Publications by authors named "Stefano Cinti"

40 Publications

Sweat urea bioassay based on degradation of Prussian Blue as the sensing architecture.

Anal Chim Acta 2022 Jun 29;1210:339882. Epub 2022 Apr 29.

Department of Pharmacy, University of Naples "Federico II", Via D. Montesano 49, 80131, Naples, Italy; BAT Center - Interuniversity Center for Studies on Bioinspired Agro-Environmental Technology, University of Naples Federico II, 80055, Naples, Italy. Electronic address:

Urea provides pathophysiological information on renal and hepatic disorders. Among the secretion pathways via several bio-fluids, sweat urea represent an important and non-invasive strategy to evaluate kidney and liver pathologies. In this work, a rapid and reliable colorimetric urea bioassay assisted by chemometrics design of experiments has been obtained. The sensing method is based on the hydrolysis of urea to ammonia catalyzed by urease. If urea is present in the sample, the enzymatic reaction leads to an alkaline environment that is capable to ruin the structure of Prussian Blue. For the first time Prussian Blue is adopted as a precision pH sensing element. Alkaline solution destroys the structure of Prussian Blue, leading to a dramatic colorimetric response from blue to colorless. Design of experiments has been adopted to optimize experimental setup by evaluating correlation among variables. The colorimetric method was shown to be able to detect urea down to 0.05 mM, with a linearity up to 2 mM and a relative standard deviation (RSD) lower than 10%. Sweat samples have been satisfactorily analyzed, and the high accuracy of the portable device has been demonstrated with liquid chromatography with tandem mass spectrometry analysis of the same sweat samples.
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http://dx.doi.org/10.1016/j.aca.2022.339882DOI Listing
June 2022

Heavy metals detection at chemometrics-powered electrochemical (bio)sensors.

Talanta 2022 Jul 29;244:123410. Epub 2022 Mar 29.

Department of Pharmacy, University of Naples "Federico II", Via D. Montesano 49, 80131, Naples, Italy; BAT Center-Interuniversity Center for Studies on Bioinspired Agro-Environmental Technology, University of Napoli "Federico II", 80055, Naples, Italy. Electronic address:

Heavy metals represent a serious issue regarding both environmental and health status. Their monitoring is necessary and it is necessary the development of decentralized approaches that are able to enforce the risk assessment. Electrochemical sensors and biosensors, with the various architectures, represent a solid reality often involved for this type of analytical determination. Although these approaches offer easy-to-use and portable tools, some limitations are often highlighted in presence of multi-targets and/or real matrices. However, chemometrics- and artificial intelligence-based tools, both for designing and for data analyzing, display the capability in producing novel functionality towards the management of complex matrices which often contain more information than those that are visualized with sensor detection. Design of experiment, exploratory, predictive and regression analysis can push the world of electrochemical (bio)sensors beyond the state of the art, because is still too large the number of analytical chemists that do not deal with multivariate thinking. In this paper, the use of multivariate methods applied to electrochemical sensing of heavy metals is showed, and each approach is described in terms of efficacy and outputs.
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http://dx.doi.org/10.1016/j.talanta.2022.123410DOI Listing
July 2022

Non-invasive electrochemistry-driven metals tracing in human biofluids.

Biosens Bioelectron 2022 Mar 22;200:113904. Epub 2021 Dec 22.

Department of Pharmacy, University of Naples "Federico II", Via D. Montesano 49, 80131, Naples, Italy; BAT Center-Interuniversity Center for Studies on Bioinspired Agro-Environmental Technology, University of Napoli "Federico II", 80055, Naples, Italy. Electronic address:

Wearable analytical devices represent the future for fast, de-centralized, and human-centered health monitoring. Electrochemistry-based platforms have been highlighted as the role model for future developments amid diverse strategies and transduction technologies. Among the various relevant analytes to be real-time and non-invasively monitored in bodily fluids, we review the latest wearable achievements towards determining essential and toxic metals. On-skin measurements represent an excellent possibility for humankind: real-time monitoring, digital/fast communication with specialists, quick interventions, removing barriers in developing countries. In this review, we discuss the achievements over the last 5 years in non-invasive electrochemical platforms, providing a comprehensive table for quick visualizing the diverse sensing/technological advances. In the final section, challenges and future perspectives about wearables are deeply discussed.
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http://dx.doi.org/10.1016/j.bios.2021.113904DOI Listing
March 2022

Advanced nanoengineered-customized point-of-care tools for prostate-specific antigen.

Mikrochim Acta 2021 12 14;189(1):27. Epub 2021 Dec 14.

Department of Pharmacy, University of Naples "Federico II", Via D. Montesano 49, 80131, Naples, Italy.

Change in the level of human prostate-specific antigen (PSA) is a major element in the development and progression of prostate cancer (PCa). Most of the methodologies are currently restricted to their application in routine clinical screening due to the scarcity of adequate screening tools, false reading, long assay time, and cost. Innovative techniques and the integration of knowledge from a variety of domains, such as materials science and engineering, are needed to provide sustainable solutions. The convergence of precision point-of-care (POC) diagnostic techniques, which allow patients to respond in real time to changes in PSA levels, provides promising possibilities for quantitative and quantitative detection of PSA. This solution could be interesting and relevant for use in PCa diagnosis at the POC. The approaches enable low-cost real-time detection and are simple to integrate into user-friendly sensor devices. This review focuses on the investigations, prospects, and challenges associated with integrating engineering sciences with cancer biology to develop nanotechnology-based tools for PCa diagnosis. This article intends to encourage the development of new nanomaterials to construct high-performance POC devices for PCa detection. Finally, the review concludes with closing remarks and a perspective forecast.
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http://dx.doi.org/10.1007/s00604-021-05127-yDOI Listing
December 2021

Point-of-Care for Evaluating Antimicrobial Resistance through the Adoption of Functional Materials.

