INTRODUCTION:
Bioengineering techniques apply engineering principles
to address challenges in the fields of biology and medicine. The word bioengineering
was coined by British scientist and broadcaster Heinz Wolff in 19541.
Herbal companies all over the world produce a
lot of cosmetics for one or the other purpose. The cosmetics are generally used
externally like moisturizing lotion, fairness cream, sunscreen lotions,
anti-aging creams etc. they show direct effect on the skin after short or long
term use.
When a herbal
cosmetic comes to market it is obvious that it had passed through several
evaluation parameters direct from the crude drug to the finished product as per
one or the other regulations. There are several guidelines for the efficacy
evaluation of cosmetic products e.g. Colipa
guidelines 2. Instrumental
tests are part of all the efficacy studies, which are not other than
bioengineering techniques. Bioengineering techniques
closely relates to the substantiation of cosmetics that have been well
developed. Nowadays, the internal structure of human skin and cutaneous cells can be studied non-invasively using these
methods. .
Such
measurement enables us to perform numerical assessment of skin. Skin conditions
that have conventionally been categorized as normal can now be classified into
various types on the basis of numerical values. Efficacy studies using
bioengineering techniques are often being carried out in the companies
producing cosmetics.
Skin and skin surface properties:
The skin is the
largest organ of the body, with a surface area of approximately 1.75 m2 in the
average adult3. The skin weighs between 3.5 – 4.5 kg, comprising
about 7% of body’s total weight. It is composed of three different layers: the
epidermis, dermis, and subcutaneous layers. The epidermis, the outer-most
layer. The stratum corneum (SC) is the outer-most
layer of the epidermis and is the part of the skin that is in direct contact
with the environment. It is composed of approximately 20 layers of dead skin
cells. 4-5
Measurement
of firmness
Firmness of skin is measured in terms of collagen
content and texture.The total collagen content of the
skin decreases, leading to the potential decrease in firmness. The stimulation
of collagen production is necessary in aged individuals in order to maintain
firm and healthy skin. Various herbal
extracts e.g. extracts of Gottu Cola (Centella Asiatica), have the
ability to stimulate dermal fibroblast and increase collagen synthesis. Herbal
moisturizers are also available for these purpose of different brands e.g.
The way in which skin reacts to the mechanical
constraints of pinching, twisting, pulling and creasing vary from one person to
another. The methods used will attempt to measure the degree of deformation and
the time required for the skin to return to its original state. The skin's
firmness and elasticity reflect the elastic properties of the connective tissue
in the dermis and the overlapping of collagen and elastin
fibres. Over time, this network becomes disorganised, causing this firmness and suppleness to
decline. Instruments that measure firmness are:
1.
Torquemeter
2.
Densi-score
3.
Extensometer
4.
Torsional Ballistometer
5.
Gas
bearing electrodynamometer
6.
Vesmeter
7.
Cutometer
8. Reviscometer
TORQUEMETER:
Torque
meter is a proven method for the evaluation of stratum corneum
elasticity, hydration & frictional properties. It is adaptable for either
stratum corneum or full skin thickness studies. Automated analysis of skin is based on
Windows™ based applications software.
The dermal torque meter provides a tortional
force to the skin and measures the response of the skin to this force; the
force is then removed and the recovery of the skin is measured.
The DTM consist of a sensor
head, a control unit and a accompanying computer. The sensor head is
constructed of a torque-motor and an angle sensor, with the torque motor being
connected to the flat disc at the end of the sensor head. A concentric torque
ring around the torque disc defines an annular ring gap, which in turn
determines the skin area to be examined. The force is transferred to the skin
by securing it to both the torque disc and torque ring using double-sided
adhesive tape. The torque disc may then be rotated relative to the torque ring,
which supports the surrounding skin. Torque is applied for a pre-determined
time and the resulting angular displacement is recorded. When the torque is
removed, restoring forces within the skin attempt to return the torque disc to
its original position and this is similarly recorded. On initial application of
torque an immediate deformation (extensibility) of the skin occurs (Ue). This is followed by a slower deformation, which
reflect the visco-elasticity of the skin. After a
suitable time period (e.g. 15 secs) the torque is
removed and an immediate recovery (
Adapted from: Dia-stron
limited
Fig 2 Torquemeter
Supplied by: Dia-stron limited
DENSI-SCORE:
Densi-score is a simple instrument that is
operated manually. L’Oreal patents this device.
This device works on the principle of
correlating "skin density" with skin creasing. A baby's skin does not
show any creases when pressed between two fingers, whereas that of an older
subject will show multiple. This is because a baby's skin has a higher density.
Fig 3 Densi-score Supplied by: : Dia-stron
limited
Densi-score has two detachable parts which
together forms a aperture in the middle. The size of the aperture can be
adjusted by the application of force. It consists of applying a reproducible
mechanical creasing force of 40% on the forearm. The calibration enables the
number of creases to be correlated with the skin's density. This diminishes
with age due to the destructuring, which takes place
in the dermis and rigidification of the horny layer,
resulting in creases becoming more frequent. Scales of creasing are therefore
drawn up according to density and age. These are then used to assess the
efficiency of an anti-age product designed to improve skin firmness.
