Bettazzi Francesca, Laschi Serena, Mascini Marco
Università degli Studi di Firenze, Dipartimento di Chimica, Via della Lastruccia 3, 50019 Sesto Fiorentino, Firenze, Italy.
Anal Chim Acta. 2007 Apr 18;589(1):14-21. doi: 10.1016/j.aca.2007.02.062. Epub 2007 Mar 3.
Screen-printing technology offers the possibility to produce a large number of sensors at low cost. Thus, due to their intrinsic characteristics and reproducibility, screen-printed electrodes can be used in the development of disposable electrochemical devices. In the present work, carbon-based screen-printed electrodes (SPCEs) have been used to develop a one-shot-measure biosensor for the detection of photosynthetic inhibitors in discrete samples. The measurement was based on the electrochemical evaluation of the activity of photosystem II (PSII), a protein complex present in photosynthetic organisms and involved in the photosynthesis. The biosensor was prepared by the modification of the working electrode of a SPCE, using thylakoid membranes extracted from spinach leaves. The modified sensors were then used as one-shot system to measure the presence of PSII activity inhibitors in discrete standard solutions. The coupling of the developed biosensor with a custom-made cell made it possible to perform tests using only 50 microL of total sample volume with a measurement time of 10 min. Inhibition curves were recorded for some photosynthetic inhibitors in a concentration range of 10(-6) to 10(-8) molL(-1). A reproducibility (relative standard deviation, R.S.D.%) of 10% was found and the calculated limit of detections (LODs) were in the nanomolar range. The effect of storage on sensitivity and reproducibility of a biosensor prepared by direct lyophilisation of thylakoid membranes on the electrode surface was also evaluated, confirming the possible use of the modified sensor up to one week after the preparation. Measurements on real samples were also reported, comparing the results with those obtained using a fluorescence-based commercial instrument for the analysis of photosynthetic inhibitors.
丝网印刷技术提供了以低成本生产大量传感器的可能性。因此，由于其固有特性和可重复性，丝网印刷电极可用于一次性电化学装置的开发。在本工作中，基于碳的丝网印刷电极（SPCEs）已被用于开发一种一次性测量生物传感器，用于检测离散样品中的光合抑制剂。该测量基于对光合系统II（PSII）活性的电化学评估，PSII是光合生物中存在的一种蛋白质复合物，参与光合作用。通过使用从菠菜叶中提取的类囊体膜修饰SPCE的工作电极来制备生物传感器。然后将修饰后的传感器用作一次性系统，以测量离散标准溶液中PSII活性抑制剂的存在。将开发的生物传感器与定制的细胞相结合，使得仅使用50微升的总样品体积、测量时间为10分钟就可以进行测试。记录了一些光合抑制剂在10(-6)至10(-8)molL(-1)浓度范围内的抑制曲线。发现重现性（相对标准偏差，R.S.D.%）为10%，计算出的检测限（LODs）在纳摩尔范围内。还评估了通过直接冻干电极表面的类囊体膜制备的生物传感器的储存对其灵敏度和重现性的影响，证实了修饰后的传感器在制备后长达一周内仍可使用。还报告了对实际样品的测量结果，并将结果与使用基于荧光的商用仪器分析光合抑制剂所获得的结果进行了比较。
