Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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Bioactive and Hydrophilic Coating
of Polymer Substrates
Field of Invention
The present invention relates to a process for forming a
hydrophilic and bioactive coating on a surface of a polymer
substrate, to a product with a substrate coated in this way.
Prior Art
Generally, colonization and proliferation of bacteria on
surfaces is an unacceptable phenomenon that is frequently
linked to detrimental consequences. Bacterial populations in
drinking water and beverage-production equipment can lead to
diminished quality that poses a threat to health. Bacteria in
and on packaging frequently cause foodstuffs to spoil or even
give rise to infections in consumers. In biotechnical systems
that are to be operated so as to be sterile, bacteria that are
foreign to the system pose a considerable risk from the
standpoint of process technology. Such bacteria can be
introduced with raw materials, or can remain in a11 parts of
the system as a consequence of inadequate or improper
sterilization. Some elements of the bacterial population can
remain invulnerable to the exchange of liquids during flushing
and cleaning processes because of adhesion, and then multiply
within the system.
In addition, bacterial colonies can be found in water-
treatment plants (used, for example, for desalination by
membranes) or in tanks filled with dissolved or liquid,
undiluted organic substances and provide good conditions for
bacterial populations. Such microbial contents can lead to
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extensive blockages and/or corrosion damage in the plant.
Protection against bacterial adhesion is especially
important in nutrition, nursing (particularly geriatric
nursing), and medicine. In the case of large-scale food
preparation or if large quantities of beverages are dispensed,
there are considerable risks if, in order to reduce waste,
disposable containers are not used, and reusable containers
are insufficiently washed. The harmful spread of bacteria in
hoses and pipes that convey foodstuffs is as well-known as the
proliferation in storage tanks and in textiles, in a warm and
moist environment, e.g., in baths. Such facilities are
preferred living spaces for bacteria, as are certain surfaces
in areas heavily used by the public, such as hospitals,
telephone call boxes, schools and, in particular, public
toilets.
As far as geriatric and sick nursing is concerned, the
patients' resistance, which is frequently low, demands special
measures to prevent infections, particularly in intensive care
situations and in the case of home nursing.
Particular care is required when medical articles and
equipment are used during medical examinations, treatments,
and surgical procedures, particularly if such articles or
equipment come into contact with living tissue or body fluids.
In the case of long-term or permanent contact, as seen, for
example, in the case of implants, catheters, stems, cardiac
valves, and cardiac pacemakers, bacterial contamination can
become a life-threatening risk for the patients.
Many attempts have already been made to suppress surface
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colonization and proliferation of bacteria. S.E. Tebbs and
T.S.J. Elliot, writing in J. Microbio. Chemoth, 31 (1993), pp.
261-271, describe lacquer-like coatings with quaternary
ammonium salts as components with an antimicrobial action. It
is a known fact that these salts are dissolved out of the
coating material by water, aqueous or other polar media, and
body fluids, and that they remain effective for only a limited
time. This also applies to the incorporation of silver salts
in coatings, as described in WO 92/18098.
T. Ouchi and Y. Ohya, writing in Progr. Polym. Sci., 20
(1995), 211 et seq., describe the immobilization of
bactericides on polymer surfaces by covalent bonding or ionic
interactions. In such cases, the germicidal effects are often
significantly reduced vis-a-vis the pure substances. Hetero-
polar compounds are frequently not sufficiently stable.
Furthermore, as a rule, killing the germs leads to undesirable
deposits on the surfaces, and these mask the further
bactericidal effect and form the basis for subsequent
bacterial colonization.
W. Kohnen, et al. ( Zbl. Bakt. Suppl., 26, Gustav Fischer
Verlag, Stuttgart-Jena-New York, l994, pp. 408-410) report
that the adhesion of Staphylococcus epidermidis on a
polyurethane film is reduced if the film is pretreated with a
corona discharge in the presence of oxygen, and grafted with
acrylic acid.
As discussed, it is important that when medical articles
and equipment are used during medical examinations, treat-
ments, and surgical procedures, any bacterial contamination of
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such articles and equipment be prevented. With many such
articles and items of equipment, which come into contact with
living tissue or body fluids over the mid-term or the long-
term, any adhesion and proliferation of the bodies own cells
is also highly undesirable. Thus, cellular colonies that
occur with medium-term catheters that are applied intra
corporally are just at injurious as long-term, implanted
stem s or cardiac valves.
In addition, the transparency of intra ocular lenses can
deteriorate continuously as a result of cellular colonization.
A number of procedures are intended to prevent cellular
colonization by the incorporation of certain metals or
metallic salts in the holders used for intraoccular lenses;
the effect achieved is in most instances incomplete and not
lasting. WO 94/16648 describes a process intended to prevent
cellular proliferation on the surfaces of intra occular lenses
that are of polymer material.
EP 0 431 213 describes how cell-repellant properties are
to be imparted to polymers by hyrophilising their surfaces
with strong mineral acids. However, in most instances, the
long-lasting chemical modification of polymer surfaces is not
even. As a rule, there are places that are treated
inadequately or not at a11, and these act as starting points
for cellular colonization. In addition, the cell-repellant
properties of the surfaces treated in this way are frequently
not lasting.
On the other hand, for certain applications it is
desirable to have objects that have bacterio-repellant
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surfaces but still encourage cellular colonization. This is
so, for example, for a number of equipment types used for
medical examinations, treatments, and surgical procedures, and
similarly for many prostheses that are meant to become
incorporated into the tissue within which they have been
implanted. Such devices and prostheses as artificial hip
joints or teeth are frequently of polymer-coated materials
such a titanium.
Finally, materials used for devices and apparatuses that
come into contact with body fluids such as blood or lymph, or
with tissue, must be compatible with their alien environment.
Hemocompatibility is an important and highly desirable
characteristic. To the highest degree possible, the materials
must possess anti-thromboplastic properties.
Thus, there are different, and in some instances mutually
exclusive, demands made on the bioactive characteristics of
the surfaces of polymers used in medical applications. They
must always be bacterio-repellant and compatible with body
fluids and tissue, although--if so desired--they should either
be cellulostatic or promote cellular proliferation.
