Gabriele Pitingolo, Enza Torino and Raffaele Vecchione
Center for Advanced Biomaterials for Healthcare, Istituto Italiano di tecnologia (IIT@CRIB), Largo Barsanti e Matteucci, 53, 80125 – Napoli – Italy.
Why is this useful?
Common systems to connect microfluidics devices with classic fluidic equipment (such as syringe or peristaltic pumps) are based on the use of commercial connectors which are not always compatible with the device material.
Upchurch (Oak Harbor, WA, USA) NanoPorts™ assemblies are the first commercially available products to provide consistent fluid connectors for microfluidic chips. These products bond easily to some chip surfaces such as glass and polydimethylsiloxane (PDMS) with the provided preformed adhesive rings. All NanoPort™ components are made of inert, biocompatible PEEK™ polymer (nuts and ports) and Perlast® perfluoroelastomer (ferrules and gaskets). However, many microfluidic devices are made of polymethylmethacrilate (PMMA) and in this case the preformed adhesive rings are not suitable.
Here, we demonstrate an easy and effective way to bond NanoPorts to PMMA microdevices. Our approach is a hybrid system which glues the commercial nanoports with an alternative epoxy adhesive. Also remarkably this is a reusable system, in fact the Flat Bottom Port and the Flat Bottom Port Gasket may be removed and re bonded on another device as explained in the procedure.
What do I need?
- Fully cured PMMA microchip with via holes to microchannels
- UPCHURCH® SCIENTIFIC NanoPort Assemblies 
- Loctite Super Attak Power Flex Gel (5g)
- Binder Clip Medium 1-1/4in
- FEP Tubing, 1/16’’ x 0.25 mm 
- Scalpel and tweezers
What do I do?
1. Prepare the PMMA surfaces (clean with water and dry with an absorbent cloth) and NanoPort™ for bonding (Figure 1). The Inlet and Outlet holes must be of a diameter below the inner diameter of the Nanoport (around 2 mm) to guarantee no leakage at the Nanoport-PMMA interface.
2. Put a few drops of Loctite Super Attak Flex Power Gel (5g) on a surface, in our case we used a piece of PMMA (Figure 2). Take the UPCHURCH® SCIENTIFIC NanoPort, insert the gasket seal into the recess in the bottom of the port (Figure 3) and touch the port to the drop of Loctite Super Attak in order to deposit the right amount of glue on the bonding surface (Figure 4). Eliminate the excess glue with the aid of a scalpel and attach the flat bottom port gasket directly on the bottom of the port (Figure 5).
3. Take the complete Nanoport (flat bottom port and gasket) and touch the drop of Loctite super attack, eliminating the excess glue with the aid of a scalpel. Center and place the complete Nanoport on your final substrate surrounding the access hole (Figure 6).
4. Clamp the port to the substrate (Figure 7) for 3 hours.
5. Your well-bonded NanoPort interconnect to PMMA (Figure 8) is now ready to use.
6. It is possible to remove the Nanoport from the PMMA surface. Use ethanol to weaken the epoxy (Figure 9) and after 30 minutes punch with a hammer to separate the NanoPort™ from the PMMA device.