Micro/Nanofluidic‐Enabled Biomedical Devices: Integration of Structural Design and Manufacturing

Abstract

Micro/nanofluidic devices and systems have attracted ever‐growing attention in healthcare applications over the past decades due to low‐cost yet easy‐customizable functions with the demand of only a small volume of sample fluid. The continuous development, in particular, supported by the emergence of new materials, capable of meeting critical needs in next‐generation, wearable, and multifunctional biomedical devices for at‐home, personalized healthcare monitoring, is challenging the principles and strategies of structural design, manufacturing, and their seamless integration. This review summarizes the progress in micro/nanofluidic‐enabled biomedical devices with a focus on structural design, manufacturing, and applications in healthcare. Structures of fluidic channels and liquid actuation strength are given to elucidate the manipulations and controls of fluid transports that help capture desirable information of interest, including component separation, extraction, measurements, and disease diagnoses. Manufacturing processes of fluidic devices in micro‐ and nanoscales and their basic working principles are also presented, ranging from lithography in traditional hard materials to 3D printing in emerging soft materials. The selected examples and demonstrations are illustrated to highlight applications of biomedical fluidic devices in a broad variety of disease detection and diagnosis. The associated challenges and future opportunities are discussed.

Production and Reconfiguration of Double Emulsions by Temperature Control

“…Due to their core−shell geometry and multiple compartments, double emulsions have great potential as reservoirs for entrapped substances when stored or loaded into other systems, or as versatile templates for designing functional microcapsules. 1−6 Therefore, they have attracted considerable attention and are widely used in both science and engineering, e.g., as drug carriers, 7,8 miniature photonic devices, 9−12 microreactors, 3,13 microsensors, 14,15 and in water remediation 2 and cosmetic 3 and food industries. 16,17 Microfluidic devices are frequently applied in producing welldefined double emulsions, consisting of monodispersed inner water droplets in one outer oil droplet, such as plasma desorption mass spectrometry channels, 2,3,5 glass capillaries, 1,16 and capillary flow-focusing devices.…”

“…Double emulsions are droplets inside droplets of which the most common type is water-in-oil-in-water. Due to their core–shell geometry and multiple compartments, double emulsions have great potential as reservoirs for entrapped substances when stored or loaded into other systems, or as versatile templates for designing functional microcapsules. – Therefore, they have attracted considerable attention and are widely used in both science and engineering, e.g., as drug carriers, , miniature photonic devices, – microreactors, , microsensors, , and in water remediation and cosmetic and food industries. , Microfluidic devices are frequently applied in producing well-defined double emulsions, consisting of monodispersed inner water droplets in one outer oil droplet, such as plasma desorption mass spectrometry channels, ,, glass capillaries, , and capillary flow-focusing devices . However, the fabrication of such microfluidic devices with sophisticated channels entails demanding process conditions and precision instruments, such as soft photolithography, plasma cleaners, micropipette pullers, and microforges. , Moreover, considerable expertise is necessary for the proper surface treatment of different channel segments, precise alignment of channel parts, and reliable assembly of channel architectures .…”

Optical Characteristic Measurement of Micro/Nanodroplet on Embedded Grating Nanostructure for Digital Microfluidic’s Electrode

“…On a smaller scale, fabrications were conducted using electron beam lithography (EBL), focused ion beam lithography (FIB), nanoimprint lithography (NIL) techniques, etc. Especially for biomarkers detection, structures, materials, and fabrication techniques were focused on the device compatibility with the biomarker and its environment [12], [13]. There were already works that integrated optical sensor system with digital microfluidic technology, one of them is colorimetry coupled with ITO arrays of electrode based on active matrix electrowetting-ondielectric (AM-EWOD) which could detect glucose in a human blood serum.…”