Rapid and stain-free quantification of viral plaque via lens-free holography and deep learning

A plaque assay, the gold-standard method for measuring replication-competent lytic virions, requires staining and >48 h runtime. This study demonstrates a combination of lens-free holographic imaging and deep learning to automate and expedite the assay. The compact device captures label-free phase information at ~0.32 gigapixels per hour per well, covering 30 × 30 mm² and a 10-fold larger dynamic range than standard assays, quantifying infected area and plaque-forming units (PFUs). For vesicular stomatitis virus (VSV), the assay detected initial cell lysis at 5 h and >90% PFUs at <20 h with 100% specificity. Incubation time was reduced by ~48 h for herpes simplex virus type 1 and ~20 h for encephalomyocarditis virus. This stain-free assay is suitable for virology research, vaccine development, and clinical diagnosis.

Tairan Liu, Yuzhu Li, Hatice Ceylan Koydemir, Yijie Zhang, Ethan Yang, Merve Eryilmaz, Hongda Wang, Jingxi Li, Bijie Bai, Guangdong Ma, Aydogan Ozcan