CASE STUDY: Reagent Dispensing Robot
Next-generation sequencing (NGS) library preparation involves fragmenting a genomic DNA sample and ligating specialized adapters to both fragment ends. This high-quality sample serves as the input for a sequencing instrument to perform the gene sequencing process. As the price tag of sequencing instruments has dropped significantly in recent years, there is now motivation to similarly cost-reduce the library preparation machine, from roughly $100,000 down to the $25,000 range.
Simplexity was approached by a client whose goal was to produce a low-cost, high-volume library preparation system. We were tasked with developing the motion systems for liquid handling and reagent deployment from pre-filled cartridges. Our solution was a low-cost, X-Y-Z gantry robot situated above the cartridge containing the reagent capsules. The Z-axis was the deployment direction, along which the robot pierced the cartridge and released the reagent.
For cost-reduction and miniaturization purposes, Simplexity developed a custom gear train and belt drive. By customizing gear trains and belt drives, we can more effectively integrate these robots into the product in a much smaller package size. Customization also gives more flexibility that limited off-the-shelf solutions. When creating a custom gear train, our engineers have the freedom to design for higher loads and looser center-to-center shaft tolerances. Cluster gears can be designed to be compact and to have just the right gear ratio. Even the brushed DC servo motor is custom.
HOW DID THE CLIENT BENEFIT?
In addition to being miniaturized and low-cost, the robot was also intended to be manufactured in high volume. For instrument volumes of more than 500 per year, Simplexity recommends that the client consider a breakeven cost analysis for various tooling strategies. As volumes increase, production yields and production efficiencies become increasingly important. A single custom sheet metal or injection-molded part can sometimes replace 5 off-the-shelf parts in the bill of materials, which reduces chances for failure and saves on assembly time. Applying these techniques to the library preparation system, Simplexity successfully created a compact, low-cost, high-volume reagent dispensing robot.