J. Biol. Macromol., 12(1), 3-15 (2012)

Review
Hair keratin film as a substitute device for human hair
- Application in hair care science -Toshihiro Fujii
Bioengineering Course, Division of Applied Biology, Faculty of Textile Science andTechnology, Shinshu University, 3-15-1, Tokida, Ueda, Nagano 386-8567, JAPANReceived March 13, 2012; Accepted March 29, 2012

Keratin film prepared from human hair samples can be considered a model
which represents an average human hair. In this study, the investigations werefocused on whether the keratin film can withstand physical and chemical
stimulations such as ultraviolet (UV), bleach, perm, and thermal treatments or not.
Obtained data indicated that keratin film responded to such hair damage factors inthe similar manner as hair, and responses of keratin film were significantly higher
than those of hair. Keratin film can be used as a substitute device for human hair, toaccurately evaluate hair damage for the development of hair care related products.

Keywords: Hair damage, keratin film, UV, bleach, perm, heat

Introduction

harm. Hair thatadorns our head

Human hair is a physiologicalcontinues to be one of the objects oftissue, which is a specialized part ofinterest for many people, because it is

the skin. This tissue helps to maintaina part of their fashion or anti-aging

bodily temperature in heat or cold, andtool.

it also protects our body from outside

The water content of human bodyE-mail: fujiit1@shinshu-u.ac.jp

should be more than 50%, whereas that of

4

A novel evaluation technology in hair care sciencehair tissue is less than 20% and 70 tolong axis and construct macrofibril and

80% of it consists of proteins. Thiscortex. KAPs function as glue likeconfiguration is made of 3 layers: fromsubstance which fills the spaces amongout to in, cuticles, cortex, and medulla

microfibrils. The strength and flexibility(Fig. 1). The major components ofof hair depends on the multi-layered

proteins are keratin (40 to 65 kDa) andstructure of keratin based fibers (1).

keratin associated proteins (KAPs; 6 toIn the development of hair care

30 kDa). Keratin, which possesses the

products, accurate evaluation of hairsimilar fibrous proteins to collagen anddamage is essential for examining the

microtubules, forms intermediate

benefits of pharmaceuticals or devices

filaments that are 10 nm in diameter.

used. However, I and collaborators

They gather systematically on the line of

think

that

the

researchand5

T. Fujiihair itself, not only the individual

Emost of evaluation methods are mail:based on qualitative ways such asfuji
it1@s
the sense of sight andhinshmorphological observations. Thus,u-u.ac.
they might not be suitable for jp

differences, but also varying

attaining objective viewpoints orconditions even between roots

quantitative data.

development have been difficult due tothe following problems.

1. Since the experimental material isand end tips within a piece of hair

3. As shown in Fig. 1, the analysis

causes samples to beof cortex which determines theheterogeneous. Therefore, a lot of

nature of hair is rather difficult,experiments are needed in orderbecause it is covered by hardto evaluate hair damages

cuticles.

accurately.
2. As shown in Table 1, hair

4. The changes in mechanicalstrength happen at last stage ofdamages are evaluated fromhair damage and thevarious approaches. At present,

reproducibility of data is poor.

6

A novel evaluation technology in hair care science

Method”

(2,

3).

This

methodisTo solve these problems, a novel

effective on tissues which include hard

method has been invoked to estimate

keratin, such as hair, nails, and wool.

accurate hair damage. If the three

Obtaining

dimensional and heterogeneous hairsolution with little protein degradation

samples could be turned into two

is possible in a short time. By using

dimensional and homogeneous film

hairsamples, this could be used as a newchemicaltreatments

such

as

hair

substitute device for hair, in the fieldcoloring

orproteins

wereof hair science including hair damage

solubilized by Shindai method.

analysis (Fig. 1). Keratin film has

Hair keratin is a major component ofbeen developed and proposed as suchcytoskeletal proteins, which belong to

new device.

intermediate filaments with a diameterIn this review, effects of major hairkeratinwithoutanyperms,

(hair

past

proteins)

historyofof around 10 nm (4, 5). Intermediate

damage factors such as UV, bleach,proteins

containing

keratins

retainperm, and heat on the keratin films

self-assembly ability even after theare introduced, in comparison to

depolymerization using denaturant. By

those on hair samples.

changing conditions of the solution, it
is possible to induce repolymerization

Solubilization of proteins from hairand remold original filaments. Keratin

and formation of keratin film

solution,withdifferent

denaturant

We have developed protein extraction

combinations or with reduced pH,

method from hair called “Shindai

would induce aggregate and mold it7

T. Fujii

Ema
il:
fuji
it1
@s
hin
sh
u-u
.ac.
jp

into a form of film. These methods

surface and white to light beige color

according to the varying combinationsin appearance. According to the SEM

and conditions are named Pre-castobservation

method,andparticles less than 1 μm in diameter inSoft-post-cast method (6, 7). Whena form of filaments were observed,

solubilizing

which

Post-castthese

method,

films

again

by

of

the

constructedkeratinirregular

film,

and

Shindai method, the films were foundreticular structure around 5 μm in

to be consisted mainly of keratin, lowdiameter by gathering together (Fig. 1).

molecular weight keratin associated

It has become evident that the keratin

proteins (KAPs), and high molecular

films can be used for different types ofweight proteins.

experiments related with hair damage.

