What if diagnosing pneumonia were as simple as breathing into a device? A new breath test uses nanoparticles and a chip-scale sensor to detect disease biomarkers.
A breath test developed by engineers at Massachusetts Institute of Technology could allow doctors to detect diseases such as Pneumonia within minutes. Instead of relying on chest X-rays or lab tests that take hours, the approach analyzes compounds in a patient’s breath using a sensor. A patient inhales nanoparticles and then breathes into a device that detects disease biomarkers released in the lungs.
The system combines inhalable nanoparticles with a chip-scale sensor that captures molecular signals in exhaled breath. Called PlasmoSniff, it is designed for integration into a handheld diagnostic device for clinics or home use. The approach relies on Plasmonics, which studies how light interacts with materials at the nanoscale. Molecular bonds vibrate in characteristic ways, creating signatures that the team detects using Raman Spectroscopy, where small shifts in scattered light reveal the molecules’ vibrational fingerprints.
Because disease biomarkers appear in small amounts in breath, the sensor must capture the molecules and strengthen their optical signals. To do this, the device uses a nanoscale structure that traps biomarkers and increases the signal detected by Raman Spectroscopy. The sensing surface consists of a gold film with gold nanoparticles placed above it, each surrounded by a silica shell that forms a gap of about five nanometers between the particle and the surface. The silica shell binds with water molecules, which attach to biomarkers through hydrogen bonding, so when breath vapor passes through the sensor, the biomarkers stick to these water molecules and remain in the sensing region.
This gap also concentrates light through plasmonic resonance. When light hits the gold structures, electrons on the metal surface oscillate together, creating an electromagnetic field within the gap. Biomarkers located in this region experience a stronger field, which increases their Raman scattering signal. The scattered light is then measured and compared with molecular fingerprints to confirm the presence of biomarkers.
To evaluate the sensor, the researchers tested it using lung fluid samples from mice. Pneumonia biomarkers were added, and the mixture was heated in a vial to generate vapor similar to exhaled breath. The sensor was placed in the vial cap while a Raman spectrometer measured scattered light as the vapor passed through the sensing structure. The experiments showed the device could detect pneumonia biomarkers even at low concentrations.
The next step is to integrate the sensor with a breath collection system. One design uses a mask that captures exhaled breath while a handheld device performs the Raman measurement. In this setup, a patient inhales the nanoparticles first and then breathes into the mask for several minutes while the system analyzes the released biomarkers.