PDMS stamps are pieces of polydimethylsiloxane (PDMS), a silicone, that have been patterned usually against a master mask to form a relief pattern used in

soft lithography In technology, soft lithography is a family of techniques for fabricating or replicating structures using "elastomeric stamps, molds, and conformable photomasks". It is called "soft" because it uses elastomeric materials, most notably PDMS. ...

. This PDMS stamp can be used in either its current form as a relief surface for techniques such as

microcontact printing Microcontact printing (or μCP) is a form of soft lithography that uses the relief patterns on a master polydimethylsiloxane (PDMS) stamp or Urethane rubber micro stamp to form patterns of self-assembled monolayers (SAMs) of ink on the surface o ...

or can also be attached to an external source by tubing so that liquid may be passed through channels on its surface. In this second case it will often be laminated to a surface so that chemistry can be performed on that surface producing a pattern of the PDMS stamp on to the surface. Alternatively a PDMS stamp can be laminated to a second piece of PDMS to form a contained device. It is possible to pattern PDMS with

nanometre 330px, Different lengths as in respect to the Molecule">molecular scale. The nanometre (international spelling as used by the International Bureau of Weights and Measures; SI symbol: nm) or nanometer ( American spelling) is a unit of length ...

resolution. PDMS stamps can be procured from some commercial sources such as Research Micro Stamps. Many techniques have been developed to modify the basic setups to perform a range of tasks such as assays on small volumes. These kinds of devices are often referred to as microfluidic devices. Because of the small dimensions of these devices flow is

laminar Laminar means "flat". Laminar may refer to: Terms in science and engineering: *Laminar electronics or organic electronics, a branch of material sciences dealing with electrically conductive polymers and small molecules * Laminar armour or "banded ...

not

turbulent In fluid dynamics, turbulence or turbulent flow is fluid motion characterized by chaotic changes in pressure and flow velocity. It is in contrast to a laminar flow, which occurs when a fluid flows in parallel layers, with no disruption between ...

which can lead to many useful properties; however, this reduces the ability of fluid streams to mix.

A new concept of PDMS stamp for multiplexing: the macrostamp

The main drawback of microcontact printing for biomedical application is that it is not possible to print different molecules with one stamp. To print different (bio)molecules in one step, a new concept is proposed : the macrostamp. It is a stamp composed of dots. The space between the dots corresponds to the space between the wells of a microplate. Then, it is possible to ink, dry and print in one step different molecules. File:Macrotimbre 2.png, examples of macrostamp and magnetic macrostamp

A new PDMS stamp : the Magnetic Stamp

To apply a homogeneous pressure during the printing step, a magnetic force is used. For that, the stamp is sensitive to a magnetic field by injecting iron powder into a second layer of PDMS. This force can be adjusted for nano and micro-patterns. Fully automated micro contact printing equipment was developed. It consists of the steps of the micro contact printing process : loading, inking, drying, printing, alignment, cleaning, unloading. A pipeting module is used to deposit some drop of liquids like ethanol. This equipment is named InnoSTAMP40.InnoSTAMP40
Innopsys File:Protocol for magnetic stamp.png, protocol to fabricate magnetic stamp File:Magnetic field assisted micro contact printing.png, description of magnetic field assisted microcontact printing

References

{{reflist Silicones Lithography (microfabrication)