Evaluation of different strategies for the development of amperometric biosensors for l-lactate

• Published in: Biosensors & bioelectronics 2007-05, Vol.22 (11), p.2663-2668
• Main Authors: Prieto-Simón, Beatriz, Fàbregas, Esteve, Hart, Alan
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Biosensing Techniques - instrumentation; Biosensing Techniques - methods; Biotechnology; Coated Materials, Biocompatible; Electrochemistry - instrumentation; Electrochemistry - methods; Equipment Design; Equipment Failure Analysis; Fundamental and applied biological sciences. Psychology; L-Lactate Dehydrogenase - chemistry; l-Lactate dehydrogenase-based biosensors; Lactic Acid - analysis; Lactic Acid - chemistry; Microelectrodes; Polymers - chemistry; Polysulfone and redox mediators; Reproducibility of Results; Sensitivity and Specificity; Sol–gel; Sulfones - chemistry
• ISSN: 0956-5663; 1873-4235
• DOI: 10.1016/j.bios.2006.10.034

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 μA/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 μM) 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 × 10 −4 and 2.48 × 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 × 10 −6 to 1.2 × 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 < 30 s). Furthermore, repeatability and reproducibility values were notably improved, especially when working with electrodes covered with a polyamide layer prepared with N-(2-aminoethyl)-piperazine.