World-to-Chip interface


  1. 1 Commercial microfluidic interface
  2. 2 Commercial microfluidic instruments
  3. 3 Tubings for microfluidic applications
  4. 4 Thermoplastic Microfluidic Chips
    1. 4.1 1. Direct tube insertion (with assist of epoxy etc. to seal)
    2. 4.2 2. screw thread adapters
      1. 4.2.1 2.a. custom-made PMMA 1/4-28(UNF) thread adapter
      2. 4.2.2 2.b. M6 thread PC adapters
    3. 4.3 3. bondable luer interface
    4. 4.4 4. Nanoport
  5. 5 PDMS microfluidic chip
    1. 5.1 1. Direct tube insertion
    2. 5.2 2. screw thread adapters 
      1. 5.2.1 silane assisted bonding
      2. 5.2.2 Loctite plastics bonding systems
    3. 5.3 3. silicone tube interface
    4. 5.4 4. stainless steel small tube
      1. 5.4.1 4.a. Tygon tube 
      2. 5.4.2 4.b. interfacing with chemically inert HPLC tubings
    5. 5.5 5. Luer interface
    6. 5.6 6. Nanoport
  6. 6 Punching holes on PDMS chips
    1. 6.1 1. Manual biopsy punch
    2. 6.2 2. semi-automated punch
      1. 6.2.1 Syneo
      2. 6.2.2 CorSolutions
  7. 7 Connecting tubings to the syringes
    1. 7.1 1. Direct needle insertion
      1. 7.1.1 1/16" tubing
    2. 7.2 2. HPLC fittings
      1. 7.2.1 1/16" tubing
      2. 7.2.2 1/8" tubing 
  8. 8 On chip reservoir
    1. 8.1 1. Modification of Bio-Rad microspin  empty column
    2. 8.2 2. microfluidic chipshop
    3. 8.3 3. labsmith
    4. 8.4 4. use of standard micropipette tips
  9. 9 Off chip Reservoir for pneumatic pressure pumps
    1. 9.1 1. Elveflow
    2. 9.2 2. Fluigent
    3. 9.3 3. microdata instruments
    4. 9.4 4. Cellix
    5. 9.5 5. Corsolutions
    6. 9.6 6. Custom make reservoir 
    7. 9.7 7. HPLC solvent cap
  10. 10 Interface with flow sensors
  11. 11 Flow switches
    1. 11.1 1. 3-way Stopcock
    2. 11.2 2. Fluigent flow switch
  12. 12 Glass microfluidic chip
    1. 12.1 1. Direct tube interfacing via epoxy fixing
    2. 12.2 2. Nanoport
    3. 12.3 3. ChipGenie from microfluidic chip shop
  13. 13 Literature review

Commercial microfluidic interface

  1. Dolomite
  2. Micrux
  3. IDEX
    • flange fittings
    • flangeless fittings
    • super flangeless fittings
    • Nanoport
  4. Micronit
  5. SER coporation
  6. Labsmith
  7. Fluigent
  8. Gesim - MicCell
  9. Lumicks - u-Flux
  10. Kieraia
  11. Corsolutions
  12. マイクロ化学技研株式会社
  13. microfluidic chipshop
  14. Precigenome

commercial microfluidic chips commonly employ injection molded  Luer interface. such as the ones from Microfluidic chipshop
with regards to interface, microfluidic chipshop may have the most variety.
standard luer, mini luer, and olive interface for small configuration of interface.
others mostly use a precision-machined or injection molded manifold and assemble as well as seal to the microfluidic chip using a gasket.

manifold-gasket assembly

Commercial microfluidic instruments

unigo pumps 30psi ~2 bars
pneumatic output:6mm 
7. Festo
8. Takasago fluidics system micropumps
9. microdata instruments 
12. Aline
    small wireless animal use pumps could be useful for integrated applications
Mitos P-Pump

Tubings for microfluidic applications


Thermoplastic Microfluidic Chips

1. Direct tube insertion (with assist of epoxy etc. to seal)

xxxx add figure later

2. screw thread adapters

2.a. custom-made PMMA 1/4-28(UNF) thread adapter

The adapters are used by Ji-Yen Cheng's group at RCAS, Academia Sinica (Taiwan). 
Originally it costs NTD$10( ¢30) for each piece. Recently, they used adaptors that are injection molded, which brings the cost down further to NTD$2 (~¢7). 1/4-28 compatible fittings from IDEX are used with it.

2.b. M6 thread PC adapters

Alternatively, I have been using M6 threaded hex nuts made in polycarbonate from NBK japan (SPC-N-M6) which is about ¥300 every 25 pc making each piece around ¥12 each piece.
It is working well with all M6 fittings from IDEX. However, some problems with 1/8" tubings are seen from time to time. The ferrule may stuck in the nut after experiment.  In this case a superflangeless fittings is recommended since it is a bit smaller in diameter.
plastic thread adapters can be bonded to the thermoplastic chip using cyanoacrylate.

