Page 22 - IJB-9-3

International Journal of Bioprinting

RESEARCH ARTICLE
Monolayer heterojunction interactive hydrogels

for high-freedom 4D shape reconfiguration by
two-photon polymerization

1
Yufeng Tao *, Chengchangfeng Lu , Xuejiao Wang , Zhiduo Xin , Xia Cao *,
1
3
1,2
1
Yunpeng Ren 1
1 Institute of Micro-nano Optoelectronics and Terahertz Technology, Jiangsu University, Zhenjiang,
212 013, China
2 Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology,
Wuhan, 430 074, China
3 Whiting School of Engineering, Johns Hopkins University, Baltimore, 21218-2688, U.S.A.

Abstract

Mimicking natural botanical/zoological systems has revolutionarily inspired four-
dimensional (4D) hydrogel robotics, interactive actuators/machines, automatic
biomedical devices, and self-adaptive photonics. The controllable high-freedom
shape reconfiguration holds the key to satisfying the ever-increasing demands.
However, miniaturized biocompatible 4D hydrogels remain rigorously stifled due to
current approach/material limits. In this research, we spatiotemporally program micro/
nano (μ/n) hydrogels through a heterojunction geometric strategy in femtosecond
*Corresponding author: laser direct writing (fsLDW). Polyethylene incorporated N-isopropylacrylamide
Yufeng Tao as programmable interactive materials here. Dynamic chiral torsion, site-specific
(Taoyufeng@ujs.edu.cn)
Xia Cao mutation, anisotropic deformation, selective structural coloration of hydrogel
(Caoxia@ujs.edu.cn) nanowire, and spontaneous self-repairing as reusable μ/n robotics were identified.
Hydrogel-materialized monolayer nanowires operate as the most fundamental
Citation: Tao Y, Lu C, Wang X, et al.
2023, Monolayer heterojunction block at nanometric accuracy to promise high freedom reconfiguration and high
interactive hydrogels for high- force-to-weight ratio/bending curvature under tight topological control. Taking use
freedom 4D shape reconfiguration of this biomimetic fsLDW, we spatiotemporally constructed several in/out-plane self-
by two-photon polymerization.
Int J Bioprint, 9(3): 678. driven hydrogel grippers, diverse 2D-to-3D transforming from the same monolayer
https://doi.org/10.18063/ijb.678 shape, responsive photonic crystal, and self-clenched fists at μ/n scale. Predictably, the
Received: August 22, 2022 geometry-modulable hydrogels would open new access to massively-reproducible
robotics, actuators/sensors for microenvironments, or lab-on-chip devices.
Accepted: October 21, 2022
Published Online: February 3, 2023
Keywords: Interactive hydrogel; Heterojunction nanostructures; Spatiotemporal
Copyright: © 2023 Author(s). programming; Chiral torsion; High freedom
This is an Open Access article
distributed under the terms of the
Creative Commons Attribution
License, permitting distribution,
and reproduction in any medium, 1. Introduction
provided the original work is
properly cited. Shape-reconfigurable materials have evolved ubiquitously in the nature, encompassing
Publisher’s Note: Whioce the living organism, plants, muscles, and peristaltic cells, featuring high-strength, and
Publishing remains neutral with multi-dimensional shape reconfiguration over its long history . For instance, plants
[1]
regard to jurisdictional claims in
published maps and institutional utilize water-sorption-to-desorption for morphogenesis, and a blooming flower changes
[2]
affiliations. its petals curvature in a few hours or days . Flytrap snaps at ultrafast speed to switch its
Volume 9 Issue 3 (2023) 14 https://doi.org/10.18063/ijb.678