ROS from Physical Plasmas: Redox Chemistry for Biomedical Therapy

Table 1

Overview of reported studies on penetration depths of plasma-derived ROS in original and artificial tissue models.

Penetration depth	Plasma treatment	Tissue or biosurface studied	References
In vivo models
10 μm	kINPen09	Human skin	[255]
	kINPen09	In ovo tumour of pancreatic adenocarcinoma cells	[106]
~65 μm	MicroPlaSter β plasma torch system	Skin wounds in 129 Sv/Ev female mice	[110]
2.8 mm	Helium plasma jet	Bladder carcinoma tumors in BALB/c nu/nu male mice	[256]
~50 μm	Atmospheric-pressure helium plasma jet	Skin of BALB/c female mice	[257]
~300–400 μm	kINPen09	Hair follicles	[60]
In vitro surrogate models for real tissues
1 mm	Helium plasma jet	ROS delivery through pig skin into liquid	[256]
500–1500 μm	Helium+0.5% O2 plasma jet	ROS delivery through pig muscle into various liquids	[258]
100–470 μm	Helium+0.5% O2 plasma jet	KI starch-containing gelatin films	[259]
150 μm	Helium plasma jet	2,7-Dichlorodihydrofluorescein/gelatin model	[260]
150 μm	Helium plasma jet	ROS sensor-containing phospholipid vesicles in gelatin	[261]
1 mm	Helium linear- and cross-field plasma jets	ROS delivery through gelatin or gelatin+NaNO2 films into distilled water	[262]
1 mm	Helium plasma jet	ROS delivery through gelatin, gelatin+BSA, or poly(vinyl alcohol) targets into various liquids	[263, 264]
6 mm (6 min); 8 mm (36 min); 11 mm (66 min)	Argon plasma jet	KI starch gel	[265]
2 mm (36 min); 4 mm (66 min)		2% agarose
1.5–5.8 mm	Low-temperature plasma jet	ROS delivery through agarose films into liquid	[256, 266–269]
1–2 mm	Helium plasma jet	Agarose films	[270, 271]
2 mm	Helium plasma jet	DNA damage in HEPES solution, phospholipid vesicles, or DNA embedded in gelatin	[272]
In silico models
Plasma ROS: 10–20 μm; H2O2, O2^-: 1–1.2 mm; HO2: 20–250 μm; O3: 5–40 μm	Low-power He-O2 plasma	Highly hydrated biofilms and plasma-tissue interaction models	[273]

Retrospectively measured with software from published images.