Anal Chem 2022 01 22;94(1):26-40. Epub 2021 Nov 22.

Department of Pharmacy, University of Naples "Federico II", Via D. Montesano 49, 80131 Naples, Italy.

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http://dx.doi.org/10.1021/acs.analchem.1c03856DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8756393PMC
January 2022

Paper-Based Lateral Flow Device for the Sustainable Measurement of Human Plasma Fibrinogen in Low-Resource Settings.

Anal Chem 2021 10 6;93(41):14007-14013. Epub 2021 Oct 6.

Centre for Research in Biosciences (CRIB), Department of Applied Sciences, University of the West of England, Coldhar-bour Lane, Bristol BS16 1QY, U.K.

Fibrinogen concentration is a major determinant of both clotting and bleeding risk. Clotting and bleeding disorders cause extensive morbidity and mortality, particularly in resource-poor and emergency settings. This is exacerbated by a lack of timely intervention informed by measurement of fibrinogen levels under conditions such as thrombosis or postpartum haemorrhage. There is an absence of simple, rapid, low-cost, and sustainable diagnostic devices for fibrinogen measurement that can be deployed in such environments. Paper-based analytical devices are of significant interest due to their potential for low-cost production, ease of use, and environmental sustainability. In this work, a device for measuring blood plasma fibrinogen using chromatography paper was developed. Wax printing was used to create hydrophobic structures to define the test channel and sample application zone. Test strips were modified with bovine thrombin. Plasma samples (22 μL) were applied, and the flow rate was monitored over 5 min. As the sample traversed the strip, clotting was induced by the conversion of soluble fibrinogen to insoluble fibrin. The flow rate and distance travelled by the sample were dependent on fibrinogen concentration. The device was able to measure fibrinogen concentration in the range of 0.5-7.0 ± 0.3 mg/mL ( < 0.05, = 24) and had excellent correlation with laboratory coagulometry in artificial samples ( = 0.9582, = 60). Devices were also stable at 4-6 °C for up to 3 weeks.
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http://dx.doi.org/10.1021/acs.analchem.1c03665DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8529579PMC
October 2021

Electrochemical Biosensors for Tracing Cyanotoxins in Food and Environmental Matrices.

Biosensors (Basel) 2021 Sep 4;11(9). Epub 2021 Sep 4.

Department of Pharmacy, University Naples Federico II, Via Domenico Montesano 49, 80131 Naples, Italy.

The adoption of electrochemical principles to realize on-field analytical tools for detecting pollutants represents a great possibility for food safety and environmental applications. With respect to the existing transduction mechanisms, i.e., colorimetric, fluorescence, piezoelectric etc., electrochemical mechanisms offer the tremendous advantage of being easily miniaturized, connected with low cost (commercially available) readers and unaffected by the color/turbidity of real matrices. In particular, their versatility represents a powerful approach for detecting traces of emerging pollutants such as cyanotoxins. The combination of electrochemical platforms with nanomaterials, synthetic receptors and microfabrication makes electroanalysis a strong starting point towards decentralized monitoring of toxins in diverse matrices. This review gives an overview of the electrochemical biosensors that have been developed to detect four common cyanotoxins, namely microcystin-LR, anatoxin-a, saxitoxin and cylindrospermopsin. The manuscript provides the readers a quick guide to understand the main electrochemical platforms that have been realized so far, and the presence of a comprehensive table provides a perspective at a glance.
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http://dx.doi.org/10.3390/bios11090315DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8468299PMC
September 2021

A Smartphone-Based Chemosensor to Evaluate Antioxidants in Agri-Food Matrices by In Situ AuNP Formation.

Sensors (Basel) 2021 Aug 12;21(16). Epub 2021 Aug 12.

Department of Chemistry "Giacomo Ciamician", Alma Mater Studiorum-University of Bologna, Via Francesco Selmi 2, I-40126 Bologna, Italy.

In recent years, there has been a continuously growing interest in antioxidants by both customers and food industry. The beneficial health effects of antioxidants led to their widespread use in fortified functional foods, as dietary supplements and as preservatives. A variety of analytical methods are available to evaluate the total antioxidant capacity (TAC) of food extracts and beverages. However, most of them are expensive, time-consuming, and require laboratory instrumentation. Therefore, simple, cheap, and fast portable sensors for point-of-need measurement of antioxidants in food samples are needed. Here, we describe a smartphone-based chemosensor for on-site assessment of TAC of aqueous matrices, relying on the antioxidant-induced formation of gold nanoparticles. The reaction takes place in ready-to-use analytical cartridges containing an hydrogel reaction medium preloaded with Au(III) and is monitored by using the smartphone's CMOS camera. An analytical device including an LED-based lighting system was developed to ensure uniform and reproducible illumination of the analytical cartridge. The chemosensor permitted rapid TAC measurements of aqueous samples, including teas, herbal infusions, beverages, and extra virgin olive oil extracts, providing results that correlated with those of the reference methods for TAC assessment, e.g., oxygen radical absorbance capacity (ORAC).
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http://dx.doi.org/10.3390/s21165432DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8401892PMC
August 2021

Nano-engineered screen-printed electrodes: A dynamic tool for detection of viruses.

Trends Analyt Chem 2021 Oct 21;143:116374. Epub 2021 Jun 21.

