New Jetting Technology Enables Hot Wax<br>Dispensing for Lab-on-a-Chip Applications

Hot wax is used as a gate or valve, to contain fluids on a chip until the critical time when they are released to interact with other fluids or specimens deposited on a chip for diagnostic testing. A wax gate or valve, when used in place of a mechanical valve, provides a cost-effective solution that is easier to manufacture. Asymtek's DispenseJetR DJ-9000 jet precisely dispenses an exact amount of wax onto discrete locations on the chip. The wax keeps the fluids used in the biological test in place on the chip and contaminant-free. When the chip is heated to a specified temperature, the wax designed for that temperature melts, releasing each specific fluid into the flow path at the point it is needed in the testing process. Hot wax is a phase change material, changing from a solid to a liquid when it is melted, then reverting back to a solid when cooled. Waxes can be formulated to melt at a specific temperature for the application, and multiple formulations can be used on the same chip. Jetting is an automated, non-contact process that dispenses fluids quickly, cleanly, accurately and reliably. With jetting, the wax is maintained in the jet at the precise temperature needed for optimal dispensing. Wax jetting technology can be used for lab-on-a-chip applications in all stages of development and manufacturing including prototyping, preproduction runs for clinical tests or FDA certification, as well as for mass production of lab-on-a-chip test kits. "Jet dispensing technology creates new possibilities for lab-on-a-chip applications," said Jim Klocke, senior business development manager of Asymtek. "Hot wax jetting is perfect for biomedical and laboratory applications because it is highly accurate and meets clean room conditions with no risk of contamination." Fluids can be jetted into spaces as tight as 175 micrometers. Fillet sizes as small as 300 micrometers, dot diameters of 0.20mm, shot volumes of 1.0 nanoliters, and a jet stream size as small as 50 microns can be achieved using Asymtek's jet. Fluids with viscosities from 1 to 250,000 centipoise (cps) can be jetted for a variety of medical applications, including medical electronics device assembly.