Electrochemical biosensors for sensitive molecular diagnostics

Biosensors are self-contained analytical devices in which a bioreceptor is integrated with a transducer. The interaction between the bioreceptor and a target analyte generates a signal suitable for analytical purposes. In electrochemical biosensors, a change in the redox state of the biorecognition/analyte system generates a change in an electrochemical quantity which can be monitored by electroanalytical techniques. Electrochemical sensors can also be miniaturized using ultramicroelectrodes and nanoelectrodes and their arrays as transducers. These devices are characterized by high specificity and sensitivity and improved detection limits. Within the frame of the TRANS2CARE project, the Laboratory of Electrochemical Sensors (http://lsegroup.wix.com/website-lse-group) of the University Ca’ Foscari of Venice is collaborating with some of the project partners in order to develop bioelectrochemical sensors/nanosensors for clinical/molecular diagnostics

Molecular diagnostics with electrochemical biosensors and arrays

Biosensors are self-contained analytical devices in which a bioreceptor is integrated with a transducer. The interaction between the bioreceptor and a target analyte generates a signal suitable for analytical purposes. In electrochemical biosensors, a change in the redox state of the biorecognition/analyte system generates a change in an electrochemical quantity which can be monitored by electroanalytical techniques. Electrochemical sensors can be miniaturized using ultramicroelectrodes and nanoelectrodes and their arrays as transducers. These devices are characterized by high specificity and sensitivity and improved detection limits. Biosensors can be used by non-specialist operators at the point of care. For the above reasons, within the frame of the Trans2care project, the Laboratory of Electrochemical Sensors of the University Ca’ Foscari of Venice will collaborate with the project partners to develop electrochemical sensors suitable for specific clinical needs

Supplementary data for the article: Habtamu, H. B.; Sentic, M.; Silvestrini, M.; De Leo, L.; Not, T.; Arbault, S.; Manojlovic, D.; Sojic, N.; Ugo, P. A Sensitive Electrochemiluminescence Immunosensor for Celiac Disease Diagnosis Based on Nanoelectrode Ensembles. Analytical Chemistry 2015, 87 (24), 12080–12087. https://doi.org/10.1021/acs.analchem.5b02801

Supporting information for: [https://doi.org/10.1021/acs.analchem.5b02801]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/2014

Supplementary data for the article: Habtamu, H. B.; Sentic, M.; Silvestrini, M.; De Leo, L.; Not, T.; Arbault, S.; Manojlovic, D.; Sojic, N.; Ugo, P. A Sensitive Electrochemiluminescence Immunosensor for Celiac Disease Diagnosis Based on Nanoelectrode Ensembles. Analytical Chemistry 2015, 87 (24), 12080–12087. https://doi.org/10.1021/acs.analchem.5b02801

Supporting information for: [https://doi.org/10.1021/acs.analchem.5b02801]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/2014

Detection of DNA hybridization by methylene blue electrochemistry at activated nanoelectrode ensembles

Nanoelectrode ensembles (NEEs) obtained by electroless gold deposition in track-etched polycarbonate (PC) membranes are functionalized and applied for DNA hybridization detection, using methylene blue (MB) as electroactive probe. To this aim, an amine terminated ss DNA probe is immobilized on the PC surface of the NEE by reaction via carbodiimide and N -hydroxysulfosuccinimide. In order to increase the number of carboxylic groups present on PC and suitable for the functionalization, the surface of NEEs is oxidized with potassium permanganate. The presence of carboxylic functionalities is verified by spectrochemical titration with thionin acetate (THA) and the effect of the activation treatment on the electrode performances is evaluated by cyclic voltammetry (CV). After activation and functionalization with the probes, the NEE-based sensor is hybridized with complementary target sequences. The effect of the functionalization of the NEEs both with the ss DNA probe alone and after hybridization with the target, is studied by measuring the changes in the MB reduction signal by square wave voltammetry (SWV), after incubation in a suitable MB solution, rinsing and transfer to the measurement cell. It was observed that this peak signal decreases significantly after hybridization of the probe with the complementary target. Experimental evidences suggest that the interaction between MB and the guanines of ss DNA and ds DNA is at the basis of the development of the here observed analytical signal. The proposed approach allows the easy preparation and testing of NEE-based sensors for the electrochemical DNA hybridization detection

