The advancement of tissue engineering and regenerative medicine has created increasing demand for 3D biomimetic scaffolds capable of replicating the structural complexity of the native extracellular matrix. An ideal scaffold requires not only micro- and nanoscale architectures and excellent biocompatibility but also suitable mechanical properties. Femtosecond laser additive manufacturing offers unique capabilities for mask-free, true three-dimensional microfabrication within photosensitive hydrogels. However, conventional single-wavelength processing faces inherent physical limitations. Short wavelengths such as 400 nm provide high linear absorption efficiency but induce severe volumetric heating and bubble formation. Long wavelengths such as 800 nm minimize thermal damage but suffer from insufficient two-photon absorption cross-sections, resulting in poor mechanical strength and structural fidelity.
A team led by Professor Baoshan Guo from the School of Mechanical Engineering at Beijing Institute of Technology applied a femtosecond laser dual-wavelength dual-pulse spatiotemporal synergy strategy to the fabrication of 3D hydrogel cell scaffolds, effectively overcoming the inherent limitations of single-wavelength processing and achieving the fabrication of mechanically enhanced, bubble-free multilayer scaffold structures with cross-scale architecture.
The team published their findings in Nano Research on July 15, 2026.
The research employs a temporal sequence in which a 400 nm pulse first excites the photoinitiator, followed by an 800 nm pulse after a precisely controlled delay to drive crosslinking polymerization. Under optimal conditions, the dual-wavelength processing reduced the polymerization threshold to 0.2 mW, approximately one-thirtieth of the 6 mW required for single 800 nm processing. While single 400 nm processing exhibited bubble formation after only 3 layers and single 800 nm processing showed structural degradation after 10 layers, the dual-pulse approach achieved a homogeneous, bubble-free 20-layer structure with clear interlayer bonding. The dual-wavelength scaffolds exhibited an average Young's modulus of 148 kPa, significantly higher than 27.7 kPa for single 800 nm processing and 88 kPa for single 400 nm processing. Fluorescence staining revealed that cells on the dual-wavelength scaffolds exhibited the strongest actin cytoskeleton signal, indicating that the 3D scaffolds prepared by the dual-wavelength approach provide a favorable microenvironment for cells.
"We have demonstrated that optimizing the energy deposition path through spatiotemporal coordination of dual pulses enables the fabrication of 3D biomimetic cell scaffolds with high mechanical properties and cross-scale architecture at extremely low power input with minimal thermal damage," said Prof. Guo. "This work provides a new technical approach for the manufacturing of high-performance tissue engineering scaffolds."
Other contributors include Yan Tan, Chong Zhang, and Ruonan Li from the Laser Micro/Nano Fabrication Laboratory, School of Mechanical Engineering, Beijing Institute of Technology; Ze Pei and Shuwei Zhang from the Department of Orthopedics, Chinese PLA General Hospital; Yaning Wei from the Tianjin Key Laboratory of Composite and Functional Materials, School of Materials Science and Engineering, Tianjin University.
This work was supported by the National Key R&D Program of China (2023YFB4603203) and the National Natural Science Foundation of China (52475424).
DOI Link:
https://doi.org/10.26599/NR.2026.94909032
About Nano Research
Nano Research is a peer-reviewed, open access, international and interdisciplinary research journal, sponsored by Tsinghua University and the Chinese Chemical Society, published by Tsinghua University Press on the platform SciOpen. It publishes original high-quality research and significant review articles on all aspects of nanoscience and nanotechnology, ranging from basic aspects of the science of nanoscale materials to practical applications of such materials. After 18 years of development, it has become one of the most influential academic journals in the nano field. Nano Research has published more than 1,000 papers every year from 2022, with its cumulative count surpassing 8,000 articles. In 2025 InCites Journal Citation Reports, its 2025 IF is 9.4 (8.3, 5 years), and it continues to be the Q1 area among the four subject classifications. Nano Research Award, established by Nano Research together with TUP and Springer Nature in 2013, and Nano Research Young Innovators (NR45) Awards, established by Nano Research in 2018, have become international academic awards with global influence.
Nano Research
Fabrication of cross-scale biomimetic 3D hydrogel scaffolds with thermo-mechanical optimized properties via femtosecond laser dual-wavelength dual-pulse regulation
15-Jul-2026