Adapted from: Dia-stron
limited
TORSIONAL BALLISTOMETER
A dynamic technique for assessing the intrinsic viscoelastic properties of a material, i.e., determining
physical properties of materials which do not depend on the method of
measurement.
The ballistrometer is based on the "drop
impact" of a body onto a stationary surface. A collision in one dimension
is provoked by allowing a bard body to drop from a given height onto the skin
surface to be tested. After the collision, the impacting body undergoes a
variable number of rebounds decreasing in amplitude. By measuring the height of
the rebounds, the amount of energy returned by the tissue is calculated in
terms of coefficient of restitution e. An increase of e was
observed when a high water content was present in the skin 7-8.
IDRA®Version 3.0 (Integrated Dynamic Rebound Analyzer) is a
PC-based (USB port linked) Ballistometer, which
employs a dynamic technique for assessing the intrinsic viscoelastic
properties of a material, i.e., determining physical properties of materials
which do not depend on the method of measurement. For relatively soft
materials, such as skin, the measurement technique generally involves a
light-we ight hammer, anchored at one end, which
freely falls onto the test surface under gravitational force, recording and
analysis of the resulting hammer oscillatory displacement-time data, and the
determination of characteristic physical parameters. IDRA® Version 3.0 is
installed as an Excel COM Add-in DLL, which greatly extends the functionality
of the Instrument. IDRA® hardware/software components and Microsoft's excel
synergize to make a powerful diagnostic tool.
Adapted from: Elweco, Inc.
Supplied by: Elweco, Inc.
GAS BEARING ELECTRODYNOMETER
Gas Bearing Electrodynamometer allows us to measure
objectively the viscoelastic properties of the
stratum corneum in vivo and to
evaluate, in terms of skin softness, the changes of this parameter induced by
the application of emollients. The Gas Bearing Electrodynamometer (GBE) has
been used for the last 20 years to obtain sensitive measurements of the stratum
corneum 9
.
It is able to apply a sinusoidal loading stress of less
than 5g parallel to the skin surface, with a resulting displacement of less
than 1mm in each direction. This is achieved by suspending an armature in a gas
bearing to create near friction-free movement. Changes in the magnetic field
generated by a surrounding coil cause the armature to oscillate at a known
frequency and amplitude. The coil is activated by a sinusoidal signal from a
low frequency function generator or from a suitable software trigger. The
armature of the instrument is typically attached to the skin surface by a stiff
wire probe bent to 90o at its free end. A small plastic stub is
usually cemented to the free end of the probe and used to attach the probe to
the skin surface using a circular piece of double-sided sticky tape.
Displacement of the armature is measured by a sensitive LVDT, mounted coaxially
with the coil. Coil and LVDT outputs (force and displacement) are amplified and
then supplied for analysis to either a storage oscilloscope or a computer
equipped with suitable software.
Results of force and displacement measurements of skin
are typically displayed as a hysteresis loop. Analysis of the gradient of the
loop (force/displacement or displacement/force) yields derivatives of the
dynamic spring rate (DSR) usually expressed as g/mm (a measure of the force
required to stretch or compress the skin per unit extension), mm/N or µm/g
(measures of stretching or compression of the skin in response to a given
applied force). Such analysis yields information about the elastic properties
of the skin. Analysis of the phase lag between force and displacement responses
yields information about the viscous properties of the skin10
VESMETER:
It is a novel method using a
computer-linked device to
simultaneously quantify physical properties of the skin such as
hardness, elasticity and viscosity.
Skin hardness was calculated by measuring the
depth of an indenter pressed onto the skin. The Voigt model was used to calculate skin elasticity,
viscosity, visco–elastic ratio and
relaxation time by analyzing the waveform of skin surface behaviour.
When the probe is placed at a right angle on the
skin,
the indenter is depressed onto the skin at a constant speed by
means of electromagnetic power, and the position sensor constantly traces the
path of the indenter. The hardness of an object can then be expressed
as the area of the depression divided by the pressure of the
indenter. The stress relaxation behavior of viscoelastic
materials can be
analysed by using the Voigt model that
consists of two components, a purely viscous dashpot and a purely
elastic spring connected in parallel. Elasticity (G), viscosity (
),
visco–elastic ratio (VER) and the
relaxation time (
) can be calculated by analysing
the waveform of the stress relaxation behaviours
of the skin
with a computer. VER is related to the superiority of the viscous
element over the elastic element. The relaxation time is related to the time taken
by the deformed material to return to its original state. Before this device
is used for the human skin,
accuracy of the measurements is examined by using test samples made
with polyurethane or silicon gel of a known hardness, elasticity and
viscosity. The measurements thus obtained are compared with those of
the standards of the American Society for Testing and Materials
(ASTM) for hardness and of the International Organization for Standardization
(ISO) for elasticity and viscosity. The range of the samples measured
fully covered the range of human skin from normal to extremely hard11.
