Graduate School of Systems Life Sciences, Kyushu University, Fukuoka 819-0395, Japan.
Graduate School of Information Science and Electrical Engineering, Kyushu University, Fukuoka 819-0395, Japan.
ACS Sens. 2022 Jul 22;7(7):1819-1828. doi: 10.1021/acssensors.2c00093. Epub 2022 Jun 22.
The fabrication of chemiresistive sensors by inkjet printing is recognized as a breakthrough in gas-sensing applications. One challenge of this technology, however, is how to enhance the cross-selectivity of the sensor array. Herein, we present a ketjen black (KB) ink and molecularly imprinted sol-gel (MISG) inks to support the fabrication of a fully inkjet-printed chemiresistive sensor array, enabling the highly accurate recognition of volatile organic acids (VOAs) on the molecular level. The MISG/KB sensor array was prepared on a glossy photographic paper with a three-layer structure: a circuit layer by a commercial silver ink, a conductive layer by a KB ink, and an active selective layer by MISG inks imprinted by different templates. Hexanoic acid (HA), heptanoic acid, and octanoic acid were used as templates to prepare the MISGs and as targets to evaluate the detection and discrimination performance of the sensor array. Three resultant MISG/KB sensors exhibited high sensitivity and selectivity to VOA vapors. The limit of detection and imprinting factor were 0.018 ppm and 7.82, respectively, for HA-MISG/KB sensors to the corresponding target. With linear discriminant analysis of the gas responses, the MISG/KB sensor array can realize high discrimination to VOAs in single and binary mixtures. Furthermore, the proposed sensor array showed strong sensor robustness with excellent consistency, durability, bending, and humidity resistance. This work developed a fully inkjet-printed chemiresistive sensor array, enabling the realization of high cross-selectivity detection, achieving low-cost, scalable, and highly reproducible sensor fabrication, moving it closer to reliable, commercial, and wearable multi-analyte human body odor analysis potential.
喷墨打印制备的电阻式传感器在气体传感应用中被认为是一项突破。然而，这项技术面临的一个挑战是如何提高传感器阵列的交叉选择性。在此，我们提出了一种使用凯夫拉（KB）墨水和分子印迹溶胶-凝胶（MISG）墨水的方案，以支持全喷墨打印的电阻式传感器阵列的制造，从而能够在分子水平上实现对挥发性有机酸（VOA）的高精度识别。MISG/KB 传感器阵列是在光泽相纸上制备的，具有三层结构：由商业银墨制成的电路层、由 KB 墨水制成的导电层和由不同模板印迹的 MISG 墨水制成的活性选择性层。己酸（HA）、庚酸和辛酸被用作模板来制备 MISG，并作为目标来评估传感器阵列的检测和区分性能。三个所得的 MISG/KB 传感器对 VOA 蒸气表现出高灵敏度和选择性。对于 HA-MISG/KB 传感器，对相应目标的检测限和印迹因子分别为 0.018 ppm 和 7.82。通过对气体响应的线性判别分析，MISG/KB 传感器阵列可以实现对单一组分和二元混合物中 VOAs 的高区分。此外，所提出的传感器阵列具有出色的一致性、耐用性、弯曲和耐湿性，表现出强大的传感器稳健性。这项工作开发了一种全喷墨打印的电阻式传感器阵列，实现了高交叉选择性检测，具有低成本、可扩展和高度可重复的传感器制造能力，使其更接近可靠、商业化和可穿戴的多分析物人体气味分析的潜力。
