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- Felini, Usisipho, et al.
(författare)
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Palladium telluride quantum dots and cytochrome P450 biosensor for the detection of breast cancer drug – tamoxifen.
- 2015
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Ingår i: <em>Sweden-Japan Seminar on Nanomaterials and Nanotechnology – SJS-Nano</em>, Linköping, Sweden, 10-11 March 2015.. - : Japan Society for the Promotion of Science (JSPS), Stockholm..
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Konferensbidrag (refereegranskat)abstract
- Tamoxifen is an oral non-steroidal anti-estrogen drug used in the prevention and treatment of all stages of breast cancer. This drug acts by competing with estrogen for binding to the estrogen receptor (ER) and reduces the transcription of estrogen dependent genes. However, approximately 30-50% of ER-positive breast cancer patients either fail to respond or eventually become resistant to tamoxifen resulting in a serious clinical challenge in breast cancer management. This, therefore, calls for new selective and sensitive methods for evaluating individual’s metabolic activities of the drug ensuring in this way reliable dosing of the drug. This paper presents a biosensor system based on the combination of thioglycolic acid-capped palladium telluride (TGA-PdTe) quantum dots (QDs) and cytochrome P450-3A4 or 2D6 (CYP3A4 or CYP2D6) enzymes for the determination of tamoxifen. Preliminary FTIR and UVs studies of the QDs confirmed the presence of the capping agent via the specific COOH and CH2 signature bands; furthermore the adsorption band at ca. 330 nm and the corresponding band gap energy, Eg, value is 3.47 eV (within the Eg value for QDs particles) confirmed the successful synthesis of the TGA-PdTe QDs. Differential pulse voltammetric (DPV) electroanalysis using the Au|Cyst|TGA-PdTeQDs|CYP3A4 (or CYP2D6) biosensor systems indicated a clear catalytic cathodic peak at -0.35 V for the tamoxifen biotransformation reaction; this signal was used, in this work, as the biosensor analytical response. The developed biosensor presented a limit of detection (LOD) of 0.98 and 2.5 ng/mL, for CYP3A4 and CYP2D6 based biosensors, respectively. These are lower than tamoxifen’s maximum steady state plasma concentration (Cmax 40 ng/L) value; these performances make the proposed biosensor a promising platform for monitoring the drug in patients.
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- Golabi, Mohsen, et al.
(författare)
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Modulated Smart Material Surfaces for Bacterial Differentiation.
- 2015
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Ingår i: <em>Sweden-Japan Seminar on Nanomaterials and Nanotechnology – SJS-Nano</em>, Linköping, Sweden, 10-11 March 2015.. - : Japan Society for the Promotion of Science (JSPS), Stockholm.. ; , s. 30-
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Konferensbidrag (refereegranskat)abstract
- A novel rapid method for bacterial differentiation is explored based on the specific adhesion pattern of bacterial strains to tunable polymer surfaces. These preliminary investigations lay the foundation for the development of an electronically tunable array of sensors that will provide patterns of information that feed into computational recognition algorithms to enable swift diffentiation of bacterial species. Different types of counter ions were used to electrochemically fabricate dissimilar polypyrrole (PPy) films with diverse physicochemical properties such as hydrophobicity, thickness and roughness. These were then modulated into three different oxidation states in each case. The dissimilar sets of conducting polymers were exposed to a number of different bacterial strains. Generally, the number of cells of a particular bacterial strain that adhered varied when exposed to dissimilar polymer surfaces, due to the effects of the surface properties of the polymer on bacterial attachment. Similarly, the number of cells that adhered varied with different bacterial strains exposed to the same surface, reflecting the different surface properties of the bacteria. Five different bacterial strains, Deinococcus proteolyticus, Serratia marcescens, Pseudomonas fluorescens, Alcaligenes faecalis and Staphylococcus epidermidis, were seeded onto various PPy surfaces. By analysis of the fluorescent microscope images, the number of bacterial cell adhered to each surface were evaluated. Principal Component Analysis showed that all had their own specific adhesion pattern with respect to the set of applied PPy areas. Hence, these strains could be discriminated by this simple, label-free method. In summary, this provides a proof-of-concept for using specific adhesion properties of bacterial strains in conjunction with tunable polymer arrays and pattern recognition as a method for rapid bacterial identification in situ.
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- Golabi, Mohsen, et al.
(författare)
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Polymer Arrays as a Novel Bio-sensing Method for Bacterial Detection
- 2014
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Ingår i: 24<sup>th </sup>Anniversary World Congress on Biosensors – Biosensors 2014. - : Elsevier.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- A novel and cost-effective recognition method for rapid bacterial detection is reported. Rapid bacterial detection is a challenge for the food and pharmaceutical industries as well as in clinical diagnostics. There is a great necessity for replacement of conventional detection methods by new rapid alternatives. Identifying microorganisms based on their specific adhesive properties to different surfaces could lead to a fast diagnostic and novel bacterial detection tool. An array of conducting polymers, which have diverse physicochemical properties like hydrophobicity, thickness and roughness, have been designed and developed for use as the recognition element in a bacterial biosensor that can distinguish bacterial strains. Electrochemically synthesised polypyrrole was doped with different counter ions in order to fabricate bacterial recognition elements. Mid-exponential phase bacterial cells were exposed to the polymers for a fixed time and the adhering cells were stained by ethidium bromide and counted using a fluorescent microscope. The results show both that the number of adhesive bacterial cells of E. coli on each polymer surface is different and that this adhesive pattern is unique for the bacterial strains tested: A. faecalis and D. proteolyticus, show different adhesive patterns in similar experiments. The results showed that with only a few different polymers, it was possible to reliably discriminate an E. coli strain from three other bacterial strains. This forms the basis for an array-type device comprising a variety of dissimilar polymers to differentiate a broad range of bacterial strains. We expect the array, in combination with an appropriate transducer and pattern-recognition software, to provide a convenient and inexpensive biosensing device able to rapidly and specifically detect bacterial strains and also to have potential applications in whole-cell biosensors.
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