FIG.
6. Photograph
(A) and configuration (B) of the probe.
The results of the measurements are displayed on the
computer screen connected to
the probe. The numbers in (B) indicate the following
components: 1, recognition mark; 2, position sensor; 3, indenter; 4,
measurement head; 5, electromagnetic coil; 6, permanent magnet; 7, power
switch.
Adapted from: Dia-stron limited”:
CUTOMETER:
It is
well-established Elasticity Measurement tool. The Cutometer®
MPA 580, controlled by a Windows® based software, is a frequently used model.
The measuring principle is based on the suction method.
Negative pressure is created in the device and the skin
is drawn into the aperture of the probe. Inside the probe, the penetration
depth is deter- mined by a non-contact optical measuring system. This optical
measuring system consists of a light source and a light receptor, as well as
two prisms facing each other, which project the light from transmitter to
receptor. The light intensity varies due to the penetration depth of the skin.
The resistance of the skin to be sucked up by the negative pressure (firmness)
and its ability to return into its original position (elasticity) are displayed
as curves at the end of each measurement. From these curves interesting
measurement parameters can be calculated.
The small, convenient size of the probe allows
successful measurement of skin areas that are difficult to reach. The probe
contains an elastic spring that provides constant pressure of the probe on the
skin. In addition, the probe can be fixed to the measured skin area by
double-sided adhesive rings. The specific calibration values of each probe are
stored in its plug, thus allowing simple and quick exchange for servicing
purpose.
Adapted from:
Courage + Khazaka electronic GmbH
Fig
7 Supplied by: Courage + Khazaka electronic GmbH
REVISCOMETER :
The reviscometer®
is used to diagnose the condition of the collagen and elastin
fibers with reference to the respective age of the individuals. The special
measurement method of the Reviscometer® RV 600 allows
investigation of new interesting fields as orientation of incision during cutaneous surgery, relation between body mass index and
elasticity, photoageing and many more.
The new aspect of
the measurement - based on Resonance Running Time of the Reviscometer®
RV 600 - in addition to finding elastic and viscoelastic
features is to determine the direction of the collagen and elastine
fibres.
The probe head
contains two sensors which are placed on the skin. One is emitting acoustical
shockwaves, the other serves as receiver. Shockwaves propagate differently
through the skin according to the state of the elastic fibres
and the moisture content of the skin. The time As the time depends to a high
amount on the fact whether the measurement is executed with the direction of
the fibres or against it, and the measurement can be
performed in different directions on the same skin site, the direction of the fibres is measured. the wave needs to travel from emitter
to receiver is the measured parameter. A
positioning top with marks for the direction in 0- 180°, 45-225°, 90-270°, and
135-315°-axis, fixed with a double sided adhesive ring, enables the user to
easily measure in all directions on one skin site. The modern, high quality
electronics of the probe allow a very quick, easy and precise measurement. Its
low weight assists in ease of handling. All calibration data are inside the
probe. Thus the probe is completely self contained and can be connected to
different device types. The accuracy of the device can easily be checked at any
time on a special silicone material.
sourced by:
Courage + Khazaka electronic GmbH
Fig 8: Supplied by: Courage + Khazaka
electronic GmbH.
Measurement of hydration
Skin properties are highly dependant of its water
content. It is easy to observe that a tanned or older skin is dryer and rougher
than the skin of a child. The polysaccharide content of the dermis is
responsible for the hydration of the skin. As we age, we experience a reduction
of these structures in the skin. A reduction of the water binding capacity of
the skin leads to the appearance of lines and wrinkles. Many herbals can
increase the skin hydration. E.g.
Fractions of Echinacea angustifolia.
CORNEOMETER:
Corneometer® provides a well-established method to determine
reproducibly and accurately the hydration level of the skin surface. It is the
world’s best skin hydration measurement
device. This is well documented in dermatology and cosmetology literature in
which the terms “corneometry” and skin hydration
measurements are inseparable.
The corneometer
or Dermodiag operates according to the principle of
electrolysis, with electrodes being applied to the skin in which the water and
associated ions circulate. Current measurements indicate the amount of water
present and therefore the degree of skin moisturisation.
It consists of a
console housing and a humidity sensing probe. The probe consists of an
inter-digital grid of electrodes covered by low dielectric vitrified material
that prevents direct contact between the electrode and the skin 12. Tile
value appears as a maximum 3-digit figure on 40 x 18 mm display. The method is
based on the fact that the dielectric constant of water varies considerably and
a suitably-shaped measuring capacitor reacts, according to the water-content,
with the various changes of capacity to samples brought about into its
measuring volume. The variations of the probe capacitor are automatically
recorded by the device. The display records a value between 0-10 when the
sensing probe is in contact with dry air and 150-160 with a completely moist
palm 13.
