4-bit adhesion logic enables universal multicellular interface patterning

Abstract

Multicellular systems, from bacterial biofilms to human organs, form interfaces (or boundaries) between different cell collectives to spatially organize versatile functions1,2. The evolution of sufficiently descriptive genetic toolkits probably triggered the explosion of complex multicellular life and patterning3,4. Synthetic biology aims to engineer multicellular systems for practical applications and to serve as a build-to-understand methodology for natural systems5–8. However, our ability to engineer multicellular interface patterns2,9 is still very limited, as synthetic cell–cell adhesion toolkits and suitable patterning algorithms are underdeveloped5,7,10–13. Here we introduce a synthetic cell–cell adhesin logic with swarming bacteria and establish the precise engineering, predictive modelling and algorithmic programming of multicellular interface patterns. We demonstrate interface generation through a swarming adhesion mechanism, quantitative control over interface geometry and adhesion-mediated analogues of developmental organizers and morphogen fields. Using tiling and four-colour-mapping concepts, we identify algorithms for creating universal target patterns. This synthetic 4-bit adhesion logic advances practical applications such as human-readable molecular diagnostics, spatial fluid control on biological surfaces and programmable self-growing materials5–8,14. Notably, a minimal set of just four adhesins represents 4 bits of information that suffice to program universal tessellation patterns, implying a low critical threshold for the evolution and engineering of complex multicellular systems3,5.

Targeted bacterial conjugation mediated by synthetic cell-to-cell adhesions

“…An alternative with a broader scope of applications may be to use synthetic cell adhesion bridges, such as those we propose here. Synthetic adhesins based on Nb–Ag interaction can drive the specific attachment of E. coli bacteria displaying the Nb to Ag-coated surfaces, mammalian cells expressing a surface Ag ( 15 ) and other E. coli bacteria displaying a cognate Ag on the surface ( 21 , 22 ). The affinity-based conjugation system that uses Nb–Ag pairs is also compatible with synthetic biology applications and will enable design and upscale of efficient liquid conjugation and mobilization events.…”

“…15 kDa) and simple structure, Nbs bind their cognate antigen (Ag) with great specificity and affinity. The surface display of Nbs with intimin Neae domain ( 19 , 20 ) mediated rapid and highly specific attachment of Escherichia coli bacteria to different cells expressing the recognized Ag on their surface, including mammalian tumor cells ( 15 ) and other E. coli bacteria ( 21 , 22 ). Furthermore, Enterobacter cloacae expressing Nbs deplete target E. coli cells producing the cognate Ag via type VI secretion system in liquid conditions ( 23 ).…”

Programming multicellular assembly with synthetic cell adhesion molecules

“…Programming the formation of new multicellular tissues de novo requires dictating specific cellular connectivity within a multicellular system 5 , 32 , 33 . Previous efforts to orthogonally control multicellular assembly, both in bacteria and mammalian systems, have generally used surface-tethering approaches 5 , 32 – 35 . Notably, recent research has enabled custom patterning of engineered bacteria through the surface expression of orthogonal nanobody–antigen pairs 33 .…”

Cell-Selective Multifunctional Surface Covalent Reconfiguration Using Aptamer-Enabled Proximity Catalytic Labeling

“…Although genetic engineering is the dominant method for accurately indicating target cells (through fluorescent protein fusion) and rewiring cell–cell assembly (by the expression of cadherins, adhesins, coiled coils, etc. ), most of these works need to label/modify separate target cells prior to mixing different cell types.…”

“…4,5 However, by introducing recognition molecules on the surface of target cells, 6−8 we can endow specific cells with sensing ability, regulate cellular functions, and reprogram cell−cell communication or interaction in situ in real biological systems, which have great application prospects in building synthetic tissues, 9−12 constructing artificial signaling pathways, 13 guiding immune cell targeting, and so forth. 14−16 Although genetic engineering is the dominant method for accurately indicating target cells (through fluorescent protein fusion) 17 and rewiring cell−cell assembly (by the expression of cadherins, 11 adhesins, 18 coiled coils, 12 etc. ), most of these works need to label/modify separate target cells prior to mixing different cell types.…”