Method of manufacturing a microfluidic device

Abstract

A method of manufacturing a microfluidic device, said method comprising placing a length of material in a liquid polymer, configuring the length of material to define the path of a microfluidic channel, curing or setting the polymer liquid to form a solid polymer around the configured length of material, and dissolving the configured length of material with a solvent to provide a microfluidic channel in the solid polymer.

Claims

1. A method of manufacturing a microfluidic device, said method comprising a. placing together in a liquid polymer, (a) a length of material that is configured to define the path of a microfluidic channel, and (b) at least one prefabricated mechanical or prefabricated electronic component, or a combination thereof where said length of material and said prefabricated mechanical and/or prefabricated electronic component(s) are together suspended in the liquid polymer, b. curing or setting the polymer liquid to form a solid polymer around the configured length of material and the prefabricated mechanical and/or prefabricated electronic component(s), and c. dissolving the configured length of material with a solvent to provide a microfluidic channel in the solid polymer comprising said prefabricated mechanical and/or prefabricated electronic component(s); wherein the length of material is formed around the prefabricated mechanical and/or prefabricated electronic component(s) and together suspended in the liquid polymer or wherein the prefabricated mechanical and/or prefabricated electronic component(s) is/are wrapped around the length of material and together suspended in the liquid polymer.

2. The method as claimed in claim 1, wherein the length of material is configured before placing the length of material in a liquid polymer.

3. The method as claimed in claim 1, wherein at least a portion of the configured length of material protrudes from the solid polymer.

4. The method as claimed in claim 3, wherein the ends of the configured length of material protrude from the solid polymer.

5. The method as claimed in claim 1, wherein the length of material is a length of polymer filament formed from a polymer selected from acrylonitrile butadiene styrene, polylactic acid, polystyrene and polyvinyl acetate.

6. The method as claimed in claim 5, wherein the length of material is a length of acrylonitrile butadiene styrene.

7. The method as claimed in claim 6, wherein the solvent is acetone.

8. The method as claimed in claim 7, wherein dichloromethane is employed as a co-solvent.

9. The method as claimed in claim 1, wherein the liquid polymer is a silicone elastomer and a curing agent.

10. The method of claim 9, wherein the silicone elastomer is Polydimethylsiloxane.

11. The method as claimed in claim 1, wherein radio frequency (RF) and/or prefabricated electronic components are suspended in the liquid polymer and set in the polymer when it is cured or set.

12. The method as claimed in claim 1, wherein the length of material is configured to define the configuration of the microfluidic channel by 3D-printing or modeling the length of material.

13. The method as claimed in claim 1, wherein the microfluidic channel is configured in three dimensions.

14. The method as claimed in claim 1, wherein the prefabricated mechanical and/or prefabricated electrical component(s) is/are embedded in the polymer adjacent or in communication with the microfluidic channel(s).

Description

(1) These and other aspects of the present invention will now be described, by way of example, with reference to the accompanying drawings in which:

(2) FIG. 1 is a schematic diagram showing the steps required to perform a method according to Example 1 of the present invention;

(3) FIGS. 2a to 2d depict examples of microfluidic channels formed according to Example 2 of the present invention; and

(4) FIGS. 3a to 3d depict examples of electronic components incorporated into devices formed according to Example 3 of the present invention.

EXAMPLE 1

(5) SYLGARD silicone elastomer 184 and SYLGARD silicone elastomer 184 curing agent were obtained from Dow Corning Corporation. A 3D SIMO pen was used for extruding 1.7 mm acrylonitrile butadiene styrene (ABS), plastic filament that was obtained from the same vendor. 3D print of Hilbert cube was ordered online and 3D printed by ridix.nl (Rotterdam, the Netherlands) using a Dimension SST 1200es printer and by 3dhubs.com using a Duplicator 4 printer. Acetone was obtained from Sigma Aldrich.

(6) The ABS plastic filament was extruded through a 500 μm nozzle (3D SIMO pen) and then modeled into the desired 3D shape with the help of a soldering iron set (100° C.) or printed with a fused deposition modeling 3D printer (see FIG. 1). The modeled ABS plastic scaffold was then immersed in a well mixed solution of 10:1 sylgard 184/sylgard 184 curing agent. The PDMS was then placed under vacuum for removing air bubbles and cured for 2 hours at 75° C., or overnight at room temperature. The PDMS was consecutively left for 12 hours in acetone, after which the microchannels were cleaned with acetone and dried with a flow of compressed air.

EXAMPLE 2

(7) Using a similar procedure to that described with reference to Example 1, many different 3D channels were readily created. These are depicted in FIGS. 2a to 2d. FIG. 2a shows spiral channels. FIG. 2b shows multiple microfluidic channels with different geometries. FIG. 2c shows microfluidic channels with compartments differing in size. FIG. 2d shows a complex 3D multilevel scaffold based on the Hilbert curve. The ABS polymer scaffold was 3D-printed utilizing ABS fuse deposition modeling. The microfluidic channel depicted in FIG. 2d was formed from a scaffold that was 35 cm long and formed of 1.4 mL of ABS. Nonetheless, it was still possible to remove the plastic with subsequent baths in dichloromethane and acetone.

EXAMPLE 3

(8) In this example, electronic circuitry, heating elements and RF components were incorporated in the microfluidic device.

(9) FIG. 3a depicts a microfluidic device containing an embedded 390 nm LED, for example, for optical detection or electronic excitation of chemicals in the microfluidic channel. The LED was inserted in the PDMS together with the scaffold before curing. Then, acetone treatment was used to remove only the scaffold, leaving the electronics intact.

(10) FIG. 3b depicts a microfluidic device containing a selective heating unit. A 200 μm nichrome resistance wire was loosely wrapped around the ABS polymer scaffold and inserted in PDMS. After curing and dissolving the ABS scaffold, a voltage of 1.2 V and current of 0.35 A was applied to the wire. This sufficed for selectively heating a thermochromic dye above 27° C. only in the part of the channel surrounded by the resistance wire. Temperatures can be varied and the 200 μm wire can be used, for example, to boil water inside the channel. This simple and selective heating element embedded in the microfluidic chip can be of great value for designing chips to perform, e.g., biological experiments like PCR, sterilization inside the microchannels or for setting different temperatures for organ-on-chips or cell cultures.

(11) FIG. 3c depicts a microfluidic device containing a solenoidal NMR microcoil. A 32 μm copper wire was wrapped around a 500 μm ABS filament, resulting in a final channel encompassed by a solenoidal NMR microcoil (FIG. 3c), with a detection volume of only 2 μL (normal NMR tubes contain about 500 μL sample volume). Because the transceiver coil matched the size of the sample, the sensitivity of the system was good. This microfluidic device was integrated on a cylindrical aluminum probe insert and placed inside a 9.4 Tesla narrow-bore superconducting NMR magnet. Tuning the resonance circuit to 376 MHz allowed high-resolution NMR spectra to be obtained (see FIG. 3c insert for spectrum). Line-widths at half peak-height were obtained of about 3 Hz and resolving heteronuclear spin-spin couplings, opening up the way to further optimization and applications. In addition, it was calculated that the material costs for fabricating this device is less than 2 Euro.

(12) FIG. 3d depicts a microfluidic device comprising an embedded color sensor and a microcontroller. An Arduino micro and a color sensor were wired together and immersed in PDMS with an ABS scaffold. After curing the PDMS and removing the ABS polymer with acetone, the resulting microfluidic channel was right on top of the color sensor. Hooking up the Arduino to a computer revealed all the components of the microcontroller and the sensor to be working properly.