Fig 9: supplied by: Courage + Khazaka electronic GmbH
: Dia-stron
limited
sourced by: Courage + Khazaka electronic GmbH : Dia-stron
limited
SKICON 200 SKIN CONDUCTANCE
METER
This is the 2nd most widely used device for
the assessment of skin hydration.
It measures high
frequency conductance of the upper layer of the stratum corneum
of which conductance is increased when the upper layer is well hydrated.
The probe of skicon contains
concentric electrodes of 2 and 4mm external diameters connected to a tuning
circuit. When the probe contacts the skin, conductance between the electrodes
is detected as a change of the resonance voltage in the tuning circuit and
displayed in micro-siemens on the digital screen.
Fig 10: Supplied by: I.B.S. Co
ltd.
Sourced by:
I.B.S. Co ltd.
HYDROSENSOR:
The worldwide unique hydration measurement device, that
considers room temperature and humidity in the measurement, thus allowing its
usage in all different climates. The result is shown quickly on a diode chain.
It works on capacitance principle. The device is light,
battery operated and portable, thus ideal to be used either on the counter, in
a beauty or hairdressers salon or at the dermatologist or pharmacy to attract
customers and to increase the sales of cosmetic products.
Fig 11: supplied by: Courage +
Khazaka electronic GmbH sourced by:
Courage + Khazaka electronic GmbH
DERMLAB-NOVA
The DPM 9003 is a portable, multifunctional electronic
laboratory instrument that measures skin impedance. It is designed to provide a
non-invasive, objective, reproducible method of measurement to quantify
biophysical characteristics and relative hydration of the skin.
It works on
electrical impedance measurement principle.
It is used on larger surface areas like the volar surface of the arm, face, back, etc. The new XPRT software, for Windows 98/2000/XP
makes collecting data with the DPM 9003 more efficient than ever. A
user-friendly interface combined with real-time data collection makes it easy
to compile databases of information about products. Use the data to create
charts and graphs making information easily presentable.
Supplied by: nova
Fig: 12
MOISTURE CHECKER
The Scalar Moisture Checker is a unique and powerful
point of purchase selling tool that instantly shows the effectiveness of
moisturizing and conditioning products, and lets you evaluate the progression
of the skin care regimen.
It uses a conductance measurement principle to measure
the water binding capacity of the stratum corneum.
Just press it onto the area to be measured during an
examination, wait for the beep, then read the display. Measurements are given
as % of moisture in the skin and can be evaluated with a simple chart. If skin
has poor moisture content you would recommend your products and treatments to
correct the condition. If moisture content is normal, the skin can look even
better by using your product or treatment and even if the moisture content is
high you would recommend continuing the use of moisturizing products,
differentiating your product.
Sourced by:
Scalar Corporation
Fig 13: Supplied by: Scalar
Corporation
CONFOCAL RAMAN SPECTROSCOPY
Introduction: Confocal Raman microspectroscopy is the first commercially available
technique that provides a non-invasive, in vivo method to
determine depth profiles of water concentration in the skin [14]. Compared with
conventional optical microscopy, confocality can
deliver a representative image of the volume to be explored at a pre-selected
depth. With spatial resolution of 1 µm in three directions, we are able to
penetrate the skin outermost, horny layer, µm by µm. Confocal
microscopy gives a clear view - with unprecedented accuracy - of keratinocytes in each epidermis layer, or it can track red
blood cells in a microcapillary. This technique is
the most recent of the major non-invasive observation methods, used in vivo.
Resolution is so high, that in addition to measuring tissue thickness (horny
layer, epidermis), cells can be counted, and melanosome
appearance and distribution in the epidermis monitored after sun exposure.
CONFOCAL RAMAN SPECTROSCOPY
Confocal Raman microspectroscopy is
the first commercially available technique that provides a non-invasive, in vivo method to determine depth profiles of water
concentration in the skin 14. skin is illuminated with specific
wavelength of light. Light inelastically scattered by
the skin contains information of its composition. Using a variably focused
laser light source and appropriate detection, this technique can be combined
with confocal microscopy .
Compared with conventional optical microscopy, confocality can deliver a representative image of the
volume to be explored at a pre-selected depth. With spatial resolution of 1 µm
in three directions, we are able to penetrate the skin outermost, horny layer,
µm by µm. Confocal microscopy gives a clear view -
with unprecedented accuracy - of keratinocytes in
each epidermis layer, or it can track red blood cells in a microcapillary.
This technique is the most recent of the major
non-invasive observation methods, used in vivo. Resolution is so high, that in
addition to measuring tissue thickness (horny layer, epidermis), cells can be
counted, and melanosome appearance and distribution
in the epidermis monitored after sun exposure.
Confocal microscopy is the method of imagery best suited to
examining the horny layer and the epidermis. It therefore complements
ultrasound echography and MRI, which are better
suited to studying the dermis and hypodermis. The technique presented has great
potential for fundamental skin research, pharmacology (percutaneous
transport), clinical dermatology, and cosmetic research, as well as for
noninvasive analysis of blood analytes, including
glucose 15.
