Bioprinting of Regenerative Photosynthetic Living Materials

Abstract

Living materials, which are fabricated by encapsulating living biological cells within a non‐living matrix, have gained increasing attention in recent years. Their fabrication in spatially defined patterns that are mechanically robust is essential for their optimal functional performance but is difficult to achieve. Here, a bioprinting technique employing environmentally friendly chemistry to encapsulate microalgae within an alginate hydrogel matrix is reported. The bioprinted photosynthetic structures adopt pre‐designed geometries at millimeter‐scale resolution. A bacterial cellulose substrate confers exceptional advantages to this living material, including strength, toughness, flexibility, robustness, and retention of physical integrity against extreme physical distortions. The bioprinted materials possess sufficient mechanical strength to be self‐standing, and can be detached and reattached onto different surfaces. Bioprinted materials can survive stably for a period of at least 3 days without nutrients, and their life can be further extended by transferring them to a fresh source of nutrients within this timeframe. These bioprints are regenerative, that is, they can be reused and expanded to print additional living materials. The fabrication of the bioprinted living materials can be readily up‐scaled (up to ≥70 cm × 20 cm), highlighting their potential product applications including artificial leaves, photosynthetic bio‐garments, and adhesive labels.

Emergent Biological Endurance Depends on Extracellular Matrix Composition of Three-Dimensionally Printed Escherichia coli Biofilms

“…Bacterial cellulose has been found to be a flexible substrate to support hydrogel-based living materials. 31 We further subjected the 3D-printed biofilms on the bacterial cellulose surface to manual distortions by folding, twisting, and crushing them ( Figure S5 ). The 3D-printed biofilms resumed their original shapes upon unfolding, untwisting, and uncrushing, indicating their high physical stability.…”

“…G. hansenii was cultured in Hestrin–Schramm (HS) medium (tryptone: 5.0 g L –1 , yeast extract: 5.0 g L –1 , disodium hydrogen phosphate: 2.7 g L –1 , citric acid: 1.5 g L –1 , and glucose: 20 g L –1 ) statically at 30 °C for 7 days to obtain a bacterial cellulose pellicle at the air–liquid interface. 31 Overnight cultures of G. hansenii were then prepared by dissolving the cellulose pellicle with cellulase (0.1 v/v %) by shaking at 180 rpm at 30 °C overnight. The obtained solution was then centrifuged at 4000 rpm for 5 min at 4 °C to obtain the cells for further experiments.…”

“…3D printing has been increasingly used for the fabrication of living functional materials from nano- to macroscales through printing algae, bacteria, fungi, yeast, plant, and animal cells. 21 − 31 3D printing allows for the spatial patterning of constituents mimicking the complex 3D microenvironments and time-evolving nature of living systems. 32 − 34 The spatial heterogeneity and mechanical robustness of natural biofilms can be simulated with a high degree of control over freedom of shape, design, and resolution provided by 3D printing.…”

Emergent Biological Endurance Depends on Extracellular Matrix Composition of Three-Dimensionally Printed Escherichia coli Biofilms

“…Since our 3D-printed biofilms adhered to bacterial cellulose, which is sustainably produced and possesses excellent mechanical properties including remarkable tensile strength (73−194 MPa) and toughness (2−25 MJ m −3 ), 19,31 we studied the deformation of the 3D-printed biofilms. Bacterial cellulose has been found to be a flexible substrate to support hydrogelbased living materials.…”

“…Bacterial cellulose has been found to be a flexible substrate to support hydrogelbased living materials. 31 We further subjected the 3D-printed biofilms on the bacterial cellulose surface to manual distortions by folding, twisting, and crushing them (Figure S5). The 3Dprinted biofilms resumed their original shapes upon unfolding, untwisting, and uncrushing, indicating their high physical stability.…”