Bioprinting is one of the most promising technologies for future healthcare as it may benefit the repairing of wounds and injuries, disease modeling and development, transplantation of organs and reduce animal testing. This thesis aim to investigate this industry further, as there is no excessive literature on how to handle the innovation in regards to entrepreneurial and biotechnological knowledge. Hence, a research gap can be spotted and the purpose of the conducted research questions should contribute to this gap. In order to fully understand the bioprinting industry, an outline of the technology is made as part of the research. In addition to this, secondary data for patents, market valuation and annual growth rates are collected to support arguments from previous literature. Also, interviews are conducted to gather specific knowledge. As a result, bioprinting may be presented as a disruptive innovation in an uncertain market, which places certain demands on companies to act more in line with the complexity of the technology. Such companies must think more strategically and design more complex and long-term strategies. The patent data shows that there has been a decline in the technological development as patent applications have decreased significantly. Even though the technology (regarding the patents) has started to slowly decline, there is still hope for some technological improvements to come. It can be concluded that developments in bioink, scaffolds, expansion of cells and diffusion is expected, and that the use of bioprinting is increasing and will most likely continue to do so.

Mycelium-based composite (MBC) is being developed and researched in multiple commercial markets as an alternative sustainable material. MBC utilizes the mycelium ability to create a web-like structure in lignocellulosic structures. However, producing the material in a natural environment and subjecting it to various tests; the study aims to examine the distress of the southern Swedish climate on MBC grown in different substrates. The selection of substrates are based on their compatibility to fungal growth, the substrates are also locally sourced and grown. This is to explore MBC material production with a focus on circular economy as biodegradable material in architecture could help develop a reuse and recycle system. Various tests were done on the different substrate MBC to determine its characteristics, limitations and opportunities. The tests were developed with a focus on architectural construction and the southern Swedish climate; meaning experiments including MBC reaction to fire, water and temperatures. The results are based on the different MBC materials reaction, this ends with a description on how the materials could be used and developed in the future.

Microalgae are considered as a potential feedstock for many promising applications. Some active substances in microalgae have plant biostimulation effects potentially useful in agriculture. However, to produce such a microalgal biomass, specific microalgae cultivation and post-treatment processes must be designed to preserve active substances. A particular focus is provided on cultivation (tubular photobioreactor) and different plausible post-treatment scenarios for microalgae separation (flocculation and centrifugation) and preservation (sterilization and drying). For each step, yield and energy consumption are modeled using data taken from literature or lab and pilot scale experiments. Industrial equipment for scale-up process is also studied by comparing existing systems. These models enable to make an economic evaluation of the whole process and to study its profitability for each scenario. The breakeven price is calculated as a function of the production rate. Several parameters are suggested to improve system efficiency and profitability at the end of this study. However, a better microalgae characterization and more experiments on potential post-treatment systems are required to improve the accuracy of the model.