Fig 14: INFRARED SPECTROSCOPY
INFRARED SPECTROSCOPY
This is a rapid, non-contact and non-invasive technique
to provide information on skin hydration of use to medical and cosmetic
research and clinical practice. A
digital imaging system has been developed to collect skin hydration data. The
system combines a near-infrared camera with a liquid-crystal tunable filter
(LCTF) to acquire spectral images at multiple narrow wavelength bands between
960 and 1700 nm. Software has been developed to control the instrument and
to process the data. Reflectance images were collected of subjects whose
forearms had been treated to increase and decrease skin moisture. The infrared
absorption band between 1400 and 1500 nm was used to calculate relative
skin moisture, and the intensity of this band was plotted as a function of
position in the form of a grayscale image
OPTO THERMAL TRANSIENT
EMISSION RADIOMETRY
Novel infra-red
remote sensing technology. Excitation spectroscopy with Opto-Thermal
Transient Emission Radiometry (OTTER) was used to measure waterkeratin
interaction energies in excised stratum corneum (SC)
under controlled ambient relative humidity (RH) conditions. Such interactions
lead to small but measurable wavelength shifts in the peaks of the absorption
spectra of the interacting molecules 16.
Measurement of
skin barrier function (TEWL)
The barrier
function of stratum corneum can be examined using a
non invasive method called transepidermal water loss which measures amount of water
being lost slowly from thebody through stratum corneum. As the skin becomes dry the lipid domains in
between the corneocytes in the stratum corneum is disrupted and the TEWL increases. Occlusives are employed to prevent transepidermal
water loss by sealing the stratum corneum.e.g.petrolatum,
beeswax. A critical function of the skin is to protect the body from the
environmental damage and moisture loss. This protection is provided by the skin
barrier that resides in the stratum corneum. It is
now well established that the barrier function is enabled by skin lipids
produced by the epidermal cells 17-18. Therefore, an adequate and
continuous production of lipids is essential for skin barrier functionality. As
one ages, the ability to produce skin lipids diminishes 19, 20.
Certain skin diseases also diminish the production of skin lipids 21, 22.
These decreases in lipid production have deleterious consequences on the
barrier function of the skin. Thus, there is a need of a technology that can
enhance the production of skin lipids.
EVAPORIMETER
Measuring transepidermal
water loss (TEWL) is a good indication of the skin barrier function efficiency.
This is carried out using an evaporimeter, consisting
of a sensor placed 3 or 6 mm above the surface of the skin. This apparatus
measure the amount of water lost by evaporation. This shows that a irritant product
will increase the water loss, while a moisterizer
will reduce it.
Supplied by:
Servo Med,
TEWAMETER TEWAMETER
Since 1990 CK has
been manufacturing one of the most accepted and best selling TEWL measurement
devices, the Tewameter® TM 210. Many international
scientific studies demonstrate its importance in dermatological and cosmetological fields.
The measurement
of the water evaporation is based on the diffusion principle in an open chamber
dm/dt=-D x A x dp/dx
where: A =
surface in m², m = water transported (in g), t = time (h), D = diffusion
constant (=0.0877 g/m(h(mm Hg), p = vapour pressure
of the atmosphere (mm Hg), x = distance from skin surface to point of
measurement (m).
The density
gradient is measured indirectly by the two pairs of sensors (temperature and
relative humidity) inside the hollow cylinder and is analysed
by a microprocessor. The small size of the probe head minimizes the influence
of air turbulences inside the probe. Also the low weight of the probe has no influence
on the skin surface structure and allows easy handling. All calibration data
are inside the probe. Thus the probe is completely self contained and can be
connected to different device types.
Open and closed
chamber measurements are possible. For quickly stable measurements the Probe
Heater PR 100 is available, which keeps the probe head to a certain temperature
of 28-32 ºC (corresponding to skin temperature). The accuracy of the probe can
be checked at any time by a small electronic unit. Separate display of the
values for the upper and lower relative humidity and temperature sensors in the
probe is present.
The information
about temperature and humidity during the TEWL-measurement is of great
importance for the evaluation of the accuracy of the TEWL results. A room
condition sensor to measure the rel. humidity and temperature of the
environment can be connected to the system and stable TEWL-measurements.
sourced by: Courage + Khazaka electronic GmbH
Fig 15: supplied by: Courage + Khazaka
electronic GmbH
Corneocytes
diagnosis
To maintain a
constant thickness of the stratum corneum the
desquamation rate and the de novo production of corneocytes
is delicately balanced. There is a continuous production of new stratum corneum. In order to maintain a constant stratum corneum thickness at a given body site super®cial
parts of the stratum corneum must be continuously
shed in the process of desquamation at a rate which balances de novo production
of corneocytes. Desquamation normally occurs
invisibly with shedding of individual cells or small aggregates of cells.
