Research on Multi-material Biomimetic Electronics Based on Investment Micro-casting 3D Printing

Academic Background

With the rapid development of biomimetic electronics, electronic skin (E-skin) and flexible sensors that mimic human perceptual functions have shown broad application prospects in robotics, medical devices, and human-computer interaction. However, existing biomimetic electronic devices face numerous challenges in material selection, structural complexity, and functional integration. In particular, how to achieve the free assembly and multifunctional integration of various challenging materials without compromising their performance has become a bottleneck in current research.

Traditional manufacturing methods, such as electrospinning, lithography, and transfer printing, often struggle to meet the demands of both material diversity and complex structures simultaneously. While 3D printing technology provides possibilities for manufacturing complex structures, it still faces issues such as material compatibility and insufficient structural resolution when dealing with multiple challenging materials. To address these problems, researchers drew inspiration from the ancient lost-wax casting technique and proposed a Boolean-logic-guided Investment Micro-casting 3D Stereolithography (BMSL) strategy, aiming to achieve the free assembly and multifunctional integration of various challenging materials.

Source of the Paper

This research was led by Chunjiang Wang and Xiaoming Chen from the Micro- and Nano-Technology Research Center at Xi’an Jiaotong University, in collaboration with research teams from the University of Hong Kong and the School of Electronic Science and Engineering at Xi’an Jiaotong University. The study was published on May 16, 2025, in the journal Device, titled “Investment Micro-casting 3D-Printed Multi-Metamaterial for Programmable Multimodal Biomimetic Electronics,” with the DOI: https://doi.org/10.1016/j.device.2024.100658.

Research Process and Experimental Methods

Research Process

1. Template Design and Preparation
   The research first used 3D printing technology to fabricate complex soluble resin templates (Pre-mold, PM), and molten wax was employed as a removable mold. Through electrowetting technology, the wax was cleaned out from the mold, forming a hollow mold.

2. Material Filling and Solidification
   Pre-treated nanocomposites were injected into the hollow mold, and after forced infusion and solidification, structures of various challenging materials were formed. Using this method, the research team successfully manufactured over 20 types of difficult-to-form materials, including electromagnetic materials, highly absorptive nanoceramics, 3D tin alloys, and hydrogels.

3. Design and Testing of Biomimetic E-skin
   Based on the BMSL technique, the researchers developed a biomimetic piezoelectric electronic skin (FMP) capable of transmitting pressure, rotation, and rigidity actions in real time. Through the design of a gradient micro-unit array, the FMP was applied to robotic operations, achieving multimodal sensing and self-recognition functionalities.

Experimental Methods

• Electrowetting Technology: By applying a spatial electric field, the researchers successfully introduced the solution into ultra-deep micropores, ensuring complete dissolution of the template.
• Hydraulic Pressure Filling: By filling the material under constant hydraulic pressure, the researchers ensured uniform distribution of the material within the micropores, avoiding local voids and structural discontinuities.
• Piezoelectric Performance Testing: The researchers conducted piezoelectric performance tests on the fabricated biomimetic E-skin, verifying its response sensitivity and stability across a wide pressure range.

Key Research Findings

1. Free Assembly of Multiple Materials
   Using the BMSL technique, the researchers achieved the free assembly of various challenging materials, including electromagnetic materials, nanoceramics, tin alloys, and hydrogels. Experimental results demonstrated that the technique enables precise manufacturing of complex structures while maintaining material performance.

2. Performance of Biomimetic E-skin
   The biomimetic E-skin fabricated with the BMSL technique exhibited excellent piezoelectric response performance, enabling high-sensitivity perception across a wide pressure range of 8–240 kPa. Through robotic operation experiments, the researchers validated the superior performance of the E-skin in grasping and stiffness perception.

3. Multimodal Sensing and Self-recognition
   Through the design of a gradient micro-unit array, the biomimetic E-skin achieved multimodal sensing and self-recognition functions. Experimental results showed that the E-skin could provide real-time feedback on the hardness and shape of grasped objects, enhancing the precision of robots in complex operations.

Research Conclusions and Significance

This study proposed a Boolean-logic-guided Investment Micro-casting 3D Stereolithography (BMSL) strategy, successfully achieving the free assembly and multifunctional integration of various challenging materials. Using this technique, the researchers fabricated over 20 types of difficult-to-form materials and developed a biomimetic piezoelectric E-skin with excellent piezoelectric response performance and multimodal sensing capabilities.

The scientific value of this research lies in providing a new technical pathway for the manufacturing of various challenging materials, addressing the challenges of material compatibility and complex structure manufacturing inherent in traditional methods. In terms of applications, this technology offers new ideas for the development of biomimetic E-skin and flexible sensors, with potential applications in robotics, medical devices, and human-computer interaction.

Research Highlights

1. Free Assembly of Multiple Materials: Using the BMSL technique, the researchers achieved the free assembly of various challenging materials, breaking through the limitations of traditional manufacturing methods.
2. Development of Biomimetic E-skin: The biomimetic E-skin fabricated with the BMSL technique exhibited excellent piezoelectric response performance and multimodal sensing capabilities, providing new technical tools for robotic operations.
3. Innovative Manufacturing Method: Drawing inspiration from ancient lost-wax casting, the BMSL technique combines modern 3D printing technology to propose an innovative manufacturing method with broad application prospects.

This research provides a significant technological breakthrough in the field of biomimetic electronics. Future studies can further explore the potential of this technique in more materials and application scenarios.