3D-printed leaf chamber measures carbon at Biosphere 2

As global temperatures rise, Biosphere 2 researchers are working to track plant-air interactions and better understand the global carbon cycle. 

Interdisciplinary Capstone Team 26040 is helping make that possible. The team 3D printed an autonomous leaf chamber that measures how plants exchange gases with the atmosphere – a key indicator of photosynthesis and plant health.

“We’re designing a device that can automatically measure gas exchange while being affordable and easy for researchers to use,” said Molly Auer, mechanical engineer and team lead.

The team’s small, transparent chamber attaches to a leaf and automatically records environmental conditions including light, air temperature, leaf temperature and humidity. When the chamber closes, it draws air through a gas exchanger that measures carbon dioxide and water vapor concentrations, letting researchers monitor plant activity more efficiently. 

“Traditionally, researchers clamp an instrument directly onto a leaf and program it to take measurements, but the process requires them to be physically present and limits how often data can be collected throughout the day,” said Joost Van Haren, director of rain forest research at Biosphere 2 and team sponsor.

The chamber collects environmental data and plant responses, helping researchers better understand how plants react to a changing climate.

Rising to the challenge

Team 26040 is tackling several technical hurdles – all at a very small scale.

“We have to create a lightweight, minimally invasive device that can form an airtight seal on the leaf for accurate measurements,” Auer said. “It also can’t alter the leaf’s environment – no trapping humidity, no raising temperature, nothing that could interfere with the plant’s natural processes.”

The device must also withstand the humid, variable conditions of the Biosphere 2 rainforest biome, requiring electronics and materials that stay durable and reliable over time.

Balancing precision with accessibility has proven to be the team’s steepest challenge. Commercial gas-exchange systems used in plant research can cost tens of thousands of dollars. The students are designing a system that delivers reliable measurements at a significantly lower cost and deploys across multiple plants at once.

To get there, the team shifted from traditional fused deposition modeling to resin 3D printing. Resin printing offers higher precision – crucial at the scale the team is working with – and helps ensure the sealing mechanism achieves an airtight fit.

If successful, the automated chamber helps researchers collect continuous data throughout the day without manually monitoring each measurement. 

Auer and her team have completed control tests, confirming their 3D-printed walls function as intended. They are now testing a different printing method to improve the chamber’s opening and closing mechanism.

"Everyone on my team brings a strong background to the table," Auer said. "Working with members from different engineering disciplines has really helped spark new ideas, curiosity and motivation to move this project forward together."

Watch interdisciplinary capstone teams showcase their work at the Craig M. Berge Design Day on May 4.