Fig. 2: Design and construction of a tubular prototissue-like vessel.

Optical microscopy bright image (a), fluorescence confocal image (b), and partial 3D reconstitution image (c) of a 1.0 wt% agarose hydrogel comprising a densely packed population of enzyme-decorated DOPC-CVs with sequestered sulforhodamine B (red fluorescence); scale bars; 50 μm. d SEM image of a lyophilized sample of hydrogel-immobilized DOPC-CVs showing intact CVs (false red coloration) physically attached to the 3D agarose network; scale bar, 30 μm. Graphic (e), and photographs viewed side-on (f) and end-on (g), showing tubular three-layer prototissue-like vessel with central 6 nm-wide channel. Spatial organization of the three protocell-loaded hydrogel modules (outer diameter, 15 mm) gives rise to concentrically arranged layers of immobilized DOPC-CVs decorated with different PA-enzymes (red, outer layer; yellow, middle layer; blue, inner layer) (g). Each hydrogel layer is 1.5 mm in thickness, with outer, middle and inner diameters of 15, 12, and 9 mm, respectively. Hydrogel modules shown in (g) are stained with Congo red (outer), Direct yellow 27 (middle), and Brilliant blue R (inner), respectively; scale bar, 5 mm. h Optical microscopy image of the interface between the middle (yellow) and outer (red) hydrogel layers. The imaged area is denoted by the rectangular box shown in (g); scale bar (h): 100 μm. Three times each experiment was repeated independently with similar results (a–d).