Cerebral stroke has become one of the leading causes of death and disability worldwide. During an ischemic stroke, oxygen and nutrient deprivation occurs, which combined lead to cell starvation, anoxia, and eventually cell death. However, when blood flow is restored, reperfusion damage occurs resulting in increased cell death through several mechanisms. One of the main reasons behind ischemia/reperfusion damage is oxidative stress due to elevated production of reactive oxygen species (ROS) during reperfusion. There are several proteins and processes that are thought to be involved in elevated oxidative stress and the formation of ROS during reperfusion, among which the NADPH oxidase (Nox) family is suggested to be the main contributor of ROS.To examine this hypothesis, in the present work, we inhibited activity of the Nox2 and Nox4 enzymes during ischemia/reperfusion with the Glucox Biotech AB (Sweden) inhibitors M4, M107, and M114 to evaluate whether reducing Nox activity could reduce the ischemia/reperfusion-induced cell death, hence be used as a potential stroke treatment, the cell viability was measured with MTS after ischemia/reperfusion induction and treatment with the Nox substances. We also examined the gene expression levels of the Nox enzymes Nox2 and Nox4 with qPCR after induced ischemia/reperfusion in the neuroblastoma cell line NB69.Our results showed a decrease in Nox4 gene expression after 1h ischemia/8h reperfusion and an increased expression after 1h ischemia/24h reperfusion in NB69 cells. Treatment with M114 resulted in increased cell viability after 2h ischemia/72h reperfusion. However, the toxic effect of ischemia/reperfusion-induced response was found to be inadequate, as indicated by extensive proliferation and lack of cell death. This unfavorable outcome is suggested to be excess of oxygen in medium, metabolization of L-glutamine, and effects of growth factors in the serum used in cell culture medium during the ischemic phase. Therefore, the cell culture protocol was modified to the use of PBS instead of glucose-free medium under serum-free condition during the ischemia. The altered ischemic conditions resulted in continuous reduction in cell viability at increasing ischemic time points with total cell death at 2h ischemia, suggesting applicable conditions for ischemia/reperfusion studies. Even though a conclusion could not be made about the inhibitors M4, M107, and M114 as the cell viability assay was performed under insufficient conditions; the Nox inhibitors shows high potential as future ischemic stroke treatments, which may help save lives and improve life quality for affected patients.

Lignocellulosic biomass has potential to chip in the chemical and biofuels supplies in future societies,even though lignocellulose is a recalcitrant structure that has to be treated in several steps. After theirproper life cycle, wood-derived materials such as particleboards have few outcomes today apart fromenergy recovery for heat production. Then, they may be used as lignocellulosic biomass sources in theproduction of molecules of interest. Fermentation from wood-derived monosaccharides imposespreliminary sugar retrieval, for instance through pre-treatment and enzymatic hydrolysis. This studyfocuses on the potential of particleboards waste for chemical and biofuel production by comparingsaccharification through simulated steam explosion pre-treatment and enzymatic hydrolysis betweennative and particleboard-derived wood, with an insight in subsequent fermentation by Saccharomycescerevisiae. Urea-Formaldehyde bound particleboard was investigated, as well as some aspects ofMelamine-Urea-Formaldehyde bound particleboard.Pre-treatment resulted in apparition of lignocellulosic degraded compounds in a much larger extent innative wood than in particleboard, which seemed to be only superficially impacted. Formation ofdegraded compounds from sugars – furfural and 5-hydroxymethylfurfural – was