Disturbances in this process results in the accumulation on the skin surface of
only partially detached cells with or without a concomitant thickening of the
stratum corneum. The severity of the disturbance may
vary from modest to very pronounced, from a barely visible scaling combined
with a feeling of roughness and dryness of the skin surface, to the
accumulation of thick brittle scales such as in psoriasis or in the various
forms of ichthyosis 23. The cosmetic
product used for the removal of dead cells contains exfoliants
like lactic acid. A well-regulated desquamation is a prerequisite for the
barrier function of the stratum corneum and for a
normal skin appearance.
MONOCHROMATIC LIGHT:
Monochromatic
light is focused at the proximal end of a coherent bundle of optical fibres. Fluorescence of skin, stained with fluorescein, is then captured by the same fibre bundle and displayed, through a dichroic
mirror, by a CCD camera. Fluorescence images are analysed
using dedicated software to measure the projected area of cells. The new device
allows the mean projected area of corneocytes to be
routinely studied and quantified on most of the skin areas of the human body.
CORNEOFIX® F 20
Desquamation
Collector: A special transparent adhesive tape which collects corneocytes from the top layer of the skin. This method
allows the visualisation of the level of dryness or
damaged skin accurately. The desquamation collector foils are a very good
addition to the Visioscan® VC 98 skin camera. With
software the number, size and area covered with flakes can be evaluated as well
as a desquamation index. The foils are absolutely harmless to the skin.
Sourced by: Courage + Khazaka
electronic GmbH
Fig 16: Supplied by: Courage +
Khazaka electronic GmbH
3S-BIOKIT® The application of the 3S-Biokit is restricted to qualified persons
under medical surveillance for obtaining skin surface strippings.
These are used for skin surface diagnosis in dermatology. The system consists
of: adhesive: cyanoacrylic acid ethyl ester 5g;
sample carrier : polyester (PET) foil 100 pcs.
Supplied by: Courage + Khazaka
electronic GmbH
Measurement of skin colour
Human skin
color can range from almost black (due to very high concentrations of the dark
brown pigment melanin) to nearly colorless (appearing pinkish white due to the
blood vessels under the skin) in different people. Skin color is determined
primarily by the amount and type of melanin, the pigment in the skin. Variation
in skin color is largely due to genetics. The human eye is very sensitive
to the distinction of colours viewed side by side.
But, as soon as they meet the eye separately, differences can often not be
detected. Furthermore, the impression the eye receives from colours
depends on the ambient lighting. To check Fairness creams
efficiecy, therefore numerical assessment is required.
MEXAMETER® MX 18
The Mexameter® MX 18 is a
very easy, quick and economical tool to measure the two components, mainly
responsible for the colour of the skin: melanin and haemoglobin (erythema). Many
international scientific studies demonstrate its benefits in all important
dermatological and cosmetological application fields.
The measurement is based on absorption/reflexion. The probe of the Mexameter®
MX 18 emits 3 specific light wavelengths. A receiver measures the light
reflected by the skin. The positions of emitter and receiver guarantee that
only diffuse and scattered light is measured. As the quantity of emitted light
is defined, the quantity of light absorbed by the skin can be calculated. The
melanin is measured by specific wavelengths chosen to correspond to different absorption
rates by the pigments. For the erythema measurement
also specific wavelengths are used, corresponding to the spectral absorption
peak of haemoglobin and to avoid other colour influences (e. g. bilirubin).
The results for both parameters are immediately shown as index numbers.
The modern, high quality electronics of the probe allow
a very quick measurement. A spring in the measuring head provides constant
pressure on the skin. Its low weight ensures easy handling. All calibration
data are inside the probe. Thus the probe is completely self contained and can
be connected to different device types. It is also a significant advantage for
quick and easy servicing of the probe. The resolution of the measuring results
is higher than in the previous model the Mexameter®
MX 16. The Mexameter® MX 18 shows the melanin and erythema values in a range from 0-999. The accuracy of the
probe can be checked any time with a special tube.
sourced by:
Courage + Khazaka electronic GmbH
Fig
17: supplied by: Courage + Khazaka electronic GmbH
MINOLTA
CHROMAMETER: supplied by Konica minolta.
Measurement of sebum level
A lipidic
film resulting from the sebum secreted by the sebaceous glands, covers a normal
skin. Between 1 and 5 grams a day are usually produced, anything in excess of
that amount tending to make the skin shiny and oily. Sebum removal or reduction
is often a mojor performance claim for cosmetic
products. Many different methods have been developed to sample sebum from the
skin surface. These include absorption into bentonite
clay, transfer to ground glass, gravimetric paper absorption, and absorption to
various tape substrates 24.
SEBUMETER® SM 815
The
Sebumeter® is the most widely acknowledged and
successful sebum measurement device for skin, hair and scalp. Various in vitro
and in vivo tests and comparisons with other measurement techniques are
documented in literature and demonstrate its importance in dermatological and cosmetological fields. The measurement with the Sebumeter® SM 815 allows determination of even slightest
changes in the skin surface sebum content.
