MARIA MINUNNI

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Papers by MARIA MINUNNI

Development of an Electrochemical Sensor Based on Screen-Printed Electrodes for Ochratoxin a in Pork Meat Samples

Ochratoxin A (OTA) is a nephrotoxic, immunosuppressive and teratogenic mycotoxin produced by Aspe... more Ochratoxin A (OTA) is a nephrotoxic, immunosuppressive and teratogenic mycotoxin produced by Aspergillus and Penicillium spp. fungi during food storage. OTA can be detected in cereal products, coffee, wine, beer, cheese and in poultry and pork meat. Many detection techniques, such as liquid chromatography coupled with immunoaffinity column or solid phase extraction cleanup, have been used for OTA determination in different samples (1). In recent years electrochemical techniques have been used for the rapid and accurate detection of OTA (2). The aim of the present study was to develop a new analytical method for OTA quantitative detection in pork meat based on electrochemical sensing, using graphite-based screen-printed electrodes and differential pulse voltammetry (DPV) as detection technique. Experiments were performed with an electrochemical transducer Palmsens, monitored with a personal computer using PSTrace software (Palm Instrument BV, Houten, The Netherlands) for data acquisi...

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Norepinephrine as new functional monomer for molecular imprinting: An applicative study for the optical sensing of cardiac biomarkers

Biosensors and Bioelectronics, 2020

The continuous research for alternatives to antibody-based detection drove, in the last decades, ... more The continuous research for alternatives to antibody-based detection drove, in the last decades, the development of numerous strategies. Molecularly imprinted polymers (MIPs) emerged thanks to the low-cost and long-term stability features, where the choice of natural functional monomer(s) represents the key step for efficient imprinting of biomolecules. The chemical structure of dopamine (DA), one of the most used natural functional monomers, provided the inspiration for this work. We wondered why norepinephrine (NE) that differs from dopamine only for an additional hydroxyl group was not investigated at all in biosensing applications. In fact, there is only one paper exploiting polynorepinephrine (PNE) in molecular recognition applications, taking advantage of molecular imprinting, but not for biosensing purposes. In contrast, hundreds of papers describe polydopamine-based sensors. Therefore, we firstly investigated how the additional hydroxyl group of NE could affect the properties of the resulting polymer, and how these properties could be exploited for biosensing applications. The results highlighted the reduced non-specific adsorption of proteins onto PNE with respect to dopamine polymer. Furthermore, as a case study, we successfully developed a PNE-based imprinted biosensor for the early detection of Troponin I, a crucial biomarker for heart failure, by coupling the MIP biosensor with surface plasmon resonance (SPR) detection. The results indicate the feasible use of imprinted PNE as synthetic receptor for biomolecules, opening new perspectives for this biopolymer, so far not considered, and encouraging further investigations on its potential application in biosensing.

Protein-templated copper nanoclusters: versatile platform for label-free detection of albumin

Proceedings of The 1st International Electronic Conference on Biosensors, 2020

The outstanding properties of metal nanoclusters, stabilized with different scaffolds, i.e., prot... more The outstanding properties of metal nanoclusters, stabilized with different scaffolds, i.e., proteins, nucleic acids, polymers and dendrimers, enable their application in a wide range of fields. The recent advances in the fabrication and synthesis of nanoclusters have revolutionized the design of biosensors, leading to significant improvements in the selective and sensitive determination of several targets. In particular, in recent years, copper nanoclusters (CuNCs) have attracted more attention mainly for their unique fluorescent properties, as well as their large Stokes shifts, low toxicity, and high biocompatibility. The high-photoluminescent features of CuNCs facilitate highly sensitive target detection even in complex biological matrices. For these reasons, in this work, we exploited the specific template-targeted CuNCs' growth for the sensitive and accurate determination of human serum albumin (HSA) in urine and human serum. HSA is the most abundant protein in plasma, acting as a carrier for many key biological molecules such as hormones, fatty acids and steroids, and it contributes to the maintenance of the oncotic blood pressure. The concentration of HSA in body fluids greatly influences the state of health of the patients. Taking into account these considerations, the quantitative detection of human serum albumin plays a key role in the early diagnosis of serious pathological conditions such as albuminuria and albuminemia. Here, we present a CuNCs-based assay in which copper nanoclusters were used as fluorescent signal indicators to detect serum albumin in a complex biological matrix.