Filtration and separation technologies remain as one of the biggest challenges humanity currently faces. The separation of different elements such as bacteria, viruses, heavy metals, particles, and chemical agents require the development of multifunctional membranes. In membrane technology, one of the most promising fabrication techniques is electrospinning, which can produce highly tailored non-woven fibrous multifunctional membranes with a high surface area. On the other hand, cellulose derivatives, like cellulose acetate, have many beneficial properties for filtering technology such as high availability and easy functionalization. Likewise, cellulose nanocrystals are used to improve mechanical properties and functionalize membranes. In this project, a cellulose nanocrystal (CNCs) functionalized cellulose acetate electrospun multifunctional membrane is developed for adsorption and separation of nanosized particles. In this work, cellulose acetate (CA) fibers with an average fiber diameter of approximately 900 nm were electrospun and tested as membranes for size and affinity based filtration. First, the electrospinning process was optimized regarding solution and process parameters. As a result, solution parameters were found to be 12 wt% solid content CA dissolved in a 1:1 acetone:acetic acid solution. Regarding process parameters, the suitable electrospinning parameters were found to be 18 kV applied voltage, a feeding rate of 5 mL/h, and a tip-to-collector distance of 20 cm.   The electrospun CA membrane was coated with cationic (+) and anionic (-) cellulose nanocrystals up to a 25 wt% concentration. The incorporation of CNCs, of either anionic or cationic surface charge, affected membrane wettability. The neat CA membrane had a hydrophobic behavior with a contact angle of 110°. The addition of CNCs decrease contact angle, to 31.5° for CA-CNCs(-) and 50° for CA-CNCs(+), which resulted in functionalized membranes with a hydrophilic behavior. Both functionalized membranes managed to maintain high flux values. CA-CNCs(-) maintained a flux of 9500 Lm−2h−1, while CA-CNCs(+) maintained a flux of 6700 Lm−2h−1. The addition of cellulose nanocrystals improved the mechanical properties of the CA membranes. The tensile strength increases from 410 kPa to 4990 kPa for CA-CNCs(-) membranes and 3010 MPa for CA-CNCs(+) membranes, and is accompanied by an increase in Young’s modulus as well. To evaluate the adsorption efficiency and size-exclusion filtration, an anionic dye (Congo red), a cationic dye (Victoria blue), and 500 nm model particles were used. CA-CNC(-) membranes achieved a removal efficiency of 96% of 500 nm particles with an affinity-based dye removal of 63% of Victoria blue dye. On the other hand, CA-CNC(+) membranes achieved a removal efficiency of 43% of 500 nm particles with a dye removal of 27% of Congo red dye. In this regard, CA-CNC(-) membranes were the best candidate for size-exclusion filtration, while also maintaining a good level of adsorption. Cellulose based composite membranes were successfully produced as multifunctional filters that could act in both size-exclusion regime and affinity-based regime. A cellulose acetate fibrous membrane was produced by electrospinning, tuning for fiber size and porosity, while the incorporation of cellulose nanocrystals functionalizes the membranes and enhance mechanical properties, and wettability.

Since the beginning of the 20th century plastic has been a widely used material, which has resulted in large quantities of plastic being produced in the last century. The plastics of today are mainly produced from fossil raw materials, which gives it a high climate impact. Plastic also has a long service life, which creates problems with handling after the new period when new plastic is produced at a faster rate than plastic debris can be recycled or incinerated. One possible approach is to switch from plastic from fossil sources to bioplastics, which is produced by renewable sources. This means a reduction in the environmental impact as the amount of fossil CO2 emissions from combustion of plastics would decrease. Polyhydroxyalkanoates (PHAs) are created by short volatile fatty acids (VFAs) added to bio sludge from a wastewater treatment plant at a pulp and paper mill where there is a lot of bacteria and microorganisms. Some of the bacteria in the sludge have the ability to accumulate PHA when VFA is added in excess and then be able to use it as an energy and carbon source in cases of starvation. This means that PHA produced in this way can be degraded by bacteria making it biodegradable while having similar properties as oil-based plastics. Production of PHA is currently expensive as it is often necessary to purchase VFA for production. To make it economically sustainable to replace oil-based plastics with PHA, the cost of PHA production must therefore be reduced. This can be done by using mixed bacterial cultures from, for example, industrial wastewater treatment plants and by creating their own composition of VFA through fermentation. At the paper mill at BillerudKorsnäs Gruvön there are several process streams that today are led to the water treatment plant, one of which is from PM6 (Paper Machine 6). By fermenting that stream, VFA can be formed with a composition of acetic acid, propionic acid, and butyric acid. The current may thus be suitable to use as a substrate in PHA production. Another way to produce VFA is to ferment the residual flow from hydrothermal carbonation (HTC) of bio sludge. According to (Samorì et al., 2019), acetic acid, butyric acid and valeric acid are formed, which means that even this stream may be suitable as a substrate for PHA production. The purpose of this thesis is to investigate the effects of the composition of VFA on the production of PHA from forest industrial bio sludge. The study covers two different cases, Case PM6 and Case HTC, where two different types of composition of VFA are added to paper sludge from the paper mill. The experiments were performed in cylindrical tanks on three occasions where the first two experiments had a volume of 30 liters and the last experiment a volume of 10 liters. On the first occasion, the maximum accumulation rate in the growth phase was studied. In the second instance, a high accumulation rate was sought, but also survival after the growth phase. The first two trials were batch trials where the sludge was dosed until saturation was achieved. On the third occasion, the possibility of carrying out PHA production with a continuous sludge exchange was studied. The experiments were analyzed by FTIR which provided information on the absorbance of the sludge which shows how the PHA concentration increased during the course of the experiments. Extractions were then performed to obtain the concentration of PHA that eventually accumulated in the sludge. The results show that biomass from BillerudKorsnäs Gruvön's mills accumulated PHA faster with VFA composition from fermented PM6 effluent compared to VFA composition from fermented HTC condensate. Calculations made with input from the experiments indicate that it is possible to produce a larger amount of PHA per year with Case PM6. The conclusion is therefore that Case PM6 is preferable if as large a PHA production as possible wants to be achieved. Case HTC is instead preferred if reduced PHA production can be tolerated in favor of biocarbon production.