In this study, keratin films preparedin the petri dishes by Pre-cast method
were used. These films had smoothUV8

A novel evaluation technology in hair care science

Carbonyl groups which are generated

When hair samples were irradiated andby UV irradiation in the skin are

observed by fluorescence microscopy, themeasured by fluorescent reagent

fluorescence intensity also increased(fluorescein-5-thiosemicarbazide), which

proportionally to UV irradiation time (9,bonds itself to carbonyl groups10). When comparing films with hairspecifically (8). When this method was

samples, it was demonstrated, that theapplied to the keratin films, thefilms showed 5-10 times more offluorescence intensity increased insensitivity than hair samples. By

proportion to irradiation time (Fig. 2).

applying this advantage, we succeeded inThus, in keratin films, the formation of

detecting carbonylated proteins which

oxidized proteins depended on thewere generated by light irradiation whichamount of UV irradiation.

was almost equal to 30 min of
mid-summer sun exposure. Compared to9T. Fujiihair samples, keratin films were more
effective in reproducibility of data andmore convenient in handling duringexperiments.

4. Bleach
It is known that when human hair is

Ema(Fourier transform infrared spectroscopy)
il:(Fig. 3). Cysteic acid was not detected infuji
it1@suntreated hair or keratin film however,hinshwhen treating hair and film by hydrogenu-u.ac.
peroxide, which was commonly used in jp
the bleaching agent. The peak appeared
around 1041 cm -1 , indicating the presencetreated by bleaching agent, disulfide

of cysteic acid. Keratin film exhibitedbond is oxidized and forms cysteic acid

5-10 times more of sensitivity in(11, 12). Thus, the formation of cysteic

detection, compared to hair sample (13).

acid was investigated using FT-IR

Spectra of the film and hair sample

10

A novel evaluation technology in hair care science

showed similarity (data not shown),

It has been reported that when treatingsuggesting one of the proofs for keratinhair with thioglycolic acid (TGA), whichfilm to be a substitute device for hair.

is commonly used in reductive permanentreagent, low molecular weight proteins

Perm
Permanent wave treatment consists ofsuch as ubiquitin and A100 are eluted
from hair samples, while keratin is not

two steps. The first step cuts plentiful(14). This is considered to be one of the

S-S bonds among keratin filaments byindicators of hair damage, since

reductive treatment and produces -SH

irreversible change is generated insidegroup. After setting up a hair style, thehair (in cortex portion). Interestingly, thesecond step recombines -SH group byprocess of elution occurred 2,000 times

oxidative treatment in order to fix such

faster in keratin films compared to that ofhair style.

hair samples, thus it only took 5 min for11

T. Fujii

was observed as it was observed in hairEmamethod (17).
il:
Keratin films were able to withstand fuji
it1@sthermal treatment of up to 200˚C, andhinshwhen treated by heat more than 180˚C foru-u.ac.
10 min, white to light beige coloredjpsamples (Fig. 4B).

keratin films turned to light yellow andkeratin films to detect changes which
took 2-3 days for hair to detect (Fig. 4A)(15, 16). When using keratin films, thesimilar elution of low molecular proteinsthen to light brown. Such observed color
Heat
Hair damage due to thermal treatmentschanges were similar to those of Japanesegray hair samples under the samehas been researched, since hair dryers

treatment (data not shown).

and hair irons are frequently used to dry

Mechanical strength of hair is known tohair or to set up hair styles. Most thermal

increase by thermal treatment; thus

damage measurements are done bycross-linkage among proteins in theobserving morphology of cuticles, which

cortex portion of hair was presumed to be

has become qualitative evaluation

generated. In order to investigate the12

A novel evaluation technology in hair care scienceamount of solubilized proteins after thecharacteristics of keratin films arethermal treatment of 80-200˚C for 10 min,compared to hair, from a perspective ofsolution containing reductive reagent andkeratin film as a device.

denaturant was used to incubate keratin
films and hair samples at 50˚C for 2 h

1. A number of responses observed in(Fig. 5). The amount of solubilizedhair samples were also detected inproteins from keratin films and hairkeratin film.

samples both decreased linearly in a

2. Compared to hair samples,

temperature-dependent manner.

responses in keratin film wereCompared to hair samples, this result wassignificantly high; 10 times as highdetected twice as high in keratin films.

in UV and bleach treatment, 2,000
times as high in perm reductive

Summary
Keratin films were able to withstandphysical and chemical stimulations suchtreatment, and twice as high inthermal treatment.
3. In regard to each hair damage factor,

as UV, bleach, perm, and thermal

reproducibility of data fromtreatments. In order to develop hair carehomogeneous keratin film was

related products, accurate hair damage

excellent.

evaluation method is essential. The

4. Keratin film prepared in petri dishes

effects from different hair damage factors

was easier to handle compared toto keratin films and hair samples have

hair samples.

been summarized in Table 2 with

5. Since experiments using keratin

investigated results. Then, thefilm can be carried out in short

13

T. Fujii

which represents an average human hair.

