On‐Chip Optical Detection of Viruses: A Review

The current outbreak of the coronavirus disease‐19 (COVID‐19) pandemic worldwide has caused millions of fatalities and imposed a severe impact on our daily lives. Thus, the global healthcare system urgently calls for rapid, affordable, and reliable detection toolkits. Although the gold‐standard nucleic acid amplification tests have been widely accepted and utilized, they are time‐consuming and labor‐intensive, which exceedingly hinder the mass detection in low‐income populations, especially in developing countries. Recently, due to the blooming development of photonics, various optical chips have been developed to detect single viruses with the advantages of fast, label‐free, affordable, and point of care deployment. Herein, optical approaches especially in three perspectives, e.g., flow‐free optical methods, optofluidics, and surface‐modification‐assisted approaches, are summarized. The future development of on‐chip optical‐detection methods in the wave of emerging new ideas in nanophotonics is also briefly discussed.