2.c. How to connect adapters to the chip

The adapters can be fixed to the chip using the following
1. cyanoacrylate
2. epoxy
3. ultrasonic bonding
4. UV adhesive 
Loctite 3310

By using screw thread adapters with HPLC fittings, An air-tight microfluidic system is complete which is useful for manipulation and moving of microfluidic chip from benchside to microscopes without concern of contamination which is especially important for cell culture applications.
Figure 1. Screw thread adapters (left) M6 adapter (right) custom made PMMA 1/4-28 UNF thread adapter

How to connect fittings to the chip

3. bondable luer interface

3.a. from Nordson medical
Built-a-Part Male Luer Interface : BDMMTL-40, BDMMTL-81
Built-a-Part Female Luer Interface : BDMFTLL-40, BDMFTLL-81, BDMFTLL-9

3.b. Luer interface 
Luer interface can also be established together with screw thread adapters.
P-624 Female Luer to 1/4-28
P-686 female luer to M6

3.c.from Labsmith

3.d. Predesigned luer interface on commercial chip through injection molding
many commercial chips come with a Luer interface on the chip.
a male luer fluid connectors can be used.
09-0508-263-09 from microfluidic chipshop can be used.
to connect to standard tubings, microfluidic chipshop recommended use of silicone tube IDxOD 0.5mm x2.5mm to connect to a PTFE tube IDxOD 0.5mmx1mm.

3.e.Microfluidic chipshop bondable Luer interface
microfluidic chipshop also has a bondable interface in PMMA topas and PC
i. Female luer lok compatible connectors
Height 8.74 mm
diameter 5.8 mm

ii. Female luer lok compatible conectors with wide base
8mm diameter bonding surface

3.f. Microfluidic chipshop bondable Mini luer 
microfluidic chipshop has a range of connectors for mini luer connectors.
Male mini luer fluid connetors 
length 10.5mm
Miniluer to pipette adapter
09-0565-0391-09 USD$1.9~0.94
Mini luer to luer adapter
09-0566-0390-09 USD$1.9~0.94

4. Nanoport

Nanoport is quite expensive and can tolerate high pressure. Thus is often used in the field of nanofluidic applications.
N-333 cone nanoport fitting for 1/16" 
¥4158 for a set

PDMS microfluidic chip

1. Direct tube insertion

Direct tube insertion is useful in most applications. but as the interface is not tight. there is always possibility of leaking. 
And also in case of sterile assembly of the chip, the tube could fell off and comprise the sterility during transportation between BSC and site of experiment (e.g. microscopy or incubator)

It can be assembled similarly as to how thermoplastic chip uses. Please refer to table 1.

2. screw thread adapters 

The screw thread adapters for thermoplastic chips can be used also. However, it will require to bond the adapters to the PDMS.
heterogeneous bonding technique will be required if the adapters are different materials.

silane assisted bonding

Loctite plastics bonding systems

Locitite plastics bonding system uses surface priming by heptane and cyanoacrylate and can bond thermoplastics with PDMS. 
However, some whitening are often observed so avoid bonding at area you need microscopy access.

3. silicone tube interface

ColeParmer 07625-24 0.76mmID , 2.54mm OD ~¥24000/roll
Use of a silicone tube interface glued on SU-8 mold and bonded with PDMS during curing is used as a interface to tubings without the need of punching out a port.
this technique is used by Amy Shen's group and Albert Folch's group on fabricating chip.
The downside is that a small dead space exists on the SU-8 mold. Also, the surface tension of PDMS will cause unflat surface near the interfaces such that imaging will be distorted due to diffraction. 
Disadvantage asides, tube or stainless tube insertion into the interface is stronger and prevented from conventional problem of easy detachment of tubing.

4. stainless steel small tube

stainless steel small tube

How to interface stainless steel small tube with tubing is tricky

4.a. Tygon tube 

One tygon tube has been used extensively with stainless steel small tubes working with Quake's microvalve technology.
from EW-06419-01 at cole parmer ~¥12000/100ft/roll
formulation Tygon ND-100-80
but will whiten after autoclave 
operation temperature -31 to 85°C

4.b. interfacing with chemically inert HPLC tubings

As mentioned in another pages. Some researchers reported toxicity originated from tygon tubing to the cells. 
We have been working with ETFE or PTFE tubings which are very inert and compatible with cells in thermoplastic chips.
There is several ways to interface small stainless steel tubes with ETFE or PTFE tubings

4.b.i. Direct insertion.

23G small tubes have OD of 0.65mm can be inserted into 1516 1/16"ODX0.02"ID or 1/16"ODX0.5mmID tubings
21G small tubes have OD of 0.81mm can be inserted into 1528 1/16"ODX0.03"ID tubings
As described in number 1 and 3 as below in the picture.

