Bacterial cellulose (BC) is an emergent living-derived material that sits at the intersection of biotechnology, materials science, and biodesign. Produced through microbial synthesis at the air–liquid interfaces, BC exhibits unique properties—high purity, mechanical robustness, and programmable growth—that make it particularly attractive for growth-driven fabrication approaches. This demo presents a biodesign-oriented micromolding strategy, referred to as biolithography, that leverages the intrinsic growth pathway of bacterial cellulose to fabricate complex microstructured architectures in a single-step, low-energy process.

Biolithography exploits the ease of patterning and oxygen permeability of polydimethylsiloxane (PDMS) molds, placed atop a liquid culture medium. Those molds allow oxygen diffusion and act as physical barriers with predefined geometries, enabling bacteria to synthesize and self-assemble BC pellicles at the mold–medium interface, faithfully replicating microscale features without post-processing or subtractive manufacturing. Using this approach, we demonstrate the one-pot fabrication of BC-based microneedles—an emerging class of minimally invasive transdermal delivery systems—produced entirely through guided biological growth.

Multiple microneedle geometries were designed and evaluated, including pyramidal and conical structures of 1000 μm and 500 μm, highlighting the method’s geometric versatility and replicability. In addition to native BC microneedles, a biomineralized variant was created via a design-integrated mineralization strategy that combines a modified growth medium with post-synthesis mineralization baths. This process yielded needles with a uniform mineral layer, enhancing mechanical robustness and penetration potential.

The demo is structured as a multi-station exploration for biodesign by a dialogue with living materials rather than a purely top-down fabrication paradigm. Stations will guide attendees sequentially from a digital design display (TinkerCad parametric models) through 3D-printed master molds, PDMS replicas, live one-pot BC microneedle growth systems, and a comparative sample station featuring wet and dried microneedles (native, in situ biomineralized, and ex situ mineralized). Functional testing stations will allow participants to observe penetration into Parafilm M layers, rehydration kinetics, and model drug delivery (rhodamine B diffusion into agarose gel) in real time. Together, this work positions bacterial cellulose biolithography as a scalable, sustainable, and materially expressive platform for future biofabrication and biodesign applications.