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Asst. Prof. Dr. Nattaya Lourith[[email protected]] 1
Skin elasticity
2
Objectives
• To be acknowledged on skin elasticity• To be informed about skin elasticity
evaluation techniques• To differentiate application of each
technique
3
Contents
• Introduction • Techniques in skin elasticity evaluation• Application of each technique
4
• Skin => tissues + fluids components• Skin = Viscoelastic body• Skin => rheology• Skin = elasticity + viscousity
Skin
5
Elasticity • Elastin : elasticity• Collagen : extensibility• Torsion extensibility sharply reduce @ 35 y
Methods
• Torsion • Suction • Wave propagation 6
Torsion = TwistometerSkin deformation with torque• Rotation sensor• Disc • Guard ring• Processor
- 4 – 57 mNm torque
- 1, 3, 5 mm skin crown
- 18 or 25 mm disc
Asst. Prof. Dr. Nattaya Lourith[[email protected]] 2
7
Torsion : Dermal torque meterExtensibility = Ue
Elasticity = Ur/Ue
8
Torsion : DensiScore
Skin density
Skin creasing
9
Torsion : DensiScore
10
Torsion : Extensometer
11
Torsion : Extensometer
12
Torsion : Ballistometer
• Indentation in skin losing because of tissue viscosity
• Impact pendulum• Storage = elastic• Loss = viscous
Asst. Prof. Dr. Nattaya Lourith[[email protected]] 3
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Torsion : Ballistometer
14
• Kinetic energy from falling object• Energy transfer => probe rebound
releasing• Greater rebound : elastic/viscosity
component is higher• No. of rebounds• Amplitude of the first rebound• Area of the first rebound
Torsion : Ballistometer
15
Suction
• Dermalab• Cutometer 16
1. Vacuum generator
2. Probe sensor
3. Data processing
- 10 mm steel ring in probe
- 0.01 mm accuracy
- 300 or 450 mbar
- 4 or 20 s suction
- 5 or 6 cycle
Suction : Dermalab
17
Suction : Cutometer
• Aperture size– 2 mm (epidermis)– 4 or 6 mm (outer layers)– 8 mm (full thickness)
• 50 and 500 mbar• Suction & relaxation time
– 0.1 – 60 s• 1 – 99 cycle
18
Ue = immediate distension
Uf = final distention distension
Uv = delayed distention
Ur = immediate retraction
Suction
Uv/Ueincrease = elasticity decrease
Asst. Prof. Dr. Nattaya Lourith[[email protected]] 4
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Parameters • Highly elasticity : Ur = Uf• R0 = Uf : passive behavior of skin to force• R1 = Uf-Ua : return to original skin state• R2 = Ua/Uf : gross elasticity =>1• R3 = last max. amplitude • R4 = last min. amplitude• R5 = Ur/Ue : net elasticity => 1• R6 = Uv/Ue : viscoelasticity => 0• R7 = Ur/Uf : skin firmness => 1• R8 = Ua : return to original skin state => 0
20
ΔUr/Uf = skin firmness3 cycles, T = 22 – 24 °C, %RH = 40 – 60% (x3)
Futrakul B, Kanlayavattanakul M, Krisdaphong P. Int. J. Cosmet. Sci. 32, 211-215, 2010.
21
Electrodynamometer • Skin elastic wave propagation
22
• Piezoelectric elements• Acoustic shockwave
emission• Receiving depend on
elastic fibers and moisture content
• Different time wave movement interpreted in to viscoelasticity of skin
Reviscometer
23
References • Edwards C, Marks R. Evaluation of biomechanical properties of
human skin. Clin. Dermatol. 13, 375-380, 1995.• Andreassi L. Bioengineering in dermatology: general aspects
and perspectives. Clin. Dermatol. 13, 289-292, 1995.• Serup J, Jemec GBE, Grove GL. Handbook of non-invasive
methods and the skin. 2nd ed. New York: CRC, 2006.• Cooper ER, Missel PJ, Hannon DP, Albright GB. Mechanical
properties of dry, normal and glycerol-treated skin as measured by the gas-bearing electrodynamometer. J. Soc. Cosmet. Chem. 36,335-348, 1985.
• Jachowicz J, McMullen R, Prettypaul D. Indentometric analysis of in vivo skin and comparison with artificial skin models. SkinRes. Technol. 13, 299-309, 2007.
• Batisse D, Bazin R, Baldeweck T. et al. Influence of age on the wrinkling capacities of skin. Skin Res. Technol. 8, 148-154, 2002.
