Effetti genotossici di nanoparticelle in organismi bioindicatori (Mytilus edulis) ed in colture cellulari di pesce

La nanotecnologia è un campo in rapido sviluppo in quanto attrae investimenti significativi da parte di industrie e governi. I nanomateriali (NMs) usati sono tipicamente descritti come nanoparticelle (NPs) o nanotubi (NTs) con dimensioni che possono variare tra 1 e 100 nm. Le piccoli dimensioni sono una delle cause delle loro peculiari caratteristiche fisico–chimiche diverse da quelle degli altri materiali solidi, e i loro effetti sull’ambiente e sugli organismi viventi sono ancora sconosciuti. E’ quindi importante e necessario comprenderne la loro tossicità, il destino e gli effetti ambientali eventualmente provocati, in modo da creare un protocollo sotto controllo legislativo prima che vengano rilasciate in natura. Inoltre, la vasta gamma di nanomateriali esistente richiede la comprensione dei rischi che ciascun composto può comportare. Nella presente tesi, condotta presso i laboratori CEFAS (Weymouth, UK), sono stati scelti Cadmio (4 nm ± 1 nm) e Argento (13 nm ± 1 nm) in forma di nanoparticelle in quanto ben nota la tossicità dei due elementi, e perché ultimamente utilizzati sotto forma di nanoparticelle in diverse applicazioni nel campo medico, nella cura dei tumori, nello sviluppo di strumentazioni, come pannelli fotovoltaici. Le nanoparticelle usate negli esperimenti di esposizione devono avere la capacità di entrare in soluzione facilmente, dunque nel presente studio, le nanoparticelle utilizzate sono state rivestite da thiol-terminated methyl polyethylene glycol in modo da inibire la formazione di agglomerati. Scopo dello studio è stata la valutazione di eventuali effetti tossici a livello del DNA negli emociti di mitilo (Mytilus edulis) e in coltura cellulare di trota arcobaleno (RTG), oltre all’attività enzimatica della lattico deidrogenasi (LDH) e la proliferazione cellulare, solo per RTG. La linea cellulare utilizzata, sebbene non appartenente ad una specie marina, è da considerarsi, come tutte le linee cellulari in generale, un modello per l’analisi degli effetti genotossici in quanto essendo state geneticamente modificate per poter sopravvivere e moltiplicarsi in vivo, si diversificano dall’animale originale. Il Comet assay, noto anche come single cell gel electrophoresis (SCGE), è una tecnica microelettroforetica per la diretta visualizzazione del danno al DNA in singole cellule. Durante l’elettroforesi i frammenti di DNA aventi basso peso molecolare si muovono più rapidamente del DNA integro (testa della cometa). Le comete e quindi l’estensione del danno al DNA, vengono misurate con un sistema di analisi dell’immagine computerizzata, che consente di rilevare la percentuale di DNA presente nella coda e nella testa della cometa. Per lo studio degli effetti genotossici è stato utilizzato il Comet assay per entrambi gli organismi. Le colture cellulari di trota non sembrano subire effetti significativi dopo una esposizione di 24 e 48 ore alle nanoparticelle di argento e cadmio a quattro diverse concentrazioni (10; 1; 0.1; 0.01 mg/L), così come non si palesano effetti statisticamente significativi sugli emociti di mitilo se non alla dose di 50mg/L, che, per il cadmio sembrano essere influenzati da effetti citotossici. Il test dell’LDH (detto anche test di citotossicità) è un saggio colorimetrico per la quantificazione della mortalità e della lisi cellulare, basato sulla misurazione dell’attività appunto della lattico deidrogenasi (LDH) rilasciata nel supernatante dal citosol di una cellula danneggiata. Nel test di proliferazione cellulare (XTT) le cellule metabolicamente attive (vive) riducono il sale di tetrazonio a composti del colored formazan; dalla misura allo spettrofotometro di questi composti è quindi possible ricavare la crescita cellulare all’interno del nostro campione

Danneggiamento e recupero degli edifici storici: l\u2019esperienza dell\u2019Aquila

La salvaguardia del patrimonio architettonico, la cui fragilit\ue0 \ue8 stata messa in evidenza dai r ecenti eventi sismici, sta diventando sempre pi\uf9 un problema sociale ed economico in molti paesi. Occorr e particolare cura nel definire il livello di sicurezza accettabile, i materiali utilizzabili e le tecniche di r ecupero che rispettino i valori culturali e storici. Inoltre, devono essere stabilite regole di buona pratica applicabili nei centri storici, caratter izzati da edifici complessi e interconnessi tra lor

Seismic vulnerability maps of Timisoara historical center based on fragility curves

The seismic vulnerability assessment on a territorial scale requires the application of simplified procedures. Data collection is usually carried out by adopting external inspections; for this reason the knowledge gained for the considered buildings is usually not complete and lack of information has to be managed. The definition of a methodology which takes into account these aspects is one of the aims of this paper. Another goal is the extension of the obtained results to buildings not directly surveyed on site, whose characteristics are similar to those of the analyzed buildings. The case study of Timisoara (Romania) is presented. A rapid survey of the historical center is performed and recurring typologies are identified. Analyses of the most significant local mechanisms of collapse are implemented, taking into account possible parameters variation. Fragility curves for each typology are then obtained allowing the definition of vulnerability maps for the whole historical center

