Riassunto analitico
In recent years, the scientific-disciplinary platform of organic electronics, based on the use of organic semiconductors in electronic devices, has undergone considerable development which has led to an increase in research products and their application in the commercial field.
Organic electronic devices are very sensitive to the environmental conditions of use and, therefore, have been widely used in the development of sensors and biosensors.
Of all the possible configurations, the Organic Electrochemical Transistor (OECT) appears to be one of the most promising architecture for biosensors in terms of selectivity and sensitivity.
OECT have now been used as biosensors to detect various molecules and biomolecules, like ions, glucose, lactose, dopamine, citrate, amino acids, epinephrine, DNA, proteins and bacteria.
The subject of this thesis is the application of OECT in detecting Interleukin 6 (an inflammatory cytokines) in biological samples.
This protein is fundamental in vital processes such inflammation and immunity.
However, a continuous and deregulated production of IL-6 is correlated with severe pathologies, such as sepsis, cancers, Acute Respiratory Distress Syndrome, autoimmune disease.
The current Covid19 pandemic has caught the whole world off guard.
Following hospitalization, the patient’s clinical situation can precipitate in a few hours, up to respiratory failure (Acute Respiratory Distress Syndrome ARDS) and in extreme cases, death.
Current studies seem to suggest that this condition, known as “cytokine storm”, is linked to the increased production of inflammatory cytokines, such as Interleukin 6 (IL-6), which destroy pulmonary alveoli. The causes are not known, but this outcome is positively correlated to factors, such as age or previous pathologies.
IL-6 appears to be a good candidate as a biomarker of disease severity.
A sensor for this purpose must be endowed with high sensitivity because of the ultra-low doses in standard physio-pathological conditions and should be accurate across three orders of magnitude of IL6 concentrations. Thus, although specificity is a compelling, the sensor must be able to operate across a wide range of concentrations for being able to monitor the whole range of possible evolution.
Organic semiconductor-based biosensors have these characteristics in addiction to stability, biocompatibility, low price.
This thesis work is aimed at verifying the possibility of using OECT devices based on the organic semiconductor PEDOT: PSS as biosensors for IL6.
After optimizing the manufacturing of OECT, the response of these devices to changes in concentration of IL6 in 6 orders of magnitude (from picomolar to nanomolar, mimicking physiological and pathological conditions) and the evolution of this response in time, have been studied.
In addition, the selectivity of the sensor was evaluated, comparing the response in presence of IL6 with that of another cytokine: Tumour Necrosis Factor α (TNFα), present in normal biological samples.
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Abstract
In recent years, the scientific-disciplinary platform of organic electronics, based on the use of organic semiconductors in electronic devices, has undergone considerable development which has led to an increase in research products and their application in the commercial field.
Organic electronic devices are very sensitive to the environmental conditions of use and, therefore, have been widely used in the development of sensors and biosensors.
Of all the possible configurations, the Organic Electrochemical Transistor (OECT) appears to be one of the most promising architecture for biosensors in terms of selectivity and sensitivity.
OECT have now been used as biosensors to detect various molecules and biomolecules, like ions, glucose, lactose, dopamine, citrate, amino acids, epinephrine, DNA, proteins and bacteria.
The subject of this thesis is the application of OECT in detecting Interleukin 6 (an inflammatory cytokines) in biological samples.
This protein is fundamental in vital processes such inflammation and immunity.
However, a continuous and deregulated production of IL-6 is correlated with severe pathologies, such as sepsis, cancers, Acute Respiratory Distress Syndrome, autoimmune disease.
The current Covid19 pandemic has caught the whole world off guard.
Following hospitalization, the patient’s clinical situation can precipitate in a few hours, up to respiratory failure (Acute Respiratory Distress Syndrome ARDS) and in extreme cases, death.
Current studies seem to suggest that this condition, known as “cytokine storm”, is linked to the increased production of inflammatory cytokines, such as Interleukin 6 (IL-6), which destroy pulmonary alveoli. The causes are not known, but this outcome is positively correlated to factors, such as age or previous pathologies.
IL-6 appears to be a good candidate as a biomarker of disease severity.
A sensor for this purpose must be endowed with high sensitivity because of the ultra-low doses in standard physio-pathological conditions and should be accurate across three orders of magnitude of IL6 concentrations. Thus, although specificity is a compelling, the sensor must be able to operate across a wide range of concentrations for being able to monitor the whole range of possible evolution.
Organic semiconductor-based biosensors have these characteristics in addiction to stability, biocompatibility, low price.
This thesis work is aimed at verifying the possibility of using OECT devices based on the organic semiconductor PEDOT: PSS as biosensors for IL6.
After optimizing the manufacturing of OECT, the response of these devices to changes in concentration of IL6 in 6 orders of magnitude (from picomolar to nanomolar, mimicking physiological and pathological conditions) and the evolution of this response in time, have been studied.
In addition, the selectivity of the sensor was evaluated, comparing the response in presence of IL6 with that of another cytokine: Tumour Necrosis Factor α (TNFα), present in normal biological samples.
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