Table 2.

Comparisons of Optical Nanoprobes Based on Different Nanomaterials in the Detection of Various Viruses

Nanoprobes	Advantages	Disadvantages	Specification	LOD	Time	Ref.
QDs-based biosensors	•large anti-Stokes shifts	•possible breakage and damage of DNA	•rely on hybridization	1–200 nM	minutes to hours	36,37
	•cost effective	•highly cytotoxic in the oxidative environment
UCNPs-based biosensors	•highly sensitive	•low upconversion luminescence efficiency	•rely on hybridization	60 fM–10 pM	minutes to hours	38
	•simple readout	•complicated processing technique	•use of spectrometers
	•high photostability
Gold immune- chromatographic assays	•safe sampling	•not suitable for the early diagnosis	•specific antigen or antibody	500 pM–10 nM	minutes	39
	•convenient and fast	•poor analytical sensitivity	•whole blood or serum
Magnetic particle based	•high specificity	•background fluorescence	•antigen or antibody	50 fM–10 pM	hours	40
Chemiluminescence (CL) immunoassays	•relatively fast	•tedious incubation and washing steps	•CL labels
			•CL substrates
			•magnetic beads
Organic fluorescent molecules-based assays	•relatively convenient	•high costs	•spectrometers	25 pM–1 nM	minutes	41
		•autofluorescence	•rely on efficient nanoquencher
		•poor photostability