Commentar y

Features and Medical Applications ofMicrofiber Cloth for Cleaning Instruments with Wipes
Graduate School of Bioresources, Mie University

Satoshi Fukuzaki

INTRODUCTION

vention guidelines strongly recommend refraining from using disinfectant on ME instrument

At medical institutions, it has been reported

touch panels and infant incubators during use4）.

that various contact‒based infections occurred

Therefore, a chemical‒free cleaning cloth thatthrough medical engineering（ME）instruments

ef ficiently wipes of f sur face contaminants by

and environmental surfaces1～3）. In par ticular,

itself or with water, while keeping soil from read-places that healthcare workers frequently comehering to the surface, is much desired.

into contact with, such as the control panels,

One such form is a woven wipe made oftouch panels, and monitoring screens of ME

ultrafine fibers. This article focuses on a microfi-

instruments as well as door knobs and railings,

ber cloth known as Toraysee for CE（hereinafter,

require appropriate wipe cleaning and disinfec-“Microfiber Cloth CE”）, which was recently con-tion to remove various contaminants and viable

firmed to be a useful material for routine clean-microbes transferred from fingers and gloves.

ing with wipes in medical practice. The manufac-

Healthcare workers generally use so‒calledturing method, product design and characteris-“environmental cloths”to wipe ME instruments

tics, wiping performance, and precautions forclean. These wipes are made of cotton cloth,

per for ming the wiping pr ocedur e ar e also

nonwoven fabrics, or wipe cleaning cloth impreg-

explained herein.

nated with a solution containing disinfectant withor without detergent. The cloth may be made of

WHAT IS AN ULTRAFINE FIBER?

cotton, polyester, rayon, polypropylene, or poly-

The unit“tex”is used to express fiber thick-

ethylene as a single material or a combination ofness（fineness）. One tex is defined as the mass

multiple materials. This wiping operation is anin grams of a 1000‒m‒long filament. A conven-important cleaning procedure because it is pos-tionally‒used unit is the decitex（dtex）, which issible to wipe an instr ument or sur face cleanequivalent to 1/10 of a tex. The relationshipwhile simultaneously disinfecting it in a safe andbetween fiber diameter and dtex is dependent on

simple manner. However, a cer tain amount of

the fiber density；e. g., polyester fibers（density

disinfectant remains on the surface after wipeof approximately 1.38 g/cm3）with a fineness of 1

cleaning. Centers for Disease Control and Pre-dtex have a diameter of approximately 10μm.

Key words：Microfiber cloth, Ultrafine fiber, Medical engineering instrument, One‒way wiping
Therapeutic Research vol. 40 no. 11 2019905

Fig. 1

Principle of manufacturing ultrafine fibers（B）
from sea‒island type composite fibers（A）

While no formal definition exists for an

polymer viscosity（fluidity）, accuracy, and posi-

ultrafine fiber, any fiber finer than silk（finenesstioning of holes on the spinneret, and specificof approximately 1.4 dtex）, which is considered

cooling and solidification conditions, in addition

to be the finest of all naturally‒occurring practi-

to special techniques and facilities for processing

cal fibers, is deemed to be an ultrafine fiber5）.

of ultrafine threads into the desired product.

Furthermore, ultrafine fibers at and below 0.5

Therefore, it is extremely difficult to spin fibers

dtex are categorized as microfibers because thewith a diameter of 10μm or less.
In the composite fiber manufacturing pro-ultrafine fiber characteristics, such as touch andcess, on the other hand, a composite fiber, com-

flexibility, are prominent in this range.

posed of two polymers with different degrees of

MANUFACTURING METHODS

solubility in solvents, is usually produced, drawn

FOR ULTRAFINE FIBERS

in the same manner as the conventional fiber toMethods of manufacturing ultrafine fibers

improve fiber characteristics, and made into

are broadly classified into filament and random

ultrafine fiber. There are two main processes of（e.g., the melt blown method）methods . As

turning composite fiber into ultrafine fiber, i. e.,examples of the filament method, direct spinning

either the peeling/separation or the sea‒islandand composite fiber manufacturing processes aretype based on the morphology of the composite

summarized below.

