| 1. |
- Jiang, TS, et al.
(författare)
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Detection of TP53 mutation using a portable surface plasmon resonance DNA-based biosensor
- 2005
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Ingår i: Biosensors & bioelectronics. - : Elsevier Science B.V., Amsterdam.. - 0956-5663 .- 1873-4235. ; 20:10, s. 1939-1945
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Tidskriftsartikel (refereegranskat)abstract
- 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. (c) 2004 Elsevier B.V. All rights reserved.
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| 2. |
- Lotierzo, M, et al.
(författare)
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Surface plasmon resonance sensor for domoic acid based on grafted imprinted polymer
- 2004
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Ingår i: Biosensors & bioelectronics. - : Elsevier Science B.V., Amsterdam.. - 0956-5663 .- 1873-4235. ; 20:2, s. 145-152
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Tidskriftsartikel (refereegranskat)abstract
- A molecularly imprinted polymer (MIP) film for domoic acid (DA) was synthesised by direct photo-grafting onto a gold chip suitable for a surface plasmon resonance (SPR) based bioanalytical instrument system, the BlAcore 3000(TM). The gold surface was first functionalised with a self-assembled monolayer of 2-mercaptoethylamine and subsequent carbodiimide chemistry was performed for covalent attachment of the photoinitiator, 4,4-azobis(cyanovaleric acid). This ensured that the formation of the MIP thin film, comprising 2-(diethyl amino) ethyl methacrylate as functional monomer and ethylene glycol dimethacrylate as cross-linker, occurred only at the surface level. Optimisation and control over the grafting procedure were achieved using contact angle measurements and atomic force microscope (AFM) imaging. The surface grafting resulted in the formation of thin and homogeneous MIP film with thickness of 40 nm. A competitive binding assay was performed with free DA and its conjugate with horseradish peroxidase, which was used as a refractive label. The sensor was evaluated for its sensitivity, cross-reactivity, and robustness by using a BlAcore 3000(TM). Likewise, monoclonal antibodies acting as natural receptors for the toxin were studied with the same BlAcore system. Results of a comparison between the artificial and natural receptors are reported. In contrast to monoclonal antibodies, the regeneration of MIP chip did not affect its recognition properties and continuous measurement was possible over a period of at least 2 months. (C) 2004 Elsevier B.V. All rights reserved.
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| 3. |
- Palchetti, I, et al.
(författare)
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Determination of anticholinesterase pesticides in real samples using a disposable biosensor
- 1997
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Ingår i: Analytica Chimica Acta. - : Elsevier Science B.V., Amsterdam.. - 0003-2670 .- 1873-4324. ; 337:3, s. 315-321
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Tidskriftsartikel (refereegranskat)abstract
- A choline amperometric biosensor based on screen-printed electrodes was assembled and used to assess the inhibitory effect of organophosphorus and carbamic pesticides on acetylcholinesterase activity both in standard solutions and real samples, Acetylcholinesterase catalyses the cleavage of acetylcholine to choline and acetate, therefore the amount of choline measured using the biosensor is directly related to the enzyme activity. The extent of enzyme inhibition can be used as an index of the amount of anticholinesterase pesticides present. The hydrophobicity of organophosphorus and carbamic pesticides led to the evaluation of organic, water miscible solvents for use in the proposed method. Berate buffer containing 1% v/v acetonitrile was selected since it exhibited the least influence on enzyme activity from the tested solvents (acetonitrile, acetone, tetrahydrofuran and ethylacetate). Other solvents (dimethylsulfoxide and methanol) were avoided as they exhibited electrochemical interferences. An inhibition calibration curve was obtained using carbofuran, a strong inhibitor of acetylcholinesterase. The lowest detectable standard solution (mean +/-3 standard deviation of the blank) was 2 mu gl(-1) following an incubation time of 10 min. The method was then applied to real samples (fruits and vegetables) showing its suitability as a rapid screening assay (12 min per test) for the assessment of anticholinesterase pesticides, The biosensor results were compared with a standard analytical technique (gas chromatography with nitrogen phosphorus detector, GC-NPD).
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| 4. |
- ALCOCK, SJ, et al.
(författare)
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THE DESIGN AND DEVELOPMENT OF NEW CHEMICAL SENSORS FOR INVIVO MONITORING
- 1991
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Ingår i: Biosensors & bioelectronics. - : Elsevier Science B.V., Amsterdam.. - 0956-5663 .- 1873-4235. ; 6:8, s. 647-652
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Tidskriftsartikel (refereegranskat)abstract
- The latest workshop of the European Community (EC) Concerted Action on Chemical sensors for in vivo monitoring was held in Nauplion, Greece, in April this year. This fifth workshop focused on The design and development of new sensors for in vivo monitoring, and was organized into five sessions: design and development of new sensors; operational considerations; performance of analytical systems; novel sensors/tissue heterogeneity; and infra-red spectroscopy.
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| 5. |
- CAGNINI, A, et al.