Department of Pharmacy, University of Naples "Federico II", Via D. Montesano 49, 80131, Naples, Italy.

There is a growing interest in the development of portable, cost-effective, and easy-to-use biosensors for the rapid detection of diseases caused by infectious viruses: COVID-19 pandemic has highlighted the central role of diagnostics in response to global outbreaks. Among all the existing technologies, screen-printed electrodes (SPEs) represent a valuable technology for the detection of various viral pathogens. During the last five years, various nanomaterials have been utilized to modify SPEs to achieve convincing effects on the analytical performances of portable SPE-based diagnostics. Herein we would like to provide the readers a comprehensive investigation about the recent combination of SPEs and various nanomaterials for detecting viral pathogens. Manufacturing methods and features advances are critically discussed in the context of early-stage detection of diseases caused by HIV-1, HBV, HCV, Zika, Dengue, and Sars-CoV-2. A detailed table is reported to easily guide readers toward the "right" choice depending on the virus of interest.
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http://dx.doi.org/10.1016/j.trac.2021.116374DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8215883PMC
October 2021

Merging office/filter paper-based tools for pre-concentring and detecting heavy metals in drinking water.

Chem Commun (Camb) 2021 Jul;57(58):7100-7103

Department of Pharmacy, University of Naples "Federico II", Naples 80131, Italy. and BAT Center-Interuniversity Center for Studies on Bioinspired Agro-Environmental Technology, University of Napoli "Federico II", Naples 80055, Italy.

A novel miniaturized and sustainable platform exploiting two merged paper-based substrates has been applied for the programmable pre-concentration of analytes of interest and electrochemical detection of mercury traces in drinking water using printable sensor strips. This strategy represents a novel versatile possibility in merging humble materials maximizing their impacts on analytical and remediation challenges.
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http://dx.doi.org/10.1039/d1cc02481gDOI Listing
July 2021

Office Paper-Based Electrochemical Strips for Organophosphorus Pesticide Monitoring in Agricultural Soil.

Environ Sci Technol 2021 07 24;55(13):8859-8865. Epub 2021 Jun 24.

Department of Pharmacy, University of Naples "Federico II", Via D. Montesano 49, 80131 Naples, Italy.

Although the use of pesticides has highlighted obvious advantages on agricultural yields, intensive and widespread pesticide use raises serious environmental and health concerns. In particular, organophosphate pesticides represent >40% of the totality used in the field of agriculture, and developing countries face the issue of agricultural poisoning, also due to scarce monitoring programs. In this work, a decentralized, miniaturized, sustainable, and portable paper-based electrochemical biosensor for the quantification of organophosphorus pesticides' level has been realized. The proposed approach highlights the use of a very common paper-based substrate, namely, office paper. Office paper offers several advantages due to its nature: it allows one to print conductive strips for electrochemical connection, loading bio-hybrid nanosized probes (Prussian blue, carbon black, and butyrylcholinesterase), evaluating pesticides and reducing waste disposal compared to plastic-based strips. The portable system has been characterized by a low detection limit of 1.3 ng/mL, and accordingly to total discovered pesticide contents in EU agricultural soils, up to ca. 3 μg/mL, it can offer a valuable tool for fast monitoring. To demonstrate its effectiveness, soil and fruit vegetables have been used to perform in situ quantification. Good recovery percentages between 90 and 110% have been achieved in different matrices, highlighting to be suitable for field measurements, and a good correlation has been obtained in comparison with LC-MS analysis.
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http://dx.doi.org/10.1021/acs.est.1c01931DOI Listing
July 2021

Multi-array wax paper-based platform for the pre-concentration and determination of silver ions in drinking water.

Talanta 2021 Sep 29;232:122474. Epub 2021 Apr 29.

Department of Chemical Science and Technologies, University of Rome "Tor Vergata", Via Della Ricerca Scientifica 1, 00133, Rome, Italy; SENSE4MED, 00128, Rome, Italy. Electronic address:

In this work, a wax-patterned chromatographic paper has been utilized as a holistic platform to 1) synthesize Prussian Blue Nanoparticles (sensing species), 2) load the reagents for the assay, 3) concentrate the sample through multistep, and 4) visualize the determination of silver ions. Waters are continuously affected by changes in the composition, thus the utilization of reagent-free analytical tools is of huge interest for smart drinking water monitoring. Herein, we report the characterization and application of a multi-array paper-based platform for the colorimetric determination of silver ions based on the conversion from Prussian Blue to its silver-based analogue, namely Ag[Fe(CN)]. In particular, the platform highlights the increase of sensitivity due to paper pre-concentration of sample, that can be easily adapted to the analytical necessities. Within the proposed experimental setup, Ag is visualized down to a detection limit of 0.9 μM, with high repeatability and satisfactory recoveries in the range comprised between 90 and 113%.
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http://dx.doi.org/10.1016/j.talanta.2021.122474DOI Listing
September 2021

Electroanalytical Sensor Based on Gold-Nanoparticle-Decorated Paper for Sensitive Detection of Copper Ions in Sweat and Serum.

Anal Chem 2021 03 19;93(12):5225-5233. Epub 2021 Mar 19.

Department of Chemical Science and Technologies, University of Rome Tor Vergata, Via della Ricerca Scientifica 1, 00133 Rome, Italy.