fiber cross section. The peeling/separation type5）

In the direct spinning process, hot molten

uses chemical or physical processing to separate

polymer is extruded through a spinneret（noz-two components；the sea‒island type produceszle）with numerous drilled holes up to a few mm

ultrafine fibers from composite fibers by dissolv-

in diameter to form multifilaments, which are

ing the“sea component”（highly soluble poly-cooled, solidified, and reeled. Fibers produced

mer）, thereby leaving the“island component”

by this technique are widely utilized for apparel（barely soluble polymer）as ultrafine fibers（Fig.

and industrial applications. However, in the case1）.

of polyester, the diameters of fibers that can be
manufactured stably for routine use in facilitates
are as low as approximately 10μm. Stable production of ultrafine fiber requires strict control of906

MANUFACTURING AND PRODUCTDESIGN OF MICROFIBER CLOTH
This article focuses on Microfiber Cloth CE,

Therapeutic Research vol. 40 no. 11 2019

which is manufactured by the sea‒island typeensuring a long‒lasting bacteriostatic action.

process using two types of polyester（100％）

Microfiber Cloth CE is pre‒washed withpolymers with different degrees of solubility. The

pure water and provided as single sheet pack-

manufacturing process star ts with composite

ages, each sealed in a clear polypropylene bag, in

spinning（spinning‒drawing）to produce sea‒consideration of various usages at medical insti-

island type fiber, followed by advanced process-tutions. The product itself is unsterilized, but theing（e.g., thread processing, plain knitting）,

sheet may be sterilized at the medical institution

refining（removal of sizing agent）, and reduction

where it is to be used, as necessary, by removing

processing（dissolution of sea component）toit from the product packaging and placing it in aultimately produce fabric cloth composed only ofsterilization bag.

microfibers approximately 2 to 5μm in diameter.
Subsequent processing procedures include staining, high‒pressure fluid spraying to form a structure of randomly entangled fibers, water jet

PRINCIPLE OF WIPING A SURFACEOR INSTRUMENT CLEAN
WITH A MICROFIBER CLOTH

punching to generate air spaces between microfi-

Cleaning cloth performance is dependent

bers, and finishing to achieve a pre‒specified

on friction between the object to be cleaned andwidth by heating the cloth while holding boththe cloth, contact area, as well as soil absorption

e n d s t o m a i n t a i n i t s t e n s i o n . T h e a b o v e‒

and retention within the cloth. While wipe clean-described process provides Microfiber Cloth CE

ing appears to be a simple procedure, a cleaning

with the fiber diameter, density, air space volume

cloth that has been impregnated with water effi-

between fibers, and surface area, in the intended

ciently facilitates dissolution and absorption ofbalance.

the soil into the cloth. That is, a cloth suitable forWith this manufacturing method, the island

wipe cleaning will have appropriate water absorp-

component（polyester）is protected by surround-tivity, adsorption affinity for the soil, and a con-ing the sea component in the earlier part up to

figuration that achieves a large specific surface

advanced processing with a fiber diameter simi-area and porosity.

lar to that of conventional fibers（in the 10 to 30

Fig. 2 shows scanning electron microscope

μm range）. This allows generation of uniform（SEM）images of the surface（A）and the crossmicrofibers having favorable characteristics

section（B）of Microfiber Cloth CE. As seen inwithout unnecessar y damage even during

the cross sectional image, the island type micro-

advanced processing, where the fiber is exposed

fiber has numerous gaps called“micro‒pockets”

to relatively strong force. The usability of routine（encircled in the image）. Liquid and solid soils

advanced processing facilities is also an indus-

picked up and trapped in these gaps are likely totrial advantage.

be quickly absorbed inside the cloth via the cap-

In addition, Microfiber Cloth CE is pro-illary phenomenon.

cessed to provide bacteriostatic proper ties toFig. 3 is a schematic diagram illustrating

suppress bacterial growth on the fibers6）. This

the concept of cleaning by wiping with a cloth

technique is not a posterior process designed towith a common fiber diameter vs. Microfiber

coat the fiber surface with a bacteriostatic agent

Cloth CE6）. A common fiber cloth has a larger

but rather a process involving the incorporation

fiber diameter, which provides a smaller workingof a pyrithione antibacterial agent into the fiber,area for wiping the object to be cleaned and an

