Table 3.

Properties of the most commonly used GECIs.

GECI	Class/Color	Excitation/ Emission (nm)	Kd for Ca2+ (μM)	Half Decay Time (s) for 1 AP	SNR	Dynamic Range	References
GCaMP6s	single-FP, GFP	485/510	0.144	0.55	4.4–66 (1–10 APs)	63.2	[24,98,114]
GCaMP6m	single-FP, GFP	485/510	0.167	0.27	20 (40 Hz)	38.1	[98]
GCaMP6f	single-FP, GFP	485/510	0.375	0.11	3.2–50.9 (1–10 APs)	51.8	[24,66,98,114]
jGCaMP7f	single-FP, GFP	485/510	0.174	0.265	17.2	40.4	[114]
GCaMP-X	single-FP, GFP	488/510	2–40	0.60	~18	5	[115]
GCaMPer	single-FP, GFP	490/540	~400	NR	NR	14	[116]
R-CEPIA1er	single-FP, RFP	498/560–800	565	NR	NR	15.6	[117]
jRGECO1a	single-FP, RFP	570/600	0.148	0.39	NR	11.6	[66]
NIR-GECO1	single-FP, GAF (NIR)	678/704	0.215	1.93	0.52	8	[118]
GAF-CaMP2	single-FP, GAF (NIR)	642/674	0.466	NR	NR	1.69	[119]
Twitch-1	FRET, YFP/CFP	432/450–600	0.25	0.80	NR	4	[92]
Twitch-2B	FRET, YFP/CFP	432/450–600	0.20	2.80	10–15	8 (1–AP)	[92]
TN-XXL	FRET, YFP/CFP	440/470	1.03	0.88	NR	1.6–11.2 (2–20 APs)	[92,120]
YC3.6	FRET, YFP/CFP	440/535	0.25	0.34	0.73	6.6	[121,122]
YC-Nano15	FRET, YFP/CFP	458/535	0.015	3–4	2.9–11.4 (1–10 APs)	14.5	[123]
LUCI-GECO1	Bioluminescent, NanoLuc	––/460	0.283	1.21	NR	26	[99]
GLICO	Bimodal, NanoLuc/GFP	480/520	0.59	2.48	0.4	22	[101]

NR—not reported.