Scientists have developed a compact electronic nose (E-nose) built on a standard complementary metal-oxide-semiconductor (CMOS) chip that can detect and distinguish volatile organic compounds (VOCs), according to a preprint posted to arXiv. The device addresses a longstanding gap in sensor technology: while microphones and image sensors have effectively replicated human hearing and vision at low cost, an affordable, miniaturized substitute for the human sense of smell has remained out of reach.

The E-nose consists of an array of 1,024 capacitive microelectrodes on a single CMOS chip. Researchers functionalized the pixel array using inkjet printing, coating different regions with a UV-curable ink and two types of metal-organic frameworks (MOFs) — ZIF-8, MIL-101(Cr), and MIL-140A. These materials create chemically distinct zones across the chip. When gas molecules are adsorbed onto these zones, they alter the local dielectric properties, which the capacitive electrodes detect as electrical signals. Different gases produce different patterns of response across the array, allowing identification of specific compounds.

In laboratory testing, ZIF-8 showed the strongest response to 2-butanone, while the UV-curable layer responded most strongly to toluene. Critically, both materials demonstrated low sensitivity to water vapor, suggesting the device could function reliably in real-world humid environments. The team also reported reproducible detection of controlled binary mixtures of toluene and 2-butanone following calibration in pure gases.

The authors highlight several advantages of their approach: low power consumption, scalability through standard CMOS fabrication, and the flexibility to apply different chemical coatings via inkjet printing for application-specific tuning. They suggest the technology could eventually be adapted for safety monitoring, medical diagnostics, agricultural sensing, and robotics by expanding the range of functionalization materials used.

Important limitations should be noted. This work is a preprint available at https://arxiv.org/abs/2603.23537 and has not yet undergone peer review. Testing was conducted under controlled laboratory conditions using only two VOCs and their binary mixtures; performance in complex, real-world gas environments with many overlapping compounds remains to be demonstrated. Sample size and independent replication data are not detailed in the abstract. The scalability of inkjet functionalization to mass manufacturing also has not been validated.