López Manel, Frieiro Juan Luis, Nuez-Martínez Miquel, Pedemonte Martí, Palacio Francisco, Teixidor Francesc
Department of Electronics and Biomedical Engineering, Faculty of Physics, University of Barcelona, Martí i Franquès street 1, 08028 Barcelona, Spain.
Institute of Materials , ICMAB-CSIC, Campus UAB, 08193 Bellaterra, Spain.
Nanomaterials (Basel). 2020 Oct 5;10(10):1974. doi: 10.3390/nano10101974.
In this paper, we investigated how different growth conditions (i.e., temperature, growth time, and composition) allows for trading off cost (i.e., In content) and performance of nanostructured indium tin oxide (ITO) for biosensing applications. Next, we compared the behavior of these functionalized nanostructured surfaces obtained in different growth conditions between each other and with a standard thin film as a reference, observing improvements in effective detection area up to two orders of magnitude. This enhanced the biosensor's sensitivity, with higher detection level, better accuracy and higher reproducibility. Results show that below 150 °C, the growth of ITO over the substrate forms a homogenous layer without any kind of nanostructuration. In contrast, at temperatures higher than 150 °C, a two-phase temperature-dependent growth was observed. We concluded that (i) nanowire length grows exponentially with temperature (activation energy 356 meV) and leads to optimal conditions in terms of both electroactive surface area and sensitivity at around 300 °C, (ii) longer times of growth than 30 min lead to larger active areas and (iii) the In content in a nanostructured film can be reduced by 10%, obtaining performances equivalent to those found in commercial flat-film ITO electrodes. In summary, this work shows how to produce appropriate materials with optimized cost and performances for different applications in biosensing.
在本文中，我们研究了不同的生长条件（即温度、生长时间和成分）如何实现纳米结构氧化铟锡（ITO）在生物传感应用中的成本（即铟含量）与性能之间的权衡。接下来，我们比较了在不同生长条件下获得的这些功能化纳米结构表面之间以及与作为参考的标准薄膜之间的行为，观察到有效检测面积提高了两个数量级。这提高了生物传感器的灵敏度，具有更高的检测水平、更好的准确性和更高的重现性。结果表明，在150℃以下，ITO在衬底上的生长形成均匀层，没有任何纳米结构。相反，在高于150℃的温度下，观察到两相温度依赖性生长。我们得出结论：（i）纳米线长度随温度呈指数增长（激活能为356毫电子伏），并在约300℃时导致电活性表面积和灵敏度方面的最佳条件；（ii）生长时间超过30分钟会导致更大的活性面积；（iii）纳米结构薄膜中的铟含量可降低10%，获得与商业平面薄膜ITO电极相当的性能。总之，这项工作展示了如何生产具有优化成本和性能的合适材料，用于生物传感中的不同应用。
