Touloupakis E.,National Research Council Italy |
Touloupakis E.,Biosensor srl |
Boutopoulos C.,National Technical University of Athens |
Buonasera K.,National Research Council Italy |
And 2 more authors.
Analytical and Bioanalytical Chemistry | Year: 2012
One of the limits of current electrochemical biosensors is a lack of methods providing stable and highly efficient junctions between biomaterial and solid-state devices. This paper shows how laser-induced forward transfer (LIFT) can enable efficient electron transfer from photosynthetic biomaterial immobilized on screen-printed electrodes (SPE). The ideal pattern, in terms of photocurrent signal of thylakoid droplets giving a stable response signal with a current intensity of approximately 335∈±∈13 nA for a thylakoid mass of 28∈±∈4 ng, was selected. It is shown that the efficiency of energy production of a photosynthetic system can be strongly enhanced by the LIFT process, as demonstrated by use of the technique to construct an efficient and sensitive photosynthesis-based biosensor for detecting herbicides at nanomolar concentrations. © 2012 Springer-Verlag.
Lavecchia T.,Biosensor srl
Advances in Experimental Medicine and Biology | Year: 2010
The importance of safety and functionality analysis of foodstuffs and raw materials is supported by national legislations and European Union (EU) directives concerning not only the amount of residues of pollutants and pathogens but also the activity and content of food additives and the health claims stated on their labels. In addition, consumers' awareness of the impact of 'functional foods' on their well-being and their desire for daily healthcare without the intake pharmaceuticals has immensely in recent years. Within this picture, the availability of fast, reliable, low cost control systems to measure the content and the quality of food additives and nutrients with health claims becomes mandatory, to be used by producers, consumers and the governmental bodies in charge of the legal supervision of such matters. This review aims at describing the most important methods and tools used for food analysis, starting with the classical methods (e.g., gas-chromatography GC, high performance liquid chromatography HPLC) and moving to the use of biosensors-novel biological material-based equipments. Four types of biosensors, among others, the novel photosynthetic proteins-based devices which are more promising and common in food analysis applications, are reviewed. A particular highlight on biosensors for the emerging market of functional foods is given and the most widely applied functional components are reviewed with a comprehensive analysis of papers published in the last three years; this report discusses recent trends for sensitive, fast, repeatable and cheap measurements, focused on the detection of vitamins, folate (folic acid), zinc (Zn), iron (Fe), calcium (Ca), fatty acids (in particular Omega 3), phytosterols and phytochemicals. A final market overview emphasizes some practical aspects of biosensor applications. © 2010 Landes Bioscience and Springer Science+Business Media, LLC.
Penu R.,Romanian National Institute for Research and Development for Biological Sciences |
Penu R.,Polytechnic University of Bucharest |
Litescu S.C.,Romanian National Institute for Research and Development for Biological Sciences |
Eremia S.A.V.,Romanian National Institute for Research and Development for Biological Sciences |
And 5 more authors.
New Journal of Chemistry | Year: 2015
An optimized electrochemical sensor was developed to assess the antioxidant capacity of carotenoids, accumulating during the life cycle of Haematococcus pluvialis cell cultures. The sensor was improved with a composite renewable surface made of immobilised phosphatidylcholine (PC) on magnetic nanobeads of iron oxide (Fe3O4) and PC/Fe3O4, and it was used to monitor the antioxidant properties of the ketocarotenoid astaxanthin against in situ generated phosphatidylcholine lipoperoxides. The surface configuration was able to mimic the natural position and orientation of astaxanthin in the cellular membrane, conferring to the whole experimental set-up good sensitivity for reactive oxygen species (limit of detection for peroxyl radicals 9.1 × 10-10 mol L-1) with a linear response ranging between 10-8 and 1.6 × 10-6 mol L-1. The sensor has been proved suitable for both batch and flow measurements. The accuracy of the flow measurements was unaffected by the magnetic field intensity. Electrochemical measurements confirmed that natural astaxanthin is a more effective antioxidant than synthetic astaxanthin, vitamin E and lutein and the protective effect of astaxanthin correlates with its concentration inside the cell. The newly developed sensor is hence useable for in-line monitoring of whole-cell based industrial bioprocesses for the production of astaxanthin. © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2015.
Husu I.,CNR Institute of Neuroscience |
Husu I.,Biosensor srl |
Rodio G.,CNR Institute of Neuroscience |
Touloupakis E.,University of Crete |
And 5 more authors.
Sensors and Actuators, B: Chemical | Year: 2013
The unicellular green alga Chlamydomonas reinhardtii was exploited as bio-sensing element for the construction of an electrochemical whole-cell based biosensor to detect herbicides in water samples. To preserve the algal photosynthetic functionality, C. reinhardtii cells were entrapped in an alginate gel directly onto the surface of commercial screen-printed electrodes. Cyclic voltammetry (CV) measurements indicated the higher performance of screen-printed carbon nanotube electrodes compared to graphite and gold as working materials. Moreover, it provided insights into the electrochemical reactions occurring at the electrode/algal cells interface, and indicated the optimum buffer pH (pH 7.0) and potential values -(0.7 ± 0.03) V vs. Ag/AgCl reference electrode to maximize current signals in chronoamperometry (CA) experiments. Electrodes with different number of cells and related chlorophyll content were tested by CA to optimize the electrochemical signal in terms of peak current intensity and signal to noise ratio. The oxygen reduction signal originated from the algal activity in response to red LEDs light exposure was monitored by amperometry, and the bio-sensing element response was expressed as a ratio between the current intensities registered in the absence and in the presence of herbicides. As competitive inhibitors of the plastoquinone (QB) binding to the reaction centre D1 protein, triazine and urea-type herbicides block the photosynthetic electron transport leading to a reduction of the biosensor output currents in a concentration-dependent manner. For linuron and simazine the limits of detection were 6 × 10-9 and 9 × 10-8 M, respectively, while the inhibition constant values (I50) were (1.2 ± 0.1) × 10-7 and (2.3 ± 0.2) × 10-6 M. The operational half-life of the bio-recognition element lasted approximately 9 h, while room temperature storage stability tests indicated a 2 and 24% signal loss after 3 and 20 days, respectively. The inhibition of the biosensor photosynthetic activity was irreversible at low herbicide concentrations, and highly reversible at medium-high doses. These results were discussed considering the presence in the Photosystem II pigment-protein complex of two herbicide binding niches with different binding affinities. Beyond introducing a promising prototype for commercial applications, this research shed light on current functional issues related to the not yet fully explored plastoquinone/herbicide binding site. © 2013 Elsevier B.V. All rights reserved.
Cano J.B.,University of Antioquia |
Buonasera K.,CNR Institute of Crystallography |
Pezzotti G.,Biosensor srl
Revista Facultad de Ingenieria | Year: 2014
Biosensor devices have applications in a variety of fields as environmental analysis, biomedical, bio-defense, food and agriculture. On this kind of sensors, a biological material (known as biomediator) reacts with target analytes and an appropriated transduction system converts that reaction to an electrical signal that can be processed, saved and transmitted by using electronic systems. In this article, two transduction methods used for biosensing applications are described: amperometry that is based on the measurement of the electron transfer occurring inside the biomediator and fluorescence, that is based on the measurement of the re-emitted light. Emphasis has been done on the electronics design, including component selection, useful circuit topologies and common problems and solutions. Electronics has been validated for the development of biosensor-based instruments characterized by low production costs and portability.