Semiconductor nanowires for biosening

Other conference contribution, 2023

Semiconductor nanowires are known to enhance the signal of fluorophores in their proximity. In our recent work, we optimized GaP nanowires to maximize the enhancement of fluorescence excitation. For that, we used optical microscopy to measure the fluorescence photobleaching rate on the nanowires, proportional to local excitation. From the measurements and modelling, we show for red fluorophores (excitation wavelength 640 nm) that nanowires with diameters of 90–130 nm enable enhancement of over a factor of 5 compared to bulk solution. We also demonstrate that a 10 nm oxide layer on the nanowires enables functionalisation using biotin-streptavidin chemistry without hindering the enhancement. Such nanowires were used in our laboratory to detect fluorescently-labelled proteins on a single molecule level. Now we employ these results for detection of down to nanomolar concentrations of DNA in solution, and in our poster, we discuss these biosensors.