Visual volumetric chips based on gas-generating reactions can potentially be applied to instrument-free point-of-care testing (POCT). However, the structures of conventional chips and their detection methods are typically complicated due to two technical issues: (1) ink, as a distance marker, must be injected into a specified position before sample introduction, and (2) the gas-generating reaction must be initiated in a sealed state. In this study, an inkless volumetric chip operated with a micropipette was developed. The volumetric chip consisted of a reaction well (R well), a substrate well (S well) containing a H₂O₂ solution as an O₂ generator, and a channel connecting the upper side of the R well and the lower side of the S well. Sample injection into the R well is followed by the insertion of a micropipette that is used to exert a negative pressure, which subsequently drives the transfer of a large portion of the H₂O₂ solution to the R well to initiate the gas-generating reaction. Meanwhile, a small portion of the H₂O₂ solution remains in the channel for use as a distance marker. The performance of the volumetric chip was evaluated by detecting Salmonella typhimurium, affording a limit of detection of 10 CFU within 20 min for culture samples and within 75 min for spiked milk samples. The volumetric chip developed herein is advantageous for POCT applications due to its simple structure and detection process.

基于气体生成反应的可视体积芯片可潜在地应用于无仪器即时检验（POCT）。然而，由于两个技术问题，常规芯片的结构及其检测方法通常很复杂：（1）作为距离标记的墨水必须在样品引入之前注入到指定位置，以及（2）发生气体的反应必须在密封状态下启动。在这项研究中，开发了一种用微量移液器操作的无墨体积芯片。体积芯片由反应孔（R孔），包含H ₂ O ₂溶液作为O ₂的底物孔（S孔）组成发生器，以及连接R井的上侧和S井的下侧的通道。样品注入R井后，插入用于施加负压的微量移液器，该吸管随后驱动大部分H ₂ O ₂溶液向R井的转移，从而引发气体生成反应。同时，一小部分的H ₂ O ₂溶液保留在通道中，用作距离标记。通过检测鼠伤寒沙门氏菌评估容量芯片的性能，对于培养样品，在20分钟之内提供了10 CFU的检测限；对于加标牛奶样品，在75分钟内提供了10 CFU的检测限。本文开发的体积芯片由于其简单的结构和检测过程而对POCT应用具有优势。