the technique of electrospun polyamide together with bromocresol purple (pH indicator) in the solution creates a highly suitable fiber for use in pH monitoring wound care. The fiber provides the possibility to construct a fabric, that have the application of detecting and changing color between the pH values in the range between 5.2-6.8, which is the critical pH range for healing wounds. Wound dressing that's interacting with healthcare staff and provides clues on how the wound is evolving could be the future of wound dressings. Not just to create the perfect environment for the wound but actively analyzing on how it is healing.

The diploma thesis if focused on the study of bioactive hydrogél and nanofiber wound dressings composed of natural biopolymers, which were functionalized by active compounds in the form of analgesic, antibiotics and enzymes. Hydrogél wound dressings were constituted from alginate and chitosan and nanofibers were created from polyhydroxybutyrate. The following 7 active compounds were selected to be added to the wound dressings: ampicillin, streptomycin, ibuprofen, papain, bromelain, collagenase and trypsin. In the theoretical part the structure of the skin and types of wound injuries were described. This part also talks about types of wound dressing and their applications, as well as treatment of skin wounds using enzymes and compounds with analgesic and antimicrobial properties. In addition, this section describes safety assays, in particular cytotoxicity assays on human cells. At the beginning of the experimental part, the process of preparation of hydrogél wound dressing was optimised. Subsequently, the dressings were enriched with active compounds and the rate of gradual releasing of the substances into model environment was monitored. In the case of enzymes, their proteolytic activity was also tested after their incorporation to the wound dressings. Furthermore, the prepared bioactive wound dressings were analyzed for possible cytotoxic effect on human keratinocytes. Finally, the wound dressing with combined content of active substances was created and also characterized for the rate of substance release, proteolytic activity and cytotoxicity. Antimicrobial activity of this wound dressings, against two selected strains of microorganisms: Escherichia coli and Staphylococcus epidermidis, was also evaluated.

Boli pripravené kryty rán na bázi prírodných látok polyvinyl alcohol/ hyaluronan/ strieborné nanočastice (PVA/ HA/ Ag-NPs). Hyaluronan bol použitý ako redukčné a stabilizačné činidlo pre syntézu nanočastíc striebra. Pri príprave Ag-NPs boli testované viaceré parametre ako koncentrácia dusičnanu strieborného ako zdroja Ag-NPs (0,01; 0,1;0,5;1 M), koncentrácia kyseliny hyalurónovej (1,2 %) a jej rozdielna molekulová hmotnosť. Kryty rán z nanovlákien boli pripravené pomocou techniky electro-spinning z roztokov líšiacich sa pomerom PVA a HA/Ag-NPs (100; 90/10; 80/20; 60/40; 50/50). Vlastnosti nanokompozitu HA/Ag-NPs boli hodnotené pomocou TEM, reológie, DLS, XRD, UV/Vis spektroskopie a kryty rán boli charakterizované pomocou SEM, TGA, FTIR a ťahovej skúšky.