It is attempted, according to the present invention, to
develop an improved process for coating surfaces, so as to
render a surface of an article permanently hydrophilic and
bioactive, namely bacterio-repellant and hemocompatible (anti-
thromboplastic), and compatible with body fluids and tissue,
and be cellulostatic or else promote cellular proliferation,
as may be desired, without any modification of the mechanical
properties of article so treated or without causing any other
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disadvantages when this is done.
Summary of the Invention
One aspect of the present invention provides a process
for forming a hydrophilic and bioactive coating on a polymer
surface of a substrate of an article, in which a hydrophilic
or hydrophilized polymer substrate is treated with a
polyalkyleneimine as a primer, and a hydrophilic, bioactive
coating polymer that contains (a) a carboxyl or carboxylate
group, (b) a sulfonic acid or sulfonate group or (c) acidic
sulfuric acid ester or sulfuric acid ester sulfate group is
applied to this pretreated substrate.
In one alternative version of the process, the polymer
substrate may be treated with ammonia-plasma instead of the
polyalkyleneimine, when the polymer substrate does not have to
be hydrophilic or hydrophilized.
A feature common to both versions of the process is that
base groups that enhance adhesion of the hydrophilic bioactive
coating polymer are formed by treating the substrate.
Another aspect of the present invention provides the
product (i.e., article), which comprises a polymer substrate
having a surface that has been hydrophilically and bioactively
coated by the process mentioned above.
The coating polymer must have at least one of the groups
named above. All or some of the acid groups can be converted
into salts by treatment with a base such as caustic soda. So,
for example, a carboxyl or carboxylate group can be present
alone or as a mixture. A group containing sulfur can be
present in addition to the carboxyl or carboxylate group, or
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in place thereof. Coating polymers that have only sulfuric
acid ester sulfate groups (i.e., neutralized sulfuric acid
ester groups) or those that contain carboxyl and/or
carboxylate groups, as well as sulfonate groups, are examples.
If the hydrophilic or hydrophilized polymer substrate is
pretreated with a polyalkyleneimine, its adhesion to the
substrate is particularly strong if the substrate has acid
groups, for example, carboxyl, sulfonic acid, or acid sulfuric
acid ester groups. Very possibly, this strong adhesion can be
attributed to ionic bonds that form between the polyalkylene-
imine and the substrate. The acid groups in the polymer
substrate may be contained in monomers that have been
polymerized to produce the polymer, or they may have been
created by surface treatment of standard polymers without
polymerized acid groups. Such surface treatments, which have
a simultaneous hyrophilising effect, are described below.
The coating of polymer substrates that contain hydrophilic or
hydrophilized acid groups with polyalkyleneimine as a primer
for the bioactive layer is a preferred embodiment of the
process according to the present invention. The polyalkylene-
imine itself adheres surprisingly strongly to the hydrophilic
or hydrophilized polymer substrate if this has no acid groups.
If the hydrophilic, bioactive polymer coating layer
contains acid groups, this layer is in its turn bonded
sonically and thus especially strongly to the polymer
substrate that has been treated with a polyalkyleneimine or
with ammonia plasma. Even hydrophilic, bioactive coating
polymers that contain only carboxylate, sulfonate, or acid
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sulfuric acid ester sulfate groups adhere remarkably strongly
to the polymer substrate that has been pretreated with a
polyalkyleneimine or ammonia plasma.
EP 0 603 987 A1 describes a hydrophilic-anionic or
hydrophilic-cationic surface layer on a hydrophobic polymer,
such as polysulfone, polyamide, or polyester, and a process
for manufacturing this. The layer consists of a complex that
results from one or more water-soluble cationic polymers
and/or one or more water soluble cationically active
surfactants, and one or more anionic polymers and/or one or
more anionically active surfactants, the ratio of cationic to
ionic groups in the complex being other than 1. The layer
that is applied is described as being adsorptively adhesive.
The cationic polymers that are listed include polyethylene-
imine. In addition, it is said that, as an option, ionic
working substances can also be bonded. In contrast to the
teachings of EP 0 603 987 A1, however, the process according
to the present invention starts from hydrophilic or hydro-
philized surfaces of substrates made of polymers. This
process creates a coating layer that adheres much more
strongly than a coating on a hydrophobic polymer substrate
under otherwise equal conditions. The polyalkyleneimine that
is applied preferably adheres sonically instead of absorp-
tively, and thus particularly strongly, and a coating polymer
that contains at least one of the cited groups is applied to
the polyalkyleneimine; this, too, adheres sonically, and thus
particularly strongly, provided that it contains acid groups.
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Advantages of the Invention
The substrates coated according to the present invention
display a remarkable combination of advantageous properties
and outstanding physiological compatibility. They exhibit a
high degree of hemocompatibility, and reduce the adhesion and
proliferation of bacteria to a very great extent and over long
time periods. Bacteria affected by this effect are, amongst
others, Staphylococcus aureus, Staphylococcus epidermis,
Streptococcus pyogenes, Klebsiella pneumoniae, Pseudomonas
aeroginosa, and Escherichia coli. In many instances, cellular
proliferation, for example of fibroblasts and endothelial
cells such as human umbilical cells, is also inhibited. The
special conditions under which a coating is bacterio-repellant
and at the same time promotes the proliferation of cells, will
be discussed below. Most polyalkyleneimines are non-toxic at
the concentrations that are used, so that the coated
substrates are also suitable for medical applications. The
treatment of the polymer substrates with ammonia plasma
entails no toxicological risk if any toxic monomers or
dissolvable fragment molecules are removed by extraction after
the coating process.
Description of Preferred Embodiments of the Invention
1. The polymer substrates
In the embodiment of the process according to the present
invention employing a polyalkyleneimine as a primer, surfaces
of the substrates made of polymers should be hydrophilic, i.e,
they contain hydrophilic groups in bulk from their production,
or have been surface hydrophilized.
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In contrast to this, in the alternative embodiment, which
involves pretreatment with ammonia plasma, the polymer
substrates do not have to be hydrophilic or hydrophilized, and
can be hydrophobic. Non-hydrophilic polymer substrates are,
however, hydrophilized by the ammonia plasma pretreatment.