Therapeutic Research vol. 40 no. 11 2019907

Fig. 3

Schematic diagram illustrating the concept of cleaning by wiping with a clothwith a common fiber diameter vs.
Microfiber Cloth CE6）©2019 TORAY INDUSTRIES, INC.

the cloth has been impregnated, will significantly
improve soil absorption by the cloth（refer to thefollowing section）. The cloth has a thickness of
530 to 550μm, which also prevents soil fromleaching outward from the sur face in contact
Fig. 2

SEM images of the surface（A）andthe cross section（B）of Microfiber
Cloth CEThe circle in panel B indicates“micro‒pockets”.

with the fingers during cleaning.
EFFECTIVENESS OF WIPE CLEANINGWITH MICROFIBER CLOTH
1

insufficient total absorption area relative to a soil

Ef fectiveness of wipe cleaning using awater‒moistened clothparticle. Also, nonwoven fabric has a very highLiquid soil is easily wiped of f, to achieve

water retention capacity, which tends to cause

cleaning, via absorption with a dr y nonwoven

readsorption of the soil back onto the surface tofabric（dry wiping）. In this case, cleanliness is

be cleaned if excess water is present. In contrast,

often limited to the so‒called“visually clean”

Microfiber Cloth CE has a smaller fiber diameterlevel. Furthermore, for organic and/or dry soil

and a greater weight per unit area of 200 to 210

adsorbed on the object to be cleaned via intermo-

g/m2, corresponding to a fiber density several

lecular interactions, dry wiping achieves minimal

times greater than that of common nonwoven

cleanliness at the microbial level. In such a case,fabric used for wiping objects/surfaces clean,

cleaning effectiveness will be greatly improved

thus providing a significantly greater contact sur-by first removing liquid dirt via absorption withface area. Therefore, the microfibers can ef fi-

an environmental cloth（dry wiping）and thenciently attract the soil on the object to befinishing by wiping with a cloth impregnatedcleaned, ef fectively picking up the soil intowith water as a cleaning medium（wet wiping）.

micro‒pockets between fibers. The soil within

Water is a medium for wet cleaning and contrib-

the cloth is thought to be further adsorbed onto

utes to basic cleaning performance because it

microfibers and stably retained inside the cloth.

dissolves and disperses many hydrophilic sub-At this stage, the presence of water, with which

stances. However, impregnating the cloth with

908

Therapeutic Research vol. 40 no. 11 2019

excess water may result in water spots on the

The wiping was performed in approximately 1cleaned object after wipe cleaning. Water drop-

second. Furthermore, the standard deviation oflets remaining on the cleaned sur face mustthe removal rate after 5 repeated wiping motions

always be wiped off as such droplets contain dis-

was 0.12％. These results support the observa-

solved soil.

tion that a water‒moistened cloth can provide

Tojo K, et al.7）compared the cleaning effectiveness of dry wiping vs. wet wiping with Micro-

excellent wiping per for mance with a highremoval rate and excellent reproducibility.

fiber Cloth CE on stainless steel surfaces con-Fig. 4 shows SEM images of microfiber

taminated with a specified amount of yeast

cloth cross sections after wiping aimed at picking

extract and reported an approximately 10 times

up P. fluorescens cells employing one‒way wiping

higher cleaning effect with wet wiping as com-

as described above. The images represent thepared to dry wiping. They also demonstrated ancross section from the wiping side（top）to theadequate amount of impregnated water to be upother side（bottom）；Fig. 4A through 4D are2

to 0.1 mL/24 cm , or even more, and that themagnified views of areas marked with corre-same side of the cloth was good for up to 10

sponding letters in the cross sectional image.

repeated uses. In addition, the cloth provided

Many adherent bacterial cells are seen on thesimilar wiping effects regardless of the weave

fibers closest to the wiping side（0 to 50μm, Fig.

direction（lengthwise versus crosswise）, which4A）. Adherent bacterial cells are also seen in theis a feature of Microfiber Cloth CE.

areas close to 200μm（Fig. 4B）and 400μm

For r efer ence, Toray Industries Inc.’s（Fig. 4C）
. These observations indicate that bac-microfiber cloth for wiping glasses, which is not

terial cells have been absorbed and become

knitted but rather a woven fabric with a much

adherent to sites near 400μm in depth with2

lower weight per unit area of 68 g/m , is not

approximately 1 second of wiping. However, very

intended for cleaning ME instruments by wiping.

few bacterial cells are seen in the deepest area

8）

further studied Microfibernear 550μm in depth from the wiping side（Fig.