Hidrogéis compreendem uma importante classe de materiais poliméricos adequados à aplicação como curativos de feridas e queimaduras. A estrutura tridimensional hidrofílica dos hidrogéis permite que estes mantenham a umidade ideal no leito das feridas, absorvam o exsudato e não causem danos ao novo tecido durante as trocas dos curativos. No caso dos hidrogéis, essas trocas podem ser menos frequentes. Além disso, curativos que auxiliem na remoção de tecidos necrosados e ainda sejam capazes de oferecer tratamentos extras que acelerem o processo de cicatrização são desejáveis. Este trabalho apresenta a produção de materiais à base de hidrogel capazes de auxiliar neste processo de diferentes maneiras. Primeiramente, são apresentados hidrogéis formados a partir de nanofibras de poli(N-vinil-2-pirrolidona) (PVP) produzidas por eletrofiação, seguido da reticulação através da utilização de radiação UV-C ou reação de Fenton. A utilização da eletrofiação como técnica auxiliar na formação dos hidrogéis permitiu o controle da porosidade através da formação de fibras de diferentes diâmetros. A evidência de tal propriedade foi constatada através da produção de materiais que apresentam diferentes perfis de liberação da proteína modelo albumina de soro bovino (BSA). O hidrogel de PVP nanoestruturado foi capaz de liberar e manter a atividade da colagenase, uma importante enzima aplicada no tratamento de feridas via desbridamento enzimático, durante as 48 horas em que foi avaliado. Além disso, hidrogéis bactericidas nanoestruturados foram produzidos a partir de nanocompósitos de PVP e nanopartículas de prata (AgNP) produzidos por eletrofiação. Esses hidrogéis apresentaram propriedades térmicas semelhantes aos hidrogéis sem AgNP, diminuindo, contudo, a sua capacidade de intumescimento. Esses hidrogéis mostraram-se ativos contra bactérias gram-positivas e gram-negativas a partir de 100 ppm de AgNPs. Adicionalmente, foi estudada a formação de um hidrogel modelo composto PVP/AgNP/Imidazol, almejando-se a produção de um material bactericida-fungicida a base de hidrogel. Este hidrogel apresentou atividade conta três espécies de Candida a partir de 500 ppm de imidazol no material. Embora exista a formação de um complexo estável entre AgNP e Imidazol, cálculos teóricos e a constatação da atividade fungicida corroboram com o fato de que derivados imidazólicos podem ser liberados a partir deste hidrogel híbrido. A produção de hidrogéis físicos compostos por blendas de PVP/Polianidridos sintetizados a partir de derivados de hidroxicinamatos e ácido salicílico, capazes de liberar moléculas de interesse biológico quando parcialmente degradados hidroliticamente, também é descrita neste trabalho. Os resultados indicam que interações hidrofóbicas entre a PVP e os polianidridos sintetizados podem ser responsáveis pela formação dos hidrogéis físicos e pela miscibilidade das blendas produzidas. Os hidrogéis físicos de PVP/Polianidridos foram obtidos na forma de filmes por evaporação do solvente. Micro- e nanofibras também foram obtidas por eletrofiação. Desta maneira, o presente trabalho contribui com o desenvolvimento de uma geração de curativos multifuncionais aplicados no tratamento de feridas crônicas e queimaduras. / Hydrogels comprise an important class of polymeric materials that finds application as wound and burn dressings. The hydrophilic three-dimensional structure of hydrogels helps to provide the ideal humidity at the wound bed, to remove exsudates and to prevent damages to the new tissue during dressing substitution. Furthermore, these wound dressings are able to remove necrotic tissues and, therefore, capable to offer extra treatments that would benefit the healing processes. This work describes the production of hydrogel based materials that are able to act in wound healing by different ways. First, it is presented hydrogels composed of poly(N-vinyl-2-pyrrolidone) (PVP) nanofibers produced by electrospinning, followed by its crosslinking using UV-C radiation or Fenton reaction. The use of electrospinning in the hydrogel formation allowed porosity control by obtaining fibers of different diameters. This was evidenced by achieving materials that present different release profiles of the model protein bovine serum albumin (BSA). The nanostructured PVP hydrogel was capable of releasing and maintaining collagenase activity during 48 hour of evaluation. This is an important enzyme that find application in wound healing based on enzymatic debridement. Moreover, nanostructured bactericidal hydrogels were produced from PVP and silver nanoparticles (AgNP) composite through electrospinning, resulting in hydrogels with thermal properties similar to those hydrogels without AgNP, decreasing its swelling ability. These hydrogels were active against gram-positives and gram-negatives bacteria starting from 100 ppm of AgNP. In addition, the production of a model hydrogel composed by PVP/AgNP/Imidazole was investigated, aiming at a bactericidal-fungicidal hydrogel based material. This hydrogel was active against three Candida having 500 ppm of imidazole into the structure. In spite of the formation of a stable complex between AgNP and imidazole, theoretic calculations and the observed fungicidal activity corroborate with the fact that imidazoles derivatives can be released from this hybrid hydrogel. Physical hydrogels composed of PVP/Polyanhydrides blends were synthesized from hydroxycinammates derivatives and salicylic acid. These materials which were capable of releasing molecules with biological potential upon hydrolysis, are also described in this work. The results indicate that hydrophobic interactions between PVP and the synthesized polyanhydrides could be responsible for the hydrogel formation and blend miscibility as well. PVP/Polyanhydride physical hydrogels were obtained from cast films. Micro- and nanofibers were also obtained by electrospinning. Thus, the present work contributes with the development of the new generation of smart dressings for wound and burn healing.