The polymer substrates can be of great variety, of
geometric forms, for example, panels, foils, tubes or hoses,
depending on the intended use of the particular article.
1.1 Hydrophilic polymer substrates
In contrast to subsequently hydrophilized standard
polymers, which will be discussed below, the hydrophilic
polymers are special products, some of which are, however,
available commercially. Suitable hydrophilic polymers are
homopolymers from hydrophilic vinyl monomers that preferably
have acid groups, or sufficiently hydrophilic copolymers that
are made from hydrophilic vinyl monomers that preferably have
acid groups and hydrophobic vinyl monomers. Preferred,
amongst the hydrophobic vinyl monomers, are for example, vinyl
chloride, ethylene, propylene, 1-butene, 1-octene, isoprene,
styrene, a-methyl-styrene, 2- and 4-vinyl toluene, 2-ethyl-
hexylacrylate, tetrafluorethylene, methylmethacrylate,
methacrylamide, 1,3-butadiene, vinyl pyridine, vinylidene
chloride, and vinyl acetate.
At 20~C, suitable hydrophilic vinyl monomers are at least
1%-wt, preferably at least 10%-wt, and in particular at least
40%-wt soluble in water, relative in each instance to the
total amount of a solution. The acid groups that may be
contained in the hydrophilic polymers are preferably carboxyl
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groups and sulfonic acid groups and their salts. The
following are examples of suitable hydrophilic monomers:
acrylic acid and derivatives thereof, for example, acrylamide,
N,N,-dimethylacrylamide, acrylonitrile, methacrylate, 2-
hydroxyethylacrylate, 2-hydroxypropylacrylate, 2-methoxy-
ethylacrylate, 2-ethoxyethylacrylate, 4-hydroxybutyl-acrylate,
and 1,4-butanedioldiacrylate, as well as methacrylic acid and
its corresponding derivatives; carboxylic acid vinyl
derivatives such as vinyl acetate, N-vinylacetamide, and N-
vinylpyrrolidone; vinyl sulfonic acids and their alkali salts,
such as sodium vinyl sulfonate; alkenylarylsulfonic acids and
their alkali salts, such as o- and p-styrenesulfonic acid and
sodium styrenesulfonate, vinyl ethers such as vinyl
methylether, vinyl ethylether, vinyl glycidylether,
diethyleneglycoldivinylether, and vinyl-n-butylether; vinyl
ketones, such as vinyl methylketone, vinyl ethylketone, and
vinyl-n-propylketone; vinyl amines, such as N-vinyl-
pyrrolidine; polyalkylene compounds with end-position allyl-,
vinyl-, acryl-, or methacryl groups, such as ethoxy-
tetraethoxyethyl acrylate or methacrylate, n-propoxydodeca-
ethyleneethylvinylether, polyethyleneglycolmonoacrylates with
molar weights from 600 or 1200,
poly(ethylene/propylene)glycol-monomethacrylatess with molar
weights from 400 and 800, as well as allyloxyoctapropylene-
oxyethanol; sugar derivatives such as vinyl-substituted
arabinoses or acryloylized hydroxypropyl cellulose; and
functionalized polyalkyleneglycols, such as triethylene-
glycoldiacrylate or tetraethyleneglycoldiallylether.
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In order to manufacture hydrophilic copolymers from
hydrophilic and hydrophobic comonomers, the hydrophilic vinyl
monomers should at the least be used in a quantity such that
the contact angle, measured at 25~C using the method described
by R.J. Good, et al (which will be described below), is <40~,
and advantageously <30~. Such a copolymer is considered to be
hydrophilic in the sense of the present invention. Homo-
polymers or copolymers that are built up exclusively from
hydrophilic vinyl monomers, also satisfy this requirement. If
necessary, the proportion of acid groups should be so large
that the cationic primer is effectively bonded ionically,
which is already the case at low concentrations. It is
expedient that the molar proportion of vinyl monomers with
acid groups in the copolymer amounts to at least 10 mol-%.
1.2 Hydrophilized polymer substrates
A large number of options with respect to the mechanical
and other properties of the polymer substrate are available as
the hydrophobic standard polymers, which are available in
large numbers. They are then hydrophilized. Suitable
standard polymers include homopolymers and copolymers, for
example polyolefines or polydienes such as polyethylene,
polypropylene, polyisobutylene, polybutadiene, polyisoprene,
natural rubbers and polyethylene-co-propylene; polymers that
contain halogen, such as polyvinylchloride, polyvinylidene-
chloride, polychloroprene, polytetrafluorethylene, and
polyvinylidenefluoride; polymers and copolymers of
vinylaromatic monomers, such as polystyrene, polyvinyltoluene,
polystyrene-co-vinyltoluene, polystyrene-co-acrylonitrile,
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polystyrene-co-butadiene-co-acrylonitrile, polystyrene-co-
ethylene-co-1-butene); poly(styrene-co-ethylene-co-2-butene),
polycondensates, for example, polyesters such as polyethylene-
t.erephthalate and polybutyleneterephthalate; polyamides, such
as polycaprolactam, polylaurinlactam, and the polycondensate
of adipinic acid and hexamethylenediamine; polyether block
amides, for example, of laurinlactam and polyethyleneglycol
with, on average, 8, 12, or 16 ethyleneoxy groups; in
addition, poly-urethanes, polyethers, polycarbonates,
polysulfones, polyether-ketones, polyesteramides and
polyesterimides, polyacrylnitrile, polyacrylates and
polymethacrylates, and silicones. Blends of two or more
polymers or copolymers can also be hydrophilized using this
process, as can combinations of different plastics that can be
joined to each other by adhesion, welding, or smelting,
including the transition areas.
The surfaces of the substrates can be hydrophilized by a
number of methods, and in the majority of cases can be
provided with acid groups at the same time. It is expedient
that they first be cleansed of any oils, greases, or other
impurities that may be adhering to them, by using a solvent.
The following hyrophilizing methods are known:
The hydrophilization of standard polymers without groups that
are sensitive to W irradiation can best be effected by means
of W irradiation, for example, in the wavelength range from
100 to 400 nm, preferably from 125 to 310 nm. Particularly
good results have been obtained with largely monochromatic,
continuous irradiation, such as that generated by excimer W
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radiators (Heraeus Co., Kleinostheim, Germany), for example
with F2, Xe2, ArF, XeCl, KrCl, and KrF as the lamp medium.
