The on-site and higly selective detection of cocaine and other important target analytes such as
antibiotic residues in waste water remains a challenging area of research. In this project, we wish to
better understand and eventually improve analytical detection systems that use short DNA
sequences for selective recognition of molecules of interest – called aptamers – followed by the
generation of electrical signals upon binding.To achieve this we will first study the fundamental
influence of structure and flexibility of aptamers on binding and current generation. This will further
be mapped using computer modelling, NMR spectroscopy and ITC measurements. After obtaining
structural knowledge, we aim to chemically stabilize the high affinity aptamers by introduction of
chemically modified building blocks in the aptamer nucleic acid sequence. The additional functional
groups thus introduced in the aptamer should allow to enhance the stability of the folded ligand
binding state of the aptamer. In this way, we hope to contribute to the development of more robust
apasensors. This should ultimately and on the long term lead to improved, robust, simple and
mobile devices allowing to be handled on-site in different fields of application (e.g. law enforcement
agencies, medical care environment, food industry).