enhanced when pretreatmentwas prolonged. Removal of a substantial fraction of the adhesive contained in theparticleboards was observed, leading to comparable concentrations in free urea, its degradedproducts, and formaldehyde between native wood and particleboards during enzymatic hydrolysis.Enzymatic hydrolysis with cellulases and hemicellulases highlighted a critical role of pre-treatment toenhance final yields, both in native wood and in Urea-Formaldehyde particleboard. Adding 20 minutessteam-explosion type pre-treatment at 160 °C resulted in glucose yields increase from 18.5 % to 32.8% for native wood and from 15.6 % to 37.4 % for particleboard. Prolonging pre-treatment residencetime to 35 minutes resulted in much better glucose extraction for native wood but only slight progressfor the particleboard, as glucose yields reached 64.5 % and 41.1 % respectively. Maximalconcentrations achieved were 277 and 184 mg/gbiomass respectively.Fermentation brought to light high inhibition from both native wood and particleboard sources ofmedia, which were attributed to components or degraded products of lignocellulose that were notanalysed in this project. Ethanol was formed during fermentation, with reduced productivity butincreased yields as compared with the control sample. Inhibition was so strong that no difference couldbe given between native and particleboard wood. In this situation, no inhibition potential of resin orits degradation products could be proved. / Lignocellulosic biomassa har potential att bidra till kemikalier och biobränsletillförsel i framtidasamhällen, trots att lignocellulosa är en rekalcitrant struktur som måste behandlas i flera steg. Idagträmaterial som spånskivor bara används för energiåtervinning och värmeproduktion efter deraslivscykel. De kan därför användas som råvara för framställning av värdefulla molekyler.Fermenteringsprocesser behöver frisättningen av trä monosackarider genom förbehandlingsprocesseroch enzymatisk hydrolys. Studien fokuserar på potentialen för avfall från spånskivor för kemisk ochbiobränsleproduktion. Vi har jämfört sackarifiering mellan nativt trä och spånskivor genom simuleradångaxplosion och enzymatisk hydrolys, med en inblick i efterföljande fermentering av Saccharomycescerevisiae. Spånskivor bunden av urea-formaldehyd undersöktes, liksom vissa aspekter av spånskivorbundna med melamin-urea-formaldehyd.Förbehandlingen producerade högre koncentration av lignocellulosa nedbrytningsprodukter frånnativt trä jämfört med spånskivor. Bildningen av nedbrytningsprodukter från sockerarter - furfural och5-hydroxymethylfurfural - ökade med längre förbehandlingar. En väsentlig fraktion av limmet borttogsfrån spånskivorna, vilket ledde till jämförbara koncentrationer i fri urea, dess nedbrytningsprodukteroch formaldehyd mellan naturligt trä och spånskivor under enzymatisk hydrolys.Enzymatisk hydrolys med cellulaser och hemicellulaser avslöjade den kritiska rollen av förbehandlingför att förbättra utbytet, både i naturligt trä och i urea-formaldehyd spånskiva. Längre (20 minuter)ångexplosion vid 160° C resulterade i högre glukosutbytet (från 18,5% till 32,8% för naturligt trä ochfrån 15,6% till 37,4% för spånskivor). Förlängning av uppehållstiden före behandlingen till 35 minuterresulterade i mycket bättre glukosekstraktion för nativt trä (64,5%) men endast liten framsteg förspånskivan (41,1%). Detta resulterade i maximalt utbyte av 277 mg Glc/g biomassa och 184 mg Glc/ gbiomassa för nativt trä och spånskivor, respektive.Fermentering visade hög hämning från lignocellulosa nedbrytningsprodukter som inte analyserades iprojektet för både nativt trä och spånskällor för media. Etanol bildades under fermentering medreducerad produktivitet men ökade utbyten jämfört med kontrollprovet. Hämningen var så stark attingen skillnad kunde ges mellan naturligt trä och spånskivor. I denna situation kunde ingenhämningspotential för lim eller dess nedbrytningsprodukter bevisas.

