Figure 2: The shape of the wells facilitates loading of the chamber with cells enclosing alginate capsules.

(a) Technical drawing of the well with sizes. (b) Close-up of the 3D-printed stamp wells imprints are protruding whereas letters are hollowed. (c) Solidified agarose gel pad after imprinting; bumps and cavities are now inverted. Note that a part of the resin block is used to hold the stamp in place [visible on the top right of (b)] and to imprint a cuvette in the upper left corner. This cuvette is used for medium exchange since a tip can be inserted here without any risk of touching the samples. (d) 3D rendering of the agarose wells after fluorescence labelling of the agarose with Dextran (see Movie 1). (e–j) Capsules manipulation is achieved by visualization with a stereomicroscope for both loading the capsules in the pipette (e–g) and placing them in the chamber (h–j). (f and i) Drawings illustrating the procedure for collecting the capsules. Capsules residing in a 60 mm petri dish in warmed medium are carefully and regularly aspirated into the mouth pipette, ensuring regular spacing (h). They are then released in each well to fill the whole frame of the chamber (i). The inset illustrates the shape of the well that has been designed to permit the insertion of the pipette (67.5° slope on the right side) and to minimize the optical aberrations (80° slope on the right side) when looking from top [for detailed dimensions, see (a)].