Fig. 2.

Diagram of a the sample preparation device assembly and b the holder. The chips is made of four PMMA layers machined using a CO₂ laser. Layer 1 (thickness = 175 μm) forms the base of the device, layer 2 (175 μm PMMA + 2 × 50 μm of double sided tape on both sides) defines the channels (width ~140 μm) and bead capture chambers, layer 3 (175 μm) contains access holes for the bead capture chamber and seals the micro-channels. Layer 4 (5 mm) provides depth to the chip and holds the pipette-to-chip adapter. b the holder contains the permanent magnets placed in slots which are separated by a distance of 1 mm. Red lines in the figure show the position of the Kapton heater strip that is placed above the magnets. c Cross sectional diagram of the pipette-to-chip adapter that interfaces with an 8-channel electronic micropipette. The adapter is fabricated using a 3D printer from a rubber-like material and accommodates the conical pipette tips. d Photograph of the device showing the 8 channel pipette; bead-target complexes are immobilised in the chamber while supernatant is collected in the waste chamber