Figure 2.

The use of optical biosensors in the detection of SARS-CoV-2 (a) Schematic representation of smartphone reader used for optical immunosensor in the detection of IgA. Reprinted with permission from Ref. [78]. (b) Preparation and operating-principle of (a) SARS-CoV-2 S protein coupled SiO₂@Ag SERS tags and (b) simultaneous detection of anti-SARS-CoV-2 antibodies. Reprinted with permission from Ref. [79]. (c) Schematic representation of localized surface plasmon resonance–based opto-microfluidic sensor to detect SARS-CoV-2 antibodies. Reprinted with permission from Ref. [83].