Researchers at Concordia University have introduced a refined 3D printing strategy that uses acoustic energy to fabricate microscopic features directly onto soft polymers such as silicone. The method, known as proximal sound printing, enhances spatial accuracy compared with earlier sound-based approaches and expands the manufacturing toolkit for delicate materials.

The technique represents a major step forward for microscale manufacturing, enabling highly detailed printing of soft, flexible materials that were previously challenging to shape. By harnessing focused ultrasound, researchers can create complex microfluidic networks, stretchable sensors, and soft robotic parts with greater accuracy, reduced energy consumption, and improved consistency. This capability paves the way for faster development of medical diagnostics, wearable technologies, and other advanced microscale devices.

From left, Researchers Muthukumaran Packirisamy, Mohsen Habibi and Shervin Foroughi. Photo via Concordia.

The study was supported by a Discovery Grant from the Natural Sciences and Engineering Research Council of Canada. 

From Proof of Concept to High-Resolution Control

The work, reported in Microsystems & Nanoengineering, outlines how focused ultrasound can initiate localized chemical reactions that solidify liquid polymers precisely where structures are required. Unlike traditional microscale fabrication methods that depend on heat or light, this acoustic technique is compatible with materials commonly used in microfluidics, lab-on-a-chip technologies and stretchable electronics, systems that are often difficult to pattern with high fidelity.

The advancement builds on the team’s earlier demonstration of direct sound printing, which established that ultrasound could cure polymers on demand. While that initial strategy validated the concept, it faced constraints in resolution and consistency. By repositioning the acoustic source closer to the target surface, the proximal configuration achieves much tighter control over energy delivery.

This adjustment translated into features up to ten times finer than those produced by the original approach. It also reduced power requirements and improved repeatability, two factors critical for scaling microscale manufacturing processes.

Looking ahead, the technology could accelerate prototyping of diagnostic platforms, wearable devices and soft robotic systems, offering a streamlined pathway for producing complex microscale components.

Acoustic Energy in Microscale Manufacturing

Using sound waves to shape materials at small scales is an emerging alternative to heat‑ or light‑driven additive processes, offering new possibilities for delicate or soft materials. The Concordia University team’s proximal sound printing stands out because it combines high resolution, material versatility, and a simple, single-step workflow, producing features up to ten times smaller than previous sound‑driven methods while reducing energy use and improving repeatability.

However, the technique remains limited to soft polymers like silicone and other compatible elastomers; it has not yet been demonstrated for harder or more chemically diverse materials. Feature sizes below the microscale, long-term material stability, and integration with multi-material printing workflows also remain untested, defining the boundaries of its current applicability.

Other acoustic 3D printing efforts help clarify this landscape. Holographic direct sound printing explores using sound holograms to structure entire parts in one step by projecting high‑pressure waves into a polymer bath, illustrating another route to non‑layered ultrasonic fabrication. Acoustophoretic 3D printing has been developed to pattern droplets of viscous fluids into solid structures using acoustic forces, showing how sound fields can expand material choices and drop formation control. 

The 3D Printing Industry Awards are back. Make your nominations now.

Do you operate a 3D printing start-up? Reach readers, potential investors, and customers with the 3D Printing Industry Start-up of Year competition. 

To stay up to date with the latest 3D printing news, don’t forget to subscribe to the 3D Printing Industry newsletter or follow us on Linkedin.

Featured image shows From left, Muthukumaran Packirisamy, Mohsen Habibi and Shervin Foroughi. Photo via Concordia.