Xu Yinchao, Stanko Allison M, Cerione Chloe S, Lohrey Trevor D, McLeod Euan, Stoltz Brian M, Su Judith
Wyant College of Optical Sciences, The University of Arizona, Tucson, Arizona 85721, United States.
Department of Biomedical Engineering, The University of Arizona, Tucson, Arizona 85721, United States.
ACS Appl Mater Interfaces. 2024 Jan 31;16(4):5120-5128. doi: 10.1021/acsami.3c16012. Epub 2024 Jan 19.
The nitric oxide radical plays pivotal roles in physiological as well as atmospheric contexts. Although the detection of dissolved nitric oxide in vivo has been widely explored, highly sensitive (i.e., low part-per-trillion level), selective, and humidity-resistant detection of gaseous nitric oxide in air remains challenging. In the field, humidity can have dramatic effects on the accuracy and selectivity of gas sensors, confounding data, and leading to overestimation of gas concentration. Highly selective and humidity-resistant gaseous NO sensors based on laser-induced graphene were recently reported, displaying a limit of detection (LOD) of 8.3 ppb. Although highly sensitive (LOD = 590 ppq) single-wall carbon nanotube NO sensors have been reported, these sensors lack selectivity and humidity resistance. In this report, we disclose a highly sensitive (LOD = 2.34 ppt), selective, and humidity-resistant nitric oxide sensor based on a whispering-gallery mode microtoroid optical resonator. Excellent analyte selectivity was enabled via novel ferrocene-containing polymeric coatings synthesized via reversible addition-fragmentation chain-transfer polymerization. Utilizing a frequency locked optical whispering evanescent resonator system, the microtoroid's real-time resonance frequency shift response to nitric oxide was tracked with subfemtometer resolution. The lowest concentration experimentally detected was 6.4 ppt, which is the lowest reported to date. Additionally, the performance of the sensor remained consistent across different humidity environments. Lastly, the impact of the chemical composition and molecular weight of the novel ferrocene-containing polymeric coatings on sensing performance was evaluated. We anticipate that our results will have impact on a wide variety of fields where NO sensing is important such as medical diagnostics through exhaled breath, determination of planetary habitability, climate change, air quality monitoring, and treating cardiovascular and neurological disorders.
一氧化氮自由基在生理环境和大气环境中都起着关键作用。尽管体内溶解一氧化氮的检测已得到广泛研究，但对空气中气态一氧化氮进行高灵敏度（即万亿分之一以下水平）、选择性和耐湿性检测仍然具有挑战性。在实际应用中，湿度会对气体传感器的准确性和选择性产生显著影响，干扰数据，并导致气体浓度的高估。最近报道了基于激光诱导石墨烯的高选择性和耐湿性气态一氧化氮传感器，其检测限（LOD）为8.3 ppb。尽管已报道了高灵敏度（LOD = 590 ppq）的单壁碳纳米管一氧化氮传感器，但这些传感器缺乏选择性和耐湿性。在本报告中，我们披露了一种基于回音壁模式微环光学谐振器的高灵敏度（LOD = 2.34 ppt）、选择性和耐湿性一氧化氮传感器。通过可逆加成-断裂链转移聚合合成的新型含二茂铁聚合物涂层实现了优异的分析物选择性。利用锁频光学回音消逝谐振器系统，以亚飞米分辨率跟踪微环对一氧化氮的实时共振频率偏移响应。实验检测到的最低浓度为6.4 ppt，这是迄今为止报道的最低浓度。此外，该传感器在不同湿度环境下的性能保持一致。最后，评估了新型含二茂铁聚合物涂层的化学成分和分子量对传感性能的影响。我们预计，我们的结果将对一氧化氮传感重要的广泛领域产生影响，例如通过呼气进行医学诊断、确定行星宜居性、气候变化、空气质量监测以及治疗心血管和神经系统疾病。