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A small heterobifunctional ligand provides stable and water dispersible core-shell CdSe/ZnS quantum dots (QDs)

Nanoscale, Jan 26, 2018

We describe a simple method to prepare water dispersible core-shell CdSe/ZnS quantum dots (QDs) 1... more We describe a simple method to prepare water dispersible core-shell CdSe/ZnS quantum dots (QDs) 1 by capping QDs with a new thiol-containing heterobifunctional dicarboxylic ligand 4 (DHLA-EDADA). This ligand, obtained on a gram scale through a few synthetic steps, provides a compact layer on the QDs, whose hydrodynamic size in H2O is 15 nm ± 3 nm. The colloidal stability is dramatically enhanced with respect to the well-known (±) α-lipoic acid (DHLA). The ligand affinity towards QDs and the water dispersibility of nanocrystals 1 are addressed by the dithiol groups of DHLA, which chelate the zinc of the shell, and by the dicarboxylic groups of the ethylenediamine-N,N-diacetic acid (EDADA) residue, respectively. The effects of pH, buffer solutions, and biological medium on the stability of QDs 1 were assessed by monitoring the photoluminescence (PL) and hydrodynamic size over time. Highly fluorescent QD dispersions, stable over extended periods of time and over broad pH ranges and buf...

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Self-powered microneedle-based biosensors for pain-free high-accuracy measurement of glycaemia in interstitial fluid

Biosensors & bioelectronics, Jan 15, 2015

In this work a novel self-powered microneedle-based transdermal biosensor for pain-free high-accu... more In this work a novel self-powered microneedle-based transdermal biosensor for pain-free high-accuracy real-time measurement of glycaemia in interstitial fluid (ISF) is reported. The proposed transdermal biosensor makes use of an array of silicon-dioxide hollow microneedles that are about one order of magnitude both smaller (borehole down to 4µm) and more densely-packed (up to 1×10(6)needles/cm(2)) than state-of-the-art microneedles used for biosensing so far. This allows self-powered (i.e. pump-free) uptake of ISF to be carried out with high efficacy and reliability in a few seconds (uptake rate up to 1µl/s) by exploiting capillarity in the microneedles. By coupling the microneedles operating under capillary-action with an enzymatic glucose biosensor integrated on the back-side of the needle-chip, glucose measurements are performed with high accuracy (±20% of the actual glucose level for 96% of measures) and reproducibility (coefficient of variation 8.56%) in real-time (30s) over th...

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Selective and simultaneous determination of NSAIDs in equine plasma by HPLC with molecularly imprinted solid-phase extraction

Bioanalysis, 2014

Background: Detection of nonsteroidal anti-inflammatory drugs (NSAIDs) in equine plasma is a sign... more Background: Detection of nonsteroidal anti-inflammatory drugs (NSAIDs) in equine plasma is a significant analytical problem in veterinary anti-doping controls. Results: A new HPLC method coupled to selective extraction with molecularly imprinted polymers was developed for the simultaneous determination in equine plasma of the NSAIDs phenylbutazone, flunixin, oxyphenbutazone, ketoprofen and naproxen. The analytical performances of the method have been evaluated both in standard solutions and equine plasma samples. Recovery: Molecularly imprinted polymers solid-phase extraction for all NSAIDs was >94% with intra-day values below 15.0% and inter-day values below 20%. Method quantification limit was 0.01 μg/ml. Conclusion: The developed method could be considered as a useful alternative to existing screening methods for the determination of NSAIDs in the context of studies of pharmacokinetics and anti-doping controls.