The growth of (bio)sensors in analytical chemistry is mainly attributable to the development of affordable, effective, portable, and user-friendly analytical tools. In the field of sensors, paper-based devices are gaining a relevant position for their outstanding features including foldability, ease of use, and instrument-free microfluidics. Herein, a multifarious use of filter paper to detect copper ions in bodily fluids is reported by exploiting this eco-friendly material to (i) synthesize AuNPs without the use of reductants and/or external stimuli, (ii) print the electrodes, (iii) load the reagents for the assay, (iv) filter the gross impurities, and (v) preconcentrate the target analyte. Copper ions were detected down to 3 ppb with a linearity up to 400 ppb in standard solutions. The applicability in biological matrices, namely, sweat and serum, was demonstrated by recovery studies and by analyzing these biofluids with the paper-based platform and the reference method (atomic absorption spectroscopy), demonstrating satisfactory accuracy of the novel eco-designed analytical tool.
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http://dx.doi.org/10.1021/acs.analchem.0c05469DOI Listing
March 2021

How Can Chemometrics Support the Development of Point of Need Devices?

Anal Chem 2021 02 26;93(5):2713-2722. Epub 2021 Jan 26.

Department of Pharmacy, University of Naples "Federico II", Via Domenico Montesano 49, 80131 Naples, Italy.

The necessity to establish novel solutions for decentralized monitoring is attracting attention in all fields of analytical chemistry, i.e., clinical, pharmaceutical, environmental, agri-food. The research around the terms "point-of-need", "point-of-care", "lab-on-chip", "biosensor", "microfluidics", etc. is/has been always aimed at the possibility to produce easy-to-use and fast-response devices to be used by nonspecialists. However, the routes to produce the optimal device might be time-consuming and costly. In this Feature, we would like to highlight the role of chemometric-based approaches that are useful in the conceptualization, production, and data analysis in developing reliable portable devices and also decrease the amount of experiments (thus, costs) at the same time. Readers will be provided a concise overview regarding the most employed chemometric tools used for target identification, design of experiments, data analysis, and digitalization of results applied to the development of diverse portable analytical platforms. This Feature provides a tutorial perspective regarding all the major methods and applications that have been currently developed. In particular, the presence of a concise and informative table assists analytical chemists in utilizing the right chemometrics-based tool depending on the architectures and transduction.
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http://dx.doi.org/10.1021/acs.analchem.0c04151DOI Listing
February 2021

Development of a data dependent acquisition-based approach for the identification of unknown fast-acting toxins and their ester metabolites.

Talanta 2021 Mar 5;224:121842. Epub 2020 Nov 5.

University of Napoli Federico II, Department of Pharmacy, School of Medicine and Surgery, Via D. Montesano 49, 80131, Napoli, Italy; CoNISMa, Italian Interuniversity Consortium on Marine Sciences, Piazzale Flaminio 9, 00196, Rome, Italy.

Phycotoxins in the marine food-web represent a serious threat to human health. Consumption of contaminated shellfish and/or finfish poses risk to consumer safety: several cases of toxins-related seafood poisoning have been recorded so far worldwide. Cyclic imines are emerging lipophilic toxins, which have been detected in shellfish from different European countries. Currently, they are not regulated due to the lack of toxicological comprehensive data and hence the European Food Safety Authority has required more scientific efforts before establishing a maximum permitted level in seafood. In this work, a novel data dependent liquid chromatography - high resolution mass spectrometry (LC-HRMS) approach has been successfully applied and combined with targeted studies for an in-depth investigation of the metabolic profile of shellfish samples. The proposed analytical methodology has allowed: i) to discover a plethora of unknown fatty acid esters of gymnodimines and ii) to conceive a brand new MS-based strategy, termed as backward analysis, for discovery and identification of new analogues. In particular, the implemented analytical workflow has broadened the structural diversity of cyclic imine family through the inclusion of five new congeners, namely gymnodimine -F, -G, -H, -I and -J. In addition, gymnodimine A (376.5 μg/kg), 13-desmethyl spirolide C (11.0-29.0 μg/kg) and pinnatoxin G (3.1-7.7 μg/kg) have been detected in shellfish from different sites of the Mediterranean basin (Tunisia and Italy) and the Atlantic coast of Spain, with the confirmation of the first finding of pinnatoxin G in mussels harvested in Sardinia (Tyrrhenian Sea, Italy).
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http://dx.doi.org/10.1016/j.talanta.2020.121842DOI Listing
March 2021

Tutorial: design and fabrication of nanoparticle-based lateral-flow immunoassays.

Nat Protoc 2020 12 23;15(12):3788-3816. Epub 2020 Oct 23.

Nanobioelectronics & Biosensors Group, Institut Català de Nanociència i Nanotecnologia (ICN2), Campus UAB, Barcelona, Spain.

Lateral-flow assays (LFAs) are quick, simple and cheap assays to analyze various samples at the point of care or in the field, making them one of the most widespread biosensors currently available. They have been successfully employed for the detection of a myriad of different targets (ranging from atoms up to whole cells) in all type of samples (including water, blood, foodstuff and environmental samples). Their operation relies on the capillary flow of the sample throughout a series of sequential pads, each with different functionalities aiming to generate a signal to indicate the absence/presence (and, in some cases, the concentration) of the analyte of interest. To have a user-friendly operation, their development requires the optimization of multiple, interconnected parameters that may overwhelm new developers. In this tutorial, we provide the readers with: (i) the basic knowledge to understand the principles governing an LFA and to take informed decisions during lateral flow strip design and fabrication, (ii) a roadmap for optimal LFA development independent of the specific application, (iii) a step-by-step example procedure for the assembly and operation of an LF strip for the detection of human IgG and (iv) an extensive troubleshooting section addressing the most frequent issues in designing, assembling and using LFAs. By changing only the receptors, the provided example procedure can easily be adapted for cost-efficient detection of a broad variety of targets.
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http://dx.doi.org/10.1038/s41596-020-0357-xDOI Listing
December 2020

Paper-based electrochemical peptide nucleic acid (PNA) biosensor for detection of miRNA-492: a pancreatic ductal adenocarcinoma biomarker.

