Figure 3.. Schematic illustration of the developed Baiya’ Rapid COVID-19’ IgM/IgG test kit. Different test results are shown. AuNPs: gold nanoparticles; C: control line; G: test line for human IgG; M: test line for human IgM; RBD: receptor-binding domain; S: Sample pad; SARS-CoV-2: severe acute respiratory syndrome coronavirus 2.