What is it about?
Cancer treatments like CAR T-cell therapy use modified viruses to deliver new genetic instructions into patient cells, but the virus and cell first have to physically collide to begin this process. In a still liquid, heavier cells sink while tiny viruses drift randomly, so the two rarely meet, making standard "static" methods inefficient (often under 10% efficiency). We previously found that simply soaking the same mixture into a dry, porous sponge could boost efficiency to over 80%, but the reason was unclear. This study combines lab experiments with particle-tracking simulations to explain why. As liquid is absorbed into the sponge's winding pores, it generates chaotic micro-currents that continuously stir cells and viruses together, giving them far more chances to collide than in a still droplet. This mixing effect accounts for most of the improvement in efficiency rather than simply trapping in the pores. Because it relies on basic fluid physics rather than special chemistry, the effect should generalize across sponge materials and gene-delivery methods.
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Why is it important?
Manufacturing cell therapies like CAR T-cells is currently slow, complex, and expensive, and inefficient viral delivery is a major reason why. This study provides the first clear physical explanation for why a simple, low-cost, reagent-free method (absorbing cells and virus into a porous sponge) works so much better than standard static incubation. By pinpointing fluid mixing during liquid absorption as the key driver, the findings give manufacturers a predictive, physics-based framework for designing better sponges and protocols, rather than relying on trial and error. The approach also uses viral material far more efficiently, which matters because producing clinical-grade virus is itself a major cost and supply bottleneck. Ultimately, this work points toward more scalable and affordable manufacturing of life-saving cell and gene therapies, and offers a general principle relevant to other situations where rare, hard-to-achieve particle collisions limit a biological or chemical process.
Perspectives
We were fascinated that something as simple as letting a droplet soak into a dry sponge could turn an inefficient gene-delivery process into a highly effective one, and set out to understand why. By building simulations that track individual cells and viruses as they move through the sponge's pores, we were able to precisely model this hidden physics and pinpoint fluid mixing during absorption as the true driver of the effect. We're excited that this kind of predictive, physics-based modeling could pave the way for computationally designed biomaterials, letting researchers engineer better sponges and scaffolds for cell therapy manufacturing before ever stepping into the lab.
Vishal Srikanth
Read the Original
This page is a summary of: Hydrodynamic dispersion drives viral–cellular contact for gene delivery in porous media, Proceedings of the National Academy of Sciences, July 2026, Proceedings of the National Academy of Sciences,
DOI: 10.1073/pnas.2603906123.
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