Multiplex sensor for fast online hygiene monitoring.
Duration: 8.2020 – 4.2022
Dr.-Ing. Shelesh Agrawal | FB 13, Fachgebiet Abwasserwirtschaft, Institut (IWAR)
Prof. Dr. Jörg J. Schneider | FB 7, Fachgebiet Anorganische Chemie, Eduard-Zintl Institut
The project will focus on interdisciplinary cooperation between experimental groups in the Departments of Civil and Environmental Engineering and Chemistry working together to study the use of carbon nanotubes as smart biomaterial for quality monitoring of drinking water. The biosensor device developed in this project is based on vertically aligned carbon nanotubes (VACNTs) which are attached onto highly conducting Si chips which serve as the sensor substrate. The VACNTs are accessible by a chemical vapor deposition (CVD) route. The lengths and arrangement of the CNTs within the VACNT structure are controlled by the CVD process parameters. By structuring processes of the catalyst, the growth is controlled. Using shadow mask and photolithography techniques it is possible to contact individual CNT sensor bundles in 8 x 8 sensor arrays electrically. These sensor arrays are the substrates for further chemical functionalization and DNA bacterial attachment. With this process it is possible to fabricate various sensor arrangements with different spatial orientation on the chip substrate, lengths and width of the individual CNT sensors. First steps towards the functionalization of the CNT structures with DNA have been made. For the functionality of the sensor, in addition to the development of the carbon nanotube-based sensor materials, specific primer probes were developed with a focus on the drinking water pathogen Ps. aeruginosa. The ecfX gene was quickly targeted because it is species-specific and it had previously been identified as a reliable genetic marker for Ps. aeruginosa in several studies. The primer probe efc164 was found to be the most suitable for both PCR and qPCR in the probes studied. However, the specific coupling of the sensor elements with the VACNTs could not be carried out further, as the aqueous solution of the probes led to dissolution of the carbon nanotubes from the sensor materials. Therefore, the primer probes were further modified to improve the coupling between VACNTs and the primer probes. Out of several modified probes, the C7 amino modified probe showed the stable coupling to VACNTs without dissolution of the carbon nanotubes.