Nanomaterials for Reagentless (Bio)Sensors

Biosensors are analytical devices that can be used in many fields like health, food, environment, defense among others. They present a high potential of development to monitor biomarker levels or contaminant exposure and as a result to allow early diagnostic, survey and trigger alerts. For their integration biosensors need to be robust, sensitive, autonomous and miniaturize. As electrochemical biosensors fulfill all these requirements, they are adapted for such integration. In addition, their performances depend intimately of the properties of the materials used for the transduction and the biorecognition and therefore an intense research work focus on development of new type of electrochemical biosensors.

Nanomaterials, by virtue of their singular properties (electronic, catalytic, as well as high surface area) are good candidates for providing electrochemical probes for making electrochemical biosensors capable of detecting species in a trace state (sub nanomolar)1 , 2 , 3 , 4 . On another hand, aptamers are a class of biorecognition elements made up of short sequences of oligonucleotides and which have many advantages (availability, stability, lower cost, etc.) compare to others such as antibody or antigen5 , 6 , 7 .

The purpose of this thesis will be to develop and test new electrochemical biosensors combining aptamers and electroactive nanomaterials (metallic nanoparticles, metal organic framework) used as an electrochemical probe. One part of the project will deal with nanomaterials synthesis, characterization and functionalization with aptamer. A second part will concern the sensor preparation that will be based on immobilization on electrodes of at least both the nanomaterial and the recognition aptamer. After each modification step the electrodes will be characterized. Several configurations will be investigated with the aim that a change in conformation of the aptamer after recognition of the target will modify the electro-oxidation of the nanoprobe initially immobilized. Thus, a reagentless biosensor allowing quantitative measurements will be made. The third part of the project will be dedicated to realizing sensing tests and evaluate the performances of the biosensor. This will include best recognition condition, limit of detection, linear range, selectivity… This is a multidisciplinary project where the Ph.D student will perform part of the tasks at the LPPI and the other part at the SensorLab as part of a co-tutelle thesis including 12 months in South Africa.

1.           Wongkaew, N., Simsek, M., Griesche, C. & Baeumner, A. J. Functional Nanomaterials and Nanostructures Enhancing Electrochemical Biosensors and Lab-on-a-Chip Performances: Recent Progress, Applications, and Future Perspective. Chem. Rev. 119, 120–194 (2019).

2.           Geagea, R., Aubert, P.-H., Banet, P. & Sanson, N. Signal enhancement of electrochemical biosensors via direct electrochemical oxidation of silver nanoparticle labels coated with zwitterionic polymers. Chem. Commun. 51, 402–405 (2015).

3.           Upan, J., Banet, P., Aubert, P.-H., Ounnunkad, K. & Jakmunee, J. Sequential injection-differential pulse voltammetric immunosensor for hepatitis B surface antigen using the modified screen-printed carbon electrode. Electrochim. Acta 136335 (2020). doi:10.1016/j.electacta.2020.136335

4.           Anik, Ü., Timur, S. & Dursun, Z. Metal organic frameworks in electrochemical and optical sensing platforms: a review. Microchim. Acta 186, 18–24 (2019).

5.           Iliuk, A. B., Hu, L. & Tao, W. A. Aptamer in Bioanalytical Applications. Anal. Chem. 83, 4440–4452 (2011).

6.           Radi, A. E., Acero Sánchez, J. L., Baldrich, E. & O’Sullivan, C. K. Reagentless, reusable, ultrasensitive electrochemical molecular beacon aptasensor. J. Am. Chem. Soc. 128, 117–124 (2006).

7.           Kashefi-Kheyrabadi, L. & Mehrgardi, M. A. Design and construction of a label free aptasensor for electrochemical detection of sodium diclofenac. Biosens. Bioelectron. 33, 184–189 (2012).

Funding category: Contrat doctoral

PHD Country: France