But other sources of radiation, such as mercury vapour lamps
with wide-spectrum radiation and radiation bands in the
visible range are suitable, providing they emit a considerable
proportion of radiation in the cited radiation ranges. It has
been shown that the presence of a small quantities of oxygen
is advantageous. The preferred oxygen partial pressure is
between 2x10-5 and 2x10-2 bar. One can work, for example, in a
vacuum of 10-4 to 10-1 bar, or using an inert gas such as
helium, nitrogen, or argon, with an oxygen content of 0.02 to
per mille. The optimal duration of radiation will depend
on the polymer substrate, the composition of the ambient gas
medium, the wavelength of the radiation, and the power of the
radiation source, and can be ascertained without difficulty by
prior testing. In general, the substrate is irradiated for a
period of 0.1 seconds to 20 minutes, in particular for 1
second to 10 minutes. Given these brief periods of
irradiation, the polymer substrate will only heat up a little,
20 and no undesirable reactions, which could result in damage to
the exposed surfaces, occur even with irradiation with
wavelengths at the hard end of the cited additional range at
irradiation times that are correspondingly brief.
(2) The hydrophilization can also be carried out by high-
frequency or microwave plasma ( e.g., Hexagon*, Techics
Plasma, 85551 Kirchheim, Germany) in an air, oxygen, nitrogen
or argon atmosphere. In general, exposure times range from 30
* Trade-mark
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seconds to 30 minutes, preferably 2 to 10 minutes. The energy
input is between 100 W to 500 W, preferably between 200 W and
300 W, for laboratory equipment.
(3) In addition, corona equipment (SOFTAL, Hamburg, Germany)
can also be used for hydrophilization. In this case, the
exposure times range from 1 second to 10 minutes, preferably
from 1 to 60 seconds.
(4) Hydrophilization by electron or gamma rays (e.g., from a
cobalt-60 source) permits short exposure times that generally
amount to 0.1 to 60 seconds.
(5) Flame treatments of the surfaces also result in hyrophil-
ization. Suitable apparatuses, in particular those with a
barrier flame front, can be built quite simply, or can be
obtained, for example, from ARCOTEC, 71297 Monsheim, Germany.
They can be operated with hydrocarbons or hydrogen as the
combustion gas. In each case, it is essential to avoid
harmful overheating of the substrate; this can be achieved by
close contact with a cooled metal surface on the substrate
surface that is remote from the flaming side.
hydrophilization is accordingly restricted to relatively thin,
flat substrates. Exposure times generally run from 0.1
seconds to 1 minute, and preferably from 0.5 to 2 seconds.
Without exception, this is done with roaring flames, with
distances to the substrate of 0.2 to 5 cm, preferably of 0.5
to 2 cm.
(6) Substrate surfaces can also be hydrophilized by treating
them with strong acids or bases. Suitable acids are sulfuric
acid, nitric acid, and hydrochloric acid. As an example,
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polyamides can be treated for 5 seconds to 1 minute with
concentrated sulfuric acid at room temperature. Alkali metal
hydroxides in water or an organic solvent are suitable strong
bases. As an example, one can allow diluted caustic soda to
act on the substrates for 1 to 60 minutes at 20 to 80~C. As
an alternative, polyamides can be activated if one allows 2%
KOH in tetrahydrofurane to act on the substrate surface for 1
to 30 minutes. Of course, after being hydrophilized with a
strong base, the polymer substrate has no acid groups,
although it can be acidified by treating it with an acid.
In many instances, e.g., in the case of extremely
hydrophobic polymers, it may be advisable to activate the
substrate surface by a combination of two or more of the
methods described above. The preferred method of hydro-
philization is with UV irradiation as described in (1) above.
Regardless of what occurs in detail at the molecular level
during the treatments that are described, the result is still
clear. Hydrophilization can be proved by the change in the
angle of contact which, if determined by the method used by
R.J. Goods et al. as described above, should be <40~, and
preferably <30~, at 25~C. The resulting acid groups are
detectable by titration with alkaline lye.
1.3 Non-hydrophilic (or hydrophobic) substrates
Using R.J. Good's method described above, such substrates
exhibit a contact angle of >40~. They can be used according
to the present invention when the pretreatment with ammonia
plasm is selected. The standard polymers discussed in Chapter
1.2 above are amongst the suitable polymers. They may be
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homopolymers or copolymers, namely polyolefins or polydienes,
polymers that contain halogens, polymers and copolymers of
vinyl aromatic monomers. As has already been discussed, the
non-hydrophilic polymer substrates are hydrophilized, and the
adhesion of the hydrophilic, bioactive coating polymer on the
treated polymer substrate is improved, by treating them with
ammonia plasma.
2 Polyalkyleneimine as primer
Polyalkyleneimines are produced by polymerization of the
monomer alkyleneimine (or aziridines) and contain primary,
secondary, and tertiary amino groups in variable proportions,
as well as straight chain, branched chain, and cross-linked
components. The best-known polyalkyleneimine is polyethylene-
imine, that is commercially available as an approximate 50%-wt
aqueous solution or as a product that is water-free for all
practical purposes. Also suitable for the present invention
are polypropyleneimine and poly(co-ethyleneimine-co-
propyleneimine). The polyalkyleneimines may have number
average molecular weights of up to several millions (i.e.,
close to 1 x 107). In the interests of good adhesion, the
molecular weight should be at least about l0,000, and
preferably between 10,000 and 2,000,000. It is advantageous
that the hydrophilic or hydrophilized polymer substrate be
treated with a 0.5 to 20%-wt solution of the polyethyleneimine
for approximately 30 seconds at room temperature or at a
moderately higher temperature of up to approximately 60~C.
The preferred solvent is water, if necessary with smaller
parts of a lower alcohol such as methanol or ethanol. After
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treatment, the polymer substrate may first be dried.
Alternatively, without drying, the hydrophilic, bioactive
layer may be applied immediately.
