Department of Mechanical Engineering , Iowa State University , Ames , Iowa 50011 , United States.
Center for Bio/Molecular Science and Engineering , Code 6900, U. S. Naval Research Laboratory , Washington, D.C. 20375 , United States.
ACS Appl Mater Interfaces. 2018 Apr 4;10(13):11125-11134. doi: 10.1021/acsami.7b19763. Epub 2018 Mar 22.
Solution phase printing of graphene-based electrodes has recently become an attractive low-cost, scalable manufacturing technique to create in-field electrochemical biosensors. Here, we report a graphene-based electrode developed via inkjet maskless lithography (IML) for the direct and rapid monitoring of triple-O linked phosphonate organophosphates (OPs); these constitute the active compounds found in chemical warfare agents and pesticides that exhibit acute toxicity as well as long-term pollution to soils and waterways. The IML-printed graphene electrode is nano/microstructured with a 1000 mW benchtop laser engraver and electrochemically deposited platinum nanoparticles (dia. ∼25 nm) to improve its electrical conductivity (sheet resistance decreased from ∼10 000 to 100 Ω/sq), surface area, and electroactive nature for subsequent enzyme functionalization and biosensing. The enzyme phosphotriesterase (PTE) was conjugated to the electrode surface via glutaraldehyde cross-linking. The resulting biosensor was able to rapidly measure (5 s response time) the insecticide paraoxon (a model OP) with a low detection limit (3 nM), and high sensitivity (370 nA/μM) with negligible interference from similar nerve agents. Moreover, the biosensor exhibited high reusability (average of 0.3% decrease in sensitivity per sensing event), stability (90% anodic current signal retention over 1000 s), longevity (70% retained sensitivity after 8 weeks), and the ability to selectively sense OP in actual soil and water samples. Hence, this work presents a scalable printed graphene manufacturing technique that can be used to create OP biosensors that are suitable for in-field applications as well as, more generally, for low-cost biosensor test strips that could be incorporated into wearable or disposable sensing paradigms.
基于石墨烯的电极的溶液相印刷最近成为一种有吸引力的低成本、可扩展的制造技术，可用于制造现场电化学生物传感器。在这里，我们报告了一种通过喷墨无掩模光刻（IML）开发的基于石墨烯的电极，用于直接和快速监测三-O 连接的膦酸酯有机磷化合物（OPs）；这些化合物是化学战剂和农药中的活性化合物，具有急性毒性以及对土壤和水道的长期污染。IML 打印的石墨烯电极具有纳米/微结构，使用 1000 mW 台式激光雕刻机和电化学沉积的铂纳米颗粒（直径约 25nm）进行修饰，以提高其导电性（片电阻从约 10000 降低至 100 Ω/sq）、表面积和电活性，从而进行后续酶功能化和生物传感。酶磷酸三酯酶（PTE）通过戊二醛交联连接到电极表面。所得生物传感器能够快速测量（5s 响应时间）杀虫剂对氧磷（一种模型 OP），检测限低（3 nM），灵敏度高（370 nA/μM），类似神经毒剂的干扰可忽略不计。此外，该生物传感器表现出高可重复性（每次检测事件灵敏度平均下降 0.3%）、稳定性（1000s 内阳极电流信号保留 90%）、长寿命（8 周后保留 70%的灵敏度）以及选择性感应实际土壤和水样中的 OP 的能力。因此，这项工作提出了一种可扩展的印刷石墨烯制造技术，可用于制造 OP 生物传感器，该传感器适用于现场应用，更普遍地说，适用于可集成到可穿戴或一次性传感模式中的低成本生物传感器测试条。
