Evaluation of new cholinium-amino acids based room temperature ionic liquids (RTILs) as immobilization matrix for electrochemical biosensor development: proof-of-concept with trametes versicolor laccase

In this work, we present new cholinium-amino acids room temperature ionic liquids (ChAARTILs) that can be used as an efficient immobilization matrix for electrochemical biosensor development. The ideal immobilization strategy should be able to ensure the highest enzyme loading and a tight enzymatic immobilization, preserving its native structure and biological activity. In this regard, ChAARTILs present different side chains on the amino acids giving rise to van der Waals, π-π stacking and hydrogen bonding interactions. All these interactions can affect the nanomaterial organization onto the electrode surface. To this aim, we have evaluated the main electrochemical parameters, namely electroactive area (AEA) and the heterogeneous electron transfer rate constant (k0), showing how both cations and anions of room temperature ionic liquids (RTILs) can independently affect multi-walled carbon nanotubes (MWCNTs) organization. In particular, [Ch][Phe] showed the best performance in terms of AEA (3.432 cm2) and k0 (4.71·10−3 cm s−1) with a homogeneous distribution of MWCNTs bundles onto the electrodes and a faster electron transfer rate

Decision making based on hybrid modeling approach applied to cellulose acetate based historical films conservation

no. 760801\NEMOSINE UID/QUI/50006/2020Preserving culture heritage cellulose acetate-based historical films is a challenge due to the long-term instability of these complex materials and a lack of prediction models that can guide conservation strategies for each particular film. In this work, a cellulose acetate degradation model is proposed as the basis for the selection of appropriate strategies for storage and conservation for each specimen, considering its specific information. Due to the formulation complexity and diversity of cellulose acetate-based films produced over the decades, we hereby propose a hybrid modeling approach to describe the films degradation process. The problem is addressed by a hybrid model that uses as a backbone a first-principles based model to describe the degradation kinetics of the pure cellulose diacetate polymer. The mechanistic model was successfully adapted to fit experimental data from accelerated aging of plasticized films. The hybrid model considers then the specificity of each historical film via the development of two chemometric models. These models resource on gas release data, namely acetic acid, and descriptors of the films (manufacturing date, AD-strip value and film type) to assess the current polymer degradation state and estimate the increase in the degradation rate. These estimations are then conjugated with storage conditions (e.g., temperature and relative humidity, presence of adsorbent in the film’s box) and used to feed the mechanistic model to provide the required time degradation simulations. The developed chemometric models provided predictions with accuracy more than 87%. We have found that the storage archive as well as the manufacturing company are not determining factors for conservation but rather the manufacturing date, off gas data as well as the film type. In summary, this hybrid modeling was able to develop a practical tool for conservators to assess films conservation state and to design storage and conservation policies that are best suited for each cultural heritage film.publishersversionpublishe

Preparation and characterization of screening methods for classification and quality control of olive oils

In questo lavoro di ricerca di Dottorato sono state sviluppate piattaforme sensoristiche, basate su elettrodi SPE modificati con nanomateriali, per permetterere una rapida, facile ed economica individuazione delle frodi legate alla produzione e al commercio dell'olio extravergine di oliva. Il risultato della ricerca è stata la creaziobne di due piattaforme in grado rispettivamente di catalogare oli extravergine di oliva a seconda della cultivar della pianta di origine e di quantificare il contenuto di antiossidanti polari in campioni incogniti di olii vegetali, permettendo di discriminare oli di oliva da oli di altri semi.In this PhD research work, sensor platforms have been developed, based on SPE electrodes modified with nanomaterials, to allow rapid, easy and economic identification of frauds linked to the production and trade of extra virgin olive oil. The result of the research was the creation of two platforms able respectively to catalog extra virgin olive oils according to the cultivar of the plant of origin and to quantify the content of polar antioxidants in unknown samples of vegetable oils, allowing to discriminate olive oils from oils of other seeds

Generation IV ionic liquids and nanomaterials to develop innovative electrochemical biosensing platforms