Biosens Bioelectron 2020 Oct 8;165:112371. Epub 2020 Jun 8.

Tor Vergata University, Department of Chemical Science and Technologies, Via Della Ricerca Scientifica, 00133, Rome, Italy; SENSE4MED, Via Renato Rascel 30, 00133, Rome, Italy. Electronic address:

Pancreatic ductal adenocarcinoma is the predominant neoplastic disease of the pancreas and it represents the fourth most frequent cause of death in cancer-related disease, with only 8% of survivors after 5-year to the diagnosis. The main issues of this type of cancer rely on fast progress (i.e. 14 months from T1 to a T4 stage), nonspecific symptoms with delay in diagnosis, and the absence of effective screening strategies. To address the lack of early diagnosis, we report a cost-effective paper-based biosensor for the detection of miRNA-492, which is recognised as a biomarker for pancreatic ductal adenocarcinoma. To design a miniaturised, sensitive, and robust paper-based platform, an electrochemical sensor was screen-printed on office paper previously wax-patterned via wax-printing technique. The paper-based sensor was then engineered with a novel and highly specific peptide nucleic acid (PNA) as the recognition element. The formation of PNA/miRNA-492 adduct was evaluated by monitoring the interaction between the positively charged ruthenium (III) hexamine with uncharged PNA and/or negatively charged PNA/miRNA-492 duplex by differential pulse voltammetry. The paper-based biosensor provided a linear range up to 100 nM, with a LOD of 6 nM. Excellent selectivity towards one- and two-base mismatches (1MM, 2MM) or scrambled (SCR) sequences was highlighted and the applicability for biomedical analyses was demonstrated, measuring miRNA-492 in undiluted serum samples.
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http://dx.doi.org/10.1016/j.bios.2020.112371DOI Listing
October 2020

Novel bio-lab-on-a-tip for electrochemical glucose sensing in commercial beverages.

Biosens Bioelectron 2020 Oct 8;165:112334. Epub 2020 Jun 8.

Department of Chemical Science and Technology, University of Rome "Tor Vergata", Via della Ricerca Scientifica 1, 00133, Rome, Italy. Electronic address:

The development of portable and user-friendly sensing platforms is a hot topic in the field of analytical chemistry. Among others, electroanalytical approaches exhibit a high amenability for reaching this purpose, i.e. the commercial strips for diabetes care are an obvious success. However, providing fully-integrated and reagent-free methods is always a leitmotiv. In this work, we evaluated the use of a disposable pipette tip, opportunely configured to demonstrate the first example of an electrochemical biosystem in a pipette tip, namely bio-lab-on-a-tip. The combination of a pipette tip, wire electrodes, enzyme, and cotton wool filter, allows the fabrication of a novel electroanalytical platform that does not need expertise-required tasks. To demonstrate the feasibility of this novel method, glucose is detected in beverages by means of chronoamperometry. The experimental setup, entirely built inside the pipette tip, is able to 1) block impurities/interferences from matrix, 2) load/release reagents for the bio-assay, 3) reduce the operating task to zero, and 4) perform electrochemical detection. With optimized experimental parameters, the bio-lab-on-a-tip is able to detect glucose linearly up to 10 mM with a detection limit of 170 μM. The effectiveness of the platform was confirmed by testing commercial beverages, e.g. Coca-Cola and Coca-Cola Zero, with high accuracy. In addition, the shelf-life of the novel device was evaluated, highlighting the role of cotton wool filter for providing a suitable environment for glucose oxidase stability. The novel concept can be easily generalized for further applications in the field of non-invasive clinical diagnostics and in-situ environmental monitoring.
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http://dx.doi.org/10.1016/j.bios.2020.112334DOI Listing
October 2020

Carbon black as an outstanding and affordable nanomaterial for electrochemical (bio)sensor design.

Biosens Bioelectron 2020 May 29;156:112033. Epub 2020 Jan 29.

University of Rome "Tor Vergata", Department of Chemical Science and Technologies, Via della Ricerca Scientifica, 00133, Rome, Italy.

Advances in cutting-edge technologies including nanotechnology, microfluidics, electronic engineering, and material science have boosted a new era in the design of robust and sensitive biosensors. In recent years, carbon black has been re-discovered in the design of electrochemical (bio)sensors thanks to its interesting electroanalytical properties, absence of treatment requirement, cost-effectiveness (c.a. 1 €/Kg), and easiness in the preparation of stable dispersions. Herein, we present an overview of the literature on carbon black-based electrochemical (bio)sensors, highlighting current trends and possible challenges to this rapidly developing area, with a special focus on the fabrication of carbon black-based electrodes in the realisation of sensors and biosensors (e.g. enzymatic, immunosensors, and DNA-based).
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http://dx.doi.org/10.1016/j.bios.2020.112033DOI Listing
May 2020

Experimental Comparison in Sensing Breast Cancer Mutations by Signal ON and Signal OFF Paper-Based Electroanalytical Strips.

Anal Chem 2020 01 7;92(2):1674-1679. Epub 2020 Jan 7.

Nanobioelectronics & Biosensors Group , Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST , Campus UAB , Bellaterra , 08193 Barcelona , Spain.