Diet, lifestyle and quality of life in breast cancer patients

Despite much research investigating the role of diet and lifestyle in breast cancer, the evidence for many dietary factors remains uncertain. The main focus of this thesis concerns the role of dietary patterns and fat in breast cancer risk and also recurrence and survival in breast cancer patients. Meta-analyses conducted in this thesis have suggested that a prudent dietary pattern may reduce the risk of breast cancer, whilst a drinker dietary pattern may increase risk. High saturated fat intake was also found to be associated with breast cancer mortality. Data obtained from participants of the DietCompLyf study, a prospective cohort of breast cancer patients in the UK, was used in this thesis to investigate dietary patterns and fat intake in relation to breast cancer recurrence and quality of life. The physical activity questionnaire used in the DietCompLyf study was also retrospectively validated in this thesis to determine how best to use the physical activity information as a confounder in the" diet and breast cancer recurrence and quality of life analyses in this thesis. In participants of the DietCompLyf study, adherence to a Traditional dietary pattern was associated with an increased risk of breast cancer recurrence. A prudent dietary pattern was associated with a better quality of life, whilst Western dietary patterns associated with a poorer quality of life in unadjusted analyses. The complicated nature of the diet and quality of life relationship was highlighted when adjustment for potential confounders modified and attenuated the observed associations. Results observed in this thesis suggest possible roles for diet in both risk of breast cancer and breast cancer mortality. Further analyses of data obtained from the DietCompLyf cohort should be conducted in the future to clarify theses observations.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Chinese students' perceptions of humour in British academic lectures

My PhD study explores humour in British academic lectures and Chinese students' perceptions of it. The research interest was derived from my personal experience as an international student in Britain, when I repeatedly encountered occasions on which the lecturers' jokes fell flat for me. Britain is one of the most popular destinations for international students, but there are hardly any investigations into humour in academic contexts or international students' understanding of it, and none on Chinese students' problems with humour in lectures. In my study, instances of humour, referred to as 'humour episodes' (REs), were identified and analysed in a large number of lectures recorded in the British Academic Spoken English (BASE) corpus and nine academic lectures recorded by me. Some Chinese students, non-Chinese students and all of the lecturers at the lectures in my corpus, commented on selected REs in interviews and group discussions. Analysis of the REs was informed by interactional sociolinguistic and pragmatic theories. Major formal, semantic, and functional properties of humour in the lectures were identified. Humour arose from the incongruous interplay between these properties. The lecturers used humour to carry out teaching tasks and interpersonal activities. Humour heightened the lecturers' stances toward their topics. These stances embodied sociocultural values. The Chinese students had evident problems comprehending their lecturers' humour. Some expressed a feeling of alienation at having to laugh with other classmates without understanding the cause. The lecturers were often unaware of the Chinese students' perceptions of their humour, and sometimes appeared to be insensitive to their negative feelings. Expression of stance in the humour was particularly problematic to the Chinese students, but they tended to consider it peripheral to the main purpose of their studies. My study has implications for Chinese students' experience in British universities, and the internationalisation of British higher education.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Pyrolyzed photoresist carbon electrodes in aprotic solvent: bilirubin electrochemistry and interaction with electrogenerated superoxide

Pyrolyzed photoresist carbon electrodes (PPCEs) are fabricated by the photopatterning of a negative tone epoxy-based photoresist, SU-8, through optimized standard UV photolithography. The electrochemical characteristics of PPCEs are investigated in dimethyl sulfoxide (DMSO), observing a wider accessible potential window and a smaller capacitance with respect to glassy carbon electrodes. PPCEs are used to study the cyclic voltammetric behavior of bilirubin (BR) in DMSO. Detailed information is obtained on the multiple steps involved both in the electrochemical oxidation and reduction of BR. Interesting points concerning the electrochemical oxidation of BR to biliverdin are clarified, identifying the formation of an intermediate whose fate depends on the time scale of the electrochemical experiment. PPCEs are also used to electrogenerate the superoxide anion O2−• in DMSO for studying possible reactions between BR and O2−•. The results obtained demonstrate that BR is an efficient superoxide scavenger and that a concentration 2 mM of BR is high enough to consume all the O2−• generated by oxygen reduction at the PPCE/DMSO interface