• Petti L, Fogouang L, Uhoda I. et al. Regional variation in mottled subclinical melanoderma in the elderly. Exp. Gerontol. 38, 327-331, 2003.
Skin image & color
Asst. Prof. Dr. Nattaya Lourith[[email protected]] 5
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Objectives
• To be acknowledged on the important of skin image and color
• To be informed on the techniques used for skin image and color analysis
26
Contents
• Introduction • Techniques used in skin image• Techniques used in skin color
27
Wrinkles • Crinkles
– A very fine micro-wrinkling – Disappear on stretching – @ 75 y has crinkled skin
• Glyphic wrinkles– Primary lines of normal skin surface marking– Caused by solar radiation– Appear on neck, cheek
• Linear facial wrinkles – Long, strait, slightly curve– Do not disappear on stretching 28
Glyphic wrinkles in a 65 y F
Glyphic wrinkles in a 84 y M
29
Facial linear wrinkles
• Horizontal frown lines along the forehead
• Crows feet radiating from the lateral canthus of the eye
• Crease from the nose to the corners of the mouth
• Creases on the upper and lower lips radiated from the mouth
30
Facial wrinkles
Horizontal lines in a 72 y M
Crows feet in a 58 y M
Creases from nose and lips in a 70 y F
Asst. Prof. Dr. Nattaya Lourith[[email protected]] 6
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Digital photographed of skin
Index finger of different subject (row)1st row : bottom segment on palm side2nd row : finger tip3rd row : bottom segment on back side 32Ruamrak C, Lourith N, Natakankitkul S. Int. J. Cosmet.
Sci. 31, 41-46, 2009.
33
Profilometry
• Skin replica of forehead (56 y M) under relaxation
• Lab conditioned @ 20 – 22 ° C, 50 –57% RH
34
Profilometry
35
Age
-relat
ed c
hang
es in
wrinkle
dept
h
36Age
-rel
ated
cha
nges
in w
rink
le w
idth
Asst. Prof. Dr. Nattaya Lourith[[email protected]] 7
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Skin image analyzer
• Photography • Videography• Magnification • Different light condition• Computer program• Color analysis
– RGB– ITA° : CIELab
38
Surface topography by videomicroscopy
Microscope image of skin
39
Principle- Direct in vivo 3D method- Micromirror digital stripe projection system- Image on a digital matrix camera- Parameters:
. Average roughness (Ra)*
. Maximum difference (Rt)
. Average relief (Rz)
PRIMOS
40
Principle- Indirect method via skin replica- Oblique lighting brings shadows from the replica to the fore - Analysis of the gray shades Parameters
: number and average depth:. microrelief furrows (<55 µm)*. average wrinkles (55-110 µm). deep wrinkles (>110 µm)
- Index:. roughness index for the skin surface relief. total wrinkled surface
Skin Image Analyser (SIA)
41
Principle- Indirect method via skin replica- Laser diode scanning method- 3D image reconstitution- Parameters:
. Microrelief: complexity, average depth
. Principal wrinkles: depth, complexity and volume
Laser Profilometry
42
SIAscope
visioscope
Visioscan
Asst. Prof. Dr. Nattaya Lourith[[email protected]] 8
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Visioscan• SEr = roughness • SEsm = smoothness• SEw = wrinkles• SEsc = scaliness
44Chuarienthong P, Lourith N, Leelapornpisid P. Int. J. Cosmet. Sci. 32, 99-106, 2010.
45
VISIA (RBX)
46
Skin color
Epidermis : optical filterKeratinocytes : chromophore (melanin)Dermal capillaries : chromophore (haemoglobin)
47
• Melanin (UV)• Haemoglobin (415, 542, 577 nm)
Skin color
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Skin color
• Colorimetry– CIELab– Hyperpigmentation decreasing L*
• Chromophore mapping• Changes in skin color tone• SIAscopy• RBX
– Melanin/haemoglobin deposition across different skin type
Asst. Prof. Dr. Nattaya Lourith[[email protected]] 9
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• Photography – Normal light
• Hypomelanotic or hypermelanotic areas of dermis– UV light
• 300 – 400 nm (360 nm)• Epidermal change with non of dermal color change
detection– Polarized light
• Based on back-scattered light from tissue• Pigmented lesions are easily seen
• Reflectance spectroscopy• Tristimulus colorimetry
50
• Shining a white light on the chosen area• Measure reflected light intensity• Reflected light at 450, 560, 600 nm• CIELa*b*
– L = relative brightness– b* = pigmentation– a* = erythema or redness
Reflectance spectroscopy
51
Reflectance spectroscopy• Minolta chromameter (Minolta)• DermaSpectrophotometer (Cortex)
– 2 light emitting diodes– Green (568 nm)– Red (655 nm)
• Erythema Meter (DiaStron)• Mexameter (CK)
– 16 light emitting diodes @ 3 wavelengths– Green (568 nm) for erythema– Red (660 nm) for melanin & erythema– IR (880 nm) for melanin 52
Chromameter
Parameters. Clarity (L*). Green to red spectrum (a*). Blue to yellow spectrum (b*). ITA
Protocol design- Essay areas: forearm- Treated area and non-treated area - No photos- Repeated applications: D0-D56.
