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The spreading of infection is a significant and well-known problem in all healthcare environments today. The most prevalentways that infection spreads are either by direct contact between two individuals where one has an infection, or with anintermediate person or object as an infection carrier. This thesis aims to evaluate a method that could operate to disinfect thetype of medical equipment which is not suited to be disinfected by the commercially existing methods. In keeping with the long term goal of preventing the spread of infection, this project evaluates an ozone cabinet according to itsantimicrobial properties and investigates if the cabinet is suited to work as a disinfectant for some chosen test objects. Theobjects were borrowed from different hospital institutions at Motala Lasarett and the antimicrobial effect was evaluatedaccording to the reduction of colony forming units (CFUs) of samples taken from the object's surfaces after the treatment. The results show that the ozone cabinet is not able to kill bacterial spores (Geobacillus stearothermophilus), but could be veryefficient at killing living bacteria. Concentration setting 4 (56 ppm) in combination with a treatment period of at least 40minutes proves bacterial reductions varying between 83-98 %. Nevertheless, the sources of error are numerous and there is agreat variation between identical runs which indicates that more studies need to be performed in order to obtain clearer results.

Användandet av 3D-skrivare har ökat inom sjukvården, och möjliggjort utskrift av anatomiska modeller. Karolinska Universitetssjukhuset i Solna planerar att starta ett 3D-laboratorium, med möjlighet till egen produktion av anatomiska modeller. För detta behövs kunskap kring vilka riktlinjer som ska följas, samt möjlighet till kvalitetssäkring av skrivare. I detta arbete undersöks regelverken kring 3D-printing, och ett kvalitetssäkringsobjekt för framtida kvalitetssäkring tas fram. Regelverket för medicintekniska produkter undersöktes bland dokument från EU, USA, och Australien. Tolkningen av EU:s publikationer görs via kontakt med Läkemedelsverket och Socialstyrelsen. Södertälje Sjukhus, jurister, samt professorer vid Stockholms Universitet och Kungliga Tekniska Högskolan kontaktas också med frågor kring riktlinjer. Resultatet visar på ett vagt och subjektivt tolkat regelverk inom EU, där 3D-printade anatomiska modeller kan tolkas som specialanpassade- eller egentillverkade produkter. Kvalitetssäkringsobjektet tas fram med grund i 13 kriterier. De kriterier som i detta arbete ej visar skillnad mellan utskrivna modeller, däribland negativa vinklar, spiral (form), kantighet och ömtålighet spiral, kan bytas ut eller specificeras på annat sätt. Kriterier som minsta hålbredd, kvalitetssäkringsobjektets bottenarea, släthet, självsprickor, spiral (kvalitet) och sprickor (hål) visade på kvalitetsskillnader hos utskrifterna. / Utveckling av 3D-laboratorium på Karolinska Universitetssjukhuset