Biosensing Approach in Natural Product Research

Detection, Isolation, and Structural Determination, Second Edition, 2007

The analysis of natural constituents of herbal drugs, herbal drug preparations, and herbal medici... more

Aptamer-Based Bioanalytical Assays: Amplification Strategies

Aptamers in Bioanalysis

Aptamers hold great promise as molecular recognition tools for their incorporation into analytica... more Aptamers hold great promise as molecular recognition tools for their incorporation into analytical devices, and in particular, they can be used as immobilized ligands in separation technologies (Clark and Remcho, 2002), as affinity probes in capillary electrophoresis-based quantitative assays (Kotia and McGown, 2000), in affinity matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS)(Dick and McGown, 2004), and as biocomponents in biosensors (Tombelli et al., 2005). Other aptamer-based bioanalytical ...

Analytical Applicationsof QCM-based Nucleic Acid Biosensors

Piezoelectric Sensors

Recent advances in nucleic acid-based detection coupled to piezoelectric transduction will be rep... more Recent advances in nucleic acid-based detection coupled to piezoelectric transduction will be reported here. The main aspects involved in the development of nucleic acid sensors are considered: the immobilization of the probe, the sample pretreatments (DNA extraction, amplification, denaturation of the amplified material), the sensitivity and specificity, etc. These systems have been applied to different fields from environmental analysis to clinical diagnostics. Examples taken from different analytical problems will be reported. Another ...

Examples of Biosensors for the Measurement of Trace Medical Analytes

Handbook of Biosensors and Biochips, 2008

Analyses in the clinical laboratory concern metabolites in human blood and urine in the millimola... more Analyses in the clinical laboratory concern metabolites in human blood and urine in the millimolar concentration range. However, a better understanding of several diseases requires the measurements of different analytes, such as those reported in Table 1, in the micro-and submicromolar range. Steroids, drugs and their metabolites, hormones, and protein factors represent the molecular targets of many clinical analyses for elucidating several diseases. The concentration of these molecules is in the range 10− 11–10− 6 mol ...

Development of a New Analytical Tool for Traceability of Transgenes in Genetically Modified Plants

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A DNA-based piezoelectric biosensor: Strategies for coupling nucleic acids to piezoelectric devices

Talanta, 2006

A DNA-based piezoelectric biosensor has been here studied in terms of probe immobilisation and DN... more A DNA-based piezoelectric biosensor has been here studied in terms of probe immobilisation and DNA sample pre-treatment. The biosensor is specific for the detection of the mecA gene of methicillin-resistant Staphylococcus aureus (MRSA). Methicillin-resistant S. aureus is responsible of several infections in humans, like pneumonia, meningitis and endocarditic. MRSA is also a major cause of hospital-acquired infections worldwide. The antibiotics resistance is conferred by the gene mecA, codifying for an anomalous protein. Two different immobilisation procedures of the probe specific for mecA gene are reported: immobilisation via streptavidin-biotin interaction and direct immobilisation of thiolated probes. After the study with synthetic oligonucleotides, the system has been applied to the analysis of bacterial DNA from MRSA, amplified by polymerase chain reaction. These samples were pre-treated with two different denaturation procedures and the performances of the sensor in the two cases were compared. The two immobilisation methods and denaturation protocols were here used to study the influences of these parameters on the performances of the sensor, applied here to the detection of the mecA gene. Better results in terms of sensitivity and reproducibility were obtained when using the biotinylated probe and the PCR-amplified samples treated by a denaturation procedures involving the use of high temperature and blocking oligonucleotides.

