Pneumatically Driven Microfluidic Platform for Micro-Particle Concentration

Summary

The present protocol describes a pneumatic microfluidic platform that can be used for efficient microparticle concentration.

Abstract

The present article introduces a method for fabricating and operating a pneumatic valve to control particle concentration using a microfluidic platform. This platform has a three-dimensional (3D) network with curved fluid channels and three pneumatic valves, which create networks, channels, and spaces through duplex replication with polydimethylsiloxane (PDMS). The device operates based on the transient response of a fluid flow rate controlled by a pneumatic valve in the following order: (1) sample loading, (2) sample blocking, (3) sample concentration, and (4) sample release. The particles are blocked by thin diaphragm layer deformation of the sieve valve (Vs) plate and accumulate in the curved microfluidic channel. The working fluid is discharged by the actuation of two on/off valves. As a result of the operation, all particles of various magnifications were successfully intercepted and disengaged. When this technology is applied, the operating pressure, the time required for concentration, and the concentration rate may vary depending on the device dimensions and particle size magnification.

Introduction

Due to the importance of biological analysis, microfluidic and biomedical microelectromechanical systems (BioMEMS) technologies^1,2 are used to develop and study devices for the purification and collection of micromaterials^2,3,4. Particle capture is categorized as active or passive. Active traps have been used for external dielectric⁵, magnetophoretic⁶, auditory⁷, visual⁸, or thermal⁹ forces acti....

Protocol

1. Designing the microfluidic platform for particle concentration

1. Design the pneumatic microfluidic platform consisting of one pneumatic valve for fluid flow in the 3D flow network and three pneumatic valves for sieve (Vs), fluid (Vf), and particle (Vp) valve operation (Figure 1).
   NOTE: Vs blocks concentrate particles from the liquid, and Vf and Vp allow fluid and particle release after concentration. Three pneumatic ports provide compressed air from the fluid/pneumatic supply layer (normally open) and the pneumatic valve light outlet to actuate the valve. The microfluidic channel network is designed wi....

Results

Figure 8 shows the flow rate of the fluid rates for a four-stage platform operation, as mentioned in Table 2. The first stage is the loading state (a state). The platform was supplied with fluid with all valves open, and the working fluid (Qf) and particles (Qp) are almost identical as the microfluidic channel network exhibits structural symmetry. In the second stage (b state), compressed air was transported to Vs to block the particles, and as the Vs diaphragm deformed, the.......

Discussion

This platform provides a simple way to purify and concentrate particles of various sizes. Particles are accumulated and released through pneumatic valve control, and no clogging is observed because there is no passive structure. Using this device, the concentration of particles of three sizes is presented. However, the operating pressure, the time required for concentration, and the rate may vary depending on the device dimensions, particle size magnification, and the pressure at Vs^18,<.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
1.5 mm puncture	Self procduction	Self procduction	This puncture was made by requesting a mold maker based on the Miltex® Biopsy Punch with Plunger (15110-15) product.
4 inch Silicon Wafer/SU-8 mold	4science	29-03573-01	4 inch (100) Ptype silicon wafer/SU-8 mold
Carboxyl Polystyrene Crosslinked Particle(24.9 μm)	Spherotech	CPX-200-10	Concentrated bead sample1
Flow meter	Sensirion	SLI-1000	Flow measurement
High-speed camera	Photron	FASTCAM Mini	Observation of concentration
Hot plate	As one	HI-1000	heating plate for curing of liquid PDMS
KOVAX-SYRINGE 10 mL/Syringe	Koreavaccine	22G-10ML	Fill the microfluidic channel with bubble-free demineralized water.
Laboratory Conona treater/Atmospheric plasma	Electro-Technic	BD-20AC	Chip bonding/atmospheric plasma
Liquid polydimethylsiloxane, PDMS	Dow Corning Inc.	Sylgard 184	Components of chip
Microscope	Olympus	IX-81	Observation of concentration
PEEK Tubes	SAINT-GOBAIN PPL CORP.	AAD04103	Inject or collect particles
Polystyrene Particle(4.16 μm)	Spherotech	PP-40-10	Concentrated bead sample3
Polystyrene Particle(8.49 μm)	Spherotech	PP-100-10	Concentrated bead sample2
Pressure controller/μflucon	AMED	μflucon	Control of air pressure
Spin coater	iNexus	ACE-200	spread the liquid PDMS on SU-8 mold