Analys, elimination och reduktion av negativa bieffekter vid användning av elektriska fält i syfte att orientera molekylära motorer

Sammanfattning: The molecular motors of muscle are of potential interest in nanotechnology. These motors consist of the protein, myosin II interacting with actin filaments. It would be of interest to control the interaction between actin and myosin, e.g. in order to steer their direction of motion. Because these proteins are electrically charged their motion in a cell filled with a solution could potentially be controlled by an electric field. Here I have addressed several problems associated with experiments of this type. A main problem was found to be excessive heating of the solution. Another complication was electroosmotic flow and chemical reactions on the cell surface. The electric field can also cause electrophoretic motion of the proteins, which in some cases is undesired. The most effective way to reduce the heating of the solution was to keep the ratio between the cross sectional area of the cell and its cooling surfaces as small as possible. External cooling of the cell and keeping the ionic concentration in the solution as low as possible also prevented overheating. The electroosmotic flow could be stopped with agarose plugs at the cell openings and the surface reactions can probably be avoided if trimethylchlorosilane (TMCS) coated glass rather than nitrocellulose film is used for myosin adsorption. If electrophoretic motion turns out to be a problem it can be reduced/stopped with an electroosmotic flow in the opposite direction. A further conclusion of this study is that actin filaments may be oriented by relatively small field strengths whereas it can be necessary to use electric field strength of 1 MV/m or more to orient myosin. At this extremely high field strength the heat production, in a cell with a rectangular cross section, would probably will be to high. However, if a cell with a circular and very low cross sectional area, i.e. a capillary, is used the heating can possibly be held under an acceptable limit.