Cloth CE for wiping effectiveness with feline cali-

4D）. This means that bacterial cells did not

civirus（dried）
attached to stainless steel surfaces

leach outward onto the fingers of the operator.

and reported a remarkably higher removal rate

However, absorbed virus par ticles repor tedlyof 99.9％ with wet wiping（2 mL/144 cm ）, versusreached the finger side when a similar wiping

only 84.2％ with dry wiping.

procedure was repeated 10 times8）.

Tojo K, et al.

2

Matsumoto I, et al.9）examined Microfiber

Microfiber cloth is effective for wiping not

Cloth CE for the removal profile of dried

only hydrophilic but also oily soil. Amauchi M, etmicrobes（Pseudomonas fluorescens）attached toal.10）examined the wipe cleaning performances

the surface of polyethylene terephthalate（PET）,

of Microfiber Cloth CE, cotton gauze, and non-which is a material constituting ME instrument

woven fabric moistened with water（1.0 mL/24

touch panels. They found that dry wiping barelycm2）on a PET sheet surface contaminated withremoved bacterial cells on the PET surface while

mineral oil containing adenosine triphosphate

the microfiber cloth which had been moistened（ATP, 34,602 relative light unit［RLU］）. The

with water（0.8 mL/9 cm2）
removed at least 99.8％

results demonstrated that the amount of ATPof the cells（2.0×10 cells/mm ）in one wiping

remaining after wipe cleaning with a microfiber

motion in a single direction（one‒way wiping）.

cloth（77 RLU）was significantly lower than that

5

2

Therapeutic Research vol. 40 no. 11 2019909

Fig. 4

SEM images of P. fluorescens cells trapped in various parts of Microfiber Cloth CE after one‒way wiping9）
From Ref. 9：Matsumoto Y, et al., reproduced with permission.

with cotton gauze（4,834 RLU）
or nonwoven cloth

wiping with wet Microfiber Cloth CE using（653 RLU）. This finding supports the effective-

bovine viral diarrhea virus（BVDV）attached toness of microfiber cloth for removing sebaceous

stainless steel surfaces. The results indicated thedirt transferred from the fingers to ME instru-

log reduction value for the BVDV infection titerments by wipe cleaning. They also investigatedto be 2.9（reduction rate of 99.88％）with one‒the amount of ATP leaching outward onto theway wiping and 3.8（reduction rate of 99.98％）

finger‒contact side and found that Microfiberwith back‒and‒forth wiping；the mean removal

Cloth CE（27 RLU）was particularly good for

rate was higher for the latter, but the difference

preventing this leaching as compared with cottonin effectiveness between the two did not reachgauze（1,920 RLU）and nonwoven fabric（396statistical significance（p＝0.27）.
In similar experimental systems, a clean

RLU）.
Wipe cleaning performance and soil read-stainless steel surface was wiped with Microfiber

sorption in one‒way vs. back‒and‒for th

Cloth CE that had been used to wipe surfaces

wipingcontaminated with feline calicivirus or BVDV,In environmental wipe cleaning, it is a com-and any viral particles readsorbed on the surface

mon practice to use the wipe cleaning cloth in aafter wiping were present at levels below theback‒and‒forth manner and to use the wiping

detection limit8,11）. These findings support theside several times, rather than disposing of the

supposition that Microfiber Cloth CE does notwipe cleaning cloth after using one side in one

allow readsorption of vir us par ticles once an

direction. These practices raise the issue of soil

object/surface has been cleaned.

2

readsorption from the wipe cleaning cloth.
11）

Tojo K, et al.

