# Photosynthetic Biomanufacturing in Mechanically Robust, 3D Printed Hydrogels

## TL;DR

This paper explores using cyanobacteria in 3D printed hydrogels to create materials that produce chemicals using light energy, while also affecting the material's strength.

## Contribution

Demonstrates the first viable integration of photoautotrophic cyanobacteria into hydrogels for biomanufacturing with modulated mechanical properties.

## Key findings

- Cyanobacteria remained viable only in a bovine serum albumin-conjugated acrylate hydrogel.
- Encapsulated cyanobacteria produced 719 mg L–1 of 2,3-butanediol over four days.
- Bioproduction of 2,3-butanediol influenced the compressive modulus of the hydrogel material.

## Abstract

Engineered living
materials (ELMs) integrate synthetic polymers
with engineered cells to create systems that sense, respond, and adapt
to their environment. While promising as sustainable alternatives
to traditional materials, ELMs remain underexplored for use with photoautotrophic
organisms. In this study, we evaluate the viability of the cyanobacterium Synechococcus elongatus PCC 7942, which converts
carbon dioxide into valuable chemicals using light energy, in three
hydrogel matrices previously shown to support heterotrophic cells. S. elongatus remained viable and metabolically active
only in a hydrogel formed from bovine serum albumin-conjugated acrylates.
When engineered to produce 2,3-butanediol (23BDO), encapsulated cells
generated 719 mg L–1 over four days. Incorporating
cells increased the compressive modulus of the material, while accumulated
23BDO reduced it, indicating that bioproduction influences mechanical
properties. Fluorescence imaging confirmed high viability and physical
immobilization. These results establish that cyanobacteria-based ELMs
can enable autotrophic chemical production while modulating material
mechanics for sustainable applications.