Lignocellulosic biomass has potential to chip in the chemical and biofuels supplies in future societies,even though lignocellulose is a recalcitrant structure that has to be treated in several steps. After theirproper life cycle, wood-derived materials such as particleboards have few outcomes today apart fromenergy recovery for heat production. Then, they may be used as lignocellulosic biomass sources in theproduction of molecules of interest. Fermentation from wood-derived monosaccharides imposespreliminary sugar retrieval, for instance through pre-treatment and enzymatic hydrolysis. This studyfocuses on the potential of particleboards waste for chemical and biofuel production by comparingsaccharification through simulated steam explosion pre-treatment and enzymatic hydrolysis betweennative and particleboard-derived wood, with an insight in subsequent fermentation by Saccharomycescerevisiae. Urea-Formaldehyde bound particleboard was investigated, as well as some aspects ofMelamine-Urea-Formaldehyde bound particleboard. Pre-treatment resulted in apparition of lignocellulosic degraded compounds in a much larger extent innative wood than in particleboard, which seemed to be only superficially impacted. Formation ofdegraded compounds from sugars – furfural and 5-hydroxymethylfurfural – was enhanced when pretreatmentwas prolonged. Removal of a substantial fraction of the adhesive contained in theparticleboards was observed, leading to comparable concentrations in free urea, its degradedproducts, and formaldehyde between native wood and particleboards during enzymatic hydrolysis.Enzymatic hydrolysis with cellulases and hemicellulases highlighted a critical role of pre-treatment toenhance final yields, both in native wood and in Urea-Formaldehyde particleboard. Adding 20 minutessteam-explosion type pre-treatment at 160 °C resulted in glucose yields increase from 18.5 % to 32.8% for native wood and from 15.6 % to 37.4 % for particleboard. Prolonging pre-treatment residencetime to 35 minutes resulted in much better glucose extraction for native wood but only slight progressfor the particleboard, as glucose yields reached 64.5 % and 41.1 % respectively. Maximalconcentrations achieved were 277 and 184 mg/gbiomass respectively. Fermentation brought to light high inhibition from both native wood and particleboard sources ofmedia, which were attributed to components or degraded products of lignocellulose that were notanalysed in this project. Ethanol was formed during fermentation, with reduced productivity butincreased yields as compared with the control sample. Inhibition was so strong that no difference couldbe given between native and particleboard wood. In this situation, no inhibition potential of resin orits degradation products could be proved. / Lignocellulosic biomassa har potential att bidra till kemikalier och biobränsletillförsel i framtidasamhällen, trots att lignocellulosa är en rekalcitrant struktur som måste behandlas i flera steg. Idagträmaterial som spånskivor bara används för energiåtervinning och värmeproduktion efter deraslivscykel. De kan därför användas som råvara för framställning av värdefulla molekyler.Fermenteringsprocesser behöver frisättningen av trä monosackarider genom förbehandlingsprocesseroch enzymatisk hydrolys. Studien fokuserar på potentialen för avfall från spånskivor för kemisk ochbiobränsleproduktion. Vi har jämfört sackarifiering mellan nativt trä och spånskivor genom simuleradångaxplosion och enzymatisk hydrolys, med en inblick i efterföljande fermentering av Saccharomycescerevisiae. Spånskivor bunden av urea-formaldehyd undersöktes, liksom vissa aspekter av spånskivorbundna med melamin-urea-formaldehyd. Förbehandlingen producerade högre koncentration av lignocellulosa nedbrytningsprodukter frånnativt trä jämfört med spånskivor. Bildningen av nedbrytningsprodukter från sockerarter - furfural och5-hydroxymethylfurfural - ökade med längre förbehandlingar. En väsentlig fraktion av limmet borttogsfrån spånskivorna, vilket ledde till jämförbara koncentrationer i fri urea, dess nedbrytningsprodukteroch formaldehyd mellan naturligt trä och spånskivor under enzymatisk hydrolys. Enzymatisk hydrolys med cellulaser och hemicellulaser avslöjade den kritiska rollen av förbehandlingför att förbättra utbytet, både i naturligt trä och i urea-formaldehyd spånskiva. Längre (20 minuter)ångexplosion vid 160° C resulterade i högre glukosutbytet (från 18,5% till 32,8% för naturligt trä ochfrån 15,6% till 37,4% för spånskivor). Förlängning av uppehållstiden före behandlingen till 35 minuterresulterade i mycket bättre glukosekstraktion för nativt trä (64,5%) men endast liten framsteg förspånskivan (41,1%). Detta resulterade i maximalt utbyte av 277 mg Glc/g biomassa och 184 mg Glc/ gbiomassa för nativt trä och spånskivor, respektive. Fermentering visade hög hämning från lignocellulosa nedbrytningsprodukter som inte analyserades iprojektet för både nativt trä och spånskällor för media. Etanol bildades under fermentering medreducerad produktivitet men ökade utbyten jämfört med kontrollprovet. Hämningen var så stark attingen skillnad kunde ges mellan naturligt trä och spånskivor. I denna situation kunde ingenhämningspotential för lim eller dess nedbrytningsprodukter bevisas.