In addition, a clean PET sheet surface wascompared the wipe cleaning

wiped with Microfiber Cloth CE, cotton gauze, or

per formance of one‒way vs. back‒and‒for th

nonwoven fabric that had been used to wipe off

910

Therapeutic Research vol. 40 no. 11 2019mineral oil containing ATP as described above10）,
and the amount of mineral oil readsorbed was
lower for Microfiber Cloth CE（77 RLU）than for
either cotton gauze（1,646 RLU）or nonwoven
fabric（412 RLU）.
It should be noted that the aforementioned
experiments on readsorption do not provide
information on the time elapsed from the initial
wiping until the readsorption experiment.
3

Precautions for wiping procedure

Use of the best wipe cleaning cloth may notachieve good cleaning results, if the wiping procedure is not adequate.
Matsumoto Y, et al. 12）investigated theeffects of wiping speed and water absorption into
the cloth on the removal of bacterial cells by
one‒way or back‒and‒forth wiping with Microfiber Cloth CE using P. fluorescens cells（2.7×105
cells/mm2）attached to the PET surface（Fig.
5A）. With one‒way wiping, the residual ratio ofbacterial cells on the PET surface was less than
0.4％ regardless of the wiping procedure within
the ranges of wiping speeds（1.7 to 100 mm/s）
and moisture levels（0.1 to 1.0 mL/9 cm2）examined（Fig. 5B）.
With back‒and‒forth wiping, on the other
hand, bacterial cells remained along the wiping
direction（shown by arrows）and the residual
ratio of bacterial cells on the PET surface was
12.5％（Fig. 5C）. The residual ratio of bacterial
cells after back‒and‒forth wiping tended to behigher as the speed of wiping and the water
absorption level increased. In this experimental
system, it was confirmed that little bacterial readsorption on the PET sur face from the clothFig. 5SEM images of P. fluorescens
cells remaining on PET surface
after one‒way or back‒and‒forth
wiping with Microfiber Cloth
CE12）（A）Before wiping,（B）after one‒way wiping,（C）after back‒and‒forth wiping.
The arrows indicate the direction of wiping.
From Ref. 12：Matsumoto Y, et al., reproduced with permission.

occurred after repetitions of one‒way wiping（outward only）up to 10 times9）. These observations indicate that the change of wiping direction

excessive water absorption into the wiping clothfrom outward to inward triggers bacterial cell

as it may facilitate transfer from the cloth back totransfer from the cloth to the PET surface. In

the PET sur face and lower the cleaning ef fi-

addition, caution should be exercised to avoid

ciency of back‒and‒forth wiping.

Therapeutic Research vol. 40 no. 11 2019911

This study further compared the effective-

the wipe14）. In this regard, PET, the material ofness of back‒and‒forth wiping as a function ofwhich Microfiber Cloth CE is made, is less reac-

the time to switch（waiting time）from one‒waytive with NaClO and NaClO 2 than with other（outward）wiping to back‒and‒forth（inward）

fiber materials14,18）. Therefore, PET material has

wiping. As the waiting time increased from 0 to

the advantage of being less prone to the loss of

60, 300, and 600 sec, the residual ratio of bacte-

an effective chlorine concentration after impreg-rial cells on the PET surface decreased sequen-

nation with a chlorine‒based oxidant.

tially from 53.8 to 19.9, 15.9, and 4.1％, respec-

Additionally, wipes impregnated with com-

tively. Matsumoto Y, et al. pointed out that theplex chlorine‒based disinfectant/detergent that“elapsed time”after wiping of bacterial cells until

releases hypochlorous acid have recently comeirreversible adsorption on the fiber surface of theinto widespread use. These products have also

cloth is a critical factor that governs bacterial

been reported to inactivate various bacteria andreadsorption behavior with inward wiping.

feline calicivirus attached to hard surfaces19,20）.

