Biosensors play a crucial role in many fields, including healthcare, food safety, and environmental monitoring, due to their ability to detect targeted analytes quickly and specifically. A key aspect of their design lies in the chemistry used to immobilize bioreceptors on the sensor’s sensitive area. This factor strongly influences signal transduction efficiency and resistance to fouling, thereby directly affecting the overall performance of the biosensor and the reliability of the measurements.

The aim of this thesis work is to investigate the feasibility of depositing plasma polymers on electrodes to functionalize them with aptamers for use as electro-aptasensors. The main challenge is to carry out this polymer deposition using a novel cold atmospheric plasma polymerization technique via dielectric barrier discharge (DBD-CAP). This innovative deposition method offers several advantages: it requires neither solvents nor vacuum and can be performed at room temperature. It is therefore compatible with a wide range of materials and allows rapid coverage of large surfaces.

In this context, various monomers known as precursors of conductive polymers, such as pyrrole and thiophene, were tested for the functionalization of electrochemical sensors. However, due to stability issues in aqueous media, only thiophene was retained. Following the optimization of deposition parameters and a post-deposition annealing step, water-stable polythiophene films were obtained. Thiophene was then co-deposited with an amino-substituted derivative to create a chemically reactive layer suitable for aptamer grafting. To evaluate the application of this plasma poly(thiophene-co-thiophene-2-ethylamine) film, an aptamer targeting human interferon-gamma (IFN) was selected from the literature. This aptamer was used to study IFN detection via electrochemistry and quartz crystal microbalance with dissipation monitoring (QCM-D).

​The results demonstrated the feasibility of using the developed copolymer as a binding layer for electro-aptasensor functionalization. Electrochemical detection of IFN was successfully achieved for concentrations ranging from 1 nM to 10 nM. These findings suggest that this surface functionalization strategy could represent a promising approach for the development of biochips.