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Published January 19, 2021 | Supplemental Material + Published
Journal Article Open

Photosynthesis-assisted remodeling of three-dimensional printed structures


The mechanical properties of engineering structures continuously weaken during service life because of material fatigue or degradation. By contrast, living organisms are able to strengthen their mechanical properties by regenerating parts of their structures. For example, plants strengthen their cell structures by transforming photosynthesis-produced glucose into stiff polysaccharides. In this work, we realize hybrid materials that use photosynthesis of embedded chloroplasts to remodel their microstructures. These materials can be used to three-dimensionally (3D)-print functional structures, which are endowed with matrix-strengthening and crack healing when exposed to white light. The mechanism relies on a 3D-printable polymer that allows for an additional cross-linking reaction with photosynthesis-produced glucose in the material bulk or on the interface. The remodeling behavior can be suspended by freezing chloroplasts, regulated by mechanical preloads, and reversed by environmental cues. This work opens the door for the design of hybrid synthetic-living materials, for applications such as smart composites, lightweight structures, and soft robotics.

Additional Information

© 2021 National Academy of Sciences. Published under the PNAS license. Edited by Zhigang Suo, Harvard University, Cambridge, MA, and approved December 10, 2020 (received for review August 4, 2020). Q.W. acknowledges the funding support from the Air Force Office of Scientific Research (Grant FA9550-18-1-0192, program manager: Dr. Ming-Jen Pan) and the NSF (Grants CMMI-1762567 and CMMI-1943598). Data Availability: All study data are included in the article and SI Appendix. K.Y. and Z.F. contributed equally to this work. Author contributions: K.Y., Z.F., Q.W., N.X.F., and C.D. designed research; K.Y., Z.F., H.D., A.X., K.H.L., K.L., Y.S., and Q.W. performed research; K.Y., Z.F., H.D., A.X., K.H.L., K.L., Y.S., and Q.W. contributed new reagents/analytic tools; K.Y., Z.F., Q.W., N.X.F., and C.D. analyzed data; K.Y., Z.F., H.D., A.X., K.H.L., K.L., Y.S., Q.W., N.X.F., and C.D. wrote the paper; and Q.W. conceived the idea and supervised the team. Competing interest statement: The University of Southern California has filed a patent application related to the work described here. This article is a PNAS Direct Submission. This article contains supporting information online at https://www.pnas.org/lookup/suppl/doi:10.1073/pnas.2016524118/-/DCSupplemental.

Attached Files

Published - e2016524118.full.pdf

Supplemental Material - pnas.2016524118.sapp.pdf

Supplemental Material - pnas.2016524118.sm01.mp4

Supplemental Material - pnas.2016524118.sm02.mp4


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Additional details

August 22, 2023
October 23, 2023