53
• DHA = dihydroxyacetoneJermann R, Toumail M, Imfeld D. Development of an in
vitro efficacy test for self-tanning formulations. Int. J. Cosmet. Sci. 24, 35-42, 2002.
54
Mexameter• Infrared radiation• Skin functions as a light conductor • Melanin content and erythema value• Measure under light protection
Phototype Description Melanin contentI Celtic type 0-150II Caucasian white 50-250III Mixed type 100-350IV Mediterranean type 150-500V Asian/Indian 150-650VI Black 600-999
Asst. Prof. Dr. Nattaya Lourith[[email protected]] 10
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Mexameter
Tengamnuay P, Pengrungrungwong I, Pheansri I, Likhitwitayawuid K. Artocarpus lakoocha heartwood extract as a novel cosmetic ingredient: evaluation of the in vitro anti-tyrosinase and in vivo skin whitening activities. Int. J. Cosmet. Sci. 28, 269-276, 2006.
56
Taylor hyperpigmentation scale
A series of laminated plastic cards imprinted with different color
57
References • Hatzis J. The wrinkle and its measurement – a skin
surface profilometric method. Micron 35, 201-219, 2004.• Akazaki S, Imokawa G. Mechanical methods for
evaluating skin surface architecture in relation to wrinkling. J. Dermatol. Sci. 27, S5-S10, 2001.
• Callaghan TM, Wilhelm KP. A review of ageing and an examination of clinical methods in assessment of ageing skin. Part 2: clinical perspectives and clinical methods in the evaluation of ageing skin. Int. J. Cosmet. Sci., 30, 323-332, 2008.
• Taylor S, Westerhof W, Im S et al. Noninvasive techniques for the evaluation of skin color. J. Am. Acad. Dermatol. 54, S282-S290, 2006.
Skin Surface Lipid, pH and
temp.
59
Objectives
• To be acknowledged on skin surface measurement
• To be familiar with skin pH and temperature determination
• To relate each parameter to skin function
60
Contents
• Skin surface lipid and determination technique
• Measurement techniques of skin pH and temperature
Asst. Prof. Dr. Nattaya Lourith[[email protected]] 11
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Surface Lipid
Surface lipid component• Epidermal lipids• SebumEpidermal lipids influence
on lipid mixture
62
Surface lipid
• 10% @ 1 °C increase• circadian rhythm, high @ noon, low @
evening• provokes at puberty• reduces in elderly • 5 – 6 h refatting of forehead• 100 h refatting of scalp
63
Epidermal lipids
• phopspholipids• glycosyl ceramides• ceramides• cholesterol• cholesteryl esters• fatty acids• triglycerols• hydrocarbons
64
Functions
• cohesion between the skin layers• regulates the skin permeability • skin barrier @ 10.3 g/m2h TEWL• 5 – 10 to 25 – 40 μg/cm2
• Emollient • No moisturizing effect
65
Sebum
• Free fatty acid ~ 30%• Triglycerides ~ 33%• Wax ~ 15%• Sterol esters ~ 5%• Squalene ~ 5%• Paraffin ~ 7%• Moisturizer independent
66
Sebum secretion region
• orange peel skin
•Large pore & greasy skin
-Skin roughness
-Make-up diminishing wearability
-acne
Asst. Prof. Dr. Nattaya Lourith[[email protected]] 12
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Sebum secretion at different age
68
Extraction techniques• Solubility in organic solvents• Cylinder in known dimension contact to skin• Chromatographic analysisAbsorption techniques • Sponge wipe
– Few epidermal component• Cigarette paper
– Forehead– 4 sheets + gauze + rubber band – 3 h collection (sebum secretion rate)– Ether soke
• Bentonite clay– Larger lipids– 12 h (sebum secretion rate by glands)
Absorption/Extraction
r = 0.89
69
Cigarette paper adsorption
