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Inhomogeneity of treatment and free bonds decay very fast after plasma treatment
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DBD microplasma
time [s]
tem
pe
ratu
re o
f skin
duri
ng
treatm
ent [°
C]
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tem
pe
ratu
re o
f skin
durin
g
treatm
ent [°C
]
Ageing effect of plasma treated skin can be described by 2 exponential functions: Fast increase – recovery from plasma treatment Slow increase – drying process and evaporation of water molecules Wet skin samples tc~ 30-40 hours
Dry skin samples tc ~10-15 hours
Fast increase (inverse correlated with contact angle) tb ~20-90 minutes
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0 200 400 600
con
tact
an
gle
(d
eg
ree)
treatment time (s)
dry skin (Ar)
wet skin (Ar)
■ Microplasma irradiation increases water contact angle – the most efficient on surface on electrode by Ar plasma
■ Roughness of the skin sample has minor effect on water contact angle (plasma treatment is nonhomogeneous)
■ Ageing effect can be describe by decaying of plasma effect and drying of the skin sample
■ Wet skin samples has lower water contact but after plasma treatment, contact angle is increasing due to water evaporation
■ Microplasma treatment increase oxygen and nitrogen atoms on the skin surface
Surface Modification of Stratum Corneum for Drug Delivery and Skin Care by Microplasma Discharge Treatment
J. Kristof , T. Aoshima, M. G. Blajan and K. Shimizu
Shizuoka University, Nakaku, Johoku, Hamamatsu, 432-8561, Japan
e-mail: [email protected], [email protected]
Conclusions
Experiment
Stratum corneum is first barrier that protect our body and does not allow penetration of amount of objects such as drugs. Intercellular route is very often used for drug penetration when stratum corneum lipids are extracted or their structure is changed. Change of properties of the skin surface can change flow of transdermal drug delivery – if the drug is force to adsorb on the skin surface.
Skin treatment at distance 1 mm from electrode: only He and Ar plasma cause increase of O and N atoms on the skin surface
Ageing of contact angle:
Skin temperature is under 45°C – No temperature damage of the skin
Contact angle measurement Treatment time effectivity
Contact angle measurement Distance effectivity
Ar microplasma discharge
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100
co
nta
ct
an
gle
(d
eg
ree
s)
distance (mm)
He
N2
Ar
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con
tact
an
gle
(d
eg
ree)
treatment time (s)
air
Ar
He
N2
O2
25
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45
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105
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80
con
tact
an
gle
(d
eg
rees)
time (hr)
Ar-experiment
fit
F1
F2
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con
tact
an
gle
(d
eg
ree)
treatment time (s)
wet skin (Ar)
wet skin (O2)
dry skin (Ar)
dry skin (O2)
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110
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con
tact
an
gle
(d
eg
ree)
treatment number
30 s
60 s
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600 s
acc
control air N2 He Ar O20.6
0.7
0.8
0.9
1.0
1.1
(O+
N)/
C (
a.u
.)
sample
control air N2 He Ar O20.6
0.7
0.8
0.9
1.0
1.1
(O+
N)/
C (
a.u
.)
sample
Drug reservoir
Epidermal layer
Dermal layer
Blood stream
Drug delivery is given by: 1. Concentration of drug in reservoir 2. Diffusivity in epidermal layer 3. Properties of vehicle (drug solvent)
Concentration of drug near surface can be change by surface properties – characterized by water contact angle
Plasma treatment of the skin can functionalize and increase of adhesion properties of the skin
Contact angle of dry skin depending on treatment distance for He, N2 and Ar plasma
Dry/Wet skin treatment
Ar and O2 plasma are the most effective when skin is in contact with electrode
𝑪𝑨 𝒕 = 𝑨 + 𝑩 𝟏 − 𝒆𝒙𝒑 −𝒕
𝒕𝑩+ 𝑪 𝟏 − 𝒆𝒙𝒑 −
𝒕
𝒕𝑪= 𝑨 + 𝑭𝟏 + 𝑭𝟐
Skin treatment in contact with electrode
Atomic concentration on the skin surface Skin treatment in contact with electrode: All plasma treated sample caused increase of O and N atoms on skin surface
Skin treated the same time several times: Slight decrease of contact angle
Skin treatment 1 mm from electrode
Repeated treatment of the skin surface
Skin covered by water after plasma treatment
Nonhomogeneous covered by water
Temperature of plasma treated skin
200 μm 200μm
12mm
Introduction