The
measurement is based on grease-spot photometry. A special tape becomes
transparent in contact with the sebum on the skin surface. For the
determination of the sebum, the measuring head of the cassette is inserted into
the aperture of the device, where the transparency is measured by a light
source sending light through the tape which is reflected by a little mirror behind
the tape. A photocell measures the transparency. The light transmission
represents the sebum content on the surface of the measuring area. A
microprocessor calculates the result, which is shown on the display in µg
sebum/cm² of the skin.
The
measuring head of the cassette exposes a 64 mm2 measuring section of the tape.
For a measurement the tape is transported forward by a trigger at the side of
the cassette to expose a new section of the tape. The used tape is rewound
inside the cassette. One cassette can be used for approx. 450 measurements. The
scale from 1-0 on the trigger shows how much of the tape is still unused. For
hygienic reasons when exhausted, the cassette is simply replaced. The modern,
high quality electronics allow a very quick measurement. A spring in the
measuring head provides constant pressure on the skin. Its low weight makes
handling easy.
Fig
18: SEBUFIX® F 16
SEBUFIX® F 16
Sebum Collecting Tape: A special tape that collects
sebum in a very short time. It shows spots for the activity of the sebacious glands. Using the Sebufix®
together with the Visioscope® allows the sebum
production to be watched live. A microporous film is applyied to a previously cleansed area of the skin for one
hour. Sebum secretions are absoded, staining the
film. The number and extent of spots have then to be quantified in order to
measure sebaceous gland activity. Sebutape can characterise a oily skin and check the efficiency of a
boosting lipid synthesis product for dry skin or one designed to reduce
excessive secretions of sebum.
Measurement of lines and wrinkles
Wrinkles are fine lines or deep furrows, where the skin
has become thinned and damaged. As we age, our skin undergoes changes that make
it more difficult for the skin to repair itself, and these changes lead to
wrinkles. causes of wrinkles and Changes that occur in skin as age
advances.
Ø Changes in epidermis: The epidermal cells
become thinner as age advances .They also lose their stickiness.
This change in epidermal cells allows the
moisture to escape instead of retaining it back causing dryness of the skin. As
we get old the epidermal cells start dividing slowly and the rate of repairing
process also retards.Thus thinning of skin leads to
wrinkles
Ø
Changes
in dermis:
·
The
collagen fiber production reduces.
·
The elastin fibers wear out.
·
The
production of sebum from sebaceous glands decreases.
·
There
will be a decrease in number of sweat glands.
·
The
supply of nutrients also decreases. All the above mentioned changes lead to
formation of wrinkles.
Ø Changes in subcutaneous tissues: The fat
cells get smaller with age. All these changes in three layers of skin lead to
wrinkles and sagging.
Ø The factors that cause early aging and
formation of wrinkles
1. Sun: Constant exposure to U-V radiations
from sun cause premature aging of skin. Due to constant exposure to sun the
epidermis becomes thin and many harm full lesions like basal cell carcinoma and
squamous cell carcinomas occur. Sun light also
damages collagen fibers of dermis causing early aging.
2.
Hormones: The hormonal changes due to menopause or decreased
estrogen production may lead to
changes in skin.
MAPPING WRINKLE TOPOGRAPHY BY SKIN REPLICA:
Close observation of the surface of human skin, over
the whole body, reveals a relief featuring a great many forms of considerably
different shapes and sizes. This microrelief is a
marker of ageing and methods of topographical mapping have proved invaluable
for assessing the skin and the efficiency of cosmetic products
The principle is to scan the replica or skin surface,
using one or two light beams, or a grazing incidence light and to measure both
the cast shadows and the deformation of a beam of fringes
A
preliminary and essential step, to any study of the relief, is the preparation
of a mould or a print. Easy and rapid to obtain, polysilicone
or araldite replica must be extremely accurate, since it will be studied by profilometry or a scanning microscope. Wrinkle orientation,
density and depth can be plotted, and of course efficiency of cosmetics
designed to attenuate wrinkles and fine lines, measured.
FRICTIOMETER ® FR 770
The frictional resistance is influenced by skin
roughness, wrinkles and the skin care products on the skin surface.
Consequently there is also a variety of different readings. It is possible to
classify normal and dry skin, wrinkly and less wrinkled skin and appropriate
changes of the skin condition after applying cosmetic products. This is an
important aspect for the product development. It allows for instance to
determine that a W/O emulsion offers better smoothing characteristics than an
O/W emulsion. surfaceIn addition, the penetrating
capacity of a formulation can time-dependently be measured; if it stays on the
skin for a long time there will be only a very insignificant change in the
frictional values.