USE OF WIPE CLEANING
MATERIAL IMPREGNATED
WITH A CHEMICAL AGENT

The effectiveness of a chlorine‒based oxidant in
combination with Microfiber Cloth CE is anticipated to be a focus of future research.
On the other hand, impregnating nonwoven

Although chemical‒free wipe cleaning isfabric wipes with ethanol for disinfection pur-much desired, as mentioned in the first section ofposes significantly reduces the removal ef fi-

this article, wipe cleaning with a chemical agent

ciency of protein by wipe cleaning13,14）. This is

is preferred for some objects in medical practice.

due to the reduced solubility of proteins in etha-

If the object to be cleaned is suspected ofnol solution. When wipe cleaning material

harboring bacteria or viruses, healthcare work-

impregnated with ethanol is used for environ-ers would want to use a wiping cloth impreg-

mental disinfection, it first requires the use ofnated with a disinfectant, from the viewpoint ofwater‒moistened wipes to remove（clean off）

infection prevention. Nonwoven fabric wipes

organic soil as thoroughly as possible, prior to

impregnated with chlorine‒based oxidant pos-

wipe cleaning to achieve disinfection.

sessing cleaning and bactericidal effects, such as
sodium hypochlorite（NaClO）and sodium chlorite（NaClO2）, show improved wiping per for-

EFFECTIVENESS AND ASSESSMENT OFWIPE CLEANING IN MEDICAL PRACTICE

mance for proteinaceous soil on hard surfaces,

Hatakeyama T, et al.21）compared the wipe

as compared to wipes impregnated withcleaning effectiveness of wet Microfiber Cloth

13,14）

water. Because the cleaning performances of

CE and 5 different environmental cloths impreg-

NaClO and NaClO2 are nearly the same, in terms

nated with quaternary ammonium salt, by apply-of the removal of both proteins and bacterial

ing a wiping test, on infusion pumps and syringe

15～17）, wipes impregnated with these chlo-

pumps used in clinical settings with ATP（＋rine‒based oxidants also seem to be effective foradenosine monophosphate：AMP）
serving as thethe removal of bacterial cells. The presence ofindicator. The results demonstrated that only

chlorine at a certain efficacy level in the nonwo-

Microfiber Cloth CE achieved a level of cleanli-

ven fabric wipe impregnated solution also rapidly

ness not exceeding 500 RLU, which is the target

reduces the number of viable bacterial cells on

control level for noncritical medical instruments,

cells

912

Therapeutic Research vol. 40 no. 11 2019in wiping tests conducted after a wipe cleaning

Hatakeyama T, et al. 22）stated that the use ofoperation. The cleaning effect was significantly

environmental cloths alone for achieving andhigher than those of other environmental cloths.

maintaining the cleanliness already achieved by

Furthermore, it was also confirmed that after a

the introduction of Microfiber Cloth CE will

10‒day reuse test（by washing with water after

require more environmental cloths, which raises

each use）the cleanliness level was sustained atconcerns about increased costs.
Yamafuji T, et al.23）evaluated the reusability

a level below 500 RLU.
Hatakeyama T, et al.

22）further investigatedof Microfiber Cloth CE, specifically, the wiping

the residual ATP level changes on syringe

per formance of washed/recycled Microfiber

pumps, which were returned to the ME center

Cloth CE on ar tificial contaminants and theirafter being used for assessment, during theircleanability. The results demonstrated that wip-

repeated routine usage following the introduc-

ing per for mance and cleanability after 60tion of Microfiber Cloth CE at their medical insti-

repeated washes/reuses were both similar totution. The results demonstrated a gradual ATP

those of unused products. Although disposable

decrease over time；the ATP level after one anduse（single use）is regarded as being desirable

a half years was less than 1,000 RLU, which isfor Microfiber Cloth CE from the viewpoint of

the target control level for healthcare workers

infection control, the authors consider this prod-

after hand washing, indicating that the use of

uct to also be useful as a cloth for environmental

Microfiber Cloth CE also contributed to infection

maintenance/cleaning, depending on the object

14）

control . Also, the ATP level after wipe cleaning

to be cleaned and its usage, based on the resultswith wet Microfiber Cloth CE was around 100

indicating the potential for washing and reuse.

