The overall aim of this project was to produce homogeneously sized polysaccharide microparticles and apply these and similar sized particles as probes for investigation of mucin layers as a model for a biological barrier. Small polysaccharide particles have many applications, e.g. within the medical field of drug delivery. In this study a microfluidic system was developed to produce alginate beads, which can be used in drug delivery systems. Different designs, continuous phases and concentrations were tested in order to find an optimal system. Beads in the size range of 10 µm were produced using a device with T-shaped design and three inlets. An electrostatic bead generator was also used to make alginate beads, however the beads produced were too large to be used in the experiments with the mucin layers.One of the many challenges when working with drug delivery systems is the mucus barrier protecting the epithelial cells. In this study a model mucus barrier was made by immobilizing mucins, the glycoprotein responsible for the physical properties of the barrier. A procedure for fluorescence labelling of polystyrene beads with quantum dots was developed, and penetration of these beads into the model barrier was measured with total internal reflection fluorescence (TIRF) microscopy. In TIRF the excitation field intensity decays exponentially, and the emitted fluorescence intensity from the beads gives an indication of the distance between the beads and the surface. Measurements performed on mucin layers of different concentrations indicate that mucin concentrations above 0,5 mg/ml will result in a layer too thick or too dense to give a intensity signal. At mucin concentration 0,05 mg/ml fluorescence was observable in TIRF, and it was clearly weaker than for the control with a bead directly on a glass surface. This indicates that the beads hover over the surface due to the mucin layers, and show that it is in principle possible to measure the penetration depth of beads into mucin layer using TIRF. To simulate the condition in the lungs of cystic fibrosis (CF) patients, the mucin layers were incubated with alginate. Measurements were performed to see how this affected the penetration of the beads into the layer. A weaker fluorescent signal was obtained for these samples in TIRF, which suggests that there has been interaction between mucin and alginate. It was in addition investigated how different concentrations of G-blocks in the solution affected the penetration into the mucin-alginate layer. These testes were carried out using both TIRF and atomic force microscopy (AFM) nanoindentation experiments. The TIRF measurements were inconclusive, while the nanoindentation experiments showed decreased interaction between mucin-alginate layer and a bead.

Psoriasis er en kronisk, inflammatorisk hudsykdom som gir tykke skjelldannelser på en rød hudoverflate. Sykdommen rammer 2-3% av den europeiske befolkningen. Ultrafiolett (UV) stråling som bruk i behandling av psoriasis er effektivt og naturlig. Solens UV-stråling vil forbedre de fleste av pasientenes psoriasisflekker. Samtidig som solen har en positiv effekt, vil overeksponering kunne forårsake direkte DNA-skade i hudcellene som igjen kan forårsake hudkreft. I den forbindelse vil det være viktig å finne mengden UV som vil gi størst klinisk utbytte for psoriasisflekkene, samtidig som den skader den omkringliggende friske huden minst mulig. Hypotesen bak, er at en optimal strålemengde også vil gi det beste kliniske resultatet. Oppgaven vil utforske UV-dose til 24 pasienter som deltok på en treukers klimabehandling på Gran Canaria i november 2010. Under oppholdet ble den maksimalt tilgjengelige UV-intensiteten målt kontinuerlig fra taket av behandlingssenteret. Dette ble samkjørt med at pasientene notert når og hvor lenge de hadde vært eksponert for solen i dagbøker. I tillegg bar hver pasient UV-dosimetre, ett på håndleddet og ett festet til badetøyet. Denne oppgaven skulle sammenstille de to målemetodene for å finne UV-dosen for hver pasients hud. Sammenligninger av de UV-doser funnet med de to metodene skulle også utføres og resultatene av målingene ble vurdert.Gjennomsnittlig individuell kumulativ dose for (målt med UVB-Biometeret i samsvar med dagbøkene) var på 216,527,8 SED. Målt individuell kumulativ gjennomsnittsdose (målt med dosimetrene) var på 107,225,6 SED og 63,521,6 SED for henholdsvis dosimeteret på håndleddet og det på badetøyet. Soleksponering i tre uker førte til en gjennomsnittlig Psoriasis Area and Severity Index (PASI)-reduksjon på 77,416,3%. Ingen signifikante verdier ble funnet som kan forutsi utfallet for psoriasispasientene. Det ble heller ikke påvist noen sammenheng mellom tid eksponert for solen og UV-dose eller dosen absorbert av huden i forhold til PASI- reduksjon.Dosimeteret festet til håndleddet fikk i gjennomsnitt 50% av den maksimalt tilgjengelige intensiteten. Den makstilgjengelige intensiteten vil måles for et horisontalt plan, og alle andre målinger med dosimetre på ulike områder av kroppen, kan sees på som en fraksjon av dette. Hvor på kroppen psoriasisflekken befinner seg vil ha mye å si for hvor høy UV-dose den faktisk vil få. Forskjellen mellom de ulike områdene vil være stor, i hovedsak grunnet ulik vinkling til forhold til solen. Dosen dosimetrene gir vil derfor bare være veiledende for hvor stor dose de ulike psoriasisflekkene faktisk fikk, avhengig av hvor på kroppen de var i forhold til dosimeteret.62,5% av pasientene oppnådde PASI75 (PASI-reduksjon75%). Studien ble gjennomført i november som er en av månedene med lavest UV-indeks. Pasienter som får klimabehandling andre måneder av året med langt høyere UVI vil kunne få for høy eksponering for ultrafiolett stråling.

