Experimental and simulation studies of nucleic acid transport through nanosized channels, both biological and synthetic, has become a rapidly growing research area over the last decade. While the utilization of the alpha-hemolysin channel as a sequencing device is soon to be realized, other biological nanochannels may hold advantages that are yet unknown. Motivated by this, the first reported molecular dynamics simulations of DNA translocation through a connexon 26 channel were accomplished, for single-strandeed DNA with a length of 24 nucleotides and with a sequence containing only adenine, cytosine, guanine or thymine bases. Transmembrane voltages between 40 mV and 8.4 V were applied for up to ~2 ns, and the minimum voltage needed for translocation was found to be at 2.4 V. Higher voltages led to shorter translocation times in most cases. Non-translocation or slow translocation events were normally the result of a high degree of foldedness at the entrance of the “funnel” region, the narrowest part of the connexon channel. Distinct differences were seen between the bases, in particular through slower translocations for the purines than for the pyrimidines. Comparison with published literature of alpha-hemolysin translocation found that some of the results were on the same order of magnitude for translocation through connexon channels subject to constraints. It was concluded that to characterize the translocation mechanisms, further investigations should be carried out; both by the use of experiments as well as more simulation studies.

RGD-functionalized and non-functionalized oil-in-water nanoemulsions of approximately 100 nm containing DSPC, PEGylated DSPE, cholesterol and Gd-DTPA-DSA at a molar ratio of 1.1/0.15/1/0.75 were prepared. In vitro uptake and trafficking in HUVECs of the nanoemulsions was characterized using confocal laser scanning microscopy and flow cytometry. The RGD peptide recognizes αvβ3 and αvβ5 integrin receptors, which play central roles in angiogenesis. Moreover, the αvβ3 integrin receptor is overexpressed in the endothelium of angiogenic tumor vasculature. It was found that the RGD-emulsion showed a remarkably high uptake in HUVECs expressing αvβ3 integrins compared to its non-conjugated control version. Furthermore, the RGD-emulsion was able to evade the lysosomes at least within the first 3 hours of incubation, while the control-emulsion was not. The uptake of both emulsions was mainly facilitated by caveolae-mediated endocytosis, but also to a lesser extent by clathrin-mediated endocytosis and other un- known mechanisms. It was shown that RGD and control-emulsions were internalized or sorted into distinct vesicles. Both emulsions bypassed the early endosomes, and it was hypothesized that they were mainly trafficked to caveosomes before subsequent traffick- ing of control-emulsion to late endosomes/lysosomes and of RGD-emulsion to cis-Golgi or endoplasmatic reticulum. The results suggest that the RGD-emulsion has promising feasibility as a site-specific targetable delivery system.

An increasingly important part of food technology is nanotechnology. Inorganic nanoparticles are added directly or indirectly to food in order to create new tastes, appetizing looks or to preserve it longer. Exposure to these nanoparticles is fairly unknown, and there is a need to evaluate the dose that humans are exposed to. In this master thesis, two inorganic substances have been chosen. The first one is silver nanoparticles, commonly known as an antimicrobial agent and added to plastic food containers to preserve food. The second is the food colour E171, titanium dioxide. This is not defined as a nanoparticle because of an average particle size of 200-300 nm, but it is assumed that the size distribution may include nanoparticles. In both cases the intention has been to create an exposure model. For silver, experiments were performed to evaluate the leaching from the food containers to food simulant. The experiments show that first time use of the plastic container will give a concentration in the food simulant of up to a total of 30 ng Ag/g. However, after some use the concentration will be lower than 1 ng Ag/g. The silver experiments show that usage of silver doped food containers will not result in an increase in silver exposure and in general the food containers will not have the claimed antimicrobial effect. However, disposable packaging containing silver may be of concern as the dose of silver leaching from this may be larger.Titanium dioxide data is based on a literature review. Analysis of an E171 sample, showed that up to 50 % of the particles were nanoparticles with a size smaller than 100 nm. Modeling of the exposure to titanium dioxide (TiO2) shows that exposure is diet dependent with an average of 1-3 mg/day/kgbw. The modeling shows that children consume a larger dose than adults, and are more exposed to dietary products containing TiO2. For TiO2 the average dose is larger than the background of 5 mg/day, but lack of an effect threshold makes it difficult to conclude whether this is a unsafe or safe dose.Exposure to inorganic nanoparticles through food will be very dependent on the way of distribution. If added to consumer products the exposure is likely to be less than nanoparticles added directly to the food. Some of the results in this project have been unexpected, like the lack of silver leaching from the plastic containers and a large fraction of nanoparticles in E171. The project only includes two substances and further research into human exposure to other inorganic materials is recommended.

This project aims at the fabrication of a rough polydimethylsiloxane(PDMS) surface with patterned smooth areas. The idea is that such a surface will allow for water capturing on the smooth areas of the surface. The applications for this kind of surface are many, but especially the prospects of a surface able to trap droplets of cells in suspension by simply dipping the surface into the suspension is intriguing.From a previous project[1], and another student’s master’s thesis[2], the use of an etched copper surface seemed promising for the fabrication of a rough mold. This was abandoned after sandpaper turned out to be an even better mold, giving superhydrophobic PDMS(162, 33 ± 1, 40degrees).The negative photoresist SU-8 5 was used to pattern the sandpaper with small, circular features on the P1000 sandpaper(400μm and 1mm in diameter). The PDMS replica from this mold was a rough surface with smooth wells. This was not able to capture water droplets effectively, partly because air bubbles were trapped in the wells during the immersion in water. To avoid this, another mold was procured by the silanization of the previously made PDMS surface. The PDMS replica of the silanized PDMS had smooth pillars instead of wells, and did not succeed in trapping water droplets either. In fact, the smooth wells seemed to better at capturing the water.This project has succeeded in producing high enough roughness on PDMS to alter the contact angle with water by ∼ 61 degrees to a contact angle exceeding the lower limit for superhydrophobic surfaces by ∼ 12 degrees. The use of a sandpaper mold has proven to is simple, inexpensive and effective at producing PDMS with high contact angles.