Building RNA concentration fields

Abstract

Biomolecular reactions produce concentration fields that serve as maps to pattern fly compound eyes, weave nerves into brain circuitry, and organize microbial communities. Creating such fields in vitro across diverse scales could enable breakthroughs in fields from materials science to tissue engineering. Here, we present a strategy to form stable, intricately structured fields of an RNA sequence. RNA is transcribed in hydrogel “generators” and degraded in bulk, producing a sustained concentration gradient with a well-defined shape. The concentrations of fields produced by generators sum so that composite fields with complex patterns, e.g., hills and valleys, can be created by prescribing generator positions. Using an empirical model, we automatically design a desired field by optimizing generator placements. This versatile approach supports multi-hour stability and is readily extensible to 3D or to fields of multiple sequences. RNA concentration fields provide a new means to pattern materials, direct self-assembly, and orchestrate cell organization.