Fig 1.
Overview of designing and building a custom instrument using the Multifluidic Evolutionary Component (MEC) system.
The instrument is designed by arranging MEC symbols on a schematic, then the schematic is used to guide the assembly of MEC “building blocks” into the finished instrument. For many applications involving manipulating fluids on the milliliter scale, the “off the shelf” macroMEC components (like the manual valve shown) are adequate for building complete instruments. For instruments that must manipulate fluids on the microliter or nanoliter scale, microMECs can be arranged into a micro-schematic (like the mixer chip shown), fabricated using conventional microfabrication techniques, packaged in a MEC shell, and plugged into the rest of the instrument.
Fig 2.
Design standard for the MEC system.
Standardized sizing and spacing allows MECs to be connected together in all three spatial dimensions, and interface points (circles) can be designed to allow fluid, electricity, or light to flow between MECs.
Fig 3.
Selected Multifluidic Evolutionary Components (MECs), including macroMECs that can be “clicked together” (A–D) and microMECs that are fabricated into microfluidic integrated components (E).
Fig 4.
Two integrated components, microfluidic chips containing several microMECs combined together and fabricated using soft lithography of PDMS (A) and wet etching of glass (B).
The integrated components are packaged in a MEC-standard shell that plugs into the fluidic socket macroMECs (SA1-10 or SB1-20 in Fig 3A). By packaging a microfluidic chip in a MEC shell in this manner, virtually any microfluidic chip can be integrated into the MEC system.
Fig 5.
Three sample instruments built using the MEC system.
(A) A MEC-based multiscale fluidic router designed to mix fluids from nine different fluid storage MECs in volumes spanning five orders of magnitude (from 400 nanoliters to 10 milliliters). (B) A MEC-based acid-base titration instrument suitable for educational applications in classrooms. By toggling the manual valves SU1, SU2, and SV1, different ratios of water: sodium hydroxide solution: phenolphthalein are delivered to a microcentrifuge vial. The observed range of phenolphthalein colors (from clear in pure water to pink in 4.0 × 10−5 mass concentration NaOH) confirms the successful operation of the instrument. (C) A MEC-based bioreactor capable of culturing cells. The optical density macroMEC (OD1 in Fig 3B) measures the concentration (via optical density) of the cells as they grow and react to stimuli. (D) A growth curve obtained by using the bioreactor in C to culture Saccharomyces cerevisiae yeast cells. The bioreactor is sensitive enough to detect important metabolic checkpoints in the growing yeast, including the diauxic shift (when the yeast cells switch from glycolysis to the aerobic oxidation of ethanol) and the entry into G0 (when the yeast cells exhaust all nutrients and enter stationary phase).