Polystyrene nanoparticles interactions with Calbindin D9k and Monellin

Nanomedicine and the use of nanoparticles (NPs) are growing like never before. It is therefore important to investigate the interactions in the nano world and the possible hazards. Proteins in organisms can adsorb to NPs and change the proteins structure and therefore their functions. This could be a potential danger and thus an interesting research field. Here, we explore how the proteins Calbindin D9k and Monellin interacts with polystyrene NPs using fluorescence spectroscopy and NPs colloidal stability using dynamic light scattering (DLS). We show that similar charges repel and the opposite attract proteins to NPs, proteins hydrophobic patches allow them to adsorb to hydrophobic NPs and the size of the NPs seems to affect how fast the proteins adsorbs to the NPs.The invisible tree is falling, will we hear it? Some people say what we cannot see does not exists. Today, media and social media are letting us see what is going on all around the world, things that 20 years ago we could not see but still existed. However, there are things we cannot see, not 5 000 km away but right where we live. We are exposed to these things every day, whether we are brushing our teeth, sun bathing or walking down the street. These things are called nanoparticles (NPs) and they are invisible for the human eye. Their size is incomprehensible, by definition they have at least one dimension less than 100 nanometers or in English, they are super, super tiny. Let us say you would win 10 million dollars on the lottery and this would equal one meter. One nanometer would then be like winning 1 penny on the lottery. The NPs in the everyday products and from many different industries can eventually make their way to the sewage systems and later end up in lakes and oceans. Because of their small size they can be consumed by algae, the algae are then eaten by small fish which are then eaten by bigger fish and maybe if you like to eat fish, you will eat the bigger fish. This means that the NPs will follow the whole food chain. The problem with NPs inside organisms is that they do not degrade and their size allows them to get into all tissues in the body. Inside an organism the NPs will meet a huge vary of different molecules, e.g. proteins. When they meet they either play nice or get into a fight. This is because when proteins meet the NPs they tend to stick to them and when they do they can alter its shape just like humans can change their behavior when meeting different people. How proteins work is mainly due their shape and when their shape is altered their way of working might be changed as well. Therefore, NPs in organisms can be really dangerous. In recent years, we have started to understand how some proteins and NPs bind to each other and we have been trying to use this to benefit us. You could see proteins as a kind of a key but also as a key hole and a lot of the things that keeps us alive is dependent on how certain keys fit to certain key holes. All our different cells inside our bodies have specific key holes and to get into a cell you must have the right key. Unhealthy cells e.g. cancer cell have certain key holes and by fitting the right key onto NPs, we can get the NPs inside of these unhealthy cells. By putting medicine e.g. cancer treatment medicine inside the NPs with the right key we can be sure that the medicine only will affect the unhealthy cells. Using NPs in medicine is called nanomedicine and could have a huge impact on how we treat patients. How proteins and NPs interact is still a young field of research and due to the vast amount of different proteins in organisms it is very difficult to predict how NPs will affect organisms. This is why I have been studying how different proteins interact with NPs of varying sizes. The results showed that the total charge, positive or negative and the hydrophobicity of the proteins along with the NPs size are key factors for how they interact. The method in this study can tell us if proteins binds to NPs and somewhat if the proteins shape changes. Therefore, further research with other technics is needed. The results take us one step closer to creating our own Rosetta stone of the protein-nanoparticle language. Supervisor: Martin Lundqvist Degree Project 15 credits in molecular biology 2016 Department of Biology/Department of Biochemistry and Structural Biology Lund Universit

Failures and complications in patients with birth defects restored with fixed dental prostheses and single crowns on teeth and/or implants

OBJECTIVES: To assess retrospectively, over at least 5 years, the incidences of technical and biological complications and failures in young adult patients with birth defects affecting the formation of teeth. MATERIAL AND METHODS: All insurance cases with a birth defect that had crowns and fixed dental prostheses (FDPs) inserted more than 5 years ago were contacted and asked to participate in a reexamination. RESULTS: The median age of the patients was 19.3 years (range 16.6-24.7 years) when prosthetic treatment was initiated. Over the median observation period of 15.7 years (range 7.4-24.9 years) and considering the treatment needs at the reexamination, 19 out of 33 patients (58%) with reconstructions on teeth remained free from all failures or complications. From the patients with FDPs and single unit crowns (SCs) on implants followed over a median observation period of 8 years (range 4.6-15.3 years), eight out of 17% or 47% needed a retreatment or repair at some point due to a failure or a complication. From the three groups of patients, the cases with amelogenesis/dentinogenesis imperfecta demonstrated the highest failure and complication rates. In the cases with cleft lip, alveolus and palate (CLAP) or hypodontia/oligodontia, 71% of the SCs and 73% of the FDPs on teeth (FDP T) remained complication free over a median observation period of about 16 years. Sixty-two percent of the SCs and 64% of the FDPs on implants remained complication free over 8 years. Complications occurred earlier with implant-supported reconstructions. CONCLUSIONS: Because healthy, pristine teeth can be left unprepared, implant-supported SCs and FDPs are the treatment choice in young adults with birth defects resulting in tooth agenesis and in whom the edentulous spaces cannot be closed by means of orthodontic therapy. However, the trend for earlier and more frequent complications with implant-supported reconstructions in young adults, expecting many years of function with the reconstructions, has to be weighed against the benefits of keeping teeth unprepared. In cases with CLAP in which anatomical conditions render implant placement difficult and in which teeth adjacent to the cleft require esthetic corrections, the conventional FDP T still remains the treatment of choice