The
probe contains a motor, a steering unit and the friction head. A constant
rotational speed (adjustible to different speeds) is
applied onto the skin by the friction head. The torque is measured and the
result is displayed as Frictiometer® units in the MPA
software. The probe contains a rotating teflon disc
which is applied on the skin. A selection of different teflon
discs is available.
sourced by: Courage + Khazaka
electronic GmbH
Fig 19: supplied by: : Courage + Khazaka
electronic GmbH
VISIO FACE
The
camera takes pictures of the entire face. It provides color images and allows
UV diagnoses with image analysis. Photos taken before and after the cosmetic or
dermatological treatment or pictures taken over a longer period can be
superimposed on the other which allows to completely document the progress of a
treatment. An advantage here is that imaging conditions are reproducible and
costly locations can be avoided.
source by: Courage + Khazaka
electronic GmbH
Fig 20: supplied by: Courage +
Khazaka electronic GmbH
SKIN-VISIOMETER® SV 600
The
device features a parallel light source and a b/w CMOS-camera with 640 * 480
pixels. The replica is placed between these. The light absorption of the blue
color is known. When the light penetrates the replica, it is absorbed according
to the thickness of the silicone material. The replica reproduces the heights
and depths of the skin as a negative, i.e. wrinkles are higher in the replica
as the silicone is thicker in this place.
The amount of absorbed light is calculated by Lambert
and Beer’s Law. The outgoing light is proportional to the incoming light, the
thickness of the material and the material constant k.
sourced by: Courage + Khazaka
electronic GmbH
Fig 21: supplied by: Courage +
Khazaka electronic GmbH
Microcirculation
The blood supply to the skin is provided by a network
of arterioles, capillaries and venules organized into
a superficial and a deep plexus. The assessment of skin microcirculation is of
valuable interest in cosmetology in the quantification of the sun protection
factor, skin irritation and efficacy of antiredness
treatments. Skin microcirculation can be measured by means of different
techniques, based mainly on the quantification of optical and thermal
properties of the skin which are modified by the amount of blood perfusion.
Relevant and reproducible data can be obtained only through the understanding
of the biophysical background of the technique(s) utilized. Standardization of
measuring conditions and procedures is particularly required for blood flow
assessment.
LASER DOPPLER VELOCIMETRY
With this method light is transmitted from a helium
–neon laser source in the instrument to the skin via an optical fibre.the laser provides light of single frequency 632.9 nm
and allows the Doppler effect to be exploited. The incident radiation enters
the skin tissue and is multiplied scattered and reflected by non moving
components and by the mobile red blood cells that are encountered as the
radiation penetrates to the depth of 1-1.5mm. a portion of scattered/reflected
incident radiation exits the skin and is collected by 2nd or 3rd
optical fibre that carry the light back to the
instrument. He returning radiation falls on the photodetector
and is converted to the electrical signal
SKIN-THERMOMETER
The measurement is based on contact free infrared
reading of the reflection of the skin surface and read with a specific sensor
within the probe. The temperature of the skin indirectly informs on the blood
circulation. Well supplied skin parts are warmer than less circulated areas.
sourced by: Courage + Khazaka
electronic GmbH
Fig 22: supplied by: Courage + Khazaka
electronic GmbH
Miscellaneous
SPECTRONIC 20
SPECTROPHOTOMETER 320-400 NM
Effectiveness of several
sunscreens using a Spectronic 20 spectrophotometer in
the 320 to 400 nm range can be evaluated and the SPF rating of the laboratory
prepared sunscreen lotion can be determined. Although this UV radiation is in
the UVA range, general trends in UV absorption can be observed allowing the sunscreen
lotions to be quantitatively compared.
SKIN-PH-METER ® PH 905
An adequate pH value is essential for a healthy skin.
It can be measured with the Skin-pH-Meter. Recommended measuring areas are the
back of the hand, the forearm, the front and the cheeks, however readings are
also possible on any other body part. The measurement of the pH-level on the
skin surface is an important parameter for evaluating the quality of the hydrolipidic film on the skin especially in developing
soaps, cleanser or detergents
sourced by: Courage + Khazaka
electronic GmbH
Fig 23: supplied by: Courage +
Khazaka electronic GmbH
VISIOSCOPE
This unique video camera delivers very impressive
images of skin, hair and scalp. The camera shows a skin area of 6 x 8 mm and
monitors: skin texture (smoothness, wrinkles), desquamation (scaliness), skin impurities (reddening, pigmentation spots,
acne, comedones etc.), hair structure, dandruff and
condition of the scalp. The camera must be connected to a video monitor.
Sourced by: Courage + Khazaka
electronic GmbH
fig 24: Visioscope®
Color 32
CONCLUSION:
Subjective
observation that can be recognized only by the observer himself lacks
reproducibility and reliability. The instrumental measurement of the living
skin has been developed based on the idea of analytical science to understand
skin conditions through analyzing instrumental measurement data. The effect of
cosmetics can be numerically assessed and also one product can be compared to
other very conveniently.
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Received on 24.12.2009 Accepted on 20.02.2010
©A&V Publications
all right reserved
Res. J. Topical and Cosmetic Sci. 1(1): Jan. – June
2010 page 1-12