Riboflavin, also known as vitamin B2 and one of the most easily absorbed nutrients,can be found in many different organisms. The most abundant source of riboflavin ismilk and dairy products; however it is also present in meat, fish and certain types ofvegetables and fruit. Riboflavin is an important part of a healthy diet in order to keep skin, eyes and nervous systems healthy. Some studies indicate that riboflavin plays an important role in cancer and cardiovascular diseases.As known, milk is extremely sensitive to light. Riboflavin is one of the factorsresponsible for the light-induced degradation of milk. In combination with light andoxygen riboflavin may act as a photosensitizer. When vitamin B2 absorbs blue-greenlight, an excited triplet state of riboflavin is generated through a process called intersystem crossing. Reactive oxygen species, such as singlet oxygen, is then formed by reaction of excited riboflavin triplet with dissolved oxygen present in milk. Light exposure of milk can lead to off-flavor and damage of vitamins by reaction of singlet oxygen with amino acids and lipids in milk. Unfortunately, most of the packaging materials today do not protect milk from light completely. The formation of singlet oxygen can also be prevented by adding quenchers that are able to deactivate riboflavin triplets.Certain amino acids and carotenoids are well known flavin quenchers.The purpose of this study was to investigate how well riboflavin triplets can bequenched by amino acids cysteine, histidine, methionine, tyrosine and tryptophan. Thequenching properties of hydrophilic carotenoid crocin were studied as well. Crocinhas been under investigation of researches at the Departement of Physics at NTNU.Lumiflavin, which is one of the riboflavin’s photodegradation products, was used instead of riboflavin. The former is more stable and has similar photochemical characteristics as the latter.The quenching of lumiflavin triplets was studied by using laser flash photolysis. Itconsists of irradiating the sample under investigation with a short-lived laser flash. The method was used to measure the kinetic decay rate of lumiflavin in aqueous buffer with and without different concentrations of a quencher. The data were fitted to two different decay models. From pseudo-first-order rate constants the quenching rate constants were determined for each amino acid and crocin. All amino acids and crocin used in this study showed a quenching effect on the lumiflavin triplets. Further, it was determined whether the fitting models are suitable for these kind of measurements by simulating the decay of lumiflavin with and without any quencher. More studies on the fitting models have to be done to be able to get reliable results.

Material models has been developed for anionic and/or cationic hydrogels, with a simulation framework implemented in MATLAB and the finite element software ABAQUS. The geometry of the simulations is a hemispheroidal hydrogel, divided into a core with a shell, covalently attached to an optical fiber. The material models have been used to estimate the chemical parameters of poly-acrylamide hydrogels containing anionic or cationic monomer groups. Simulations comparing free and constrained swelling has been conducted in order to determine the effect of the geometrical constriction to the optical fiber. Constrained hydrogel swelling featuring shells with different properties than the core was also investigated.The aim of the study was to validate the material models and examine the effects of geometrical constrictions together with shell-impregnation. The anionic material model was shown to reproduce experimental swelling data, while the cationic material model only reproduced the data for ionic strength greater than 100 mM. Restricting the hydrogel to an optical fiber resulted in decreased change in volume and an increase in the axial swelling. The model was able to reproduce reported reduction in the swelling for an impregnated anionic hydrogel by using a neutral shell in the simulations, but failed to recreate the shape of the swelling curve. With the reduction of swelling as a basis, a new method for estimating thin-layer properties has been developed.