Different types of modified electrodes have been prepared and tested to assembly and construct portable sensing devices, useful to analyze, in a simple, fast and economic way, many analytes. Bare glassy carbon electrodes (GCE) of the screen-printed type (SPE), with silver electrode as reference, have been modified, via drop casting on the working electrode surface, with a mixture of generation IV room temperature ionic liquids (RTILs) and nanomaterials. The ionic liquids choline-amino acids, were synthetized in our laboratory following the methodology known in literature1. These RTILs differ from the previous generation ones because they are nontoxic and completely biodegradable2,3. Like those of the previous generations, the RTILs used in this work have interesting properties regarding low volatility, low flammability, high ionic conductivity, high chemical and electrochemical stability4. Furthermore, these compounds allow to significantly increase the work potential range (V), electroactive area (Aea) and electron transfer constant (k0), so that anode or cathode peaks can be detected even for extremely low concentration of analytes. The nanomaterials used in this work were Multi-Walled Carbon Nanotubes (MWCNT) and Titanium Dioxide nanoparticles (anatase form). These two nanomaterials have been used both alone and together in different proportions with the chosen RTIL [Ch] [Phe]. All the so developed electrodes have been studied by means of cyclic voltammetry measurements to calculate the electroactive area (Aea) of the working electrode, in order to find the best combination of nanomaterials/ionic liquid/water for the drop casting mixture. All the proposed combinations have also been studied for stability: cyclic voltammetry measurements have been carried out at various time intervals after the preparation to investigate variations of the Aea of the modified electrodes. The electrochemical platform so developed has been used, after functionalization with the proper enzyme, as a biosensor. In particular, it has been tested for measuring glucose in food matrices and antioxidants in olive oils using Glucose Oxidase5 and Lipase6 respectively. References 1. S. De Santis, G. Masci, F. Casciotta, et al.; Phys. Chem., 2015, 17,20687. 2. J. Arning, S. Stolte, A. Böschen, F. Stock, W.R. Pitner et al.; Green Chem., 2008, 10, 47-58. 3. A. Romero, A. Santos, J. Tojo, A. Rodriguez; J. Hazard Matter, 2008,151,268-273. 4. J.S. Xu, G.C. Zhao;Int. J. Electrochem. Sci., 2008, 4, 519-527. 5. M.L. Antonelli, F. Arduini et al.;Biosensors and Bioelectronics, 2009,24,1382-88. 6. Álvarez G.A., J.A. Rodríguez, J.C. Escamilla, C.A. Galán;J. Mex. Chem. Soc., 2015, 59, 19-23

Photoautotrophs–Bacteria Co-Cultures: Advances, Challenges and Applications

Photosynthetic microorganisms are among the fundamental living organisms exploited for millennia in many industrial applications, including the food chain, thanks to their adaptable behavior and intrinsic proprieties. The great multipotency of these photoautotroph microorganisms has been described through their attitude to become biofarm for the production of value-added compounds to develop functional foods and personalized drugs. Furthermore, such biological systems demonstrated their potential for green energy production (e.g., biofuel and green nanomaterials). In particular, the exploitation of photoautotrophs represents a concrete biorefinery system toward sustainability, currently a highly sought-after concept at the industrial level and for the environmental protection. However, technical and economic issues have been highlighted in the literature, and in particular, challenges and limitations have been identified. In this context, a new perspective has been recently considered to offer solutions and advances for the biomanufacturing of photosynthetic materials: the co-culture of photoautotrophs and bacteria. The rational of this review is to describe the recently released information regarding this microbial consortium, analyzing the critical issues, the strengths and the next challenges to be faced for the intentions attainment

Innovative Eco-Friendly Conductive Ink Based on Carbonized Lignin for the Production of Flexible and Stretchable Bio-Sensors

In this study, we report a novel way to produce carbon-based conductive inks for electronic and sensor technology applications. Carbonized lignin, obtained from the waste products of the Eucalyptus globulus tree paper industry, was used to produce a stable conductive ink. To this end, liquid-phase compositions were tested with different amounts of carbonized lignin powder to obtain an ink with optimal conductivity and rheological properties for different possible uses. The combination that showed the best properties, both regarding electrochemical properties and green compatibility of the materials employed, was cyclohexanone/cellulose acetate/carbonized lignin 5% (w/w), which was used to produce screen-printed electrodes. The electrodes were characterized from a structural and electrochemical point of view, resulting in an electrochemically active area of 0.1813 cm2, compared to the electrochemically active area of 0.1420 cm2 obtained by employing geometrically similar petroleum-based screen-printed electrodes and, finally, their performance was demonstrated for the quantification of uric acid, with a limit of detection of 0.3 μM, and their biocompatibility was assessed by testing it with the laccase enzyme and achieving a limit of detection of 2.01 μM for catechol as the substrate. The results suggest that the developed ink could be of great use in both sensor and electronic industries, reducing the overall ecological impact of traditionally used petroleum-based inks