Continuous quantification of viral plaque dynamics using ultra-large-area label-free imaging enables rapid antiviral susceptibility testing
Organizations: Department of Electrical and Computer Engineering, University of California, Los Angeles, CA, USA, 90095 · Department of Bioengineering, University of California, Los Angeles, CA, USA, 90095 · 3California NanoSystems Institute (CNSI), University of California, Los Angeles, CA, USA, 90095 · Department of Biochemistry, University of California, Los Angeles, CA, USA, 90095 · Department of Computer Science, University of California, Los Angeles, CA, USA, 90095 · JDI Display America, Inc., San Jose, CA 95110, USA · 7Sensor Department, Application Engineering Division, Japan Display Inc., Tokyo 105-0003, Japan · Department of Surgery, University of California, Los Angeles, CA, USA, 90095
Abstract
The plaque reduction assay (PRA) remains the gold standard for antiviral susceptibility testing, evaluating drug potency by measuring reductions in plaque-forming units (PFUs). However, the traditional PRA is time-consuming, labor-intensive, prone to manual counting errors, and offers limited scalability. Moreover, its reliance on destructive fixation and chemical staining reduces the assay to a static, endpoint observation, obscuring the dynamic, time-resolved kinetics of dose-dependent viral inhibition. Here, we introduce a label-free, time-resolved PRA platform that transforms the conventional assay into a continuous, high-dimensional measurement of viral infection dynamics. Our system integrates a compact lens-free imaging setup with a custom-designed ultra-large-area (100 cm^2) thin-film transistor (TFT) image sensor and deep learning-based algorithms to autonomously quantify PFU dynamics within an incubator. Validated using herpes simplex virus type-1 (HSV-1) treated with acyclovir, the platform matched chemically-stained ground truth measurements with zero false positives while accelerating readout by ~26 hours. Crucially, our system revealed that increasing drug concentrations induce temporally distinct delays and suppress new PFU formation, enabling conclusive drug efficacy evaluations within ~60 hours post-infection. This scalable, label-free framework redefines antiviral susceptibility testing as a rapid, time-resolved and information-rich measurement framework, providing a generalizable platform for virology research, high-throughput drug screening, and clinical diagnostics.