RLU, achieving a level comparable to the target

Microfiber Cloth CE has also been used forcontrol level for steel tools and other materials

wipe cleaning of lenses on medical optical instru-

used in the operating room. The practical resultsments due to the product’s intrinsic features. In

reported above indicate that, on a daily basis, therecent years, it has begun to be applied to wiping

introduction of Microfiber Cloth CE effectively

lenses on cameras used for endoscopic surgery.

maintained the cleanliness of medical instru-

However, for use in the operating room, microfi-

ments at a higher level than could previously be

ber cloths must fulfill requirements, such as

achieved.

prior sterilization and radiographic compatibility

As Microfiber Cloth CE is currently being

to assure medical safety. New microfiber clothused routinely in clinical practice, cost effective-

products that meet these requirements are now

ness is now an issue. In general, environmental

commercially available from Toray Industries,

cloths cost 10 yen or less per sheet, while Micro-

Inc.

fiber Cloth CE costs more than 200 yen per
sheet, making the price 20 to 30 times higher

CONCLUSION

than that of the former. However, MicrofiberWith the advent of Microfiber Cloth CE,

Cloth CE is used in various applications, from anwipe cleaning procedures have advanced fromalternative to nonwoven cloth to its usage forwiping with conventional nonwoven fabric tomaintenance of medical instr ument details,

wipe cleaning that can achieve cleanliness at thebased on being cut into small pieces, making it

microbial level. Particularly, the use of a moist-

dif ficult to unconditionally assess the cost.

ened cloth impregnated with water has been

Therapeutic Research vol. 40 no. 11 2019913

proven to provide ver y high wiping ef fectiveness. However, the actual situation is not that
simple and the use of Microfiber Cloth CE by
itself does not immediately provide the desired
level of cleanliness. Effective wipe cleaning procedures must be established by selecting anappropriate wipe, cloth, and impregnating solution depending on the object to be cleaned andthe type of soil requiring removal. Other issues
include prevention of slight“readsorption”seenwith back‒and‒forth wiping. Repeated one‒way
wiping is recommended based on current knowledge. It should be noted that the data presented
in this article do not necessarily apply to all products that are referred to as being comprised of
microfibers. There is no doubt that productdesign with full consideration of wipe cleaning
performance is essential. In the future, various
interfacial phenomena should be elucidated fortheir impacts on wipe cleaning with Microfiber
Cloth CE and, furthermore, wipe cleaning procedures/conditions need to be established for the
optimal prevention of readsorption.
CONFLICTS OF INTEREST
The author declares no conflicts of interest assosiated with this manuscript.

REFERENCES
1）Dancer SJ. Hospital cleaning in the 21st century. Eur
J Clin Microbiol Infect Dis 2011;36:1473‒81.
2）Gastmeier P, Stamm‒Balder rjahn S, Hansen S,
Nitzschke‒Tiemann F, Zuschneid I, Groneberg K,
Rüden H. How outbreaks can contribute to prevention of nosocomial infection: analysis of 1,022
outbreaks. J Infect Control Hosp Epidemiol
2005;26:357‒61.
3）Weber DJ, Anderson D, Rutala WA. The role of thesurface environment in healthcare‒associated infections. Curr Opin Infect Dis 2013;26:338‒44.
4）Rutala WA, Weber DJ, Healthcare Infection Control
Practice Advisory Committee. Guideline for Disinfection and Sterilization in Healthcare Facilities,
2008. https://www.cdc.gov/infectioncontrol/pdf/
914

