An official website of the United States government
Hybrid microfluidic systems that are composed of multiple different types of substrates have been recognized as a versatile and superior platform, which can draw benefits from different substrates while avoiding their limitations. This review article introduces the recent innovations of different types of low-cost hybrid microfluidic devices, particularly focusing on cost-effective polymer- and paper-based hybrid microfluidic devices. In this article, the fabrication of these hybrid microfluidic devices is briefly described and summarized. We then highlight various hybrid microfluidic systems, including polydimethylsiloxane (PDMS)-based, thermoplastic-based, paper/polymer hybrid systems, as well as other emerging hybrid systems (such as thread-based). The special benefits of using these hybrid systems have been summarized accordingly. A broad range of biological and biomedical applications using these hybrid microfluidic devices are discussed in detail, including nucleic acid analysis, protein analysis, cellular analysis, 3D cell culture, organ-on-a-chip, and tissue engineering. The perspective trends of hybrid microfluidic systems involving the improvement of fabrication techniques and broader applications are also discussed at the end of the review.
more »
« less
Component library creation and pixel array generation with micromilled droplet microfluidics
Abstract Droplet microfluidics enable high-throughput screening, sequencing, and formulation of biological and chemical systems at the microscale. Such devices are generally fabricated in a soft polymer such as polydimethylsiloxane (PDMS). However, developing design masks for PDMS devices can be a slow and expensive process, requiring an internal cleanroom facility or using an external vendor. Here, we present the first complete droplet-based component library using low-cost rapid prototyping and electrode integration. This fabrication method for droplet microfluidic devices costs less than $12 per device and a full design-build-test cycle can be completed within a day. Discrete microfluidic components for droplet generation, re-injection, picoinjection, anchoring, fluorescence sensing, and sorting were built and characterized. These devices are biocompatible, low-cost, and high-throughput. To show its ability to perform multistep workflows, these components were used to assemble droplet “pixel arrays, where droplets were generated, sensed, sorted, and anchored onto a grid to produce images.
more »
« less
- Award ID(s):
- 2027045
- PAR ID:
- 10566396
- Publisher / Repository:
- Nature Publishing Group
- Date Published:
- Journal Name:
- Microsystems & Nanoengineering
- Volume:
- 11
- Issue:
- 1
- ISSN:
- 2055-7434
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
Biodiesel is an eco-friendly renewable fuel that can be derived from microalgae. Maximization of biomass and lipid productivities are considered the main challenges for algal biodiesel production. Since conventional batch cultures are time-, space-, and reagent-consuming with many restrictions to apply many replicates, microfluidic technology has recently emerged as an alternative low-cost and efficient technology with high throughput repeatability and reproducibility. Different applications of microfluidic devices in algal biotechnology have been reported, including cell identification, sorting, trapping, and metabolic screening. In this work, Chlorella vulgaris was investigated by encapsulating in a simple droplet-based micro-array device at different light intensities of 20, 80, and 200 µmol/m2/s combined with different nitrate concentrations of 17.6, 8.8, and 4.4 mM. The growth results for C. vulgaris within microfluidic device were compared to the conventional batch culture method. In addition, the effect of combined stress of deficiencies in irradiance and nitrogen availability were studied to illustrate their impact on the metabolic profiling of microalgae. The results showed that the most optimum favorable culturing conditions for Chlorella vulgaris growth within the microfluidic channels were 17.6 mM and 80 µmol/m2/s.more » « less
-
Abstract There is a great interest in low-cost, versatile microfluidic platforms of which the fabrication processes are rapid, straightforward, and translatable to industrial mass productions. In addition, it is beneficial for microfluidic devices to be reconfigurable in the field, so that multiple functions can be realized by a minimum number of devices. Here, we present a versatile acrylic-tape platform which allows highly accessible rapid prototyping of microfluidic devices, as well as device reconfiguration to realize different functions. The clean-room-free fabrication and sealing process only requires a laser cutter, acrylic, and tapes and can be done by an untrained person in the field. We experimentally characterized the relationship between the capillary flow speed and the channel height, the latter of which can be well controlled by the fabrication process. Reconfiguration of microfluidic functions was demonstrated on a single acrylic-tape device, thanks to the reversible sealing enabled by functional tapes. Different pumping mechanisms, including on-chip pumps for better portability and syringe pumps for precise fluid control, have been employed for the demonstration of two-phase flow and droplet generation, respectively. The low-cost and versatile acrylic-tape microfluidic devices are promising tools for applications in a wide range of fields, especially for point-of-care biomedical and clinical applications.more » « less
-
Fabrication of microfluidic devices by photolithography generally requires specialized training and access to a cleanroom. As an alternative, 3D printing enables cost-effective fabrication of microdevices with complex features that would be suitable for many biomedical applications. However, commonly used resins are cytotoxic and unsuitable for devices involving cells. Furthermore, 3D prints are generally refractory to elastomer polymerization such that they cannot be used as master molds for fabricating devices from polymers ( e.g. polydimethylsiloxane, or PDMS). Different post-print treatment strategies, such as heat curing, ultraviolet light exposure, and coating with silanes, have been explored to overcome these obstacles, but none have proven universally effective. Here, we show that deposition of a thin layer of parylene, a polymer commonly used for medical device applications, renders 3D prints biocompatible and allows them to be used as master molds for elastomeric device fabrication. When placed in culture dishes containing human neurons, regardless of resin type, uncoated 3D prints leached toxic material to yield complete cell death within 48 hours, whereas cells exhibited uniform viability and healthy morphology out to 21 days if the prints were coated with parylene. Diverse PDMS devices of different shapes and sizes were easily cast from parylene-coated 3D printed molds without any visible defects. As a proof-of-concept, we rapid prototyped and tested different types of PDMS devices, including triple chamber perfusion chips, droplet generators, and microwells. Overall, we suggest that the simplicity and reproducibility of this technique will make it attractive for fabricating traditional microdevices and rapid prototyping new designs. In particular, by minimizing user intervention on the fabrication and post-print treatment steps, our strategy could help make microfluidics more accessible to the biomedical research community.more » « less
-
Electrowetting-on-dielectric (EWOD) has been extensively explored as an active-type technology for small-scale liquid handling due to its several unique advantages, including no requirement of mechanical components, low power consumption, and rapid response time. However, conventional EWOD devices are often accompanied with complex fabrication processes for patterning and wiring of 2D arrayed electrodes. Furthermore, their sandwich device configuration makes integration with other microfluidic components difficult. More recently, optoelectrowetting (OEW), a light-driven mechanism for effective droplet manipulation, has been proposed as an alternative approach to overcome these issues. By utilizing optical addressing on a photoconductive surface, OEW can dynamically control an electrowetting phenomenon without the need for complex control circuitry on a chip, while providing higher functionality and flexibility. Using commercially available spatial light modulators such as LCD displays and smartphones, millions of optical pixels are readily generated to modulate virtual electrodes for large-scale droplet manipulations in parallel on low-cost OEW devices. The benefits of the OEW mechanism have seen it being variously explored in its potential biological and biochemical applications. This review article presents the fundamentals of OEW, discusses its research progress and limitations, highlights various technological advances and innovations, and finally introduces the emergence of the OEW technology as portable smartphone-integrated environmental sensors.more » « less