The development of paper-based electroanalytical strips as powerful diagnostic tools has gained a lot of attention within the sensor community. In particular, the detection of nucleic acids in complex matrices represents a trending topic, especially when focused toward the development of emerging technologies, such as liquid biopsy. DNA-based biosensors have been largely applied in this direction, and currently, there are two main approaches based on target/probe hybridization reported in the literature, namely Signal ON and Signal OFF. In this technical note, the two approaches are evaluated in combination with paper-based electrodes, using a single strand DNA relative to H1047R (A3140G) missense mutation in exon 20 in breast cancer as the model target. A detailed comparison among the analytical performances, detection protocol, and cost associated with the two systems is provided, highlighting the advantages and drawbacks depending on the application. The present work is aimed to a wide audience, particularly for those in the field of point-of-care, and it is intended to provide the know-how to manage with the design and development stages, and to optimize the platform for the sensing of nucleic acids using a paper-based detection method.
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http://dx.doi.org/10.1021/acs.analchem.9b02560DOI Listing
January 2020

Preparation of paper-based devices for reagentless electrochemical (bio)sensor strips.

Nat Protoc 2019 08 3;14(8):2437-2451. Epub 2019 Jul 3.

Department of Chemical Science and Technologies, University of Rome Tor Vergata, Rome, Italy.

Despite substantial advances in sensing technologies, the development, preparation, and use of self-testing devices is still confined to specialist laboratories and users. Decentralized analytical devices will enormously impact daily lives, enabling people to analyze diverse clinical, environmental, and food samples, evaluate them and make predictions to improve quality of life, particularly in remote, resource-scarce areas. In recent years, paper-based analytical tools have attracted a great deal of attention; the well-known properties of paper, such as abundance, affordability, lightness, and biodegradability, combined with features of printed electrochemical sensors, have enabled the development of sustainable devices that drive (bio)sensors beyond the state of the art. Their blindness toward colored/turbid matrices (i.e., blood, soil), their portability, and the capacity of paper to autonomously filter/purge/react with target species make such devices powerful in establishing point-of-need tools for use by non-specialists. This protocol describes the preparation of a voltammetric phosphate sensor and an amperometric nerve agent biosensor; both platforms produce quantitative measurements with currents in the range of microamperes. These printed strips comprise three electrodes (graphite for working and counter electrodes and silver/silver chloride (Ag/AgCl) for the reference electrode) and nanomodifiers (carbon black and Prussian blue) to improve their performance and specificity. Depending on analytical need, different types of paper (filter, office) and configurations (1D, 2D, 3D) can be adopted. The protocol, based on the use of cost-effective manufacturing techniques such as drop casting (to chemically modify the substrate surface) and wax/screen printing (for creating the channels and electrodes), can be completed in <1 h.
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http://dx.doi.org/10.1038/s41596-019-0186-yDOI Listing
August 2019

A 96-well wax printed Prussian Blue paper for the visual determination of cholinesterase activity in human serum.

Biosens Bioelectron 2019 Jun 19;134:97-102. Epub 2019 Mar 19.

Department of Chemical Science and Technologies, University of Rome Tor Vergata, Via della Ricerca Scientifica 1, 00133 Rome, Italy. Electronic address:

In the last decades, there is a growing search for analytical strategies to ensure clinical analysis without the need of laboratory set-up and skilled personnel. Indeed, user-friendly and low-cost devices are highly valued in the era of sustainability for their capability to be applied in low-resource contexts, such as developing countries. To address this issue, herein we report a 96-well paper-based and laboratory setup-free optical platform for the detection of butyrylcholinesterase enzyme (BChE) activity in human serum. We used chromatographic paper to realize a novel analytical tool exploiting its porous structure for reagentless synthesize Prussian Blue Nanoparticles (the sensing element), as well to load all the reagents required for the measurement. The principle of BChE activity detection relies on the reaction between the enzymatic product thiocholine and Prussian Blue, giving the Prussian White with subsequently Prussian Blue's fading, detected by a common office scanner supported by ImageJ software. Using this novel paper-based optical platform, BChE activity was linearly detected in the 2-15 U/mL range with a detection limit down to 0.8 U/mL. The accuracy was successfully demonstrated by recovery study with spiked serum and by comparing the data with the gold standard method.
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http://dx.doi.org/10.1016/j.bios.2019.03.037DOI Listing
June 2019

Novel paper-based electroanalytical tools for food surveillance.

Authors:
Stefano Cinti

Anal Bioanal Chem 2019 Jul 21;411(19):4303-4311. Epub 2019 Feb 21.

Department of Chemical Science and Technologies, University of Rome "Tor Vergata", Via della Ricerca Scientifica 1, 00133, Rome, Italy.

Analytical strategies to ensure the quality and safety of food products without the need for skilled personnel are highly required. The simplicity of glucose strips for diabetes monitoring should be translated to the agri-food sector, ensuring easy evaluation of certain molecules and/or the freshness of a beverage/foodstuff. In addition to the well-known advantages that are characteristic of electroanalytical methods over other methods, paper-based materials are being used to further reduce the gap between complex laboratory testing and simple point-of-need testing. This article highlights some of the most recent advances in the development of paper-based electrochemical approaches for food surveillance, specifically focusing on the use of novel paper-based materials. Two examples are discussed: the development of a miniaturized biosensor realized on copy paper for the quantification of ethanol in commercial beers, and the measurement of ascorbic acid in food supplements within printed electronics supports. Paper-based materials have the potential to lower economic costs, simplify the operative tasks, and most importantly reduce waste generation. The continued combination of manufacturing methods and functional (smart) materials will facilitate the implementation of food analysis at the point of need.
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http://dx.doi.org/10.1007/s00216-019-01640-5DOI Listing
July 2019

Paper-Based Strips for the Electrochemical Detection of Single and Double Stranded DNA.

