Practical applications for an actomyosin-based biosensor in Baltic Sea water

Abstract: Seawater and wastewater all around the world contain toxins and pollutants, not the least drug residues, including hormoneswhich disturb the ecosystems and antibiotics with growing multi-drug resistance of bacteria as a result. The effects onecosystems and mankind can be severe and with this general fact the need for proper analysis devices increases. This haspromoted further studies to establish devices for detection of analytes with high selectivity and high sensitivity. In this thesis Ipresent a unique device exploiting capture of antigen on antibody conjugated actin filaments and subsequent transportationof the antigen in Baltic Sea water using heavy meromyosin (HMM) motor fragments from muscle myosin. The model-antibody,anti-rIgG, used in the study, was covalently attached to the actin filaments, capturing a model-analyte, rIgG that was dissolvedin the Sea water. Furthermore, the effect of Baltic Sea water on HMM propelled actin filament transportation in the in vitromotility assay was studied. An effect was observed with Baltic Sea water, supplemented with standard adenosine 5’-triphosphate (ATP) and oxygen scavenger systems, reducing the sliding velocity by approximately 80%. However the effect wasreversible which is of great advantage in relation to the development of a future biosensor device incorporating actomyosindriven transports. Additionally, evidence was found that the substance A slightly enhanced the function of the proteins whenstored on a motility assay surface at 4-8 °C for up to ten days, of value for practical applications of a potential biosensordevice. The results demonstrate the potential that antigen from sea water could be captured and transported by actomyosinto certain detector areas and eventually become concentrated which would increase the sensitivity of the device.