Table 1. Analysis of histone H2AX phosphorylation in response to THz radiation exposure.

	Ref. [33]	Ref. [34]	Ref. [35]	Ref. [28]	This study
Sample	artificial human skin tissues equivalents	human embryonic stem cell line hESM01	human Fetal Foreskin Fibroblasts (HFFF2)	human adult dermal fibroblasts	human adult dermal fibroblasts
THz source	0.1-2 THz	2.3 THz	0.1-0.15 THz		0.1-3 THz
Repetition rate	1 kHz		2.5 Hz (for macropulse)		100 Hz
Pulse duration	∼1.7 ps			4 μs a	0.5 ps
Exposure conditions	Iav = 57 mW/cm2, Ipeak = 66 MW/cm2, WTHz b  = 220 kV/cm, WTHz c  = 70 kV/cm	Iav = 0.14 W/cm2, Ipeak = 4 kW/cm2	Iav = 0.40 mW/cm2, Pav ≤ 10 mW		Iav=0.84 mW/cm2, Ipeak=32 GW/cm2
Exposure time	10 min	60 min	20 min		10, 30, 90, 180 min
Ambient temperature	21°C	24°C, cells were kept under 36.5–37.5◦C	16°C	20°C	37°C
Temperature control	No	Yes, infrared imager	Yes, infrared camera		No
Expected temperature increase	ΔT = 0.7°C (calculated)		ΔT = 0.3°C (calculated)		ΔT = 2.8°C (calculated)
Type of analysis	Qualitative, immunochemical	Quantitative, Immunochemical	Quantitative, Immunochemical		Quantitative, Immunochemical
Time post exposure prior to analysis			30 min, 2 hrs, 24 hrs		0, 24 hrs
Induction of H2AX phosphorylation observed	Yes	No	No	No	Yes

^a Each macropulse consists of 50 ps long micropulses with a 330 ps spacing between them

^b “High” THz energy mode, E_THz=1 μJ

^c “Low” THz energy mode – E_THz=0.1 μJ