The complexity in Microfluidics Product Development originates in the requirement to integrate and optimize the functional performance of a variety of dissimilar components that are coupled together in close proximity. It involves a combination of biological and materials science and engineering to create a robust product solution. Any product that performs tests and measurements is fundamentally an information producing system. The quality of the information depends critically on how well each of it’s disparate components are harmonized to become ‘more than the sum of the parts’.
This is where an understanding of the science is critical to success. In microfluidic systems, the high surface area to volume, shorter diffusion paths, and smaller thermal masses can reduce the time to reach the measurement end point. This is one advantage of microfluidic systems. However, if in performing a multi-step assay, inadequate washes, or an incorrect washing approach is implemented, the opposite will occur. Instead, the system will exhibit degraded sensitivity or dynamic range, or have greatly increased testing times and produce poor quality information. Some poorly designed systems require very high volumes of wash fluid which creates a large mismatch in the fluid components.
Another feature of some more complex tests is to try to translate the exact protocol done in bench top instrumentation or on robotic systems, into a device. This can lead to half a dozen reagent storage packs or more followed by cumbersome mechanical interfaces. Just remember, each component of the system that requires some sort of separate performance validation is adding complexity, and a risk for failure. A better product strategy is to optimize the assay to require no more than three separate reagents.
From an engineering and design for manufacturing perspective, the fewer mechanical parts there are, and the lower the tolerances for the interconnections of these components, the better. Some simple things to remember include taking advantage of the force of gravity…it’s free and it’s dependable! Another simple pointer regarding cartridge alignment is to never design the alignment of the cartridge into the instrument along an edge. This creates constraints on the precision of the disposable component, the very thing you are trying make as inexpensively as possible.
Some of the tougher engineering issues to solve involve the ability to do thermocycling. Here the science, engineering, and system design all need to happen together to ensure that a design feature in one component doesn’t add complexity or risk to another component. Even the nature of the nucleic acid detection test itself can affect the system design and choice of materials, so it’s prudent to map out reasonable specifications on performance of the assay at the outset and chose the disposable design, and interface to the detection and other electro-mechanical components early.
Our approach to supporting systems engineering is to design and develop sub components instruments, such as the ADEPT and ADEPT+, that can be customized and modified to test the integration of each component. Our instruments include cartridge clamping, modules for pneumatic, pumping, and thermal control to provide a means for semi-automated control of the assay being performed. By doing this early in the development program, the overall development risk is lowered and the quality of the final product enhanced.
Learn more about our systems approach by viewing our new Systems Engineering Brochure