4.b.ii. Interface with help of silicone tubes

5. Luer interface

It is possible to create slip luer interface on pdms chip provided the pdms chip has enough thickness, a hole can be punched out (4mm).
However Luer-Lok type interface will demand a more difficult approach.
The hole can be used with the on-chip reservoir as decribed below.

6. Nanoport

Punching holes on PDMS chips

1. Manual biopsy punch

several companies manufactures stainless punch for biopsy in dermatology and oncology.
a. Harris
b. WPI

with price, we have been purchasing the biopsy punch from Kai. It is relatively cheaper.
there is an additional special order for the 0.5mm

BP-A05F - 0.5mm ~¥2000/ea, 20ea/cs
BP-10F  - 1mm 
    good for beckman dickinson PE tubing
BP-15F - 1.5mm
    good for 1/16" PTFE tubing
BP-20F - 2.0mm
BP-30F - 3.0mm 
    good for 1/8" PTFE tubing
BP-40F - 4.0mm ¥8559, 20ea
BP-80F - 8.0 mm ¥8764, 20ea

BPP-10F - 1mm with plunger 8-5845-01, ~¥600/ea
BPP-20F - 1.5mm with plunger 8-5845-02, ~¥600/ea
biopsy punch with plunger is easier to expel the PDMS plug after punching.

2. semi-automated punch


Syneo MP-10-UNV ~2.8million yen
Many microfluidic research labs use the tube-punching machine manufactured by Syneo to punch holes on PDMS device.
The advantage of using it is to provide a perfectly perpendicular hole in comparison to manual punching.
Also, with digital camera add-on, one can see and align the chip.
The focal depth of the camera is not great. So it might take some tweaking.


Corsolutions also have a PDMS punching station.

Connecting tubings to the syringes

1. Direct needle insertion

1/16" tubing

2. HPLC fittings

1/16" tubing

1/8" tubing 

On chip reservoir

1. Modification of Bio-Rad microspin  empty column

Luer interface
micro-biospin column
732-6204 ~¥145/ea, 100ea/pk
0.8mL bed volume
total length:35.7mm
4.25mm diameter of the luer head
8.0mm middle body diameter
top diameter ~12.0mm
size of the lid:
distance that can clear Tokai hit incubator 20mm

bio-spin column
732-6008 ~¥281/ea, 100ea/pk
standard Luer,
head diameter 4mm
total length:63mm

2. microfluidic chipshop

16-0604-0387-09 single tank piercing interface $USD0.54~2.5
bottom diameter of luer head 
3.5mm top of luer interface 
3.95mm end of luer interface
total length 25mm

3. labsmith

chip reservoir that goes with bonded port from Labsmith
height 12.7mm 

4. use of standard micropipette tips

on a 0.75mm or 1mm hole.
It is very appealing to use common micropipette tips as direct on chip reservoir.
But the problem is the bevel design of it and the surface energy modification of micropipette tips prevented wetting of surface, thus can easily trap bubbles. Bubble free refill of the reservoir is more difficult.

Off chip Reservoir for pneumatic pressure pumps

1. Elveflow

2. Fluigent

Fluiwell 1C-15~¥70000
Fluiwell 4C ~ ¥250000
4 of 0.5 ~2.0mL
P-CAP2-LP ~¥70000
for eppendor 1.5 or 2.0mL

3. microdata instruments


4. Cellix

5. Corsolutions

6. Custom make reservoir 

Christopher Wong et al., from Prof. David Juncker's group at McGill University

7. HPLC solvent cap
50mL GP32 blass bottle
ISD0050C ¥1400/ea
50mL probably is the smallest bottle that can have solvent cap for HPLC applications. Bigger ones are also available, 1L, 3L, 20L. But these might have less use for microfluidics.

OM4412 GL32 bottle cap ¥2200/ea (00932T-2 GL32 2 port Tseries bottle cap, Diba & Kinesis)
hole directly compatible with 1/8" tubings

OM4252S ¥460/ea 1/8" to 1/16" connector for BL32 bottlecap

2.5mm ID luer
3.0mm ID luer
4.0 mm ID luer for 6x4mm pneumatic tubings

each set cost about ¥4000

8. Dolomite

Interface with flow sensors




Flow switches

1. 3-way Stopcock

For cell applications where sterility is essential. we prefer to buy reasonably priced medical components in phlebotomy,fluid displacement,and transfusion therapy. they are proven medical instrument and usually reliable.
Nipro 3W-RC 3 way sotck cock. ~¥93/ea, 50/cs

2. Fluigent flow switch

Glass microfluidic chip

1. Direct tube interfacing via epoxy fixing

2. Nanoport

3. ChipGenie from microfluidic chip shop

Literature review

1. van dam group
van dam group

2. David Beebe 

3. Albert Folch

4. pin header!divAbstract


World to chip interface