Toward nanoanalytical chemistry : case of nanomaterial integration into [bio]sensing systems

Analytical chemistry-oriented nanotechnology, or nanoanalytical chemistry, at nanometer or macroscale, at both nanometer and macroscale dimensions, is on its way to becoming a field of great potential. Nanoanalytical chemistry concepts are finding rapid acceptance in molecular biology and other fields. The design of novel nanostructures with special optical and electrochemical properties and their integration into [bio]sensing systems represent only one aspect of the research in this new field. Analytical chemistry-oriented nanotechnology, or nanoanalytical chemistry, will provide new tools for various applications in fields like medicine, environmental studies, and industry. Nanoanalytical chemistry examples related to gold nanoparticles, quantum dots, and carbon nanotubes will be presented in the present paper. DNA detection by ICPMS of gold nanoparticle tags as well as direct electrochemical detection of the same nanoparticles will be described here as the first example. The use of quantum dots for the design of so-called DNA chips in solution will be the second example. The integration of carbon nanotubes in an epoxy matrix forming a novel composite material with interesting applications in sensor technology will be the paper's final example.La nanotecnologia orientada al camp de la química analítica, o química nanoanalítica, ja sigui a escala nanomètrica o a macroescala, s'està convertint en una matèria de gran potencial. Els conceptes associats a aquesta química nanoanalítica són acceptats ràpidament, entre d'altres, pel camp de la biologia molecular. El disseny de noves estructures amb propietats òptiques i electroquímiques especials i la seva integració en sistemes de [bio]detecció representen alguns dels molts aspectes relacionats amb la investigació en aquest nou camp. La química nanoanalítica haurà de proporcionar noves eines per a diferents aplicacions, ja sigui en el camp mèdic, mediambiental o industrial. Es presenten exemples de química nanoanalítica relacionats amb nanopartícules d'or, quantum dots i nanotubs de carboni. Com a primer exemple, es descriurà la detecció de DNA mitjançant ICPMS de nanopartícules d'or, així com la detecció electroquímica d'aquestes mateixes partícules. El segon exemple serà l'ús de quantum dots per al disseny dels anomenats «xips de DNA en solució». Finalment, es presentarà la integració de nanotubs de carboni en una matriu de resina epoxi per formar un nou material compòsit amb aplicacions interessants en la tecnologia dels sensors

La Seguretat alimentària : un repte del nou segle per als biosensors

En un futur serà possible un control més exhaustiu de les matèries primeres i els productes alimentaris, tant a peu de procés en la indústria com pels mateixos consumidors finals. Les agències reguladores i els laboratoris de control de qualitat podran disposar de dispositius biosensors capaços de realitzar anàlisis de manera més ràpida i econòmica en mostres alimentàries complexes.Food agencies and food control laboratories would dispose of biosensing devices for the rapid and low cost testing of complex food samples. In a near future, in-field control of raw food and final products for food industry and final consumers would be possible

Toward an ICPMS-linked DNA assay based on gold nanoparticles immunoconnected through peptide sequences

Gold nanoparticles modified with anti-mouse IgG have been used to trace oligonucleotides carrying a c-myc peptide. Two strategies, a dot-blot format as well as inductively coupled plasma mass spectrometry (ICPMS) have been used to detect the nanoparticle tracer. For both cases, oligonucleotide-peptide conjugates were first applied to a nitrocellulose membrane using a manifold attached to a suction device. After immobilization of the oligonucleotide by UV radiation, the samples were incubated with an anti-c-myc monoclonal antibody. In the case of the dot-blot format strategy, it was followed by incubation with a secondary antibody conjugated to horseradish peroxidase and development with luminol as chemiluminescent substrate. In the case of ICPMS strategy, it was followed by incubation with the secondary antibody (anti-mouse IgG) conjugated to gold nanoparticles and their ICPMS detection after dissolving. The nonspecific adsorptions were found to be around zero. The limit of detection for peptide-modified DNA was 0,2 pmol. The method may have significant potential as an important ICPMS-based nonradioactive DNA detection method for the simultaneous determination of various sequences by labeling different kinds of inorganic nanoparticles. © 2005 American Chemical Society.This work was financially supported from MEC (Madrid) (Projects BIO2004- 02776, MAT2004-05164), by Spanish foundation “Ramón Areces” (project ‘Bionanosensores’). A.M. thanks the “Ramón y Cajal” program of Ministry of Science and Technology (Madrid).Peer reviewe

Chemistry research in Catalonia : 1996-2002

The seven-year period studied here differs very little from the sixyear period described in the previous Report (1990-1995) [1]. Sustained growth was observed in almost all the indicators used to evaluate the resources invested and the scientific results obtained

Simultaneous titration of ternary mixtures of Pb(II), Cd(II) and Cu(II) with potentiometric electronic tongue detection

An automatic titration method is reported to resolve ternary mixtures of transition metals (Pb²⁺,Cd²⁺ and Cu²⁺) employing electronic tongue detection and a reduced number of pre-defined additions of EDTA titrant. Sensors used were PVC membrane selective electrodes with generic response to heavy-metals, plus an artificial neural network response model. Detection limits obtained were ca. 1 mg L¯¹ for the three target ions and reproducibilities 3.0 % for Pb²⁺, 4.1 % for Cd²⁺ and 5.2 % for Cu²⁺. The system was applied to contaminated soil samples and high accuracy was obtained for the determination of Pb²⁺. In the determination Cd²⁺ and Cu²⁺,sample matrix showed a significant effect

Colangitis esclerosante primaria. Presentación de un caso y revisión del tema

The patient was admitted to hospital presenting an abdominal pain localized in the epigastrium, with irradiation to the left hypochondrium and a discrete jaundice; at first it was indicative of an ischemic heart disease because of the typical electrocardiographic changes it presented. After undergoing an abdominal ultrasonography, an acute cholecystitis was diagnosed. An endoscopic retrograde cholangiopancreatography was indicated. It showed an acute cholangitis, without lithiasis in the main bile duct. An endoscopic sphincterotomy was carried out. The patient underwent an emergency cholecystectomy. It was necessary to repeat the cholangiopancreatography because of the persistent jaundice and the suspicion of sclerosing cholangitis was confirmed. The patient received antibiotic treatment (ampicillin) and steroids; his general condition improved and was discharged.Se presenta un paciente de 65 años de edad con antecedentes de hipertensión arterial y fiebre reumática que ingresa con un cuadro de dolor abdominal localizado en el epigastrio, con irradiación al hipocondrio derecho e íctero discreto que, inicialmente, fue sugestivo de una cardiopatía isquémica por presentar cambios electrocardiográficos propios de ella; se le diagnosticó una colecistitis aguda después de realizar un ultrasonido abdominal. Se indicó una colangiopancreatografía retrógrada endoscópica que demostró una colangitis aguda, sin litiasis en la vía biliar principal, y se le realizó una esfinterotomía endoscópica; se intervino de urgencia y se le efectuó una colecistectomía, posteriormente fue necesario repetir la colangiopancreatografía debido al íctero persistente y se confirmó la sospecha de colangitis esclerosante. El paciente llevó tratamiento con antibióticos (ampicillina) y esteroides, mejoró su estado general y fue egresado