An optical DNA-based biosensor for the analysis of bioactive constituents with application in drug and herbal drug screening

Talanta, 2005

The efficient and rapid detection of bioactive compounds in complex matrices of different origins... more The efficient and rapid detection of bioactive compounds in complex matrices of different origins (natural or synthetic) is a key step in the discovery of molecules with potential application in therapy. Among them, molecules able to interact with nucleic acids can represent important targets. In this study, an optical DNA biosensor, based on surface plasmon resonance (SPR) transduction, has been studied in its potential application as new analytical device for drug screening. This device was applied to the analysis of pure synthetic or natural molecules and also to some fractions obtained by chromatographic separation of an extract of Chelidonium majus L. (great celandine), a plant containing benzo[c]phenanthridinium alkaloids having intercalating properties. The ability of these molecules to interact with the double stranded nucleic acid (dsDNA) immobilised on the sensor surface has been investigated. The optical sensing relies on the SPR-based bench instrument Biacore Xtrade mark and represents an example of multiuse sensor. The results obtained demonstrate the potential application of this device for the rapid screening of bioeffective compounds. The characteristics of the biosensor offer the possibility to be coupled to chemical analysis as in hyphenated technologies.

Determination of phenylbutazone and flunixin meglumine in equine plasma by electrochemical-based sensing coupled to selective extraction with molecularly imprinted polymers

Sensors and Actuators B: Chemical, 2013

Phenylbutazone and flunixin meglumine are non-steroidal anti-inflammatory drugs with antiinflamma... more Phenylbutazone and flunixin meglumine are non-steroidal anti-inflammatory drugs with antiinflammatory and analgesic activities widely used for the treatment of bone and joint inflammations, laminitis and soft tissue inflammation in the horse. The aim of the present study was to develop a new, selective, sensitive and fast analytical approach for phenylbutazone and flunixin quantitative detection in equine plasma. Differential pulse voltammetry experiments were performed with a portable electrochemical transducer by using miniaturized disposable graphite based screen-printed electrodes. The electrochemical detection by differential pulse voltammetry was coupled to prior selective extraction using dedicated molecularly imprinted solid phase extraction (MISPE) columns to reduce/avoid possible interferences present in plasma. Recovery after MISPE for both phenylbutazone and flunixin was >96%, with intra-day values below 5.0% and inter-day values below 6.5%. Method limit of quantification was 0.01 μg/ml for both phenylbutazone and flunixin. The results obtained with DPV method showed a good correlation with those provided by an HPLC reference method. The method can be proposed as a suitable alternative to the existing chromatographic methods for the determination of phenylbutazone and flunixin in equine plasma samples.

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In vivo cytogenetic effects of natural humic acid

Mutagenesis, 1996

As humic compounds are naturally widespread in the environment and present in surface water, stud... more As humic compounds are naturally widespread in the environment and present in surface water, studies on their genotoxicity are justified. Humic acid (HA) has not been demonstrated to be genotoxic either in vitro or in vivo. In the present paper we investigated its activity both in intestinal and bone marrow cells following a single dose (100 mg/kg b.w. corresponding to 0.5 ml per animal of an aqueous solution of 4 g/1) of HA administered to mice by gastric intubation, to mimic the most likely route of human exposure. HA induced structural and, in particular, numerical chromosome abnormalities in intestinal cells. A marginal, non-significant induction of aneuploidy was also found in bone marrow cells.

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Bulk acoustic wave affinity biosensor for genetically modified organisms detection

IEEE Sensors Journal, 2003

Abstract Bulk acoustic waves have been applied as affinity sensors. In particular, a nucleic acid... more Abstract Bulk acoustic waves have been applied as affinity sensors. In particular, a nucleic acid sensor for hybridization studies has been developed and applied for detecting DNA target sequences in solution. A DNA probe is immobilized on the sensor surface while the target sequence is free in solution; the interaction between the two complementary strands (hybridization) is followed in real-time, without the use of any label. The system has been applied to analytical problems, ie, genetically modified organisms (GMOs) detection. The ...

