Aptamers and Odorant Binding Proteins –
Innovative Receptors for Electronic Small Ligand Sensing
PROF. DR. WOLFGANG KNOLL & PROF. DR. CHRISTOPH KLEBER
Partner:
Prof. Frank Rosenau, Universität Ulm
Prof. Sabine Szunerits, Universität Lille
Quantitative monitoring of small analytes in clinically relevant fluids or in air remains a challenge both from a fundamental point of view as well as for practical applications.
In all cases, one is facing three major problems: (i) the sensitivity of the transducer; (ii) the selectivity needed to differentiate between competing analytes; and (iii) the suppression of non-specific binding events. When dealing with electronic sensing concepts, Graphene-based Field-Effect Transistors (gFETs) stand out for their small size, excellent electrical characteristic, and high sensitivity to near surface charges and electrical fields. Specificity to the target analyte can be integrated into gFETs via surface attachment of target-specific receptors; yet the very small Debye length in (physiological) buffer solutions limits the signal strength considerably.
gFETs in liquid gate configuration for THC sensing.
A first focus of the proposed research is the impact of the applied surface chemistry used for the immobilization of these receptor on the transducer surface and how this coupling affects the final sensing signals. A second effort addresses options for manipulating the Debye limitations by the co-assembly of polymer brushes on the sensor surface. For the extension of these studies to monitoring THC directly in air, we propose to mimic the natural mucosa by an ultrathin (a few 10 nm in thickness) hydrogel coating on top of the transistor that protects the sensitive bioorganic components against air by keeping them in a fully hydrated state, without preventing the VOCs getting access to the receptors on the sensor surface by diffusing through the hydrogel layer. The members of the DPU team are highly complementary in their expertise to tackle these complex and multidisciplinary challenge: they have been working for many years on OBPs for smell sensing, on the use of aptamers for medical biosensing, and has experts in surface immobilization of receptors and electronic sensing.
