Vacuum-driven power-free microfluidics utilizing the gas solubility or permeability of polydimethylsiloxane (PDMS)

Abstract

Suitable pumping methods for flow control remain a major technical hurdle in the path of biomedical microfluidic systems for point-of-care (POC) diagnostics. A vacuum-driven power-free micropumping method provides a promising solution to such a challenge. In this review, we focus on vacuum-driven power-free microfluidics based on the gas solubility or permeability of polydimethylsiloxane (PDMS); degassed PDMS can restore air inside itself due to its high gas solubility or gas permeable nature. PDMS allows the transfer of air into a vacuum through it due to its high gas permeability. Therefore, it is possible to store or transfer air into or through the gas soluble or permeable PDMS in order to withdraw liquids into the embedded dead-end microfluidic channels. This article provides a comprehensive look at the physics of the gas solubility and permeability of PDMS, a systematic review of different types of vacuum-driven power-free microfluidics, and guidelines for designing solubility-based or permeability-based PDMS devices, alongside existing applications. Advanced topics and the outlook in using micropumping that utilizes the gas solubility or permeability of PDMS will be also discussed. We strongly recommend that microfluidics and lab-on-chip (LOC) communities harness vacuum energy to develop smart vacuum-driven microfluidic systems.

Compact and Thermosensitive Nature-inspired Micropump

“…Thus, they are required to be miniaturized and integrated with several fluidic components without using an external macro-scale power source or controller. To meet these demands, various types of non-mechanical micropumps utilizing capillary force, surface tension, evaporation, vacuum-driven, and paper-based devices, have been developed410111213. However, most of them still have technological limitations of single-use, short-term operation, or needs of additional integration with a dedicated flow controller.…”

“…This is a multiple-use pumping system applicable to any hydrophilic liquid including therapeutic agents. Using this system, we can resolve the technical limitations of single-use or short-term use encountered in capillary-based or paper-based micropumps410111213. The LIM can also cope with the thermally sensitive flow rate of conventional evaporative micropumps, whose flow rate is passively determined on the basis of temperature, by using thermo-sensitive hydrogels, poly( N -isopropylacrylamide) (PNIPAAm) (Table 1)1415161718192021222324.…”

Roll-to-roll fabrication of integrated PDMS–paper microfluidics for nucleic acid amplification

“…The operation principle of this configuration is explained in detail in ref. 18. In brief, PDMS is a highly air permeable material.…”

Materials for Microfluidic Immunoassays: A Review

“…[15] Using the vacuum methods to driven liquids, some vacuum-driven microfluidic platforms are invented. [32] The porous filter membrane sandwiched between two PDMS layers, vacuum power can accelerate the reaction (Figure 1c). [16] This vacuum-accelerated microfluidic immunoassay (VAMI) chip can finish the whole experiment in 15 min.…”