Ecotoxicological effects and bioaccumulation of BPA analogues and their mixture in the clam Ruditapes philippinarum

Bisphenol A is recognized as an endocrine disruptor that can affect several biological processes in marine species. Consequently, its use has been restricted and it has been replaced with other similar compounds named bisphenol A analogues (BPA analogues). BPA analogues are speculatively considered safer compounds than BPA and their usage is increasing with a consequent higher environmental release. In this study, specimens of the clam Ruditapes philippinarum were exposed to three main BPA analogues, namely BPAF, BPF, BPS and their mixture at an environmentally relevant concentration of 300 ng/L for 7 and 14 days. Effects on biomarkers indicative of cytotoxicity, oxidative stress and damage and neurotoxicity were evaluated. In addition, bioaccumulation of the compound tested was analysed in clam soft tissues. Results showed that BPA analogues at an environment concentration affected cellular parameters and antioxidant system causing also oxidative damage, suggesting that BPA analogues can be harmful compounds for clams

IoT and Biosensors: A Smart PortablePotentiostat With AdvancedCloud-Enabled Features

Recent advances in Internet-of-Things technology have opened the doors to new scenariosfor biosensor applications. Flexibility, portability, and remote control and access are of utmost importanceto move these devices to people’s homes or in a Point-of-Care context and rapidly share the results withusers and their physicians. In this paper, an innovative portable device for both quantitative and semi-quantitative electrochemical analysis is presented. This device can operate autonomously without the needof relying on other devices (e.g., PC, tablets, or smartphones) thanks to built-in Wi-Fi connectivity. Thedeveloped hardware is integrated into a cloud-based platform, exploiting the cloud computational powerto perform innovative algorithms for calibration (e.g., Machine Learning tools). Results and configurationscan be accessed through a web page without the installation of dedicated APPs or software. The electricalinput/output characteristic was measured with a dummy cell as a load, achieving excellent linearity.Furthermore, the device response to five different concentrations of potassium ferri/ferrocyanide redox probewas compared with a bench-top laboratory instrument. No difference in analytical sensitivity was found.Also, some examples of application-specific tests were set up to demonstrate the use in real-case scenarios.In addition, Support Vector Machine algorithm was applied to semi-quantitative analyses to classify theinput samples into four classes, achieving an average accuracy of 98.23%. Finally, COVID-19 related testsare presented and discussed (PDF) IoT and Biosensors: A Smart Portable Potentiostat With Advanced Cloud-Enabled Features. Available from: https://www.researchgate.net/publication/355214115_IoT_and_Biosensors_A_Smart_Portable_Potentiostat_With_Advanced_Cloud-Enabled_Features [accessed Oct 25 2021]

A Wi-Fi cloud-based portable potentiostat for electrochemical biosensors

The measurement of the analyte concentration in electrochemical biosensors traditionally requires costly laboratory equipment to obtain accurate results. Innovative portable solutions have recently been proposed, but usually, they lean on personal computers (PCs) or smartphones for data elaboration and they exhibit poor resolution or portability and proprietary software. This paper presents a low-cost portable system, assembling an ad hoc -designed analog front end (AFE) and a development board equipped with a system on chip integrating a microcontroller and a Wi-Fi network processor. The wireless module enables the transmission of measurements directly to a cloud service for sharing device outcome with users (physicians, caregivers, and so on). In doing so, the system does not require neither the customized software nor other devices involved in data acquisition. Furthermore, when any Internet connection is lost, the data are stored on board for subsequent transmission when a Wi-Fi connection is available. The noise output voltage spectrum has been characterized. Since the designed device is intended to be battery-powered to enhance portability, investigations about battery lifetime were carried out. Finally, data acquired with a conventional benchtop Autolab PGSTAT-204 electrochemical workstation are compared with the outcome of our developed device to validate the effectiveness of our proposal. To this end, we selected ferri/ferrocyanide as redox probe, obtaining the calibration curves for both the platforms. The final outcomes are shown to be feasible, accurate, and repeatable

A self-calibrating IoT portable electrochemical immunosensor for serum human epididymis protein 4 as a tumor biomarker for ovarian cancer

Nowadays analytical techniques are moving towards the development of smart biosensing strategies for point-of-care accurate screening of disease biomarkers, such as human epididymis protein 4 (HE4), a recently discovered serum markers for early ovarian cancer diagnosis. In this context, the present work represents the first implementation of a competitive enzyme-labelled magneto-immunoassay exploiting a homemade IoT Wi-Fi cloud-based portable potentiostat for differential pulse voltammetry readout. The electrochemical device was specifically designed capable of autonomous calibration and data processing, switching between calibration and measurement modes: in particular, firstly a baseline estimation algorithm is applied for correct peak computation, then calibration function is built by interpolating data with a four-parameter logistic function. The calibration function parameters are stored on the cloud for inverse prediction to determine the concentration of unknown samples. Interpolation function calibration and concentration evaluation are performed directly on-board, reducing the power consumption. The analytical device was validated in human serum, demonstrating good sensing performance for analysis of HE4 with detection and quantitation limits in human serum of 3.5 and 29.2 pM, respectively, reaching the sensitivity required for diagnostic purposes, with high potential for applications as portable and smart diagnostic tool for point-of-care testing