guidelines/disinfection-guidelines-H.pdf. Accessed
June 3, 2019.
5）Horiguchi T, Watanabe K. Ultrafine fiber－Manufacturing method and evolution. J Textile Machinery
Soc Jpn 2003;56:203‒9（In Japanese）.
6）TorayseeTM for CE（Medical Equipment and Instruments Maintenance Cloth）http://www.toraysee.
toray/en/medical/. Accessed July 6, 2018.
7）Tojo K, Nakamura K, Sato E, Hayami S, Fujii M,
Miyaji K. Effectiveness of microfiber cleaning clothused for medical equipment. Ther Res 2013;34:399‒
407（In Japanese）.
8）Tojo K, Nojima Y, Sagehashi N, Nakamura K, Sato
M, Fujii M, et al. Evaluation of virus removal efficiency with a microfiber cleaning cloth. Ther Res,
2014;35:827‒36（In Japanese）.
9）Matsumoto Y, Takahashi K, and Urano H. Removalof bacterial cells adhering to surface by using a wiping cloth. J Antibact Antifung Agents 2015;43:3‒7（In
Japanese）.
10）A m a u c h i M , S o m a n K , H i r a t a A , F u s h i m i R ,Okamoto N, Takahashi R, et al. Study of wiping,transferring and oozing of three kinds of wipes（materials）by evaluating ATP. J Healthcare‒assoc
Infect 2016;9:42‒51（In Japanese）.
11）Tojo K, Fujii M, Nakamura K, Sato M, Nojima Y,
Sagehashi N. Evaluation of virus removal efficiency
with a microfiber cleaning cloth. Jpn J Med Instrument 2017;87:40‒6（In Japanese）.
12）Matsumoto Y, Takahashi K, Urano H. Effect of thewiping speed and the water content of the cloth
when wiping for ward and back on the efficacy ofremoving bacterial cells from polyethylene terephthalate sur faces. J Antibact Antifung Agents2018;46:181‒6（In Japanese）.
13）Kawakami H, Nishikubo H, Hirayama K, Suzuki S,
Sato Y, Kikuchi Y. Effects of NaOCl aqueous solutions and ethyl alcohol solutions on removing protein surface contaminants and re‒establishing antibacterial activities of copper‒alloyed stainless steel.
Biocontrol Sci 2015;20:193‒8.
14）Yoshida S, Ogata R, Yokomizo M, Araida Y, Fukuzaki
S. Antimicrobial action and wipe‒off performance of
weakly acidic sodium chlorite solution‒impregnatednon‒woven fabrics. Prep Foods Technol 2018;24:1‒
8（In Japanese）.
15）Fukuzaki S. Mechanisms of actions of sodium hypochlorite in cleaning and disinfection processes. Biocontrol Sci 2006;11:147‒57.
16）Takahashi K, Tanaka R, Fukuzaki S. Cleaning actionof sodium chlorite in removing protein adsorbed on

Therapeutic Research vol. 40 no. 11 2019

stainless steel surfaces. J Antibact Antifung Agents2017;45:437‒44（In Japanese）.
17）Takahashi K, Tanaka R, Fukuzaki S. Cleaning actionof sodium chlorite in removing Vibrio parahaemolyticus adhering to stainless steel surfaces. J Antibact Antifung Agents 2017;45:529‒32（In Japanese）.
18）Hatano R, Yoshida S, Ogata R, Yokomizo M, Araida
Y, Fukuzaki S. Reactivity of sodium hypochlorite
solution with wiping non‒woven fabric fibers. Prep
Foods Technol 2017;23:103‒11（In Japanese）.
19）Yokota K, Watanabe T, Hayashi T, Watanabe S,
Kokeguchi S, Hirai Y, et al. Effect of the disinfectant
impregnation wipe of the environmental contaminant bacteria. J Antibact Antifung Agents 2018;46:3‒
8（In Japanese）.
20）Nojima Y, Ogura Y, Ozawa T, Hayashi N, Kikuno R.
Removal efficacy of a complex‒type chlorine‒based

disinfectant cleaner against feline calicivir us
attached to hard sur faces. J Antibact Antifung
Agents, 2018;46:235‒9（In Japanese）.
21）Hatakeyama T, Matsuda K, Osawa M, Sagehashi N,
Kumagai M. Study on usefulness of Toraysee® for
CE. J Jpn Assoc Clin Engineer Technologists
2015;53:67‒71（In Japanese）.
22）Hatakeyama T, Matsuda K, Osawa M, Sagehashi N,
Kumagai M. Change in cleanliness over time following introduction of microfiber cloth for wipe cleaning of medical instruments. J Jpn Assoc Clin Engineer Technologists 2016;56:100‒3（In Japanese）.
23）Yamafuji T, Kashima H, Fushimi R, Okamoto N, Yagi
T, Sagehashi N, et al. Abstracts of the 138th Meeting of the Association of Central Services and Infection Prevention, 2017;p.6‒7（In Japanese）.
＜Received on September 17, 2019＞

Therapeutic Research vol. 40 no. 11 2019915