Sepsis is aggressive and severe inflammatory body response to an infection and is considered to be one of the most common death causes in patients. The current diagnosis of sepsis is not fast enough to help those who get sepsis, due to its fast progression. The current golden standard for sepsis diagnosis is blood culturing. However, the biggest downside of it is the long time. Research is now focused on finding a faster way to diagnose sepsis on early stages. The most promising one tends to be the usage of biomarkers. Today, there are 260 defined sepsis biomarkers, however, only few of them are clinically used. Among them, C-reactive protein, and procalcitonin. Another potential biomarker could be miRNAs. The research about that today is at early stage. To use miRNAs as biomarkers, they need to be quantified. One way to quantify miRNAs is the two-tailed RT-qPCR method together with absolute quantification. This study focused on evaluating the best extraction method of small RNA for later quantification of specific miRNA. The blood plasma from healthy donors was divided into spiked and non-spiked samples, where the synthetic miRSeps-3 served as a spike-in positive controls. All samples were extracted using two methods, manual and robotic with Qiacube (Qiagen). Absolute quantification was applied to quantify miRNA in all samples. The successful results indicated that the two-tailed RT-qPCR was sensitive enough. More optimization is required for the methods, however, the whole method has a good potential to become helpful for clinical usage in the future

The diagnosis of chronic kidney disease (CKD) by examination of the urine has the potential to improve patients outcome by means of earlier detection. Due to the fact that the urine contains metabolic signatures for many biochemical pathways, this biofluid is ideal for metabolomics. A feature unique to diseases of the kidney is that the components of the kidney excrete urine. On the basis of this, analysis of urine have great potential for discovering new biomarkers for renal failure. The aim of this study was therefore to compare urine samples obtained from CKD patients with healthy volunteers, in order to observe differences in metabolite concentration. Four different methods were applied for metabolite analysis. The three first methods used targeted analysis with gas chromatography coupled with single and triple quadrupole mass spectrometry and two different derivatization techniques were evaluated, alkylation and silylation respectively. The fourth method used untargeted analysis with hydrophilic interaction liquid chromatography coupled to a time-of-flight mass spectrometer. The combination of these techniques covers a large part of the urine metabolome by enabling detection of amino- and nonamino acids, sugars, sugar alcohols, purines, pyrimidines etc. The first method identified 36 amino- and nonamino acids in the in-house library as well as finding one unidentified compound present in the samples. The second method identified 59 metabolites using silyaltion as derivatization techniques and identified metabolites which are not amino- and nonamino acids, hypoxanthane and uracil respectively. The third method identified 46 amino- and nonamino acid with absolute quantification. The fourth method using mass profiler professional for feature selection algorithm found 6 accurate masses higher represented in the CKD group, however later it was found that these masses were present in both groups. The results from this study showed differences in metabolite concentration between the CKD group and the control group, where the excretion of almost all components into urine was decreased for the chronic kidney disease subjects. However, some compounds such as benzoate and proline were observed to be at higher concentration. Finally, the results were comparable with previous studies as well as observing metabolite variations between the two groups. However, there is still a long way to go before this can be applied in clinical settings. Future work needs to be performed on a larger group where the patients are with same diagnosis and off medications.