Development of combined DNA-based piezoelectric biosensors for the simultaneous detection and genotyping of high risk Human Papilloma Virus strains

Clinica Chimica Acta, 2007

Background: Human Papilloma Virus (HPV) is a DNA virus belonging to the Papovavirus family. Genit... more Background: Human Papilloma Virus (HPV) is a DNA virus belonging to the Papovavirus family. Genital HPV types have been subdivided into medium-low risk, and high-risk (HPV 16 and 18), frequently associated with cervical cancer. Three DNA-based piezoelectric biosensors were here developed for a quick detection and genotyping of HPV. Methods: We developed a method for the detection and genotyping of HPV in human cervical scraping samples based on coupling DNA piezoelectric sensors with Polymerase Chain Reaction (PCR). The novelty of this work was the design and immobilisation of a degenerate probe (chosen in a conserved region of the viral genome) for the simultaneous detection of 16 virus strains and of two specific probes (chosen in a lessconserved region of the viral genome) for genotyping. Results: The three biosensors were optimised with synthetic oligonucleotides with good reproducibility (HPVdeg CV% av 9%, HPV16 CV% av 9%; HPV18 CV% av 11%) with a detection limit of 50 nM. Cervical scraping samples after PCR amplification (in 40-200 nM range), were tested without the need of label with high selectivity and reproducibility. The results were in agreement with a reference method used in routinary analysis. Conclusion: Piezoelectric biosensors have proven to be suitable for detection and genotyping of HPV.

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Analytical applications of aptamers

Biosensors and Bioelectronics, 2005

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Quartz crystal microbalance (QCM) affinity biosensor for genetically modified organisms (GMOs) detection

Biosensors and Bioelectronics, 2003

A DNA piezoelectric sensor has been developed for the detection of genetically modified organisms... more A DNA piezoelectric sensor has been developed for the detection of genetically modified organisms (GMOs). Single stranded DNA (ssDNA) probes were immobilised on the sensor surface of a quartz crystal microbalance (QCM) device and the hybridisation between the immobilised probe and the target complementary sequence in solution was monitored. The probe sequences were internal to the sequence of the 35S promoter (P) and Nos terminator (T), which are inserted sequences in the genome of GMOs regulating the transgene expression. Two different probe immobilisation procedures were applied: (a) a thiol-dextran procedure and (b) a thiol-derivatised probe and blocking thiol procedure. The system has been optimised using synthetic oligonucleotides, which were then applied to samples of plasmidic and genomic DNA isolated from the pBI121 plasmid, certified reference materials (CRM), and real samples amplified by the polymerase chain reaction (PCR). The analytical parameters of the sensor have been investigated (sensitivity, reproducibility, lifetime etc.). The results obtained showed that both immobilisation procedures enabled sensitive and specific detection of GMOs, providing a useful tool for screening analysis in food samples.

Detection of TP53 mutation using a portable surface plasmon resonance DNA-based biosensor

Biosensors and Bioelectronics, 2005

A DNA-based surface plasmon resonance (SPR) biosensor has been developed for the detection of TP5... more A DNA-based surface plasmon resonance (SPR) biosensor has been developed for the detection of TP53 mutation using the inexpensive and commercially available instrument, SPREETA TM SPR-EVM-BT, from Texas Instruments. A direct immobilisation procedure, based on the coupling of thiol-derivatised oligonucleotide probes (Probe-C6-SH) to bare gold sensor surfaces, was optimized using synthetic oligonucleotides. Hybridisation reactions between the immobilised probe and a short sequence (26 mer) complementary, non-complementary and one-point mutation DNA were then investigated. The main analytical parameters of the sensor system were studied in detail including selectivity, sensitivity, reproducibility and analysis time. Finally, the sensor system was successfully applied to polymerase chain reaction (PCR)-amplified real samples, DNA extracted from both normal, wild-type, (Jurkat) and mutated (Molt 4), carrying the mutation at codon 248 of the TP53 cell lines. The results obtained demonstrate that the DNA-based SPR biosensor was able to distinguish sequences present in the various samples that differ only by one base; and hence, it appears to be a strong candidate technique for the detection of gene mutation.

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