Fig. 3.

Application of click chemistry to detect viral infection. (a) To detect DENV, magnetic nanoparticles (MNPs) are functionalized with capture (Gus11) and high-affinity monoclonal antibodies (1H7.4) against DENV NS1 protein via bio-orthogonal Cu-free click chemistry (Antunes et al., 2015). The presence of the target antigen NS1 triggers MNP agglutination and the formation of nanoclusters with rapid kinetics enhanced by external magnetic actuation (Antunes et al., 2015). The amount and size of the nanoclusters correlate with the target concentration and can be quantified using an optomagnetic readout method (Antunes et al., 2015). (b) The sialic acid-mimic peptide dimer was immobilized on the alkyne-terminated BDD electrode via a click reaction, and the capture of the influenza virus was detected electrochemically (Matsubara et al., 2016). (c) Biotin-modified capture DNA was linked on Streptavidin MagneSphere Paramagnetic Particles and hybridized with hepatitis B virus DNA, followed by hybridizing the target DNA with DNA-CuS particles to form a sandwich like structure (Yue et al., 2014). Subsequently, CuS particles on the sandwich structures were destroyed by acid to form Cu(II) that was reduced to Cu(I) by sodium ascorbate, which in turn catalyzes the reaction between a weakly fluorescent 3-azido-7-hydroxycoumarin and propargyl alcohol to form a fluorescent 1,2,3-triazole compound (Yue et al., 2014).