title: Evaluation of different strategies for the development of amperometric biosensors for L-lactate.
abstract: Two strategies were investigated for the development of lactate biosensors based on sol-gel matrixes and polysulfone composite films, both containing L-lactate dehydrogenase (LDH). Firstly, reagentless disposable screen-printed electrodes (SPE's) with Meldola's Blue (MB) and the cofactor NAD(+) inside a sol-gel matrix were prepared. These showed relatively low sensitivities (260 microA/M). Secondly, mediator-modified-polysulfone-graphite composite films deposited over both cylindrical epoxy-graphite and SPE's. These electrodes showed enhanced performance characteristics: improved sensitivity (80 mA/M), detection limit (0.87 microM) and reproducibility (2%). Reagentless electrodes, incorporating NAD(+) in the polysulfone film, had a decreased sensitivity, although better than that achieved by the sol-gel electrodes. While sol-gel electrodes showed a linear range between 1.25 x 10(-4) and 2.48 x 10(-3)M, the epoxy-graphite composite electrodes based on polysulfone composite films allowed the detection of lactate at a linear range of lower concentrations from 1 x 10(-6) to 1.2 x 10(-5)M. Finally, the performance of the LDH-MB-polysulfone-composite film-based SPE's in a flow system was studied. Short response times were obtained (t<30s). Furthermore, repeatability and reproducibility values were notably improved, especially when working with electrodes covered with a polyamide layer prepared with N-(2-aminoethyl)-piperazine.
authors.affiliation: Grup de Sensors i Biosensors, Departament de Química, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain. beatriz.prieto-simon@univ-perp.fr <beatriz.prieto-simon@univ-perp.fr>
authors.forename: Beatriz
authors.initials: B
authors.lastname: Prieto-Simón
authors.forename: Esteve
authors.initials: E
authors.lastname: Fàbregas
authors.forename: Alan
authors.initials: A
authors.lastname: Hart
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D020099:Coated Materials, Biocompatible; D004563:Electrochemistry / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007770:L-Lactate Dehydrogenase / Q000737:chemistry*; D019344:Lactic Acid / Q000032:analysis* / Q000737:chemistry; D008839:Microelectrodes; D011108:Polymers / Q000737:chemistry*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013450:Sulfones / Q000737:chemistry*
chemical_list: D020099:Coated Materials, Biocompatible; D011108:Polymers; D013450:Sulfones; C017662:polysulfone P 1700; D019344:Lactic Acid; D007770:L-Lactate Dehydrogenase