# Tartu and IIT moth robot grows a UV sensor from artificial blood in its 3D-printed body

- Published: 2026-11-05 16:21 UTC
- Section: Machines & Making › Robots
- Tags: moth robot, artificial hemolymph, robot circulatory system, polypyrrole sensor, UV light sensor, 3D-printed robot, Italian Institute of Technology, University of Tartu, adaptive robot hardware
- URL: https://realtech.media/news/rt-f73e7119705e266ef18e1b28_tartu_and_iit/

**A prototype moth-shaped robot from the University of Tartu and IIT formed a UV sensor in its plastic body from a fluid pumped through artificial veins.**

Researchers at the University of Tartu in Estonia and the Italian Institute of Technology built a moth-shaped robot that grew a light sensor inside its own body, according to a report on eurekalert.org. The prototype pumped an artificial hemolymph through its body, and where UV light struck for about a minute, the plastic became a conductive sensor [1].

Robots usually carry sensors fixed at the factory, based on a guess of the environment they will meet. Lead author Kadri-Ann Pankratov says the aim is to give robots a circulatory system that transports molecular building blocks across the body, so the hardware is created on site, where and when it is needed [1].

## Artificial hemolymph and printed veins

The team took its blueprint from the blue underwing moth (Catocala fraxini), whose open circulatory system simply bathes the organs in hemolymph. The robot's body is 3D-printed from transparent PETG plastic. Millimetre-wide veins carry fluid across wings of 86 square centimetres each, and the gaps between printed lines form a dense network of microchannels from which the liquid soaks about 10 micrometres into the plastic. A single pump with open-loop control fills the whole body with about 3 millilitres of liquid [1].

The artificial hemolymph is a mixture of pyrrole, a light-activated initiator and a cellulose-based additive. Where UV light shone on the body for about a minute, the pyrrole inside the plastic turned into polypyrrole, an electrically conductive polymer, and the translucent body turned black there. Elsewhere it stayed unchanged. With a stencil, the team drew sensor patterns with 0.3-millimetre precision [1].

## Sensor behaviour and limits

The new material works as a UV receptor: its electrical resistance briefly drops under UV light. Before the sensor was grown, the robot did not react to UV at all. Afterwards a small onboard microcontroller detected the change and made the robot flap its wings, driven by a shape-memory wire, or blink an LED. In Pankratov's words, this is a new body part that did not exist before, not a regrown lost one [1].

The sensor did not behave like a factory-calibrated component. With each exposure it became more sensitive, as leftover pyrrole kept polymerising. The authors interpret this as a form of material memory. The sensors still worked after more than four months of storage [1].

The study is a proof of concept. It demonstrates a single, predetermined chemical pathway, and the synthesis is irreversible. The researchers decided when to fill the veins, and a stencil, rather than the surroundings, decided where the sensor formed [1].

## Sources

1. [eurekalert.org](https://www.eurekalert.org/news-releases/1149896)
2. [New Atlas](https://newatlas.com/robotics/tartu-iit-robot-moth-artificial-blood-uv-sensor)

---

Source: RealTech, realtech.media — https://realtech.media/news/rt-f73e7119705e266ef18e1b28_tartu_and_iit/