Surface Modification of Stratum Corneum for Drug Deliveryand Skin Care by Microplasma Discharge Treatment
J. Kristof , T. Aoshima, M. G. Blajan and K. Shimizu
Shizuoka University, Nakaku, Johoku, Hamamatsu, 432-8561, Japane-mail: jaroslav.kristof@gmail.com, shimizu@cjr.shizuoka.ac.jp
Introduction

Repeated treatment of the skin surface

Stratum corneum is first barrier that protect our body anddoes 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 structureis changed. Change of properties of the skin surface canchange flow of transdermal drug delivery – if the drug is force
to adsorb on the skin surface.

contact angle (degree)

110
9030 s
60 s

70

180 s
300 s

50

acc
0

1

2

3

4

5

6

7

8

9treatment number

Temperature of plasma treated skintemperature of skin during
treatment [°C]

Skin temperature is under 45°C –No temperature damage of the skin40

DBD microplasma

3940
39

38383737363635

353434333332323131303029290306090temperature of skin during
treatment [°C]

Ar microplasma discharge

Bloodstream

Drug reservoir

Skin treated the same timeseveral times:
Slight decrease of contact angle

600 s30

Drug delivery is given by:
1. Concentration of drug in reservoir
2. Diffusivity in epidermal layer
3. Properties of vehicle (drug solvent)Inhomogeneity of treatment andfree bonds decay very fast after
plasma treatment

120 150 180 210 240 270 300
time [s]Contact angle measurement
Treatment time effectivity

Epidermal Dermallayer
layer
contact angle (degree)

ExperimentConcentration of drug near surface can be change by surface
properties – characterized by water contact angle

100

air90HeAr
N280

O270

Ar and O2 plasma are
the most effective
when skin is in contact
with electrode60
504030200100

200

300
400
treatment time (s)

500

105
200μm

Ageing effect of plasma treated skincan be described by 2 exponentialfunctions:
Fast increase – recovery fromplasma treatment
Slow increase – drying process andevaporation of water molecules

95

contact angle (degrees)

200 μm8575
65
Ar-experiment

55

fit45

F135F22505 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80
time (hr)Ageing of contact angle:𝒕
𝑪𝑨 𝒕 = 𝑨 + 𝑩 𝟏 − 𝒆𝒙𝒑 −𝒕𝑩= 𝑨 + 𝑭𝟏 + 𝑭𝟐

Plasma treatment of the skin can functionalize and increase ofadhesion properties of the skin

80
70
He
N2

60
50

100

dry skin (Ar)90
wet skin (Ar)

80
70
60
50

contact angle (degree)contact angle (degrees)

90

100
contact angle (degree)

Skin covered by water
after plasma treatment𝒕+ 𝑪 𝟏 − 𝒆𝒙𝒑 −𝒕𝑪

Wet skin samples tc~ 30-40 hours
Dry skin samples tc ~10-15 hours
Fast increase (inverse correlatedwith contact angle)
tb ~20-90 minutes

Dry/Wet skin treatment

Contact angle measurement
Distance effectivity
100600400Ar

200400600

dry skin (Ar)70

dry skin (O2)

60
50
40
300200400600treatment time (s)Skin treatment in contact with electrode

Skin treatment 1 mm from electrode30

wet skin (O2)8020treatment time (s)40

wet skin (Ar)90

Atomic concentration on the skin surface202345678910distance (mm)Contact angle of dry skin depending on
treatment distance for He, N2 and Ar plasma

12mm
Nonhomogeneous
covered by water

1.1
1.0
0.9
0.8
0.7
0.6

Conclusions

Skin treatment at1.1
distance 1 mm from 1.0
electrode:
0.9
only He and Ar
0.8
plasma cause
0.7
increase of O and N
0.6
control air
O2 atoms on the skinsurface(O+N)/C (a.u.)1(O+N)/C (a.u.)

0control air

N2Hesample

ArN2HeAr

O2sample■ 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

Skin treatment incontact withelectrode:All plasma treatedsample caused
increase of O and N
atoms on skinsurface