Ilaria Palchetti

Bio: Ilaria Palchetti is an academic researcher from University of Florence. The author has contributed to research in topics: Biosensor & Working electrode. The author has an hindex of 40, co-authored 138 publications receiving 4828 citations.

Nucleic acid and peptide aptamers: fundamentals and bioanalytical aspects.

Abstract: In recent years new nucleic acid and protein-based combinatorial molecules have attracted the attention of researchers working in various areas of science, ranging from medicine to analytical chemistry. These molecules, called aptamers, have been proposed as alternatives to antibodies in many different applications. The aim of this Review is to illustrate the peculiarities of these combinatorial molecules which have initially been explored for their importance in molecular medicine, but have enormous potential in other biotechnological fields historically dominated by antibodies, such as bioassays. A description of these molecules is given, and the methods for their selection and production are also summarized. Moreover, critical aspects related to these molecules are discussed.

DNA electrochemical biosensors.

Abstract: Disposable electrochemical DNA-based biosensors are reviewed; they have been used for the determination of low-molecular weight compounds with affinity for nucleic acids and for the detection of the hybridisation reaction. The first application is related to the molecular interaction between surface-linked DNA and the target pollutants or drugs, in order to develop a simple device for rapid screening of toxic or similar compounds. The determination of such compounds was measured by their effect on the oxidation signal of the guanine peak of calf thymus DNA immobilised on the electrode surface and investigated by chronopotentiometric analysis. The DNA biosensor is able to detect known intercalating compounds, such as daunomycin, polychlorinated biphenyls (PCBs), aflatoxin B1, and aromatic amines. Applicability to river and waste water samples is also demonstrated. Disposable electrochemical sensors for the detection of a specific sequence of DNA were realised by immobilising synthetic single-stranded oligonucleotides onto a graphite screen-printed electrode. The probes became hybridised with different concentrations of complementary sequences present in the sample. The hybrids formed on the electrode surface were evaluated by chronopotentiometric analysis using daunomycin as indicator of the hybridisation reaction. The hybridisation was also performed using real samples. Application to apolipoprotein E (ApoE) is described, in this case samples have to be amplified by PCR and then analysed by DNA biosensor. The extension of such procedures to samples of environmental interest or to contamination of food is discussed.

Electroanalytical biosensors and their potential for food pathogen and toxin detection

Abstract: The detection and identification of foodborne pathogens continue to rely on conventional culturing techniques. These are very elaborate, time-consuming, and have to be completed in a microbiology laboratory and are therefore not suitable for on-site monitoring. The need for a more rapid, reliable, specific, and sensitive method of detecting a target analyte, at low cost, is the focus of a great deal of research. Biosensor technology has the potential to speed up the detection, increase specificity and sensitivity, enable high-throughput analysis, and to be used for monitoring of critical control points in food production. This article reviews food pathogen detection methods based on electrochemical biosensors, specifically amperometric, potentiometric, and impedimetric biosensors. The underlying principles and application of these biosensors are discussed with special emphasis on new biorecognition elements, nanomaterials, and lab on a chip technology.

Nucleic acid biosensors for environmental pollution monitoring

Abstract: Nucleic acid-based biosensors are finding increasing use for the detection of environmental pollution and toxicity. A biosensor is defined as a compact analytical device incorporating a biological or biologically-derived sensing element either integrated within or intimately associated with a physicochemical transducer. A nucleic acid-based biosensor employs as the sensing element an oligonucleotide, with a known sequence of bases, or a complex structure of DNA or RNA. Nucleic acid biosensors can be used to detect DNA/RNA fragments or either biological or chemical species. In the first application, DNA/RNA is the analyte and it is detected through the hybridization reaction (this kind of biosensor is also called a genosensor). In the second application, DNA/RNA plays the role of the receptor of specific biological and/or chemical species, such as target proteins, pollutants or drugs. Recent advances in the development and applications of nucleic acid-based biosensors for environmental application are reviewed in this article with special emphasis on functional nucleic acid elements (aptamers, DNAzymes, aptazymes) and lab-on-a-chip technology.

A nanoscale optical biosensor: sensitivity and selectivity of an approach based on the localized surface plasmon resonance spectroscopy of triangular silver nanoparticles.

Abstract: Triangular silver nanoparticles (∼100 nm wide and 50 nm high) have remarkable optical properties. In particular, the peak extinction wavelength, λmax of their localized surface plasmon resonance (LSPR) spectrum is unexpectedly sensitive to nanoparticle size, shape, and local (∼10−30 nm) external dielectric environment. This sensitivity of the LSPR λmax to the nanoenvironment has allowed us to develop a new class of nanoscale affinity biosensors. The essential characteristics and operational principles of these LSPR nanobiosensors will be illustrated using the well-studied biotin−streptavidin system. Exposure of biotin-functionalized Ag nanotriangles to 100 nM streptavidin (SA) caused a 27.0 nm red-shift in the LSPR λmax. The LSPR λmax shift, ΔR/ΔRmax, versus [SA] response curve was measured over the concentration range 10-15 M < [SA] < 10-6 M. Comparison of the data with the theoretical normalized response expected for 1:1 binding of a ligand to a multivalent receptor with different sites but invariant af...

Recent trends in macro-, micro-, and nanomaterial-based tools and strategies for heavy-metal detection.

