Do I need a heat press for Flexdym<sup>TM</sup>?
Yes, most heat presses or hot-embossers should work. A press that can mold at a pressure of at least 7 psi or above is ideal (a vacuum assisted press is not required). You may have to make small adjustments to optimize molding your chips. We offer a compact microfabrication kit, user friendly and plug and play system. To learn more about the Sublym100 microfabrication kit, follow this link (https://eden-microfluidics.com/sublym-mold-solutions/)
What size range is reliably micromolded with Flexdym<sup>TM</sup>?
The minimal microchannel width is 50 nm, and the depth range is 50 nm – 1 mm. However, microchannels between 1 µm and 1 mm are recommended with an aspect ratio (height to width) of 3:1 or less. Submicron structures and higher aspect ratios have also been achieved by some customers.
Which mold does Flexdym<sup>TM</sup> work best with?
Common molds used in the field of microfluidics work well. These include fragile molds, such as photoresists (e.g. SU‒8), and etched glass and silicon molds. Temperature resistant epoxy molds and traditional metallic molds (aluminum, nickel, brass molds) work also. Silicones such as PDMS work as well, however, be sure to choose a stiff silicone grade at least 20 Shore A durometers above FlexdymTM We offer EPMO epoxy material to fabricate robust mold suited (up to 6’’ size) for FlexdymTM molding without the needs to treat it with anti-sticking agent (https://eden-microfluidics.com/sublym-mold-solutions/).
How do I clean Flexdym<sup>TM</sup>?
Isopropyl alcohol, methanol or distilled water may be used. FlexdymTM has to be dry (air or hoven dried) before molding to avoid bubbling or splays (cloudiness). Tape is also recommended to remove dust particles. We recommend working with FlexdymTM in a clean room or under a laminar hood to minimize particle contamination.
Is the Flexdym<sup>TM</sup> appropriate for my fluorescence applications?
FlexdymTM material is a transparent material and has a transmittance of 50% at 295 nm and upon 90% in the visible region. See UV-vis transmittance spectra (https://eden-microfluidics.com/technologies).
How do I mold Flexdym<sup>TM</sup> as transparent as possible?
We recommend molding FlexdymTM using a very smooth mold. Metallic molds should have a mirror finish. Using glass or other transparent molds, such as epoxy or other silicones will ensure a more transparent result.
Why do I keep getting tiny bubbles in the plastic when I mold Flexdym<sup>TM</sup>?
Your setup is likely too hot or FlexdymTM is not completely dry. Lower the temperature, decrease molding time, air/oven dry FlexdymTM, or perform molding in a low humidity condition to minimize bubbling. It may take some trial to optimize micromolding with FlexdymTM on your own setup.
What is the most effective way to sterilize Flexdym<sup>TM</sup>?
Ethylene oxide, gamma irradiation or autoclave will work.
Is Flexdym<sup>TM</sup> microfluidic chips used for cell culture?
While FlexdymTM is less permeable than PDMS, it still has sufficient air permeability to sustain cell cultures. FlexdymTM grades have successfully been used for neurons, hepatocytes, endothelial, dermal, stem-cells and IPSCs cells cultures among others. FlexdymTM is UPS Class VI and ISO 10993-5 biocompatible certified material (PVC, Latex and others phthalates free).
How do I seal Flexdym<sup>TM</sup> microchannels to a substrate?
FlexdymTM is a self-sealing material that you can bond with usual microfluidics thermoplastics and materials such as PC, POC, PS, PP or glass, Si. The bonding process does not require plasma assisted or UV adhesive processes. It can be bonded at room temperature. To reduce the time of bonding and/or to improve the bonding strength, a thermal bonding process can be used (maximum 90°C). Customers have successfully sealed FlexdymTM by binding it to a substrate and storing the chip in an oven for minutes to overnight.
How do I control the hydrophilicity of Flexdym<sup>TM</sup> surfaces?
In its pristine state, FlexdymTM is slightly hydrophobic. To achieve stable hydrophilic surfaces strategies that have been used on hard plastics can also be applied to FlexdymTM surfaces. These strategies include plasma treatment or coatings with hydrophilic materials, such as poly (vinyl alcohol), polyurethane, polyacrylate, (hydroxypropyl) methyl cellulose, polyvinylpyrrolidone, or hyaluronic acid. Multiple vendors offer hydrophilic coatings through licensing models or outsourcing. Key points to consider are the cost structure, the type of coating, the coating application (e.g. dip, spray, spin, film coats), any curing step (e.g. UV or heat), and any post-processing steps (e.g. sterilization, cleaning, or storage conditions) that may affect your final chip.
How do I create inlet and outlet holes for my microfluidic channels?
Traditional biopsy punches used with silicones will not work here. The use of a rotary/hand punch or a laser cutter is recommended. Self-sealing connection pads have been developed and ensure easy and leak-free connections with any tubing.
How do I prevent nonspecific binding?
Methods traditionally used to treat hard plastics generally work with FlexdymTM as well. For example, coating the surfaces with animal caseins or BSA (bovine serum albumin) has been used with success.