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Expanded genetic code to control antibody orientation in immunodiagnostics


Antibody based diagnostic tests or immunoassays are widely used to quicken treatment decision-making and to enable patients to test themselves e.g. for pregnancy. However, the antibodies that bind the analytes in conventional immunoassays are immobilized onto a test surfaces in random orientations blocking some binding sites from the analytes. When the concentration of a disease marker used as the analyte is below the detection limit the signal could be improved by orienting the antibodies correctly. Our objective was to orientate a digoxigenin binding Fab antibody fragment by incorporating an unnatural amino acid with click chemistry properties, p-azido-L-phenylalanine. As a control, we used chemically treated Fabs with azides in random locations. The Fabs were immobilized onto DBCO coated magnetic beads and then the intensity of the bound, fluorescently labeled, digoxigenin was measured with flow cytometry. Our results showed that the controlled orientation improved the signal and made the test surface more homogeneous.


The goal of our human practice projects was to inspire children and youth into discovering the wonderful world of science and technology in a fun way. We collaborated with local organizations like STEAM Turku, LUMA center and TSYK, a local high school. Throughout our project we've been involved in events that allowed kids to do practical labwork by themselves. We taught girl scouts a practical lesson in hygiene by doing petri dish cultures of samples from their hands and allowed them to discover the difference between properly washed and unwashed hands. We also organized an advanced high school course where the students had to solve a real world-problem by cloning a gene of interest from one vector to another. We arranged short courses for kids on LUMA center's SciCruise and for the guests of Aalto University's BioGarage. Both courses included the extraction of DNA from either bananas or the guest's own saliva.