Mechatronics 60 (2019) 34–55 Contents lists available at ScienceDirect Mechatronics journal homepage: www.elsevier.com/locate/mechatronics Review Recent trends in mechanical micropumps and their applications: A review S. Mohith ∗ , P. Navin Karanth , S.M. Kulkarni Department of Mechanical Engineering, National Institute of Technology Karnataka, Surathkal, P.O. Srinivasnagar, Mangalore 575025, India a r t i c l e i n f o Keywords: Microfluidics MEMS Micropump Drug delivery system LOC μTAS a b s t r a c t In recent years micropump technology has gained considerable importance and has become the highlighted area of research particularly for microfluidic applications. The driving force towards the development of micropump technology has been the integration of pumping systems into microfluidic devices to fulfill the need for accurate delivery of fluids. The present review brings out the recent research and development in the field of micropump technology with an emphasis on mechanical micropump. This review highlights the complete history and de- scriptions of different mechanical micropump design, actuation principles, materials and performance/operating parameters with relevant schematic diagrams. A comparative study with quantitative and graphical data has been presented to address the potential advantages and disadvantages of the different actuation schemes of mechanical micropump with the emphasis on flow rate and back pressure developed. Factors such as actuator type, operating parameters, diaphragm materials, and flow rectification mechanisms and their effect on micropump performance are addressed in detail. This study also highlights the requirements and applications of micropump in different fields such as biomedical, drug delivery, thermal management, fuel cells, etc. 1. Introduction The rapid growth of sub-millimeter and microscale engineering in recent years has resulted in the development of miniaturized systems and devices. Miniaturization mainly focuses on reducing the size of the system with reduced cost and improved performance. A miniaturized device has the advantage of higher speed, lower price, portability, use of disposable materials, lower sample volume, low energy requirements, etc. [1]. The potential advantage of miniaturization has motivated many researchers to develop miniaturized systems which can handle the flu- ids and liquids at the microscale to the nanoscale range. This motiva- tion has led to the development of microfluidics through an integrated approach incorporating micro-scale engineering and fluid mechanics. Microfluidics mainly deals with manipulation and analysis of the small volume of fluids or liquids. Microfluidic devices are class of miniatur- ized pumping systems which can pump, mix, monitor and control the minute volume of the fluids [4]. Microfluidics proved to be very effi- cient in fields like chemistry, medical, biology, molecular analysis, bio- defence, molecular biology, microelectronics, pharmaceuticals, and au- tomobile engineering. Typical applications of microfluidic systems in- clude chemical analysis, biological and chemical sensing, drug delivery, molecular separation, electronic cooling and for environmental monitor- ing. Precision control systems for automotive, aerospace and machine tool industries also incorporate the microfluidic systems in their ap- plication [2,3,5]. Many researchers have contributed significantly into ∗ Corresponding author. E-mail addresses: mohith.sdattanagar@yahoo.com (S. Mohith), navinkaranth@gmail.com (P.N. Karanth), smkulk@gmail.com (S.M. Kulkarni). microfluidics which has led to the development of different varieties of microfluidic devices like micropumps, micro-mixers, micro-valves, micro-filters, micro-reactors, and micro-separators [3,5] for distinctive applications. Considering the requirement of microfluidic systems to handle fluid at micro to the nanoscale, researchers and scientists have realized the need of a pumping system which can deliver a minute quan- tity of fluid at a required pressure sufficient enough to make the fluid flow through the microfluidic system. This need has resulted in the de- velopment of different micropumps with different actuation principles and fabrication technologies. Micropump is a device which can transfer or deliver the working fluid (liquid or gas) at accurate volume from a reservoir to target. The potential advantages of the micropump include the precise delivery of fluid in microliters to milliliters per second or per minute, the flexibility of integration with different electromechani- cal systems with effective space reduction [6–8,12]. The essential components of miniaturized pumping system include miniaturized pump (micropump), reservoir of fluid to be pumped, flow sensor for flow measurement, signal conditioner unit and a controller for the flow parameters as shown in Fig. 1. Micropumps incorporated in microfluidic systems should possess sufficient flow control, a wide range of flow rate, lower power consumption, and high back pressure [9,10]. Different approaches to the development of micropumps are available in literature since their introduction in the late 1970s. Fig. 2 repre- sents the significant ones carried out between 1970s and 1990s. The micropump concept developed by Spencer et al. [13] was the first ever https://doi.org/10.1016/j.mechatronics.2019.04.009 Received 5 November 2018; Received in revised form 27 February 2019; Accepted 27 April 2019 0957-4158/© 2019 Elsevier Ltd. All rights reserved.