3 Treatment of the polymer substrate with ammonia plasma
The embodiment of the process that uses ammonia plasma to
generate basis groups that act as a primer layer entails the
advantage that no hydrophilic or hydrophilized polymer
substrates are required. Rather, non-hydrophilic (which is to
say, hydrophobic) standard polymers may be used as starting
materials. Of course, the hydrophilic or hydrophilized
polymers discussed above can be used, in which case even
better adhesion of the hydrophilic bioactive coating is
frequently achieved.
Both high-frequency plasma (in the kiloherz range) and
microwave plasma (in the gigaherz range) are suitable for
treatment with ammonia. The treatment chamber is evacuated
and a specific ammonia pressure, for example from 10 to 500
Pa, preferably from 20 to 180 Pa, is set up. The plasma
generator can operate within a broad power spectrum, for
example, from a few hundred watts such as 200 watts to a few
kilowatts, e.g., 10 kilowatts. The duration of the treatment
can also vary within wide limits, and can range from 10
seconds to 30 minutes, for example. Once the treatment has
ended, the ammonia gas is pumped out or displaced by air; it
is preferred that the treatment chamber be flushed out with
air. As an alternative, the ammonia plasma can be generated
in a flow of ammonia gas, when one feeds ammonia in and
removes it continuously, regulating the pressure within the
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required range when so doing. An optimal combination of
frequency, power, treatment time, and ammonia pressure can be
determined very easily for a giving coating job by way of test
runs.
Reactive groups, in particular amino groups, are formed
on the polymer surface by plasma treatment. If oxygen is
present, reactive groups that contain oxygen, possibly
hydroxyl, carboxyl, and/or hydroperoxy groups, are also
formed. However, the amino groups may be the most important
for the adhesion of the subsequent coating, since--as is
known--amino groups react with isocyanate groups more easily
than the known reactive groups that contain oxygen. In the
case of nitrogen-free substrates, the amino groups can be
indicated by means of ESCA, and in the case of a11 substrates,
by acid titration.
4 Hydrophilic bioactive coating
The hydrophilic bioactive coating adheres ionically to
the polymer substrate that has been treated with a
polyalkyleneimine or ammonia plasma, namely by the formation
of ammonium/ carboxylate, ammonium/sulfonate, or
ammonium/sulfate structures, since the coating polymer
contains carboxyl, sulfonic acid, or acid sulfuric acid ester
groups or their salts. The sulfonic acid group has the
formula -503H; the acid sulfuric acid ester group has the
formula -OS03H; the sulfonate group is represented by the
formula -503M; and the sulfuric acid sulfate group has the
formula -OS03M, where M is one equivalent of a cation such as
Na+ and 1/2 C2+. The coating can be applied by allowing a
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solution, preferably an aqueous solution, of an appropriate
hydrophilic bioactive coating polymer to act on the treated
polymer substrate that contains the groups referred to. The
acid groups that may be present have a double function, in
that--on the one hand--they bring about the ionic bonding of
the hydrophilic bioactive coating on the basic groups of the
polyalkyleneimine primer or of the polymer substrate that has
been treated with ammonia plasma and--on the other hand--they
initiate a biological effect, if applicable after
neutralization, i.e., with caustic soda.
The coating polymers can be homopolymers or copolymers of
hydrophilic vinylmonomers or copolymers of hydrophilic and
hydrophobic vinylmonomers. Examples of suitable hydrophilic
and hydrophobic vinylmonomers are those listed above, in
Chapter 1. In the sense of the present invention, a coating
polymer is considered to be hydrophilic if its contact angle
according to R.J. Goods et al. is less than 35~, preferably
less than 25~ at 25~C. Coating (co)polymers that are built up
exclusively from hydrophilic monomers satisfy this
requirement in every case. If a coating copolymer contains
hydrophobic vinyl monomers, the proportion of them may be only
so high that the contact angle corresponds to the above
condition. The coating (co)polymers are produced by the usual
processes, e.g., by radical-initiated solution or emulsion
polymerization in an aqueous medium. Frequently, the coating
polymers that are to be used according to the present
invention are so hydrophilic that it is no longer possible to
measure a contact angle because the water droplets spread over
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the surface.
The following are examples of suitable hydrophilic
bioactive coating (co)polymers:
(i) Poly(meth)acrylic acid, as well as hydrophilic copolymers
of acrylic, methacrylic acid or malefic acid with another
unsaturated carboxylic acid or neutral, hydrophilic or
hydrophobic comonomers. It is possible to neutralize the
carboxyl groups partially in the monomers or subsequently,
partially or completely, in the polymer. These polymers
contain no sulfonic acid and/or sulfonate groups. Suitable
other unsaturated carboxylic acids or neutral, hydrophilic or
hydrophobic comonomers are, for example, those described above
in Chapter 1.
(ii) Other suitable hydrophilic bioactive coating polymers
are copolymers of olefinically unsaturated carboxylic acids or
their anhydrides, and olefinically unsaturated sulfonic acids
and, if applicable, other neutral and hydrophilic or
hydrophobic comonomers. Here, too, the acid groups can in
part be neutralized in the monomers, or subsequently,
completely or in part, in the polymers. Of the olefinically
unsaturated carboxylic acids, the following can be cited:
acrylic acid, methacrylic acid, crotonic acid, malefic acid and
malefic acid anhydride (which usually hydrolyzes under the
conditions of the reaction), vinylsalicylic acid, itaconid
acid, vinylacetic acid, phenyl acrylic acid, 4-vinylbenzoic
acid, 2-vinylbenzoic acid, sorbic acid, chlorogenic acid,
methylmaleic acid, isocrotonic acid, fumaric acid,
methylfumaric acid, dimethylfumaric acid, dihydroxymaleic
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acid, and allylacetic acid, as well as their sodium salts.
Examples of suitable olefinically unsaturated sulfonic acids
are vinylsulfonic acid, 2- and 4-styrenesulfonic acid,
allylsulfuric acid, methallylsulfuric acid, methallylsulfonic
acid, vinyltoluene-sulfonic acid, and their sodium salts.
Examples of suitable copolymers of this kind are described in
Published Canadian Patent Application No. 2,226,129.
