Polymer micro engineering company Epigem has secured a US patent (no. 8,697,236B2 – “Fine line bonding and/or sealing system and method”) for its innovative micro fluidics gasket technology, with two key applications: creating seals for sensors, and at the same time defining the fluidic geometry and environment; and precision optics in instrumentation sealing to a window or prism.
This is attracting great interest from companies in the micro systems field which are miniaturising complex sensors capable of measuring multiple variables in a reusable manner (which significantly reduces costs).
The innovation in these applications comes from the complex patterns or circuits (similar to an electric circuit, only for fluids) where the seal follows and precisely defines in a leak-free manner the design of micro fluidics devices.
The usage has been expanded to the healthcare field where it is being used to create a connection between two chips which have a complex array of up to 42 micro fluidic input channels. One benefit is that the sealing is reversible, making the gasket de-mountable and re-usable.
The technology gives a gas and liquid-tight seal of micron scale channels, which can be temporarily sealed with only a gentle touch required, enabling fragile components to be deployed. It can form seals to sensors, which are often delicate, where the sensor can be reused in, for example, molecular diagnostics.
The technology has had powerful uses in a biological context eg culturing cells (diagnostics or medical research) or working with tissue. The micro fluidics gasket can be used to bring in nutrients or drugs to cultured cells (which would be the bottom surface), growing to near normal conditions which can be changed depending on the experiment.
The top surface can measure the change to the cell of the changing environment eg with a microscope. This is all due to the unique nature of the microgasket and combines measurement with cell culturing and modification. Ultimately the four walls of the channel can play different roles in any given application.
Micro fluidics is used to make the gasket and then creates a structure for, for example, diagnostics. This is not to be confused with an o-ring. It is much more versatile as it can deliver complex shapes. So the channel has, for example, PDMS (Polydimethylsiloxane) side walls, with the bottom being the sensor surface while the top surface can make interconnections to other components or pumps.
The gasket can also be a conductive elastomer and serve as an electrode. Typically PMMA (Poly[methyl methacrylate]) can be used as the top sheet as it is easy to drill holes, which can’t be easily achieved with PDMS or other substrates.
Another application is to fill the micro gasket with an adhesive to precisely define a permanent bond between a top and bottom substrate, where the adhesive doesn’t interfere with the process.
Tim Ryan, managing director of Epigem, said: “We are pleased to have secured this patent, which recognises our work at the forefront of integrated, complex, multiple function microfluidic device manufacture. This invention can be used in many applications and is already a key component in an increasing number of analytical instruments. We can now develop more cutting edge devices, and the patent gives us the confidence to continue investing in this exciting area.”