Stevens Researchers Heat Up Imaging-Guided Bioprinting
A cross-functional team at Stevens Institute of Technology has developed a major advance in 3D bioprinting — one that uses light-driven heat rather than expensive chemicals to create detailed structures.
This innovative Imaging-Guided Microscale Photothermal Stereolithography Bioprinting (ImPSB) method, published in the Advanced Science journal, enables the smooth, cell-compatible, precise printing required for tissue engineering and regenerative medicine.
To deliver this revolutionary approach, Shang Wang, assistant professor from the Department of Biomedical Engineering, led a team including Dilhan Kalyon, professor in the Department of Chemical Engineering and Materials Science; James Liang, professor in the Department of Chemistry and Chemical Biology; and Hongjun Wang, professor from the Department of Biomedical Engineering. They also leveraged support from the Laboratory for Multi-Scale Imaging (LMSI).
Rethinking bioprinting
“The goal of bioprinting is to create functional tissues and organs or generate structures to facilitate that regeneration,” said Shang Wang. “The output should mimic real biological tissues as much as possible. Because the natural tissue structure is so complex, it requires high-resolution bioprinting techniques to accurately deposit cells or materials and potentially reconstruct the tissue structures.”
Stereolithography is a type of 3D printing that uses light to turn liquid into solid, one layer at a time. In bioprinting, it works by shining light onto a special bioink made of living cells and supportive gel-like materials. Until now, hardening the bioink has required expensive, inflexible, light-sensitive chemicals.
The Stevens researchers’ alternative also uses light, but not to harden the bioink directly. Instead, it triggers tiny particles to start reactions that create heat, which in turn solidifies the bioink.
“It’s a cheaper and more versatile approach,” Wang said. “And because these materials are already widely used, we had many tools at our disposal.”
The team members combined their diverse expertise to introduce three innovations to enable high-resolution photothermal printing possible.
They built a first-of-its-kind imaging-guided printing system that allows users to visualize ink behavior and fine-tune laser positioning in 3D as printing occurs. They engineered a particle that converts near-infrared light into heat while carrying the chemicals that start the required heat reaction. They also created a bioink combining a gel-forming base, the heat catalyst and methyl cellulose, a thickening agent to prevent the heat from spreading too quickly.
The resulting system can print smooth, detailed structures, even thinner than a human hair. The printed materials are also safe for use with living cells, which is critical for building tissues.
The technique also works through thin layers of tissue, which could be useful for wound healing or printing inside the body during medical procedures.
Shining a light on the future
“This work is a great example of interdisciplinary innovation,” said Wang. “It brings together optics, materials science, mechanics and biology in a way that wouldn’t have been possible without collaboration among departments at Stevens.”
Next steps include applying this method to print custom tissue models for studying cell behavior and advancing real-time monitoring to improve bioprinting workflows.
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