The present study utilizes finite element analysis in order to simulate a surgical operation in the treatment of a hallux rigidus case, as designed and developed by Episurf Medical AB (Stockholm, Sweden). The surgical intervention includes an initial cheilectomy as well as an insertion of an orthopedic implant. The goal of the study was to evaluate the current concept of the medical intervention as it is manifested today, as well as to give design suggestions as how to further improve the pre-planning of the surgery. MRI-images of the first metatarsophalangeal joint in the hallux was collected from a patient suffering from hallux rigidus, and used in order to build case-specific geometrical images to be used in the FE analysis. The simulation was setup as to simulate a normal motion in the first metatarsophalangeal joint during a normal gait pattern. The first simulation was conducted without any intervention, while the second was conducted after a pre-determined operation plan in accordance with the surgical operation that Episurf Medical AB wants to perform. The results was then compared and analyzed in order to determine the post-surgical effects that such an operation could have on the patient. A third and final simulation was then performed, by using optimization algorithms in order to make suggestions to the pre-planned cheilectomy shape, as well as orientation of the implant. Two parameters were being investigated in order to assess the surgical intervention as designed by Episurf Medical AB; the contact stress on the articular side of the metatarsal head, and the strain on the implant shaft. The current manifestation of the cheilectomy did not reduce the contact stress compared to the untreated condition, as the implant failed to be a load baring surface due to the two dimensional nature of which it is conceived. Instead, the contact surface area is reduced and positioned medial and lateral to the implant head. The optimization algorithm could reduce the maximum contact stress significantly, from 295MPa and 400MPa in the treated and untreated conditons respectively, to 160MPa after the optimization algorithm. It became clear that the angle of the cheilectomy as well as the orientation of the implant angle has an incriminating effect on the post-operative results. However, the shape of the cheilectomy as well as the design of the implant would need to be revised in future embodiments, as the current concept failed to provide joint with a new articulating surface. Further development of the models formulated in this thesis is advised, as well as validating the findings with clinical data. / Den aktuella studien använder finita elementmetoden i syfte att simulera en kirurgisk operation som har utvecklats av Episurf Medical AB (Stockholm, Sverige) för att behandla ett hallux rigidus fall. Det kirurgiska ingreppet utgörs av en inledande cheilectomi,  som sedan följs av att operera in ett ortopediskt implantat. Målet med studien var att utvärdera det nuvarande konceptet för det medicinska ingrepp så som den är uttänkt idag, samt att ge designförslag för hur man ytterligare kan förbättra planeringen av operationen. MR-bilder av den första metatarsalleden i stortån samlades in från en patient som lider av hallux rigidus, som användes sedan för att bygga patient specifika geometriska bilder för att användas i FE-analysen. Simuleringen var modellerad för att simulera en normal rörelse i första metatarsofalangealleden under en normal gångcykel. Den första simuleringen genomfördes utan något ingripande, medan den andra genomfördes efter en förutbestämd operationsplan i enlighet med det kirurgiska ingreppet som Episurf Medical AB vill utföra. Resultaten jämfördes sedan och analyserades för att bestämma de resultaten som en sådan operation skulle kunna innebära för patienten postoperativt. En tredje och sista simulering utfördes sedan, med hjälp av optimeringsalgoritmer för att ge förslag på förbättringar för den förplanerade cheilectomin, samt orienteringen av implantatet. Två parametrar undersöktes för att bedöma det kirurgiska ingrepp som designats av Episurf Medical AB, kontaktbelastningen på artikulära sidan av metatarsalhuvudet, och påfrestningen på implantatet. Den nuvarande utformningen av cheilectomin minskade inte kontaktbelastningen jämfört med det obehandlade tillståndet, då implantatet inte vart belastat på grund av den tvådimensionella profilen i dess utformning. Optimeringsalgoritmen kunde minska den maximala kontaktbelastningen markant, från 295MPa i den behandlade och 400MPa i den obehandlade simuleringarna, till 160MPa efter optimeringsalgoritmen. Det blev tydligt att vinkeln på cheilectomin samt orienteringen av implantatet har en avgörande betydelse för det postoperativa resultatet. Dock skulle formen på cheilectomin liksom designen av implantatet behöva revideras i framtida utformningar, då det nuvarande konceptet inte lyckades att ge leden en ny ledyta. Vidareutveckling av de modeller som utvecklats i avhandlingen rekommenderas, samt att validera resultaten med annan kliniska data.

Ultrasound contrast agents composed of micro-bubble filled with gas are introduced to increase the backscattered power from blood. Their intravenously injection results in the improved contrast in the images. The aim of this master thesis project is to manufacture MB suspension at varied temperature and shear forces and to inspect the size distribution and concentration of the PVA-shelled micro-bubble with standard methods according to the developed protocol. A pulser-receiver (Panametrics PR 5072) setup combined with two transducers (2.25 MHz and 5 MHz) was used to investigate the backscattered enhancement of the micro-bubble suspension. Images were collected with transmission optical microscope (OLYMPUS IX71) with the aid of counting chamber. The diameter and concentration of the micro-bubbles were analyzed by Image J. The pulser-receiver setup was used to test the acoustic response. The mean diameter of micro-bubbles was from 2.03 to 4.38 µm with a standard deviation between 0.40 and 1.12 µm and the micro-bubble concentration varied from 0.07× to 5.22× MBs/ml. The enhancement of the ultrasound backscattered power was greater than 20 dB or even reached 30 dB when the energy was increased. / 3MiCRON