The aim of this experiment was to monitor the microbial communities in two biogas reactors and evaluate the efficiency of denaturing gradient gel electrophoresis (DGGE) as a technique for visualizing shifts in the microbial compositions. The reactors were followed from September 2011 to May 2012. The first reactor is a pilot scale upflow anaerobic sludge blanket (UASB) reactor situated at Foss farm outside of Porsgrunn, running on cow manure. The second reactor is lab scale and situated at Telemark University College, running on pig manure. Samples were taken from the reactors at regular intervals. DNA was extracted from the samples and amplified by polymerase chain reaction (PCR). The primers were 338f and 518r, targeting the 16S rDNA sequence. Changes in the microbial diversity were detected by DGGE in both reactors. Some bands appeared and other disappeared during the period. These changes could not be correlated to changes in operating conditions. This was probably because DGGE reflects cell amounts and not microbe activity levels. DGGE is a highly reproducible and consistently performing fingerprinting technique. It is capable of reflecting long term shifts in the microbial communities and several samples can be compared in one gel. This makes DGGE an effective method for monitoring reactors over time. Several DGGE bands were excised and sequenced, but the results were either negative, or of too poor quality, for further analysis. The probable cause was insufficient separation of bands leading to multiple sequences in the extracted DNA. This may be overcome by using a more specific primer set to reduce the amount of bands.

Breast cancer develops through multiple stages from hyperplasia to invasive and finally metastatic disease. Ductal carcinoma in situ (DCIS) is an abnormal proliferation of epithelial cells within the milk ducts in the breast without invasion beyond the basement membrane. The incidence of DCIS accounts for about 20-25% of newly diagnosed breast cancer cases. Some in situ lesions are believed to rapidly transit to invasive ductal carcinoma (IDC), while others remain unchanged or disappear. Nowadays, women who would never experience invasive breast cancer are undergoing unnecessary and potentially harmful treatment. Studies have revealed that the invasive phenotype of breast cancer is determined at the preinvasive stages of the tumor. Molecular studies of DCIS are therefore important in order to identify those lesions that have a greater risk of developing into invasive disease. The objective of this thesis was to characterize in situ and invasive breast carcinomas by gene expression profiling. Differences in gene expression within DCIS and between DCIS and invasive breast carcinomas were examined to gain insights about molecular mechanisms underlying tumor progression and to identify potential progression markers. 58 tumor tissues from 37 pure DCIS and 21 pure invasive cancers were subjected to microarray gene expression analysis using Agilent One-Color Microarray 8times 60K. Hierarchical clustering proved that the samples related more to subtype than diagnosis. The most significant genes separating the invasive cancers from DCIS were found to be involved in functions related to the extracellular matrix and tumor-stromal interaction. A subgroup of eight DCIS tumors separated from the other DCIS by high expression of genes characteristic of the invasive tumors. These genes could be potential progression markers if validated in other studies. Heterogeneity was observed among the DCIS patients and two subgroups of in situ lesions were clearly differentiated based on upregulated immune response. Elevated levels of immune signaling were found in HER2+, basal-like, normal-like and luminal B subtypes, but were completely absent in luminal A tumors. The suppressing role of the immune system compared with the promoting role needs to be further investigated, and could potentially increase our knowledge concerning the progression of in situ lesions to invasive breast cancer.

