Table 1.

Summary of Brain Organoid Characteristics in COVID-19 Studies.

S. No.	Reference	Brain Organoid Characteristics
		Brain Region	Stem Cells	Protocol	Patterning Factors	Organoid Age	Agitation
1	Zhang and others (2020)	Cortex	iPSC	iPSC → EB → Organoid	SB-431542 (TGFβ, Activin and NODAL inhibitor), Dorsomorphin (BMP inhibitor), GDNF, BDNF	35 days	Yes
2	Song and others (2020)	Whole brain	iPSC	iPSC → EBs → Matrigel embedding → Agitation → Organoid	Intrinsic	9 weeks	Yes
3	Yi and others (2020)	Cortex	hESC	hESC → EBs → Organoid	SB-431542 and IWR1 (WNT inhibitor)	6 months	Yes
4	Jacob and others (2020)	Cortex	iPSC	iPSC → EBs → Matrigel embedding → Agitation → Organoid	Dorsomorphin, A83 (BMP and TGFβ inhibitor), SB-431542, CHIR99021 (GSK3β inhibitor)	Not stated	Yes
		Midbrain			Forebrain factors + LDN-193189 (BMP and SMAD inhibitor), SB-431542, Purmorphamine (Smoothened agonist), SHH (Sonic Hedgehog), FGF8, CHIR99021, BDNF and GDNF
		Hippocampus			Forebrain factors + Recombinant human BMP-7
		Hypothalamus			Forebrain factors + SHH, Purmorphamine, IWR-1 and SAG (Smoothened Agonist)
		Choroid plexus			LDN-193189 (BMP and SMAD inhibitor), IWP-2 (WNT inhibitor), CHIR-99021, and BMP-7, BDNF, GDNF
5	Pellegrini and others (2020)	Whole brain	hESC	hESC → EBs → Matrigel embedding → Agitation → Organoid	Intrinsic	>55 days	Yes
		Choroid plexus			CHIR99021 + BMP4
6	Ramani and others (2020)	Cortex	iPSC	iPSC → EBs → Matrigel embedding → Agitation → Organoid	Dosmorphin, SB431542, BDNF, GDNF	15/60 days	Yes
7	Tiwari and others (2021)	Whole brain	iPSC	iPSC → EBs → Matrigel embedding → Agitation → Organoid	Intrinsic	80 days	Yes
8	Gleeson and others (2021)	Cortex	iPSC	iPSC → EB → Organoid	SB-431542, IWR-1, GDNF, BDNF	60 days	—
9	Wang and others (2021)	Whole brain	iPSC	iPSC → EBs → Matrigel embedding → Agitation → Organoid	Intrinsic	60 days	Yes