(författare)
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DISPOSABLE RUTHENIZED SCREEN-PRINTED BIOSENSORS FOR PESTICIDES MONITORING
- 1995
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Ingår i: Sensors and actuators. B, Chemical. - : Elsevier Science B.V., Amsterdam.. - 0925-4005 .- 1873-3077. ; 24:03-jan, s. 85-89
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Tidskriftsartikel (refereegranskat)abstract
- A disposable choline biosensor based on ruthenized carbon screen-printed electrodes has been prepared and its use for monitoring organophosphorus pesticides and carbamates is described. The presence of 0.5% ruthenium on activated carbon mixed to form a simple graphite-based ink for the working electrode surface increased the sensitivity towards hydrogen peroxide. The choline biosensor is based on such an electrode coupled with choline oxidase immobilized by adsorption. The inhibition effect of carbamates and organophosphorus pesticides on acetylcholinesterase was detected using this biosensor. With the optimized procedure described (pH, buffer composition, incubation time, substrate concentration) we are able to detect concentrations of pesticides (carbofuran) as low as 1 nM.
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| 6. |
- Cagnini, A, et al.
(författare)
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Ruthenized screen-printed choline oxidase-based biosensors for measurement of anticholinesterase activity
- 1995
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Ingår i: Microchimica Acta. - : Springer Science Business Media. - 0026-3672 .- 1436-5073. ; 121:04-jan, s. 155-166
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Tidskriftsartikel (refereegranskat)abstract
- Plastic disposable choline biosensors based on ruthenized-carbon screen-printed electrodes were prepared and their use for monitoring organophosphorus pesticides and carbamates is described. The presence of 0.5% ruthenium on activated carbon mixed to form a simple graphite-based ink for the working electrode surface increased the sensitivity towards hydrogen peroxide. The choline biosensor is based on such an electrode coupled with choline oxidase immobilized by adsorption and was used to detect the inhibition effect of carbamates and organophosphorus pesticides on acetylcholinesterase. With the optimized procedure described (pH, buffer composition, incubation time, substrate concentration), concentrations of pesticides (Carbofuran) as low as 1 nM could be detected.
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| 7. |
- Chianella, I, et al.
(författare)
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Rational design of a polymer specific for microcystin-LR using a computational approach
- 2002
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Ingår i: Analytical Chemistry. - : ACS American Chemical Society. - 0003-2700 .- 1520-6882. ; 74:6, s. 1288-1293
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Tidskriftsartikel (refereegranskat)abstract
- A computational approach for the design of a molecularly imprinted polymer (MIP) specific for Cyanobacterial toxin microcystin-LR is presented. By using molecular modeling software, a virtual library of functional monomers was designed and screened against the target toxin, employed as a template. The monomers giving the highest binding energy were selected and used in a simulated annealing (molecular dynamics) process to investigate their interaction with the template. The stoichiomettic ratio observed from the simulated annealing study was used in MIP preparation for microcystin-LR. The monomers were copolymerized with a cross-linker in the presence of the template. A control (blank) polymer was prepared under the same conditions but in the absence of template. A competitive assay with microcystin-horseradish peroxidase conjugate was optimized and used to evaluate the affinity and cross-reactivity of the polymer. The performance of the artificial receptor was compared to the performance of monoclonal and polyclonal antibodies raised against the toxin. The results indicate that imprinted polymer has affinity and sensitivity comparable to those of polyclonal antibodies (die detection limit for microcystin-LR using the MIP-based assay was found to be 0.1 mug L-1), while superior chemical and thermal stabilities were obtained. Moreover, cross-reactivity to other toxin analogues was very low for the imprinted polymer, in contrast to the results achieved for antibodies. It is anticipated that the polymer designed could be used in assays, sensors, and solid-phase extraction.
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| 8. |
- Lucarelli, F, et al.
(författare)
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Carbon and gold electrodes as electrochemical transducers for DNA hybridisation sensors
- 2004
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Ingår i: Biosensors & bioelectronics. - : Elsevier Science B.V., Amsterdam.. - 0956-5663 .- 1873-4235. ; 19:6, s. 515-530
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Forskningsöversikt (refereegranskat)abstract
- Genosensor technology relying on the use of carbon and gold electrodes is reviewed. The key steps of each analytical procedure, namely DNA-probe immobilisation, hybridisation, labelling and electrochemical investigation of the surface, are discussed in detail with separate sections devoted to label-free and newly emerging magnetic assays. Special emphasis has been given to protocols that have been used with real DNA samples. (C) 2003 Elsevier B.V. All fights reserved.
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| 9. |
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| 10. |
- Meglinski, IV, et al.
(författare)
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Laser ice scaffolds modeling for tissue engineering
- 2005
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Ingår i: LASER PHYSICS LETTERS. - : John Wiley andamp;amp; Sons, Ltd. - 1612-2011 .- 1612-202X. ; 2:9, s. 465-467
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Tidskriftsartikel (refereegranskat)abstract
- Tissue engineering is one of the most exciting and rapidly growing areas in biomedical engineering that offers vast potential for changing traditional approaches to meeting many pharmaceutics and critical health care needs. Currently the bottle-neck area in this multidisciplmiary field appears to be materials and fabrication technology for the design of artificial extracellular matrices/scaffolds that support culturing and growth of new tissue. We have shown that stable relief structures can be created and maintained in the bulk of ice by continuous s canning with computer-guided IR CO2 laser. The optimal laser beam intensity and fluence rate distribution within the ice sample, as well as the rate of scanning were estimated based on the Monte Carlo model utilized physical/optical properties of ice. The results of numerical simulation are agreed well with the observed experimental results of thermo-coupling measurements and obtained microscopic images.
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