Encapsulation of pancreatic islets in alginate microbeads and microcapsules show great promise for the treatment of Type 1 diabetes mellitus. Significant progress has been made in developing a biocompatible capsule that allows sufficient exchange of nutrients and products with the encapsulated cells, while at the same time maintaining a barrier to immune cells and preventing rejection of the transplanted cells. However, a truly biocompatible capsule has, as yet, not been developed, and implanted capsules often trigger low levels of inflammation leading to fibrosis, diminished insulin secretion, and sometimes death of the encapsulated cells. A lepirudin-based human whole blood model was used to demonstrate the inflammatory potential of a set of different alginate microcapsules and microbeads. This was performed to elucidate the effect of different capsule and bead parameters, such as the effect of a hollow versus solid inner core, polycation type, polycation concentration, alginate type, and capsule and bead diameter. Complement activation after incubation of capsules in whole blood was measured as sTCC generation. In addition, the secretion of chemokines, inflammatory cytokines, antiinflammatory cytokines, and growth factors was analyzed by ELISA and Bio-plex. Leukocyte activation as measured by CD11b expression was detected using flow cytometry. Finally, Confocal Laser Scanning Microscopy (CLSM) was used in order to screen for a set of plasma proteins and observe what proteins adsorbed to the capsule surface. TAM alginate microbeads did not trigger complement activation, secretion of cytokines, or up-regulation of CD11b expression, and thus appeared to have a minimal inflammatory potential. In addition, the protein adsorption assay showed no apparent protein surface deposition on the microbeads after 6 hours of incubation in plasma of the proteins screened for (complement protein C3, complement regulatory proteins factor H, factor I, C1 inhibitor, and vitronectin, as well as coagulation cascade proteins fibrinogen, plasminogen, and HMWK). Solid alginate APA microcapsules containing poly-L-lysine (PLL), on the other hand, showed an increase in complement component sTCC levels, in chemokine levels (IL-8, MCP-1, and MIP- 1α), in inflammatory cytokine levels (IL-6, IL-1β, and TNFα), in anti-inflammatory cytokine levels (IL-1RA and IL-10), and in growth factors levels (PDGF, HGF, and VEGF), as well as a decrease in cytokine IP-10 levels. In addition, the capsules also stimulated leukocyte activation by up-regulating the expression of CD11b. The solid APA micrcapsules showed heavy C3 adsorption, coupled with vitronectin and factor H surface deposition, indicating increased complement activity on these capsules. Hollow APA microcapsules with PLL triggered a rapid and strong sTCC response, as well as significantly increased secretion of the chemokine MCP-1. At the same time, a significant decrease in secretion of chemokines (IL-8 and MIP-1α) and inflammatory cytokines (IL-1β and TNFα), as well as a decrease in secretion of growth factor VEGF, and cytokine MIF, and an increase in cytokine IP-10 was observed. All these cytokine levels except the chemokine MCP- 1 and the complement complex sTCC suggested reduced inflammatory potential for hollow APA capsules. It was proposed that these capsules adsorbed the anaphylatoxins C3a and C5a, thus preventing the complement mediated activation of leukocytes. No increased surface adsorption of C3 was detected on hollow APA capsules compared to solid APA capsules. Conversely, the C3 adsorption was higher on solid APA capsules, thereby not reflecting the increased sTCC generation seen for hollow APA capsules. One explanation for this might be that the hollow capsules secreted some soluble molecule capable of triggering sTCC generation. No apparent change in inflammatory potential could be observed by exchanging the polycation PLL with PLO (poly-L-ornithine), except for abolishing the strong sTCC response observed for hollow APA capsules with PLL as well as lowering the MCP-1 response. It was suggested that this observation could be the result of PLO reducing the permeability of the capsules, thus preventing the diffusion of the hypothesized soluble trigger of sTCC. Increased sTCC was detected with increasing PLL concentration in High G alginate APA capsules. The same could not be observed for High M alginate capsules, however, the chemokine IL-8 and the inflammatory cytokines IL-1β and TNFα increased with increasing PLL concentration, suggesting increased inflammation with increasing PLL concentration. No change in inflammatory potential could be detected with varying alginate microbead diameter. Nor could any change in inflammatory potential be observed by the addition of HEPES in the gelling solution. TAM alginate microbeads appear to have the lowest inflammatory potential of the capsules tested, and are therefore the most suited for in vivo application from an inflammatory aspect, as demonstrated by the whole blood assay. A recent study in Type 1 diabetes patients however showed increased fibrosis when encapsulating human islet cells in barium alginate microbeads [61]. Further studies where incubation of TAM microbeads with isolated monocytes are co-cultured with fibroblasts could further elucidate the mechanisms of fibrosis on the microbeads. In addition, continued screening of protein adsorption on the bead surface should be performed.

