We present autonomously-triggered on-chip microfluidic cooling devices that utilize thermo-responsive hydrogels to adapt to local environmental temperatures. An external rotating magnetic stirrer couples with an in situ fabricated nickel impeller in these centrifugal-based microfluidic cooling devices to recirculate cooler water. Temperature-responsive hydrogels, which exhibit volumetric expansion and contraction, are integrated at the axle of the impeller. In this design, the hydrogels behave similar to an automotive clutch, to autonomously control the impeller's rotation as a function of the local environmental temperature. Therefore, the hydrogels act as both sensors and actuators and help take away the necessity for additional temperature sensing, feedback, and/or control units here. Cooling devices capable of on-chip thermal management at multiple predetermined onset operation points are realized by changes to the composition of hydrogel to alter its lowest critical solution temperature (LCST). Furthermore, the effect of magnetic stirrer frequency on the fluid cooling and flowrates for different two-blade nickel impeller designs are presented.
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http://dx.doi.org/10.1039/b617767k | DOI Listing |
Lab Chip
December 2024
Department of Energy and Power Engineering, School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China.
Sci Rep
November 2024
Ministry of Education Key Laboratory of Micro and Nano Systems for Aerospace, School of Mechanical Engineering, Northwestern Polytechnical University, 127 West Youyi Road, Xi'an, 710072, Shaanxi, People's Republic of China.
This study investigates various microfluidic chip fabrication techniques, highlighting their applicability and limitations in the context of urgent diagnostic needs showcased by the COVID-19 pandemic. Through a detailed examination of methods such as computer numerical control milling of a polymethyl methacrylate, soft lithography for polydimethylsiloxane-based devices, xurography for glass-glass chips, and micromachining-based silicon-glass chips, we analyze each technique's strengths and trade-offs. Hence, we discuss the fabrication complexity and chip thermal properties, such as heating and cooling rates, which are essential features of chip utilization for a polymerase chain reaction.
View Article and Find Full Text PDFInt J Mol Sci
October 2024
Department of Pharmaceutical Chemistry, Faculty of Pharmaceutical Sciences, Khon Kaen University, Khon Kaen 40002, Thailand.
Niosomes are employed for their improved physical properties and stability and as a controlled delivery system. However, their large-scale production and different preparation methods affect their physical properties. The microfluidic method represents a novel approach to the preparation of niosomes that enables precise control and decreases the preparation time and steps compared to alternative methods.
View Article and Find Full Text PDFMicromachines (Basel)
October 2024
Department of Electrical and Computer Engineering, Rutgers University, Piscataway, NJ 08854, USA.
In recent years, the field of micro- and nanochannel fabrication has seen significant advancements driven by the need for precision in biomedical, environmental, and industrial applications. This review provides a comprehensive analysis of emerging fabrication technologies, including photolithography, soft lithography, 3D printing, electron-beam lithography (EBL), wet/dry etching, injection molding, focused ion beam (FIB) milling, laser micromachining, and micro-milling. Each of these methods offers unique advantages in terms of scalability, precision, and cost-effectiveness, enabling the creation of highly customized micro- and nanochannel structures.
View Article and Find Full Text PDFHeliyon
October 2024
Industrial Engineering Department, College of Engineering, King Saud University, Riyadh 11421, Saudi Arabia.
Motivation And Objectives: The basic aim of this investigation is to explore the energy transfer impact on Eyring-Prandtl fluid, a topic that has not been previously examined, thereby paving the way for future researchers. The present literature is crucial for advancing thermal management in engineering applications. This study aims to numerically investigate the thermophoretic effects and Brownian motion of non-Newtonian nanofluid relying on Eyring-Prandtl fluid model across the stretching sheet.
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