Abstract: Recent Trends in Macro-, Micro-, and Nanomaterial-Based Tools and Strategies for Heavy-Metal Detection Gemma Aragay, Josefina Pons, and Arben Merkoc-i* Nanobioelectronics & Biosensors Group, Institut Catal a de Nanotecnologia (CIN2, ICN-CSIC), 08193, Bellaterra, Barcelona, Spain Departament of Chemistry, Universitat Aut onoma de Barcelona, 08193, Bellaterra, Barcelona, Spain ICREA, Barcelona, Spain

DNA biosensors and microarrays.

Abstract: Laboratoire de Génie Enzymatique et Biomoléculaire, Institut de Chimie et Biochimie Moléculaires et Supramoléculaires, 43 Boulevard du 11 Novembre 1918, Villeurbanne F-69622, France, UMR5246, Centre National de La Recherche Scientifque, Villeurbanne F-69622, France, Université de Lyon, Lyon F-69622, France, Université Lyon 1, Lyon F-69622, France, Institut National des Sciences Appliquées de Lyon, EÄ cole d’Ingénieurs, Villeurbanne F-69621, France, and EÄ cole Supérieure Chimie Physique EÄ lectronique de Lyon, Villeurbanne F-69616, France

Electrochemical Sensors and Biosensors Based on Nanomaterials and Nanostructures

Abstract: Taking advantage of exceptional attributes, such as being easy-to-operate, economical, sensitive, portable, and simple-to-construct, in recent decades, considerable attention has been devoted to the integration of recognition elements with electronic elements to develop electrochemical sensors and biosensors.Various electrochemical devices, such as amperometric sensors, electrochemical impedance sensors, and electrochemical luminescence sensors as well as photoelectrochemical sensors, provide wide applications in the detection of chemical and biological targets in terms of electrochemical change of electrode interfaces. With remarkable achievements in nanotechnology and nanoscience, nanomaterial-based electrochemical signal amplifications have great potential of improving both sensitivity and selectivity for electrochemical sensors and biosensors. First of all, it is well-known that the electrode materials play a critical role in the construction of high-performance electrochemical sensing platforms for detecting target molecules through various analytical principles. Furthermore, in addition to electrode materials, functional nanomaterials can not only produce a synergic effect among catalytic activity, conductivity, and biocompatibility to accelerate the signal transduction but also amplify biorecognition events with specifically designed signal tags, leading to highly sensitive biosensing. Significantly, extensive research on the construction of functional electrode materials, coupled with numerous electrochemical methods, is advancing the wide application of electrochemical devices. For example, Walcarius et al. highlighted the recent advances of nano-objects and nanoengineered and/or nanostructured materials for the rational design of biofunctionalized electrodes and related (bio)sensing systems.1 The attractiveness of such nanomaterials relies on their ability to act as effective immobilization matrices and their intrinsic and unique features as described above. These features combined with the functioning of biomolecules contribute to the improvement of bioelectrode performance in terms of sensitivity and specificity. Our group recently presented a general overview of nanomaterial-enhanced paper-based biosensors including lateral-flow test-strip and paper microfluidic devices.2 With different kinds of nanoparticles (NPs), paper-based biosensor devices have shown a great potential in the enhancement of sensitivity and specificity of disease diagnosis in developing countries. This Review focuses on recent advances in electrochemical sensors and biosensors based on nanomaterials and nanostructures during 2013 to 2014. The aim of this effort is to provide the reader with a clear and concise view of new advances in areas ranging from electrode engineering, strategies for electrochemical signal amplification, and novel electroanalytical techniques used in the miniaturization and integration of the sensors. Moreover, the authors have attempted to highlight areas of the latest and significant development of enhanced electrochemical nanosensors and nanobiosensors that inspire broader interests across various disciplines. Electrochemical sensors for small molecules, enzyme-based biosensors, genosensors, immunosensors, and cytosensors are reviewed herein (Figure ​(Figure1).1). Such novel advances are important for the development of electrochemical sensors that open up new avenues and methods for future research. We recommend readers interested in the general principles of electrochemical sensors and electrochemical methods to refer to other excellent literature for a broad scope in this area.3,4 However, due to the explosion of publications in this active field, we do not claim that this Review includes all of the published works in the past two years and we apologize to the authors of excellent work, which is unintentionally left out. Figure 1 Schematic illustration of electrochemical sensors and biosensors based on nanomaterials and nanostructures, in which electrochemical sensors for small molecular, enzyme-based biosensors, genosensors, immunosensors, and cytosensors are demonstrated.

Observation of Single Colloidal Platinum Nanocrystal Growth Trajectories

Abstract: It is conventionally assumed that the growth of monodisperse colloidal nanocrystals requires a temporally discrete nucleation followed by monomer attachment onto the existing nuclei. However, recent studies have reported violations of this classical growth model, and have suggested that inter-particle interactions are also involved during the growth. Mechanisms of nanocrystal growth still remain controversial. Using in situ transmission electron microscopy, we show that platinum nanocrystals can grow either by monomer attachment from solution onto the existing particles or by coalescence between the particles. Surprisingly, an initially broad size distribution of the nanocrystals can spontaneously narrow. We suggest that nanocrystals take different pathways of growth based on their size- and morphology-dependent internal energies. These observations are expected to be highly relevant for other nanocrystal systems.