Chemiresistors that are based on monolayer-capped metal nanoparticles (MCNPs) have been used in a wide variety of innovative sensing applications, including detection and monitoring of diagnostic markers in body fluids, explosive materials, environmental contaminations and food quality control. The sensing mechanism is based on reversible swelling or aggregation and/or changes in dielectric constant of the MCNPs. In this protocol, we describe a procedure for producing MCNP-based chemiresistive sensors that is reproducible from device to device and from batch to batch. The approach relies on three main steps: (i) controlled synthesis of gold MCNPs, (ii) fabrication of electrodes that are surrounded with a microbarrier ring to confine the deposited MCNP solution and (iii) a tailor-made drying process to enable evaporation of solvent residues from the MCNP sensing layer to prevent a coffee-ring effect. Application of this approach has been shown to produce devices with ±1.5% variance—a value consistent with the criterion for commercial sensors—as well as long shelf life and stability. Fabrication of chemical sensors based on dodecanethiol- or 2-ethylhexanethiol-capped MCNPs with this approach provides high sensitivity and accuracy in the detection of volatile organic compounds (e.g., octane and decane), toxic gaseous species (e.g., HCl and NH₃) in air and simulated mixtures of lung and gastric cancer from exhaled breath.

基于单层封端金属纳米粒子 (MCNP) 的化学电阻器已用于各种创新传感应用，包括检测和监测体液、爆炸材料、环境污染和食品质量控制中的诊断标志物。传感机制基于 MCNPs 的可逆溶胀或聚集和/或介电常数的变化。在本协议中，我们描述了一种生产基于 MCNP 的化学电阻传感器的过程，该传感器可从设备到设备以及从批次到批次进行重现。该方法依赖于三个主要步骤：（i）金 MCNP 的受控合成，(ii) 制造被微屏障环包围的电极以限制沉积的 MCNP 溶液和 (iii) 定制的干燥过程，以使溶剂残留物从 MCNP 传感层蒸发，以防止咖啡环效应。这种方法的应用已被证明可以生产出具有 ±1.5% 差异的设备——这个值与商业传感器的标准一致——以及长的保质期和稳定性。使用这种方法制造基于十二烷硫醇或 2-乙基己硫醇封端的 MCNP 的化学传感器在检测挥发性有机化合物（例如辛烷和癸烷）、有毒气体物质（例如 HCl 和 NH）时具有高灵敏度和准确度 5% 的方差——与商业传感器标准一致的值——以及长保质期和稳定性。使用这种方法制造基于十二烷硫醇或 2-乙基己硫醇封端的 MCNP 的化学传感器在检测挥发性有机化合物（例如辛烷和癸烷）、有毒气体物质（例如 HCl 和 NH）时具有高灵敏度和准确度 5% 的方差——与商业传感器标准一致的值——以及长保质期和稳定性。使用这种方法制造基于十二烷硫醇或 2-乙基己硫醇封端的 MCNP 的化学传感器在检测挥发性有机化合物（例如辛烷和癸烷）、有毒气体物质（例如 HCl 和 NH）时具有高灵敏度和准确度₃）在空气和模拟混合气中的肺癌和胃癌的呼出气。