Introduction : L'Accident Vasculaire Cérébral (AVC) est la 1ère cause de handicap acquis chez l'adulte, dans les pays industrialisés. 20% des patients décèdent dans le mois qui suit, 75% des survivants gardent des séquelles définitives, 33% deviennent dépendant à vie. Il n'existe pour l'heure aucune thérapie de récupération quand les déficits fonctionnels sont en place hormis la rééducation. Chez l'homme, 80% des AVC thrombotiques touchent l'artère cérébrale moyenne, qui irrigue le cortex moteur primaire (M1). M1 projette des axones jusque dans la moelle épinière et forme le Faisceau Cortico Spinal (FCS). Après une atteinte de M1, ce faisceau dégénère et cela induit des déficits fonctionnels de force et de dextérité. M1 est indispensable pour les mouvements volontaires dextres garants de l'indépendance du patient. Objectif : Mise au point d'un modèle de lésion cérébrale, chez un primate non humain, le marmouset, qui permette d'évaluer la récupération fonctionnelle motrice afin d'étudier l'effet de neuro-implants. Méthode : 14 marmousets ont servi à caractériser le nouveau modèle lésionnel induit par une injection stéréotaxique d'une toxine inhibant le métabolisme cellulaire. Des tests comportementaux, évaluant le score neurologique, la dextérité et la force de traction du membre supérieur, ont permis d'évaluer la récupération fonctionnelle en phase aiguë, subaiguë et chronique jusqu'à 6 mois après la lésion. Le suivi longitudinal structural et fonctionnel de la lésion et de la récupération a été réalisé par IRM (T1, T2, DTI). Le suivi de l'intégrité du FCS a été étudié, pour la première fois chez le marmouset, grâce à une technique (ME-MRI, manganese-enhanced-MRI) utilisant un agent de contraste injecté directement dans le cortex M1, capté par les neurones et traçant les voies neuronales. Une étude pilote sur 3 marmousets a testé l'effet de neuro-implants microstructurés dans la lésion cérébrale associés à l'injection de chondroïtinase ABC (enzyme de dégradation de la matrice extracellulaire). / Introduction: Stroke is the first leading cause of acquired handicap and disability in adults in industrialized countries. 20% of patients die in the following month, 75% of survivors remain with definitive sequelae, 33% become dependent for life. No therapy in the recovery phase exists today when functional deficits are installed except rehabilitation. In human, 80% of thrombotic stroke affect middle cerebral artery, which supplies the primary motor cortex (M1). M1 projects axons to the spinal cord and forms the CorticoSpinal Tract (CST). After an M1 insult, this tract degenerates and functional deficits of force and dexterity are induced. M1 is essential for voluntary dexterous movements that make patients independent. Objective: Setting up of a cerebral lesion model in a non-human primate, the marmoset, where the functional motor recovery can be assessed in order to study thereafter the effect of neuro-implant. Methods: 14 marmosets served to characterize the new lesion model induced by stereotaxic injection of a toxin inhibiting the cellular metabolism. Behavioral tests assessing the neurological score, dexterity and pulling strength of the upper limb, could assess the functional recovery in the acute, sub-acute and chronic phases until 6 months after the lesion. The longitudinal structural and functional follow-up after the lesion and during the recovery was done with MRI (T1, T2, EPI, DTI). The follow-up of the integrity of the CST was studied for the first time in the marmoset with a technic (ME-MRI, manganese-enhanced-MRI) using a contrast agent injected directly in the cortex M1, taken up by neurons and that traced neuronal tracts. A pilot study on 3 marmosets tested the effect of micro-patterned neuro-implants in the cerebral lesion associated with the injection of chondroïtinase ABC (enzyme of extracellular matrix degradation).