Anal Chem 2018 11 30;90(22):13680-13686. Epub 2018 Oct 30.

Department of Chemical Science and Technologies , University of Rome "Tor Vergata" , Via della Ricerca Scientifica 1 , 00133 Rome , Italy.

The detection of double stranded DNA (dsDNA) is often associated with the use of laboratory-bound approaches and/or with the prior generation of single stranded DNA (ssDNA), making these methods not suitable for in situ monitoring, i.e., point-of-care diagnostics. Screen-printed technology, coupled to the use of triplex forming oligonucleotides (TFO) as the recognizing probes, offers a great possibility toward the development of portable analytical tools. Moreover, the continuous demand for sustainable processes and waste lowering have highlighted the role of paper-based substrates for manufacturing easy-to-use, low-cost, and sustainable electrochemical devices. In this work, filter paper and copy paper have been utilized to produce E-DNA strips. Gold nanoparticles (AuNPs) have been exploited to immobilize the methylene blue (MB)-tagged TFO and to enhance the charge transfer kinetics at the electrode surface. Both paper-based substrates have been electrochemically characterized, and in addition, the effect of the amount of waxed layers has been evaluated. The paper-based E-DNA strips have been challenged toward the detection of three model targets, obtaining 3 and 7 nM as the detection limit, respectively, for single and double stranded sequences. The repeatability of the manufacturing (homemade) process has been evaluated with a relative standard deviation of approximately 10%. The effectiveness of the filter paper-based platform has been also evaluated in undiluted serum obtaining a similar value of the detection limit (compared to the measurements carried out in buffer solution). In addition, a synthetic PCR amplified dsDNA sequence, related to HIV, has been detected in serum samples.
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http://dx.doi.org/10.1021/acs.analchem.8b04052DOI Listing
November 2018

How to extend range linearity in enzyme inhibition-based biosensing assays.

Talanta 2018 Nov 5;189:365-369. Epub 2018 Jul 5.

Department of Chemical Science and Technologies, University of Rome Tor Vergata, Via della Ricerca Scientifica, 00133 Rome, Italy; National Institute of Biostructures and Biosystems, Viale Medaglie d'Oro, 305 Rome, Italy.

Bioassays based on enzyme inhibition are analytical tools widely employed for inhibitor analysis. Beside the conventional analytical techniques such as chromatography and mass spectrometry, these bioassays are cost-effective, easy to use, and suitable for in situ measurement but they are often characterised by a quite narrow linear range. Herein, we report a novel graphical method based on integrated Michaelis-Menten equation, valid for all types of reversible inhibition, which provides an extended linear range. The suitability of this innovative approach was demonstrated in the case of fluoride quantification using a colorimetric bioassay based on acetylcholinesterase inhibition. The "half time reaction", estimated by the progress curve of cholinesterase inhibition, was plotted versus the fluoride inhibitor concentration, observing an extended linear range up to 5 mM, instead of 0.6 mM using initial rate measurements. The applicability of this new concept was further demonstrated in the case of catalase enzyme inhibited by cyanide. Furthermore, it was demonstrated that fixed substrate conversion at level of 10-50% allows determination of inhibitor concentration in a wide linear range with high precision and in short time of analysis. This novel theoretical and practical approach allows for the extension of the linear range without any further experiments, with several advantages including low reagent consumption, reduced waste generation and time of measurement.
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http://dx.doi.org/10.1016/j.talanta.2018.06.087DOI Listing
November 2018

A lab-on-a-tip approach to make electroanalysis user-friendly and de-centralized: Detection of copper ions in river water.

Anal Chim Acta 2018 Oct 4;1029:1-7. Epub 2018 May 4.

Department of Chemical Science and Technologies, University of Rome "Tor Vergata", Via della Ricerca Scientifica 1, 00133, Rome, Italy.

The development of portable and user-friendly sensing platforms is a hot topic in the field of analytical chemistry. Among others, electroanalytical approaches exhibit a high amenability for reaching this purpose, i.e. the commercial strips for diabetes care are an obvious success. However, providing fully-integrated and user-friendly methods is the leitmotiv. In this work we evaluate the use of a disposable pipette tip, opportunely configured, to realize the first example of lab-on-a-tip. The combination of a pipette tip, wire electrodes, and cotton wool filter, highlights the suitability of producing a novel one-shot electroanalytical platform that does not require expertise-required tasks. To demonstrate the feasibility of this novel method, copper (Cu) is detected in water samples by means of anodic stripping voltammetry. The quantification is performed directly into the tip that contains a cotton wool filter: the filter has the double function of purifying the matrices from gross impurities and releasing all the pre-loaded reagents necessary for the assay. After optimizing the experimental parameters, the lab-on-a-tip was capable of detecting Cu linearly up to 300 μg/L with a detection limit of 6.3 μg/L. The effectiveness of the platform was confirmed by testing 50, 100, and 150 ppb Cu-spiked river water sample with recovery value comprised between 92 and 103%.
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http://dx.doi.org/10.1016/j.aca.2018.04.065DOI Listing
October 2018

Paper-based synthesis of Prussian Blue Nanoparticles for the development of whole blood glucose electrochemical biosensor.

Talanta 2018 Sep 4;187:59-64. Epub 2018 May 4.

