Figure 1.
Population Delivery Chip design.
A) A schematic of the device indicating the flow layer (blue) and control valve layer (red). There are 16 on-chip wells arranged in a 96-well plate format for initial loading of different worm populations. Columns and wells of the array are numbered according to order of delivery. Valves V1-V8 are multiplexer control valves and V9-V12 control flow in the main channel. B) An image of the device with its microfluidic channels loaded with food coloring dye, showing the flow layer (green) and control valve layer (orange) (scale bar ~1mm). C) A macro-scale view of the device with the 16-well array indicated by the yellow dashed lines and a schematic of worms loaded into one of the conical wells. D) A macro-scale view of the entire chip/gasket system with pressurized input lines in the experimental setup.
Figure 2.
Automated worm population delivery sequence.
A) Schematic of the device showing areas active during the sequence example as the worms are pre-staged at the first set of control valves. An image of pre-staged C. elegans worms is below the schematic (scale bar is 1 mm). B) Illustration of all steps for one full sequence cycle. Step 1: Appropriate valves open as the gasket is pressurized to send Well 1’s population to the main channel, where Main Channel Flush then accelerates the worms’ transport to the main exit. Step 2: Excess worms are cleared from the main channel towards the Main Outlet via flow from Main Channel Flush. Step 3: Flow from Exit Flush delivers the worms from the Main Outlet to an off-chip location. Step 4: “Flushback”; Exit Flush flow is redirected backwards to clear any remaining worms in the well channel back to Well 1. This step is executed on Wells 1-4 only after finishing Steps 1-3 on each of them. C) Timings for each step.
Figure 3.
Worm population delivery as a function of applied pressure.
The fraction of worm populations loaded in 4 representative on-chip wells from 4 different columns of the Population Delivery Chip that are delivered to the outlet of the device as a function of pressure applied at the gasket and the Main Channel Flush.
Figure 4.
Population mixing eliminated during automated delivery at 20 psi (~138 kPa).
The graphs show the fraction of animals collected after delivery from a given well that are of the same strain initially loaded into the well. The actual average number of collected worms over the average number of those initially loaded is indicated above each bar. A) Four distinct strains loaded in each row. B) Four distinct strains loaded in each column. A corresponding color-coded schematic on the right of both graphs indicates into which wells the strains were loaded at the beginning of both experiments. Each color represents a single type of strain.
Figure 5.
The daily change in live worm population numbers for 3 different applied pressures to the gasket relative to control in four representative wells; each well resides in a different column of the device.