Ema
for Fostering Regional Innovation inil:fuji
Nagano, granted by the Ministry ofit1@s
Education, Culture, Sports, Science andhinshTechnology of Japan. I wish to thank u-u.ac.
Senior Scientist Tomoyuki Kawasoe of jp

Since highly sensitive and reproducible

Shiseido Co. Ltd. and many others who

experimental system can be constructed,

have joined me in this program. I also

keratin film is considered suitable for thewish to thank Mrs. Momoyo Reichmannefficient screenings of many chemical

for the critical reading of this manuscript.

amount of time, operational
efficiency was improved.
Keratin film prepared from numerous
hair samples can be considered a modeland natural substances. Production
system and quality management ofReferences

keratin film have progressed, allowing

1. Robbins, C. R.: Chemical andkeratin film as the commercial item andphysical behavior of human hair, 4 th

keratin film-related trust examination oned., 25-52 (2002).

contract through Shinshu TLO since 2010

2. Nakamura, A., Arimoto, M.,(18). It is our hope that the role we have

Takeuchi, K., and Fujii, T.: A rapid

in the development of hair care products

extraction procedure of human hairthrough a number of collaborative

proteins and identification ofrelationships will ultimately contribute tophosphorylated species. Biol. Pharm.

the wellness of society.

Bull., 25 (5), 569-572 (2002).
3. Kobayashi, S. and Fujii, T.:

Acknowledgements

Preparation and properties ofThis research was supported by Program

individual protein products. Current

14

A novel evaluation technology in hair care science

Topics in Biochemical Research, 9 (1),

Biol. Pharm. Bull., 27(9), 1433-1436

29-37 (2007).

(2004).

4. Langbein, L., Rogers, M. A., Winter,

8. Fujita, H., Hirao, T., and Takahashi,

H., Praetzel, S., Beckhaus, U.,

M.: A simple and non-invasive

Rackwitz, H. R., and Schweizer, J.:visualization for assessment of

The catalog of human hair keratins. I.

carbonylated protein in the stratum

Expression of the nine type I members

corneum. Skin Research andin the hair follicle. J. Biol. Chem.,

Technology, 13, 84-90 (2007).

274(28), 19874-84 (1999).

9. Kawasoe, T., Watanabe, T. and5. Steinert, P. M. and Roop, D. R.:

Fujii, T.: Visualization of modified

Molecular and cellular biology ofhuman hair by artificial sunlight withintermediate filaments. Annu. Rev.

carbonylated proteins as an indicator

Biochem., 57, 593-625 (1988).

of hair damage. J. Jpn. Cosmet. Sci.

6. Fujii, T., Ogiwara, D., and Arimoto,
M.: Convenient procedures for humanSoc., 34(4), 287-291 (2010).
10. Kawasoe, T. Watanabe, T., andhair protein films and properties of

Fujii, T.: A novel method using aalkaline phosphatase incorporated in

keratin film for quantifying thethe film. Biol. Pharm. Bull., 27(1),photo-modification of hair proteins. J.

89-93 (2004).

Soc. Cosmet. Chem. Jpn., 45(2),7. Fujii, T. and Ide, Y.: Preparation of

100-107 (2011).

translucent and flexible human hair

11. Leszek, J. W., Hall, K., and Hui, I.:protein films and their properties.

The mechanism of hair bleaching. J.

15

T. Fujii

Soc. Cosmet. Chem., 21, 875-900(1970).
12. Signori, V. and Lewis, D. M.: FTIR
investigation of the damage producedon human hair by weathering andEhair keratin films. Fragrance J., 7, mail:fuji
46-52 (2011).
it1@s
16. Kawasoe, T., Takayama, S. Ito, Y.
hinshand Fujii, T.: Effects of reductive u-u.ac.
and/or oxidative treatment during jp

bleaching processes: implementation

permanent wave procedure on humanof different sampling techniques andhair keratin films. J. Jpn. Cosmet. Sci.

data processing. Int., J. Cosmet. Sci.,

Soc., 35(4), 306-311 (2011).

19, 1-13 (1997).

17. Ruetsch, S. B., and Kamath, Y. K.:

13. Fujii, T., Ito, Y., Watanabe, T., andEffects of thermal treatments with a

Kawasoe, T.: Effects of oxidative

curling iron on hair fiber. J. Cosmet.

treatments on human hair keratinSci., 55, 13-27 (2004).

films. J. Cosmet. Sci., in press.
14. Inoue, T., Ito, M., and Kizawa, K.:

18. Shinshu TLO homepage address:
http://www.shinshu-tlo.co.jp/topics/,

Labile proteins accumulated in

SIS., Ltd. homepage address:

damaged hair upon permanent waving

http://www.sishp.com/.

and bleaching treatments. J. Cosmet.
Sci., 53, 337-344 (2002).
15. Fujii, T.: Evaluation of damage
caused by perm treatment using theCommunicated by Tate Shinichi