Toward Plant Cyborgs: Hydrogels Incorporated onto Plant Tissues Enable Programmable Shape Control

Abstract

Engineered living materials (ELMs) that incorporate living organisms and synthetic materials enable advanced functional properties. Here, we seek to create plant cyborgs by combining plants or plant tissues with stimuli-responsive polymeric materials. Plant tissues with integrated shape control may find applications in regenerative medicine, and the shape control of living plants enables another dimension of adaptability and response to environmental threats, which can be applied to next-generation precision farming. In this work, we develop chemistry to integrate stimuli-responsive poly­(N-isopropylacrylamide) (PNIPAM) hydrogels with decellularized plant tissues assisted by 3D printing. We demonstrate programmable shape morphing in response to thermal cues and ultraviolet (UV) light. Specifically, by taking advantage of the extrusion-based 3D printing method, we deposit nanocomposite PNIPAM precursors onto silane-treated decellularized leaf surface with prescribed shapes and spatial control. When subjected to external stimuli, the strain mismatch generated between the swellable nanocomposite PNIPAM and nonswellable decellularized leaf enables folding and bending to occur. This strategy to integrate the plant tissues with stimuli-responsive hydrogels allows the control of leaf morphology, opening avenues for plant-based biosensors and soft actuators to enhance food security; such materials also may find applications in biomedicine as tissue-engineering scaffolds.

3D shape morphing of stimuli-responsive composite hydrogels

“…Reproduced with permission. [56][57][58][59][60][61] Copyrights 2016, Springer Nature, Copyright 2021, 2021 Wiley-VCH, Copyright 2021, 2022, 2022, American Chemical Society.…”

“…55 Moreover, an exhaustive and up-to-date application scenario of shape morphable composite hydrogels have been depicted, including soft robotics, 56 information encryption, 57 biomedical applications, 58,59 flexible electronics, 60 and engineered living materials. 61 For each application, we discuss in detail a few rationally designed devices, systems, or mechanisms with far-reaching perspectives. Finally, we conclude with insights into the development and barriers in shape-morphable composite hydrogels, providing an effective source to recognize the current developmental limitations and inspire innovative strategies for future smart hydrogel research.…”

4D Printing Nanocomposite Hydrogel Based on PNIPAM and Prussian Blue Nanoparticles Using Stereolithography

“…[2,3] For instance, anisotropic deformations through thermal stimulation of PNIPAM based hydrogels have been notably used to create hydrogel actuators. [4,5] Recently, an important effort has been done on improving of the PNIPAM performance regarding its mechanical properties and the possibility of the shape control. [6] In this line of thought, the introduction of inorganic nanoparticles leading to smart nanocomposite hydrogels with unusual properties has been reported in the literature.…”

Grafting-from Synthesis of Plant–Polynorbornene Biohybrid Materials

“…11−13 Another innovative approach was developed to manipulate leaf morphology, which includes adhering 3D printable stimuliresponsive gels onto the surface of decellularized leaves. 14 An alternative striking example detailed flame retardant coatings using spray coating with viscoelastic fluids to large areas of vegetation. 15 in the field of plant−polymer biohybrids, the strategies for fabrication still remain limited.…”

“…Despite these advancements, the exploration of polymer integration to more complex biological systems, such as living plants, remains largely unexplored. Limited research has focused on the integration of conductive polymers through the self-organization of these polymers within the inner structures of ex vivo plant matter or through in vivo polymerization within the root systems of intact plants. − Another innovative approach was developed to manipulate leaf morphology, which includes adhering 3D printable stimuli-responsive gels onto the surface of decellularized leaves . An alternative striking example detailed flame retardant coatings using spray coating with viscoelastic fluids to large areas of vegetation .…”