TOPIC / ACTIVITIES (ENG only)
MONITORING OF BIOLOGICAL AND CHEMICAL CONTAMINANTS IN WASTEWATER
PhD Project (ENG only)
The major concern about wastewater is that it offers optimum growth conditions for bacteria, viruses, fungi, and yeasts, including pathogenic microorganisms, that could be very harmful for human health. Moreover, also chemical contaminants could be highly toxic both for human health and for the environment, being that they are non-biodegradable substances. For these reasons, it is necessary to rely on analytical methods which have the capability to provide the results in short times: biosensors could be a good solution for a rapid, quantitative, and specific detection of these contaminants in wastewater samples.
The aim of the project is to develop biosensors able to detect chemical and biological contaminants, including microorganisms, in the integrated water cycle. Bioreceptors and protocols necessary for the analytical assays carried out with biosensors will be optimized, with the final purpose to develop rapid methods enabling an in-situ complete analysis of real samples from the integrated water cycle.
After a bibliography update, the attention will be focused on the selection of specific aptamers and on the design of a probe for the detection of pathogens and chemical substances identified as targets. Then, the objective will be the development of two different biosensors, electrochemical and QCM, and the optimization of the protocols related to the use of these rapid methods for the detection of wastewater contaminants.
To allow a complete and continuous monitoring, the final aim of the project is to develop and optimize a QCM biosensor for an in-situ analysis, able to provide immediately the results that can be used to verify in real-time the quality of the wastewater.
PROGRESS OF THE ACTIVITIES
The aim of the project was to develop an aptasensor for the specific detection of Escherichia coli whole cells in water samples taken from the integrated water cycle. This aptasensor is characterized by the use of an aptamer as biorecognition element and by the presence of an electrochemical transducer that converts the biorecognition event into a measurable signal.
The sequence of the new aptamer was tested in both its complete and reduced form, and several parameters were modified for each test to reach the final optimization of the aptasensor. More specifically, the washing buffer, the concentration and performance of the two aptamers, the correct time and temperature for the functionalization of the electrochemical chip, and the preparation of E. coli whole cells were evaluated and tested.
The results elaborated from all the tests show that the developed aptasensor has a LOD of 10 CFU/ml, but a reduced level of specificity towards the negative controls.
Now, the attention is focused on the development of an aptasensor that specifically detect only E. coli cells and on the study of new sensors for heavy metals detection in water samples.
Rapid detection of Listeria monocytogenes, Salmonella, Campylobacter spp., and Escherichia coli in food using biosensors (Food Control, 2022)
Role of real-time DNA analysis, biomarkers, resistance measurement, and ecosystem management in Campylobacter risk analysis (Chapter of “Present Knowledge in Food Safety: A Risk-Based Approach Throughout the Food Chain”, to be published in 2023)
Innovazione e ricerca: i biosensori come soluzione nella ricerca di contaminanti microbiologici all’interno del ciclo idrico integrato (Rassegna tecnica, to be published in January 2023)