Review of Electronics-Inspired Microfluidic Circuits

Microfluidic circuits use the pressure and flow characteristics of interconnected elements to regulate fluid transport and control operating sequences. Interconnection changes the operating conditions of individual elements, making their interactions important to the response of the assembled system. This paper presents a review of electronics-inspired microfluidic circuits, including their working principles, design methods and applications. The functional elements are classified according to their primary circuit functions, and their circuit representations are examined using the hydraulic–electrical analogy. Continuous flow regulation, logic and state storage, and oscillatory and sequential control are discussed in relation to the load and timing requirements. Modelling and design automation methods are considered together with fabrication and experimental verification to examine how the intended circuit response is obtained in a physical device. Applications in diagnostic assays, chemical processing, cell culture, wearable sensing and soft robotics are introduced. The advantages and limitations of different circuit arrangements are summarized, including their suitability for fixed sequences, reconfiguration and autonomous operation. The reviewed studies indicate that reliable integration requires the output pressure, available flow and switching time to be matched to the connected load. Performance evaluation should also account for the complete operating procedure, including the external equipment and user intervention required, to support the comparison and selection of circuits for different applications.