Abstract:
Bacteria attachment and sensing involve various electrical and mechanical interactions with the material. In this research work, various properties and factors that influence bacteria attachment are evaluated and compared. The key objective of this work was to investigate the properties of conducting polymers that influence the attachment of bacteria in order to increase the sensing capacity. Conducting polymers were synthesized by the ASEMS lab using chemical methods and collected in the form of films in non-reactive solutions. Conducting polymers, particularly Polypyrrole, and its composites with fullerene and sulfur/nitrogen-doped carbon dots were investigated. Moreover, Polyaniline (PANI) was also investigated as a negative control. Material properties such as topography, roughness, surface potential, work function, and young’s modulus were imaged at microscale using atomic force microscopy and correlated with the attachment of E.coli. All Polymers exhibited diverse ranges of properties that were distinct from each other. The surface potential of conducting polymers was in the range of 210 mV to -169 mV, while the work function was in the range of 4.59eV to 4.97eV. The mean roughness of conducting polymers was also diverse it was in the range of 59nm to 382nm. Polymers with a positive potential range were selected to investigate bacterial attachment as bacteria are negatively charged, while PANI was used as a negative control. Finally, Young’s modulus of selected conducting polymers was measured, and it was in the range between 4.09 GPa and 69.6 MPa. Previous studies indicate that sensing capacity for bacteria is directly related to the attachment of bacteria. Rapid detection of bacteria depends on the speed and strength of attachment to polymer surface. In order to investigate the attachment of bacteria, all polymers were treated with E.coli and their attachment was observed with a widefield microscope. Bright-field imaging technique showed that E.coli attachment to Ppy_NCD was higher than other polymers and it was least for PANI. Averaged attachment trend for our conducting polymers was negatively correlated to Young’s modulus, but positively correlated to surface potential.