A ‘society on a chip’ reveals how viruses spread

A research team led by Professor Sungsu Park of the School of Mechanical Engineering and Professor Byung Mook Weon of the School of Advanced Materials Science and Engineering at Sungkyunkwan University (SKKU) have developed a compact, centimeter-scale microfluidic “Herd-Immunity-on-a-Chip” platform that recreates key features of viral transmission in human societies within a controllable laboratory system.

Building a society on a chip

The study moves beyond conventional cell-infection assays by treating the chip as a simplified society. In this design, lung fibroblast cells act as individuals, hexagonal microchambers serve as spatially organized social spaces, and interconnecting microchannels function as controllable contact routes between those spaces. This configuration allowed the researchers to observe, in real time, how infection spreads—or fails to spread—through a structured population.

Until now, the spread of infectious diseases and the level of population immunity needed to suppress transmission have been studied largely through epidemiological observations, mathematical models, and computer simulations. These approaches are powerful, but they often rely on assumptions such as uniform mixing within a population. Such assumptions can make it difficult to reflect real-world factors, including population density, spatial separation, social distancing, and heterogeneous patterns of contact.

To address this limitation, the research team created a Herd-Immunity-on-a-Chip (HIC), a compact microfluidic platform composed of 444 interconnected hexagonal microchambers. Coronavirus-infected lung fibroblast cells were placed at the epicenter of the chip, while susceptible lung fibroblast cells and non-susceptible cells were arranged in the surrounding chambers to mimic individuals with different levels of vulnerability to infection. Viral transmission across the chip was then monitored over seven days.

When transmission breaks down

The experiments revealed how population structure shapes viral spread. When susceptible cells were densely packed, or when the initial number of infected cells was high, frequent cell-to-cell contact accelerated transmission across the network.

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By contrast, when the proportion of non-susceptible cells was increased to 80% or higher, transmission pathways became fragmented and viral spread was effectively suppressed, reproducing a herd-immunity-like phenomenon on a chip. Restricting cell movement also slowed transmission, experimentally recapitulating the effect of social distancing.

Professor Sungsu Park said “This is the first study to directly recreate and experimentally validate viral transmission and herd immunity—phenomena that have previously been predicted mainly through mathematical modeling and epidemiological studies—on a laboratory chip,”. “We expect this platform to help predict the population-level protection required when new viral variants emerge, design effective distancing strategies, and rapidly evaluate therapeutic or antiviral interventions.”