3D-Printed Sensors: Emerging Strategies and Materials

Additive manufacturing, or 3D printing, pushes conventional limits for manufacturing sensors used for monitoring environmental changes and conditions.

Because 3D printing enables the fabrication of complex geometries, it is gaining popularity for sensor manufacturing. Benefits such as allowing fabrication directly on complex, nonplanar structures make 3D printing a viable alternative for conventional manufacturing. Additionally, 3D printing can reduce cost and processing time while increasing design flexibility.

You can also read: Polymeric Biosensors: A New Era in Medical Diagnostics.

Manufacturers can embed sensor components in 3D-printed housing or, in some applications, print the entire sensor at once. Since sensors comprise various materials, they require 3D printing systems that can fabricate using multiple materials simultaneously. Few systems are currently capable of this; thus, a hybrid approach is often employed, combining various manufacturing methods.

Another key advantage of 3D printing is resource optimization, which can emphasize sustainability. Manufacturers can lower their carbon footprint with less wasted material and more precise designs. Filaments created from waste materials can also allow for manufacturing sensors from recycled materials.

What Materials are Usable for 3D-Printed Sensors?

For fully 3D-printed sensors, carbon-based inks or carbon nanotubes (CNT) are essential for printing soft sensors. For example, to fabricate a soft pressure sensor, researchers employed the photopolymer TangoPlus™ FLX930 (Stratasys) as an insulating layer. Researchers then covered the layer with CNT electrodes, then covered the electrodes with an ionic layer (1-ethyl-3-methyl-imidazolium tetrafluoroborate). Positioning the sensor between two electrodes establishes sensitive units at the intersections.

Various polymers are suitable for 3D printing; manufacturers should select a polymer based on the desired application. For example, gas sensors can detect ammonia using polylactic acid (PLA) combined with copper particles.

The more common hybrid 3D-printed sensors allow for plenty of material variety. Silicon rubber is useful for both industrial pressure sensors and, in biomedical applications, certain artificial organs. Arsenic detectors are an example of an electrochemical sensor that uses nanocomposites. Hydrogel is diversely applicable for 3D-printed sensing layers. Polyvinylidene fluoride (PVDF) has application potential for 3D printed piezoelectric devices due to its vibration detection capabilities.

You can also read: Polymeric Biosensors: A New Era in Medical Diagnostics.

Avenues for Future Research

3D printing is an exciting avenue for sensor manufacturing. Still, technological limitations pose challenges for researchers and manufacturers in this space. As aforementioned, the lack of multi-material systems prevents fully 3D-printed sensors from becoming more ubiquitous. Along the same line, not all materials are printable. Without access to the proper material, sensors may have limited performance. Additionally, 3D-printed sensors still require connection with electronic devices, and wires are not always compatible with sensor materials.

Hybrid-manufactured sensors are already commercially available. As research continues, fully 3D-printed sensors may become more feasible. This can allow manufacturers to better seize the benefits of 3D printing.