(iii) Other suitable coating polymers are the heparin-like
copolymers that are described in Published Canadian Patent
l0 Application No. 2,237,480. These contain repeating units of
the formulae:
- CR1-CHR 1-
R2 3 4 - CRl- CHR 5
(H-C-R-R )n (~ and R2
H-C-R3 R4 I
i COOR6
H
in which, independently in each instance, R1 stands for
hydrogen or methyl; R2 stands for a divalent organic radical,
for example, an aliphatic, cycloaliphatic or aromatic radical
with up to 10 carbon atoms (such as o-phenylene, m-phenylene,
and p-phenylene), or a bond; R3 stands for -0- or -NH-; R4
stands for hydrogen or -S03 -Na+, R5 stands for hydrogen,
methyl or -R2-COOR6; R6 stands for hydrogen or Na, and n = 4
20 or 5; provided that at least one of the R4 substituents is
-S03 -Na+. It is advantageous that, in at least some of the
groups, R6 stands for hydrogen. The blocks I originate from
vinylmonomers of the general formula (III):
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- CR1=CHR 1
12
C R3 R4)n
H-C-R3 R4
i
H
in which R1, R2, R3, R4, and n have the above-cited values.
Examples of suitable vinyl monomers (III) are O-sulfated 1-
hydroxy-1-desoxy-1-(4-vinylphenyl)-D-gluco(or D-manno)-
pentitol (Ia) and N-and O-sulfated 1-amino-1-desoxy-1-(4-
vinylphenyl)-D-gluco(or D-manno)-pentitol (Ib) or the sodium
salts thereof. Both monomers are obtained by a multi-stage
synthesis that proceeds from D-glucono-1,5-lactone, as
described in the above-quoted Published Canadian Patent
to Application. This also describes the production of 4-
vinylbenzoic acid, whose sodium salt is a suitable monomer
(II) .
(iv) Other suitable coating polymers are the homopolymers or
copolymers which contain a repeating unit of the formula (IV):
- CR1- CHR 1-
I~
R
I
A
in which Rl has the same values as in the formula (I), R~ is a
bridging member, and A stands for a sulfated polyol,
polyamine, or (poly)-amine-(poly)ol radical, optionally
containing one or more acetylized or aminalized carbonyl
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groups. The bridging member R7 may be of an inorganic or
organic nature, and preferably stands for 0, S, SO, 502, NR',
(where R' indicates hydrogen or a hydrocarbon radical with 1
to 12 carbon atoms), a divalent organic radical, in particular
an aliphatic, cycloaliphatic or aromatic hydrocarbon radical
with 1 to 10 carbon atoms, -O-CO-, -NR'-CO- or -O-CO-NR'-
(where R' having the above quoted value), or a chemical bond.
The homopolymers or copolymers may be those described in
Published Canadian Patent Application No. 2,237,480.
Preferred repeating units (IV) with acetylized or
aminalized carbonyl function correspond to the formula (V):
- CR1- CHR 1
R~
~_ ~C R3 R 4)n
H-C-R3 R4
i
H
wherein R1, R3, R4, R7, and n have the values as given for the
formula (I), provided that:
(1) at least one, but preferably one or two per
molecule, of the H and -R3-R4 combinations attached to the
same carbon atom, with this carbon atom, form a C=O carbonyl
function that is acetylized or aminalized, respectively, by an
hydroxyl or amino function in the 3rd position, relative to
the carbonyl function, while forming a tetrahydrofuran or
pyrrolidine ring, or by a hydroxyl or amino function in the
4th position, relative to the carbonyl function, while forming
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a pyran or pentamethyl-eneimine ring; and
(2) at least one of the R4 substituents is -S03-Na+.
Monomers of the following formula (Va) correspond to
the repeating units (V) in the (co)polymer:
~1-~ 1
R~
(H_~C-R3 R4)n (Va)
H-C-R3 R4
i
H
wherein R1, R3, R4, R7 and n have the values as in formula
(V), including the same quantitative conditions.
Examples of suitable (Va) monomers are the O-sulfated
1-(4-vinylphenyl)-D-manno(or D-gluco)-hexulo-2,6-pyranoses
to (VaA) as well as the 0-sulfated 6-(4-vinylphenyl)-D-glycero(or
L-glycero)-a-D-galactorpyranoses (VaB). Production of these
monomers is also described in Published Canadian Patent
Application No. 2,237,480.
In order to coat the hydrophilic or hydrophilized
polymer substrates that have been pretreated with the primer,
the coating polymer, preferably in a 1 to 20%-wt solution,
preferably an aqueous solution, is allowed to act for 0.1 to
minutes on the polymer substrates, generally at 25 to 50~C.
The substrate is then dried. Any acid groups that are still
2o present can be converted either wholly or in part to
carboxylate and/or sulfate groups at the surface by treatment
with a base, for example, sodium hydroxide. The layer
structure of primer and hydrophilic bioactive polymer then
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adheres firmly to the polymer substrate and cannot be loosened
by the effects of water at 60~C.
Repetitive coatinct
For many applications, it is recommended that the
coating process be repeated, including the treatment with
polyalkyleneimine or with ammonia plasma if appropriate, in
order to achieve complete coverage of the hydrophilic or
hydrophilized polymer substrate with the hydrophilic bioactive
coating. In the case of treatment with a polyalkyleneimine,
it is useful that there be carboxyl and optionally sulfonic
acid groups present in the hydrophilic bioactive coating agent
that is first applied, so that the primer can be sonically
bonded. The acid groups of the coating agent may have been
neutralized, at most in part, with a base such as sodium
hydroxide prior to being applied to the substrate. After
application, they can be completely neutralized, as discussed
above. For the remainder, the description provided above also
applies analogously to the repetitive coating processes
(treatment with polyalkyleneimine or ammonia plasma and the
application of the coating polymer).
