Nonelectric syringe pump capable of programmable sequential reagent injection for automated microfluidic device operation

Abstract

Microfluidic technology has driven significant progress in clinical diagnostics and point-of-care testing (POCT), with ongoing research investigating its diverse applications. However, a key limitation of microfluidic systems lies in the need for devices and methods to propel the liquids. In this study, we developed a programmable, nonelectric syringe pump capable of delivering multiple reagents to microfluidic devices in a sequential manner. A modular sector gear was designed to selectively cover portions of the gear with teeth, enabling precise and versatile control over the pumping timing. Considering the capabilities and characteristics of the pump, it is named Sequence Modifiable, Automated, and Runtime-Tunable pump, or SMART pump. The pump was utilized to detect Escherichia coli (E. coli) O157:H7, a deadly foodborne pathogen, through a microfluidic-based vertical immunoassay (VFA). In experiments involving the detection of E. coli O157:H7 in milk, the limit of detection (LOD) was determined to be 100 CFU/mL, demonstrating a low detection threshold. This nonelectric, multistep immunoassay automation pump, featuring both portability and automation, is anticipated to be highly suitable for POCT applications. Additionally, its capacity to automate complex assay and detection without relying on an external power source suggests its potential utility in resource-limited environments, thereby improving the accessibility of innovative microfluidics-based assays.