Wound care is a field with many treatment methods and products on the market. The healing period varies, some wounds become difficult to heal and chronic, in many cases a connection can be drawn to underlying diseases. Diabetes is a disease that could cause foot ulcers that are difficult to heal. Bioactive materials in wound care have not yet been studied to a greater extent, however it is of interest for development of new products with improved functions. Fibroblasts in the connective tissue have an important role in building and regenerating the tissue. Former studies show that the bio-ceramic calcium silicate (CS) induce tissue regeneration and promote reepithelization. It has also shown improvement of the biological functions of human epidermal stem cells and positive effects on cells in in vitro studies. The purpose of this project is to be a pre-study for further analysis of CS in wound care. The aim is to investigate additive material’s potential role in wound healing, one part will be a literature study to get an overview of the healing process of wounds and wound treatment. The other part of the study is based on three minor experiment to obtain information about how calcium silicate (CS) and CS/ β-tricalcium phosphate (β-TCP) effect human dermal fibroblasts. The method and results of literature study: The litterature study gathers information from literature and studies within the subject using the searchwords: wound, healing, biomaterials, calcium silicate, alamar blue, cell migration, recent trends, skin regeneration and diabetes. The results from the literature study demonstrates that the wound healing process is very complex and many factors must interact for good healing, some factors accelerate and inhibit healing. Furthermore, healing products with additives are already used for treatment of wounds with antibacterial and pain-relieving effects. However, only a little information about bioactive materials can be found which shows that there is lack of studies in this field. The method and results of experiments: Preparation of the two main samples: [1:10] CS in PBS together with pure water and [1:10] CS + β-TCP in PBS and pure water. The first experiment was the Inductively Coupled Plasma Optic Emission Spectroscopy (ICP-OES) made in an Optical Emission Spectrometer which detected the elements Ca 317,933 (mg/L) and Si 251,611 (mg/L) in the main samples. The second experiment was Alamar Blue which produce data about the cell survival in quantitative numbers to determine the toxicity of the diluted samples. One pre-test and two final tests (24 h apart) was made. The pre-test used the dilutions 1:2, 1:10, 1:100, and two Control Media, the pre-test indicated that CS diluted 1:2 is slightly toxic. The first final test used the dilutions 1:2, 1:10, 1:100, 1:1000, 1:10000 and one Control Media. The first final test indicated that CS diluted 1:2 is almost toxic. The second final used the dilutions 1:2, 1:10, 1:100, 1:1000, 1:10000 and one Control Media. The second final test indicated that CS diluted 1:2 is toxic. The third experiment was a Scratch Healing assay. This experiment struggled with learning how to count cells which made the analysis of this experiment difficult. The results of the Scratch healing assay shows cell migration through a before-picture right after the simulated scratch is made and a picture 24 hours after. In conclusion, two important parameters while investigating the direction of further research are toxicity and cell survival. CS as a bioactive material and additive in wound treatment could be possible but should be avoided when diluted 1:2 due to its toxicity shown in the Alamar blue test. The scratch healing assay showed that the fibroblasts migrate to some extent while interacting in solutions of CS.

Purpose Conventional arm-prosthesis are expensive to make and therefore limit the availability for users on the geographical locations there the user pays for it. This study compares the hand function of a 3D-printed prosthesis with lower production cost with a traditional prosthesis. Method A test person performed two different tests of hand function (Box and Block test and Nine-hole peg test) with a myoelectric trans radial prosthetic arm and a body powered 3D printed trans radial prosthetic arm. The test person also answered two parts of the orthotics and prosthetics users’ survey (OPUS) considering both prosthetic arms. Result The 3D-printed prosthesis performed worse than the traditional prosthesis in the two tests of hand function and generally worse in the questionnaire about the function of the prosthesis. Though it got higher values in comfort and affordability. Conclusion There was a significant difference in function between the 3D-printed prosthesis and the myoelectric prosthesis but the printed prosthesis could perform many activities in daily living. Whether the 3D-printed prosthetic device is priceworthy or not is hard to measure because of different criteria, therefore a conclusion is hard to reach.

The chemical properties of calcium phosphate cements (CPCs) are very similar to the mineral phase of bone. CPCs are, consequently, very effective substrates (scaffolds) for tissue engineering; bone and stem cells attach readily, and can proliferate and differentiate to form new bone tissue. Unlike other CPCs that may remain largely unchanged in the body for years, such as hydroxyapatite, dicalcium phosphates are remodelled by the body and rapidly converted to new bone. Unfortunately, the dicalcium phosphates are also typically too weak to support load bearing in the human body. Our laboratory has recently developed a novel, high strength brushite CPC, (hsCPC), which can reach 10-50 fold higher failure strength than many commercially available CPCs. The aim of this thesis was to investigate the physical, chemical and biological performance of hsCPCs in physiologically relevant model of drug release, load bearing, osteoconductivity, and as a scaffold for bone tissue engineering. Multiple CPCs were compared in a model of screw augmentation to determine whether the physical properties of the cement, such as bulk strength and porosity, affected orthopedic screw holding strength. In an in vitro model of bone regeneration stem cells were grown on macroporous scaffolds that were fabricated from hsCPC. Drug releasing scaffolds were fabricated to examine whether the low porosity of hsCPC impeded drug release during a 4 week incubation period. The biological activity of an incorporated drug, Rebamipide, was examined after acute and chronic incubation periods. In the drug release study it was noted that the biological response to hsCPC was significantly better than tissue culture grade polystyrene, even in groups without drug. The mechanism underlying this biological response was further investigated by testing the effect of pyrophosphate, a common cement additive, on bone cell proliferation and differentiation. This thesis concludes that a high strength cement can produce significant improvement in screw augmentation strength, if there is sufficient cortical bone near the augmentation site. The hsCPC is also cytocompatible, and can support bone and stem cell proliferation and differentiation. hsCPC scaffolds stimulated osteogenic gene expression comparable to native bone scaffolds. hsCPC scaffolds are also capable of delivering drug for up to 4 weeks, in vitro. Finally, a cement additive, pyrophosphate, stimulated differentiation, but not proliferation of bone cells.