70
Determination • Sebutape
– A lipid-absorbing polymeric film or glass– 1 – 5 scale– Translucent (or reflectance chromameter : CIE)
• Lipometry– 15 s– Transmission of sapphire plate (mV)– 25 – 500 μg/cm2
• Sebumeter– Plastic film– 30 s – 0 – 500 scale
• Staining (densitometry)– Transparent plate– Unsaturated fatty acids reduce osmic acid
Lipometry/Gravimetry
r = 0.94
71
Sebutape : CuDerm
72
Sebutape : DualTape
Asst. Prof. Dr. Nattaya Lourith[[email protected]] 13
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Sebutape : Sebufix
• Transparancy• 30 – 45 min collection• CIE
– L = 0 – 100 (black – white)– a = -60 - +60 (green – red)– b = -60 - +60 (blue – yellow)
• Adobe pixel scale
74
Sebumeter : CK• Plastic film cartrige• 300 measurements (64 mm2)
• 0 – 350 scale
• 350 = 100% transparent
• convert to μg/cm2
• unused film calibration @ t = 0
• t = 30 s
75
Correlation
• Lipometry/Sebumeter– r = 0.92
• Sebutape/Sebumeter– r = 0.53
• Sebutape image analyzer/Sebumeter– r = 0.80
76
Sebum Image • Normal light
– Color photo– Bright– Shadows– Pores & blemishes
• Black light– Bacteria’s prophyrin– P. acne in sebaceous follicle
• Cross-polarized light– Color photo– Reflection reduction -> skin surface feature– Inflammatory lesion
77
Fluorescent analysisWood’s lamp: UVA induces chromophores fluorescence
78
Sebum-image relation parameters
• Red, green, blue : color parameters
Asst. Prof. Dr. Nattaya Lourith[[email protected]] 14
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• Sweat = hypotonic solution; pH 4.5 – 5.5• Acidic skin provides defense against
microbe• Higher pH, more microbial growth• pH range 4.0 – 6.5• Means pH = 5.5 (1987)• Infant skin pH = 6.6 • Variation in region, sex, race, age• Male lower than Female• Axillary pH is higher than means pH
Skin pH
80
• Natural skin surface pH = 4.7
• Cosmetics pH labels skin pH range of 5.4 and 5.9
• pH 8 formulation : increase TEWL
• pH 3 - 4 formulation : shedding of corneocytes from outer layer
81
Skin pH
Cosmetics actions on• Solubility • Partitioning • Absorption • Penetration Towards skin
+ in vivo+ in vitro
• Sebum secretion• Sweat secretion• Skin temperature
Cosmetics efficacy particularly antiperspirant & deodorant 82
pH & temperature• Flat glass electrode• Fluorescent • Infrared • Laser Doppler
pH < 3.5 3.8 4.0 4.3 4.5 5.0 5.3 5.5 5.7 5.9 6.2 6.5 > 6.5
F acid normal high pH
M acid normal high pH
Skin pH
83
References Serup J, Jemec GBE, Grove GL. Non-invasive methods and the
skin. 2nd ed. Taylor & Francis. New York, 2006.Elsner P, Merk HF, Maibach HI. Cosmetics: controlled efficacy
studies and regulation. Springer. Heidelberg, 1999.Burry J, Coulson HF, Roberts G. Circadian rhythms in axillary
skin surface pH. Int. J. Cosmet. Sci. 23, 207-210, 2001.Gfatter R, Hackl P, Braun F. Effects of soap and detergens on
skin surface pH, stratum corneum hydration and fat content in infants. Dermatol. 195, 258-262, 1997.
Wagner H, Kostka KH, Lehr CM, Schaefer UF. pH profiles in human skin: influence of two in vitro test systems for drug delivery testing. Eur. J. Pharm. Biopharm. 55, 57-65, 2003.
Lambers H, Piessens S, Bloem A et al. Natural skin surface pH is on average below 5, which is beneficial for its resident flora. Int. J. Cosmet. Sci. 28, 359-370, 2006.
Son T, Han B, Jung B, Nelson JS. Fluorescent image analysis for evaluating the condition of facial sebaceous follicles. Skin Res. Technol. 14, 201-207, 2008. 84
Thank you for your attention