Royal College of Surgeons in Ireland
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Tailored polypeptide star copolymers for 3D printing of bacterial composites via direct ink writing

journal contribution
posted on 2024-02-06, 16:43 authored by Robert MurphyRobert Murphy, Ronnie V. Garcia, Seung J. Oh, Tanner J. Wood, Kyoo D. Jo, Javier Read de AlanizJavier Read de Alaniz, Ed Perkins, Craig J. Hawker

Hydrogels hold much promise for 3D printing of functional living materials; however, challenges remain in tailoring mechanical robustness as well as biological performance. In addressing this challenge, the modular synthesis of functional hydrogels from 3-arm diblock copolypeptide stars composed of an inner poly(l-glutamate) domain and outer poly(l-tyrosine) or poly(l-valine) blocks is described. Physical crosslinking due to ß-sheet assembly of these star block copolymers gives mechanical stability during extrusion printing and the selective incorporation of methacrylate units allows for subsequent photocrosslinking to occur under biocompatible conditions. This permits direct ink writing (DIW) printing of bacteria-based mixtures leading to 3D objects with high fidelity and excellent bacterial viability. The tunable stiffness of different copolypeptide networks enables control over proliferation and colony formation for embedded Escherichia coli bacteria as demonstrated via isopropyl ß-d-1-thiogalactopyranoside (IPTG) induction of green fluorescent protein (GFP) expression. This translation of molecular structure to network properties highlights the versatility of these polypeptide hydrogel systems with the combination of writable structures and biological activity illustrating the future potential of these 3D-printed biocomposites. 


European Union Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement No. 842599.

U.S. Army Research Office under Contract Number W911NF-09-D-0001

Cooperative Agreement W911NF-19-2-0026 for the Institute for Collaborative Biotechnologies

BioPACIFIC Materials Innovation Platform of the National Science Foundation under Award No.DMR-1933487

The National Science Foundation Graduate Student Research Fellowship Program



The original article is available at

Published Citation

Murphy RD, et al. Tailored polypeptide star copolymers for 3D printing of bacterial composites via direct ink writing. Adv Mater. 2022;35(3):e2207542.

Publication Date

27 October 2022

PubMed ID



  • Chemistry


John Wiley & Sons, Inc


  • Published Version (Version of Record)