Eurocoating, Italy, is a company that works in the biomedical sector. They have for a long time created prostheses from CAD files achieved from customers, and now they want to build their own expertise about the design. The thesis work was a part of a three year long collaborative research project between Eurocoating and University of Trento that was aiming to investigate the prostheses with open-porous surface and trabecular structure, created by Selective Laser Melting. The purpose of the thesis was to investigate and characterize 30 different trabecular structures of Ti-6Al-4V, fabricated by Selective Laser Melting. That includes investigation the effect on the morphology and porosity fraction caused by the manufacturing and the effect on mechanical and physical properties due to the different characterizations of the structures. The thesis work had its foundation in literature studies to receive deep knowledge about the subject. Practical tests were performed to investigate mechanical behaviour under compressive and tensile loading, static friction and wear resistance. The findings from these tests were compared to the porosity fraction and the morphological characterizations. The result stated that the porosity fraction was lower than the designed porosity, and that is was strongly influenced by size of the voids and struts. The strut thickness was higher than the design values, especially on the lateral surface, while the voids size were approximately as designed. Result from the compression test showed a trend of decreasing stiffness and strength with increasing porosity fraction. Also structures with same porosity fraction could have a wide range in mechanical properties which indicates high dependence on the morphological geometry i.e. pore size and shape, strut size and pore distribution. Comparisons between tensile and compression behaviour stated that the structures had a lower strength but a significant higher stiffness in tensile load. All structures from the wear test showed a good resistance while the results from the friction test needs further investigation to be fully understood. The physical and mechanical properties of the trabecular structures was found to be close to those of cortical and trabecular bone in porosity, stiffness and strength. There is a range of variations leading to possibilities to adopt the application depending on customer. Thus, these can be considered as promising structures used biomedical application to optimize osseointegration and secondary long term fixation.

An implantable hearing aid device is being developed by a project group which is part of an EU initiative. This device contains a diaphragm consisting of a submicron thick freestanding titanium film, which should be free of internal stresses. Stress is the force exerted per unit cross-sectional area of the film and it can impair the functionality and performance of the device. The stress that evolves in a thin film during deposition at a substrate is compressive or/and tensile and affects the bending that occurs of the substrate due to the lateral force applied to the substrate by the stressed film. The goal of this diploma work was to contribute to the understanding of in situ stress evolution in a micron thick titanium film and thereby by tuning different physical parameters to obtain minimal residual stress in the films after growth. Titanium films were deposited on silicon sistrates using DC magnetron sputtering. The stress in the material varied, by tuning different physical parameters such as working pressure, power, distance between magnetron and the sample and substrate bias. For this thesis, firstly two different series were done; one where the changing parameter was the distance between the sample and the magnetron and one where it was the working pressure. Later a last series were done to see what effect the bias has on the stress. A multi-beam optical sensor system (MOS) was used to measure the stress in real-time during deposition. X-ray diffraction (XRD) was later used to make post-deposition stress measurements to verify the stress obtained from the MOS. However, the MOS shows the stress evolution in real time and XRD shows a ’final’ average value that can be compared with the stress obtained from MOS-data when the deposition is finished. The results showed that the stress goes from compressive to tensile as the working pressure and the distance between the magnetron and the sample increases. There are other factors, such as the temperature/heating in the main chamber, base pressure of the main chamber, cleaning of the sample and also where the argon gas is let in to the process chamber (in this project called the main chamber (MC)), that influences the results. This will in turn influence the repeatability of the data/measurements, since these effects can affect the process of nucleation and coalescence. The stress evolution can change if a bias is applied during the initial stage of the deposition process when the film has still not grown thick. This is could be due to the bias not having much of an impact on the stress evolution when the film is thicker and thereby more porous.