Polymeric composites reinforced with bio-materials have advantages over composites with synthetic reinforcements. Bio-based composites use low-cost and renewable reinforcements, have nonabrasive properties for machining, have improved damping characteristics, and have potential for energy recycling. However, the limited use of bio-based composites is because their mechanical properties are typically much lower than those of synthetic composites. The objective of this study was to combine state-of-the-art imaging tools with emerging numerical modeling methods for an integrated, multi-level characterization of bio-based reinforcements and their composites. Digital photography (2D) will allow collection of full-field digital images of the surface of sample composites, which will be used for characterization of the morphological structure of fillers (copper wire or wood particle) and of model composites. Mechanical experiments (tension load) on isolated fillers and on model composites will allow imaging of the deformed material. By correlating relative positions of thousands of surface features between consecutive images, digital image correlation (DIC) algorithms can be used to map surface deformation fields and calculate surface strain fields. Digital imaging methods can only record deformations and strains. The interpretation of those strains in terms of material properties, such as position-dependent modulus of a heterogeneous composite material, requires simultaneous modeling. The modeling must use morphology-based methods that can handle anisotropy, heterogeneity, and the complex structure of bio-based composites such as wood plastic composites. This research used the material point method (MPM) as a modeling tool. MPM is a particle-based, meshless method for solving problems in computational mechanics. The crucial advantage of MPM over other methods is the relative ease of translating pixels from digital images into material points in the analysis. Thus digital images (2D) used in our experiments were used as direct input to the MPM software, so that the actual morphologies, rather than idealized geometries, were modeled. This procedure removes typical uncertainties connected with idealization of the internal features of modeled materials. It also removes variability of specimen to specimen due to morphology variations. Full-field imaging techniques and computer modeling methods for analysis of complex materials have developed independently. This research Coupled imaging and modeling and used inverse problem methodology for studying bio-particulate composites. The potential of coupling experiments with morphology-based modeling is a relatively new area. This work studied the morphology and mechanical properties of copper wire (for validation experiments) and wood particles used for reinforcement in polymer composites. The goal was to determine the in situ mechanical and interfacial properties of copper wire and then wood particles. By comparison of DIC results to MPM, the conclusion is MPM simulation works well by simulating 3D composite structure and using Matlab software to do qualitative and quantitative comparisons. Copper validation tests showed that copper wire is too stiff compared to polymer such that the inclusion modulus had low effect on the surface strains (DIC experimental results). Wood particle worked better because modulus of wood is much lower than copper. By qualitative comparison of the wood particle specimens, we could deduce that the in situ properties of wood particles are lower than bulk wood. Quantitative analysis concentrated on small area and got more exact results. In a 90 degree particle quantitative study, MPM simulations were shown to be capable of tracking the structure of wood particle plastic, which involved failure. The entire approach, however, is not very robust. We can get some results for mechanical properties, but it does not seem possible to extract all anisotropic properties from a few DIC tests, as some researcher have suggested. / Graduation date: 2012

Use of arsenic-rich groundwater for crop irrigation can increase the arsenic (As) content in food crops and act as a carcinogen, compromising human health. Using aquatic plant based phytofiltration is a potential eco-technique for removing arsenic from water. The aquatic moss species Warnstorfia fluitans grows naturally in mining areas in northern Sweden, where high concentrations of arsenic occur in lakes and rivers. This species was selected as a model for field, climate chamber and greenhouse studies on factors governing arsenic removal and arsenic phytofiltration of irrigation water. The arsenic and silicon (Si) concentrations in soil, water and plant samples were measured by AAS (atomic absorption spectrophotometry), while arsenite and arsenate species were determined using AAS combined with high pressure liquid chromatography (HPLC) with an anion exchange column. The arsenic content in grains of hybrid and local aromatic rice (Oryza sativa) cultivars with differing arsenic accumulation factor (AF) values was investigated in an arsenic hotspot in Bangladesh. The results showed that arsenic AF was important in identifying arsenic-safer rice cultivars for growing in an arsenic hotspot. The study based on silicon effect on arsenic uptake in lettuce showed that arsenic accumulation in lettuce (Lactuca sativa) could be reduced by silicon addition. The aquatic moss had good phytofiltration capacity, with fast arsenic removal of up to 82% from a medium with low arsenic concentration (1 µM). Extraction analysis showed that inorganic arsenic species were firmly bound inside moss tissue. Absorption of arsenic was relatively higher than adsorption in the moss. Regarding effects of different abiotic factors, plants were stressed at low pH (pH 2.5) and arsenic removal rate was lower from the medium, while arsenic efflux occurred in arsenate-treated medium at low (12°C) and high (30°C) temperature regimes. Besides these factors, low oxygenation increased the efficiency of arsenic removal from the medium. Finally, combining W. fluitans as a phytofilter with a lettuce crop on a constructed wetland significantly reduced the arsenic content in edible parts (leaves) of lettuce. Thus W. fluitans has great potential for use as an arsenic phytofilter in temperate regions. / <p>QC 20170323</p>

