Table 2.

Representative multiphoton biosensors papers for the detection of SARS-CoV-2.

Journal	Detection Limit	Analyte Types	Optical Effect	Year	Reference
IEEE Sensors Journal	2.5 ng/mL	Nucleocapsid protein	Plasmonic fiber optic absorbance	2021	[108]
Biosensors	0.047 μg/mL	SARS-CoV-2 pseudovirus	Surface plasmon resonance	2022	[109]
Biosensors and Bioelectronics	$0.77 \mathrm{fg}/\mathrm{m}{\mathrm{L}}^{-1}$	Spike protein	Raman scattering	2021	[110]
Sensors and Actuators B: Chemical	50 and 10 pfu/mL	Angiotensin-converting enzyme 2	Raman scattering	2022	[111]
ECS Meeting Abstracts	-	Antibodies to SARS-CoV-2	Surface plasmon resonance	2021	[112]
Analytical Chemistry	$45.6 \mathrm{to} 86 \mathrm{ng} \mathrm{m}{\mathrm{L}}^{-1}$	Nucleocapsid protein	Plasmonics	2022	[21]
Biosensors and Bioelectronics	2 ng/spot	spike S1, spike S1 S2, and the nucleocapsid protein	Fluorescent plasmonics	2021	[113]
Sensors	4.2 μg/mL	Spike protein	Photonics	2021	[114]
Analyst	$12 \mathrm{fg} \mathrm{m}{\mathrm{L}}^{-1}$	Spike S1 protein	Surface plasmon resonance	2022	[115]
Biomedical Vibrational Spectroscopy 2022: Advances in Research and Industry	-	Spike protein	Raman spectroscopy	2022	[116]
Plasmonics	152°/RIU	Spike proteins, membrane proteins, envelop proteins, and nucleoprotein	Surface plasmon resonance	2022	[117]
Sensors	250 μg/mL	Spike (S1 and S2) proteins	Surface plasmon resonance	2021	[118]
IEEE SENSORS 2021	8.34 ng/mL	Spike protein	Surface plasmon resonance	2021	[119]
Biosensors and Bioelectronics	1 μg/mL	Nucleocapsid antibody	Surface plasmon resonance	2022	[120]
AIP Advances	$54.04 {\mathrm{RIU}}^{-1}$	Spike glycoprotein	Surface plasmon resonance	2021	[67]
Analytical Chemistry	-	Spike surface glycoprotein	Surface-enhanced infrared absorption	2021	[13]
Matter	10 PFU/mL	Spike glycoprotein and membrane protein	Raman scattering	2022	[121]
ACS Applied Nano Materials	200 PFU/mL	Spike proteins	Raman scattering	2022	[122]
ACS Nano	0.22 pM	RNA-dependent RNA polymerase	Localized surface plasmon resonance	2020	[123]
Analytical Chemistry	-	Angiotensin-converting enzyme 2	Surface plasmon resonance	2020	[124]
Biosensors and Bioelectronics	150 ng/ml	Detect SARS-CoV-2 nucleocapsid proteins	Localized surface Plasmon resonance	2022	[125]
Analytical Methods	200 μL	Spike and nucleocapsid proteins	Surface plasmon resonance	2021	[126]
Sensors & Diagnostics	10 RU	Spike protein	Surface plasmon resonance	2022	[127]
Biosensors and Bioelectronics	$2 \times {10}^{11}$ particles/mL	Nucleocapsid phosphoprotein gene	Raman scattering	2022	[128]
BioChip Journal	1.02 pM	Antibodies against nucleoprotein	Surface plasmon resonance	2020	[129]
Nanoscale Advances	$4.5 \mathrm{fg}/\mathrm{m}{\mathrm{L}}^{-1}$	SARS-CoV-2 spike protein	Raman scattering	2022	[130]
Biosensors and Bioelectronics	0.08 ng/mL	SARS-CoV-2 spike protein	Localized surface plasmon resonance	2020	[131]
Analytical Chemistry	4 mg/mL	SARS-CoV-2 spike protein	Surface plasmon resonance	2021	[132]
Plasmonics	$1 \times {10}^{13}$ ${ \mathrm{per} \mathrm{m}}^2$	Thiol-tethered DNA of SARS-CoV-2	Surface plasmon resonance	2021	[133]
Talanta	0.046 ng/mL	SARS-CoV-2 spike protein	Raman scattering	2022	[134]
Talanta	$100 \mathrm{pg}/\mathrm{m}{\mathrm{L}}^{-1}$	Measurement of SARS-CoV-2 antibody	Photonic resonator absorption	2021	[135]
Talanta	37 nM	SARS-CoV-2 spike glycoprotein	Surface plasmon resonance	2021	[136]