The blood coagulation Factor XIII (FXIII) is a transglutaminase catalyzing γ-glytamyl ε-lysine crosslinks between various molecules. It is most known for its role in crosslinking fibrin and stabilizing the blood clot in the process of coagulation in wound healing. The Factor XIII is also essential in maintaining pregnancy, and recurrent spontaneous abortions are reported in FXIII deficient patients. The localization and the role of FXIII in the development of the placenta were investigated in this study. Preliminary, FXIII was found to be located in macrophages, and in this study we verified by immunoblotting and mass spectrometry that FXIII is present in the decidual part of the placenta. The effect of FXIII on trophoblastic invasion during placental development was also examined. The invasion process was studied with the Boyden chamber assay using both an immortalized trophoblast cell line (HTR-8/SVneo), and primary culture of extravillous trophoblasts. A significant effect of FXIII on inhibition of invasion using trophoblast cell line was found, but no effect was observed with the primary culture. The cause of the inhibition on invasion observed with the cell line was ruled out to be caused by other indirect effects of FXIII, such as cytotoxicity, effect on secretion of matrix metalloproteases and proliferation. The results showed unfortunately great variability; therefore better controls must be included in the assays in order to obtain more reliable results. Future perspectives are to optimize the existing method or to use another technique to study the more in vivo approach on invasion using primary culture. Later, it would be interesting to examine the proteomics of FXIII; to identify the molecules involved in crosslinking by FXIII in placental development. This would allow us to understand more of the physiology of FXIII and its role in placental development which could aid in recurrent abortion managements.

Iron nanoparticles occur naturally in the environment, but their exposure increases dramatically due to the field of nanotechnology and –medicine. It is poorly understood how the intracellular cooperative mechanisms of submicron particles and microorganisms function on mammalian immune system. In this study, superparamagnetic iron oxide (SPIO) submicron particles will be used to benefit the research within environmental diseases, addressing the biocompatibility of these particles. The size-dependent effects in the immune system of two carboxyl coated SPIO particles with stated sizes 100 nm and 1 µm will be studied in vitro. It would be interesting to determine whether these particles were able to activate the inflammasome, but still, the precise molecular mechanisms for the activation remain unknown. In order to reveal the biocompatibility of these particles, tests were performed as a function of particle concentration ranging from 0.01 to 100 µg/mL using both whole blood and peripheral blood mononuclear cells (PBMC) isolated from healthy donors. The monocytes were first primed with Lipopolysaccharide from Escherichia coli 0111:B4 strain, followed by stimulation with increasing concentrations of the submicron particles. Flow cytometry on whole blood samples identified up-regulation of CD11b monocytes and granulocytes by the particles. In addition, Terminal Complement Complex analyses proved activation of the complement system. It is possible that the particles have been coated with C3b by the complement and phagocytized by the monocytes through CD11b/CD18 receptor. Cytokine secretion from monocytes and whole blood was measured with sandwich ELISA and Bio-plex. The smaller particles seemed to induce higher inflammatory responses than the larger ones. It was, however, interesting to find that the particles themselves caused secretion of active IL-1β without being primed in advance. The mechanisms of the NLRP3 inflammasome activation might be explained by ROS production due to iron imbalance in the cytoplasm. Toxicity of the particles was seen at 10 µg/mL, suggesting their potentially low biocompatibility above this concentration. However, it is suggested better biocompatibility of the silica coated 1 µm particles than the polysaccharide coated 100 nm particles.