Table 2.

Various nanobodies, their sources, and mechanism of action against SARS-CoV-2.

Sl. No.	Nanobodies	Source	Dissociation constant (KD) value (nM) against protein of SARS-CoV-2	Mechanism of action	Reference
1.	Ty1	Alpaca		Targets the RBD of the Spike protein with a greater affinity.	[74], [75]
2.	H-11 D4	Ilama	39 (±2)	Blocks the attachment of the ACE2 receptor with the Spike protein	[74], [76], [77]
3.	H-11 H4	Ilama	12 (±1.5)	Blocks the attachment of the ACE2 receptor with the Spike protein.	[74], [76], [77]
4.	Sb23	Library of synbodies	10.6 (± 2)	Blocks the interaction of the ACE2 receptor and the RBD	[78], [79]
5.	K-874A	Camels (no modifications are included)	1.4	Inhibits the fusion of the viral membrane and prevents viral replication	[80]
6.	Nb11–59	Pichia pastoris	21.6	Blocks the interaction of the ACE2 receptor and the RBD	[28], [81]
7.	Nb16–68		36
8.	VNAR	Sharks	38.5–60.3	Targets the S1-RBD and breaks the salt bridge between ACE2 and RBD	[82], [83]
9.	n3113.1-Fc	–	5.3	Binds to the RBD of the Spike protein without involving ACE2 receptor	[84]