Light-triggered biosensors with dual read-out based on tailored hybrid semiconductor nanostructures

• Applicants: Professor Dr. Martin Eickhoff; Professor Dr. Fred Lisdat
• Subject Area: Analytical Chemistry ; Experimental Condensed Matter Physics
• Term: since 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 495515506

Aim of the project is the development of a light-triggered biosensor technology using the simultaneous measurement of photoelectrochemical and photoluminescence signals at hybrid semiconductor nanostructures (HNS). Particularly advantageous is the potential for a multiplexed analysis and an improvement of selectivity compared to existing technologies. The core is thus, the combined detection of photoluminescence and photocurrrents in dependence on the applied potential at the HNS. The basis of this new technology are electrochemically stable photoelectrodes of hybrid nanostructures. They consist of InGaN nanowires covered with an ultrathin coating of an oxide, oxynitride or carbon. Consequently, the photoelectrochemical properties of these coatings can be exploited after excitation and transfer of charge carriers from the InGaN nanowire core. The chemical composition of the coatings will influence the band edge positions and hence the electrochemical characteristics at the HNS surface. First, the reactions of different redox molecules will be studied. The results shall help to develop a better understanding of the interplay of band bending, electrochemical surface properties, applied potential and the presence of donor- or acceptor molecules in solution. Second, biomolecules are intended to be immobilized on the HNS in such a way that direct electron transfer becomes feasible. Here, the surface chemistry can be further adjusted also with the aim to covalently immobilize the enzymes. Thus, a sensorial detection of enzyme substrates via photoluminescence and photoelectrochemical measurements shall be achieved without further addition of reagents. The large surface of the HNS electrodes is intended to be used for spatial resolved immobilization of different biomolecules and subsequently for the parallel analysis of different analyte molecules on one sensor surface.

• DFG Programme: Research Grants