The work presented in this thesis was conducted at Uppsala University and at Swerim AB. The study aims to broaden the knowledge about the corrosion of additively manufactured bioresorbable alloy WE43 in humanlike conditions for future applications. Biodegradable metal implants are implants meant to stay in the body and support the wounded bone for a certain time period, and then degrade as new, healthy bone forms in its place. Magnesium alloys have properties that are desired for these kind of implants as it is biodegradable, non-toxic and matches the mechanical properties of bone. Furthermore, magnesium alloy WE43, containing yttrium, neodymium and zirconium, already exist on the market as a powder extruded screw that treats Hallux valgus, thus proves the alloys compatibility as a bioresorbable implant. However, in order to optimize implants for specific situations, additive manufacturing can be a powerful tool. By utilizing the advantages of additive manufacturing, patient specific, complex designs implant can be manufactured rapidly in order to be used in a patient. On the other hand, additive manufacturing is a complex method with many aspects affecting the outcome. Therefore it is important to study the influence that different parameters have on the material's properties, especially the corrosion properties. This thesis aims to study different power settings on the laser in the manufacturing process and what effect it has on the microstructure as well as the corrosion properties of as built WE43 samples. Samples of three different parameters settings were manufactured with a Powder Bed Fusion-Laser Beam 3Dprinter. These samples were analyzed regarding surface roughness and microstructure with Light Optical Microscope, Scanning Electron Microscope, Energy Dispersive Spectroscopy, Electron Backscatter Diffraction and Alicona InfiniteFocus. Furthermore, the corrosion properties of the samples were investigated by collecting and measuring hydrogen gas that is released during the corrosion process. In addition, the electrolyte were examined regarding the change in ion concentration and electrochemical tests were performed. It was found that the samples did not differ substantially in microstructure as all three parameter settings exhibited a matrix of magnesium and precipitates of alloying elements. However, the sample manufactured at the lowest energy density had pores incorporated in the bulk. Despite the porous bulk this sample performed best in the immersion tests and exhibited the lowest corrosion rate over 28 days. The reason for this behavior is not determined, however possible causes are discussed and further studies are recommended.

The relatively new and still growing field of 3D-printing has opened up the possibilities to manufacture patient-specific medical devices with high geometrical accuracy in a precise and quick manner. Additionally, biocompatible materials are a demand for all medical applications while biodegradability is of importance when developing scaffolds for tissue growth for instance. With respect to this, this project consisted of developing biocompatible and bioresorbable polymer blend and composite filaments, for fused deposition modeling (FDM) printing. Poly(lactic acid) (PLA) and polycaprolactone (PCL) were used as supporting polymer matrix while hydroxyapatite (HA), a calcium phosphate with similar chemical composition to the mineral phase of human bone, was added to the composites to enhance the biological activity. PLA and PCL content was varied between 90–70 wt% and 10-30 wt%, respectively, while the HA content was 15 wt% in all composites. All materials were characterized in terms of mechanical properties, thermal stability, chemical composition and morphology. An accelerated degradation study of the materials was also executed in order to investigate the degradation behavior as well as the impact of the degradation on the above mentioned properties. The results showed that all processed materials exhibited higher mechanical properties compared to the human trabecular bone, even after degradation with a mass loss of around 30% for the polymer blends and 60% for the composites. It was also apparent that the mineral accelerated the polymer degradation significantly, which can be advantageous for injuries with faster healing time, requiring only support for a shorter time period.