Department of Chemical Science and Technologies, University of Rome "Tor Vergata", Via della Ricerca Scientifica 1, 00133 Rome, Italy.

Nowadays, environmentally friendly synthesis pathways for preserving the environment and minimizing waste are strongly required. Herein, we propose filter paper as a convenient scaffold for chemical reactions. To demonstrate this novel approach, Prussian Blue Nanoparticles (PBNPs) were synthesized on filter paper by utilizing few μL of its precursors without external inputs, i.e. pH, voltage, reducing agents, and without producing waste as well. The functional paper, named "Paper Blue", is successfully applied in the sensing field, exploiting the reduction of hydrogen peroxide at low applied potential. The eco-designed "Paper Blue" was combined with wax- and screen-printing to manufacture a reagentless electrochemical point-of-care device for diabetes self-monitoring, by using glucose oxidase as the biological recognition element. Blood glucose was linearly detected for a wide concentration range up to 25 mM (450 mg/dL), demonstrating its suitability for management of diabetes and glucose-related diseases. The Paper Blue-based biosensor demonstrated a correlation coefficient of 0.987 with commercial glucose strips (Bayer Contour XT). The achieved results demonstrated the effectiveness of this approach, which is also extendible to other (bio)systems to be applied in catalysis, remediation, and diagnostics.
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http://dx.doi.org/10.1016/j.talanta.2018.05.015DOI Listing
September 2018

Low-cost and reagent-free paper-based device to detect chloride ions in serum and sweat.

Talanta 2018 Mar 21;179:186-192. Epub 2017 Oct 21.

Department of Chemical Science and Technology, University of Rome Tor Vergata, Via della Ricerca Scientifica 1, 00133 Rome, Italy; Interuniversity Consortium INBB (Biostructures and Biosystems National Institute), Viale delle Medaglie d'Oro 305, 00136 Rome, Italy. Electronic address:

The recent goal of sustainability in analytical chemistry has boosted the development of eco-designed analytical tools to deliver fast and cost-effective analysis with low economic and environmental impact. Due to the recent focus in sustainability, we report the use of low-cost filter paper as a sustainable material to print silver electrodes and to load reagents for a reagent-free electrochemical detection of chloride in biological samples, namely serum and sweat. The electrochemical detection of chloride ions was carried out by exploiting the reaction of the analyte (i.e. chloride) with the silver working electrode. During the oxidation wave in cyclic voltammetry the silver ions are produced, thus they react with chloride ions to form AgCl, while in the reduction wave, the following reaction occurs: AgCl + e -->Ag + Cl. These reactions at the electrode surface resulted in anodic/cathodic peaks directly proportional to the chloride ions in solution. Chloride ions were detected with the addition of only 10μL of the sample on the paper-based electrochemical cell, obtaining linearity up to 200mM with a detection limit equal to 1mM and relative standard deviation lower than 10%. The accuracy of the sensor was evaluated in serum and sweat samples, with percentage recoveries between 93 ± 10 and 108 ± 8%. Moreover, the results achieved with the paper-based device were positively compared with those obtained by using the gold standard method (Ion Selective Electrode) adopted in routine clinical analyses.
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http://dx.doi.org/10.1016/j.talanta.2017.10.030DOI Listing
March 2018

Carbon Black-Modified Electrodes Screen-Printed onto Paper Towel, Waxed Paper and Parafilm M.

Sensors (Basel) 2017 Oct 3;17(10). Epub 2017 Oct 3.

Department of Chemical Science and Technology, University of Rome "Tor Vergata", Via della Ricerca Scientifica 1, 00133 Rome, Italy.

Herein, we evaluated the use of paper towel, waxed paper, and Parafilm M (Heathrow Scientific, Vernon Hills, IL, USA) as alternative substrates for screen-printed sensor manufacturing. Morphological study was performed to evaluate the adhesion of the ink on these uncommon substrates, as well as the morphology of the working electrode. The electrochemical characterization was carried out using ferricyanide/ferrocyanide as redox couple. To enhance the electrochemical properties of the developed sensors, the nanomaterial carbon black was used as nanomodifier. The modification by drop casting of the working electrode surface, using a stable dispersion of carbon black, allows to obtain a sensor with improved electrochemical behavior in terms of peak-to-peak separation, current intensity, and the resistance of charge transfer. The results achieved confirm the possibility of printing the electrode on several cost-effective paper-based materials and the improvement of the electrochemical behavior by using carbon black as sustainable nanomaterial.
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http://dx.doi.org/10.3390/s17102267DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5676850PMC
October 2017

Electrochemical Biosensors for Rapid Detection of Foodborne Salmonella: A Critical Overview.

Sensors (Basel) 2017 Aug 18;17(8). Epub 2017 Aug 18.

Department of Chemical Science and Technology, University of Rome "Tor Vergata", Via della Ricerca Scientifica 1, 00133 Rome, Italy.

has represented the most common and primary cause of food poisoning in many countries for at least over 100 years. Its detection is still primarily based on traditional microbiological culture methods which are labor-intensive, extremely time consuming, and not suitable for testing a large number of samples. Accordingly, great efforts to develop rapid, sensitive and specific methods, easy to use, and suitable for multi-sample analysis, have been made and continue. Biosensor-based technology has all the potentialities to meet these requirements. In this paper, we review the features of the electrochemical immunosensors, genosensors, aptasensors and phagosensors developed in the last five years for Salmonella detection, focusing on the critical aspects of their application in food analysis.
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http://dx.doi.org/10.3390/s17081910DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5579882PMC
August 2017
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