6 Bioactive properties of the coated substrates
The substrates coated according to the present
invention are hydrophilic and bacterio-repellant. In
addition, when wet, the coatings of coating polymer 4 (iii)
and 4 (iv) are distinguished by particularly low coefficients
of friction. In coating polymers that have carboxyl and/or
carboxylate groups, as well as sulfonic acid and/or sulfonate
groups, the molar ratios of this groups can vary within very
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wide limits. In addition to their hydrophilic and bacterio-
repellant character, the bioactively coated polymer substrates
display outstanding cellulostatic properties when the cited
molar ratio is 0.2 to 3, and in particular from 0.4 to 2. The
coated surfaces exhibit bacterio-repellant but cellulo-
proliferating characteristics to a notable degree when the
molar ratio is 2 to 10, preferably 3 to 10, and in particular
3 to 5. A coating is considered to promote cellular
proliferation [be celluloproliferating] when, as compared to
uncoated surfaces, the adhesion and proliferation of mammalian
cells is either improved or at any rate impaired to a lesser
degree.
Coating polymers 4 (iii) and 4 (iv) exhibit
pronounced effectiveness that is analogous to heparin, as
described in greater detail in Published Canadian Patent
Application No. 2,237,480.
7 Products and the use thereof
Products (= articles) with a surface coated according
to the present invention can be used for technical, medico-
technical, hygienic, or biotechnical purposes, as has been
described above. If it is important that substrates that are
coated hydrophilically by the process according to the present
invention be free of monomers when they are used, it is
recommended that the residual monomers be extracted from the
polymer hydrophilic coating. This can be done with water, and
then with an organic solvent, for example, with hydrocarbons
such as hexane or cyclohexane, and/or with an alcohol with 1
to 4 carbon atoms, such as ethanol and n-propanol. Well suited
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for the second extraction is a mixture of n-hexane and ethanol
with 65 to 85 %-vol hexane.
Examples of products for technical, medico-technical,
hygienic, or biotechnical purposes are catheters, tubes,
stents, membranes, blood bags, wound dressings, oxygenators,
elastic gloves for medical purposes, and condoms.
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5. Examples
Materials and Processes
Table 1 - Substrates foils (F) and substrate tubes (Sch) used
Foil/tube Plastic Source Production
Number method
F1 Polyamide 12 VESTMID~ Huls Extrusion
AG
Sch 2 Polyurethane TECOFLEX~ Extrusion
THERMEDIX GmbH
Sch 3 Polyether- VESTAMID~ Extrusion
esteramide Hiils AG
F 4 Polyurethane PELLETHANE~ Extrusion
2363-A .
DOW CHEMICAL CO
F 5 Polyethylene VESTOLEN ~ A Extrusion
VESTOLEN GmbH
F 6 Polypropylene VESTOLEN ~ P Extrusion
VESTOLEN GmbH
F 7 Polyorgano- NG 37-52 Doctor knife
siloxane Silicon GmbH spread coat-
Niinchri t z ing
F 8 Polyvinyl- VESTOLIT~+Di- Brabendering
chloride ethylhexylphth-
alate
VESTOLIT GmbH
F 9 PTFE HOSTAFLON~ Extrusion
HOECHST AG
F 10 Polystyrene VESTYRON~ Pressing i
HLTLS AG
Sch 11 Polyethylene VESTOLEN ~ A Extrusion
VESTOLEN GmbH
Sch 12 Polyurethane TECOFLEX~ Extrusion
THERMEDIX GmbH
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Table 1 (cont)
Foil/tube Plastic Source Production
Number Method
Sch 13 Polyurethane PELLETHANE~ Extrusion
2363A
DOW CHEMICAL CO
Sch 14 Polyether- PEBAX~ 5S33 Extrusion
esteramide ATOCHEM S.A.
Sch 15 Polyvinyl- VESTOLIT~+Di- Extrusion
chloride ethylhexylphth-
alate
VESTOLIT GmbH
Mainly, the foils or tubes are first activated, i.e.,
hydrophilized and, insofar as hydrophilization is effected with
ammonia plasma, they are simultaneously treated according to the
present invention. Activation is effected selectively, using the
processes and conditions set out in Table 2.
Table 2 - Activation methods
Activation Activation process Conditions
No
A 1 W excimer radiation 1 - 20 min, 1 mbar
s
(172 nm) 4 distance
cm
A 2 Microwave plasma 1 - 30 min, 1 mbar
s
(argon)
A 3 High-frequency plasma 1 - 30 min, 6 mbar
s
(argon
A 4 Corona 0.1 s - 60 s,
2 distance
mm
A S Flaming CH4:air
=
1:10
4 distance
cm
A 6 NaOH solution 1~, 5 min; 60C
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Activation No Activation process Conditions
A 7 Microwave plasma (NH,) 10 s - 3 min;
- 35 - 150 Pa
A 8 High-frequency plasma 10 s - 3 min;
(NH,) 35 - 150 Pa
Table 3 - Polyalkyleneimines used
Designator Product features
P 1 Polyethyleneimine with an average molecular weight
of 7S0,000 (as determined by the light-dispersal
method) in the form of an approximate 50~-wt
aqueous solution with a pH of 10-12 in a 1~ aqueous
solution (LUPASOL~P, BASF AG) diluted with water
to
2.5~-wt solids
P 2 Polyethyleneimine with an average molecular weight
of 25,000 (as determined by the light-dispersal
method), with a solids content of 99~, with a pH
of
10-12 in a 1~ aqueous solution (LUPASOL~WF, BASF
AG) diluted with water to 1~-wt solids P2a or 5~-wt
solids (P2b).
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Table 4 - Coating polymers
Designator~~- Product features
B 1 Polyacrylic acid with an average gm/molecular
weight Mw of 2000, 5~-wt aqueous solution
B2 Terpolymer of 0-sulfated 1-hydroxy-1-desoxy-1-(4-
vinylphenyl)-D-gluco(D-manno)-pentitol, - and O-
sulfated 1-(4-vinylphenyl)-D-gluco(D-manno)-penti-
tol and sodium-4-vinylbenzoate in a molar ratio
1:1:1, Mn approx. 229,000, produced as per Patent
Application 192 20 369.8 (O.Z. 5195) as 5~-wt
aqueous solution
B3 Polyacrylic acid with an average gm/molecular
weight Mw of 450,000, S~-wt aqueous solution
B3 -[CH-CH2-CH-CHZ]" - Copolymer (1:1), gm/mol weight
Mn approx. 231,000 sulfating
p-C6H,, p-CoHa degree 3.35 radicals -SO3Na/
molecule, produced by Patent
CHOR COONa appl'n 198 O1 040.0(0.Z. 5281)
OR used as 5~-wt aqueous solution
RO
OR
OR
OR
R = H, -S03Na; p-C6H4 = p-phenylene
B4 -(CH=CH,]n- - Homopolymer, gm/mol weight
(Mn) approx. 126,000 sulfating
p-C6Ha degree 3.35 radicals -SO,Na/
molecule, produced by Patent
CHOR appl'n 198 O1 040.0(0.Z. S281)
OR used as 5~-wt aqueous solution
RO
OR
OR
OR
R = H, -S03Na; p-CbH4 = p-phenylene
B6 Poly(sodiumstyrenesulfonate-co-malefic acid), 10~-
wt in water, Mw approx. 70,000, produced from the
monomers (1:1) by conventional solution polymeri-
sation in Hz0
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Treatment with polyethyleneimine
The foils or tubes were immersed in the
polyethyleneimine solution at 25~C, slowly withdrawn within 20
sec, and dried for 5 minutes at 60~C, immersed in the solution
of coating polymer at 25~C, slowly withdrawn within 20 sec,
and once again dried for 5 minutes at 60~C. This cycle was
repeated several times as necessary, as shown in Table 5.
Treatment with ammonia plasma
The samples to be treated were either cemented to a
glass carrier or mounted on a glass apparatus so that their
position in the plasma chamber remained unchanged when a
partial vacuum was applied. The pressure was then reduced to
5 to 20 Pa and ammonia so metered in and withdrawn that a
pressure of 10 to 500 Pa and preferably 30 to 180 Pa was set
up and maintained. The plasma was ignited after a 20-second
homogenisation period for the gas. The optimal power per unit
area of the substrate depends on the size of the plasma
chamber, and can be determined very simply by tests. The
duration of the treatment can amount to 1 second to 30
minutes, depending on the substrate and the desired extent to
which basis groups are generated. The plasma chamber is then
flushed with air for approximately 1 minute. If required, a
vacuum can be reapplied in order to remove the final traces of
ammonia gas.
Measurement and testing methods
Molecular weights
A11 molecular weights Mn were determined by membrane-
osmometry; a11 molecular weights Mw were determined by the
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light dispersal method.
Determination of COOK and S on the coating
The oxygen content on the surface, which was elevated
compared to the untreated sample, was determined by ESCA; this
could be attributed to the carboxyl and/or carboxylate,
sulfonic acid and/or sulfonate and/or acid sulfuric acid ester
and/or sulfate groups. The groups of the coating polymer that
contain sulfur were identified by measuring the sulfur as a
surface element.
Determination of contact angle
A measure for the hydrophilic nature of the surface
is the change in the contact angle of the water droplets that
are applied to the surface. Such a procedure is described in
R.J. Good et al., Techniques of Measuring Contact Angles in
Surface and Colloid Science, (Published by R.J. Good), Vol.
II, Plenum Press, New York, N.Y., 1979). In the examples, the
contact angle was measured according to this method at 25~C.
The contact angle can no longer be measured in the case of
strongly hydrophilic substrates because the liquid disperses
into a thin layer on the substrate. This is referred to as
spreading in Table 6.
Determination of the coefficient of friction
The coefficient of friction ~, was determined by the inclined-
plane method. To this end, the coated substrate foil was
cemented to a round, metal disk and then kept in water or in a
0.9%-wt NaCl solution for various lengths of time (in Table 4
"Water minutes"). The metal disk was then placed--foil down--
on a flat plate coated with the uncoated polymer, and this was
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then wetted down with distilled water. The angle subtended by
the plate and the horizontal was then gradually increased.
The angle at which the metal disk began to slide was recorded.
The tangent of this angle is the coefficient of friction
Determination of primary bacterial adhesion under static
conditions
An overnight culture of the bacterial strain
Klebsiella pneumoniae in yeast extract-peptone-glucose
nutrient [1%+1%+1%] was centrifuged off and reabsorbed in
phosphate-buffered saline (=PBS; 0.05m KH2P04, pH 7,2 + 0.9%
NaCl). The PBS buffer is diluted to a cellular concentration
of l08 cells/ml. The suspended bacteria are brought into
contact with the foil sample to be tested for a period of 3
hours. To this end, round pieces of foil, coated on both
sides, diameter 1.6 cm (=4.02 cm2) are impaled on a
preparation needle and agitated with the cellular suspension.
Foils coated on one side, in the form of a round, flat disk,
4.5 cm diameter and with a supporting membrane of 2 - 3 cm
thick soft PVC are installed in a membrane filter apparatus.
The cellular suspension is applied to the uppermost side that
has the coating that is to be tested, and agitated for 3
hours. The membrane filter apparatus must be tightly closed,
i.e., no cellular suspension is to be allowed to flow through
unsealed cells.
Once the contact time has expired, the bacterial
suspension is drawn off with a water-jet pump and the pieces
of foil are agitated with 20 ml of sterile PBS solution in a
100-ml beaker for 2 minutes in order to wash them. The pieces
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of foil are one again immersed in sterile PBS solution, and
then extracted for 2 minutes in 10 ml of heated TRIS/EDTA
(0.1M tris-hydroxyethylaminomethane, 4mM ethylenediamine-
tetraacetic acid, adjusted to pH 7.8 with HC1) in a boiling-
water bath.
Small Eppendorf cups are filled with the extraction
solution and then frozen immediately at -20~C until the
bioluminescence of the extracted adenosine triphosphate (ATP)
was determined. This determination was effected as follows:
100 ~.1 of reagent mixture (Biolumineszenz-Test CLS II,
BOEHRINGER MANNHEIM GmbH) was added to a transparent capillary
tube and the light pulses were integrated for a period of 10
seconds in a LUMAT light-pulse measuring device (Laboratorien
Prof. Berthold GmbH, 75323 Bad Wildbad, Germany). Then a 100
~l sample was added, and the measurements repeated. The
relative light units (RLU) were obtained by subtracting the
light pulses in the reagent mix from the number of measured
light pulses in the complete batch. This number is related to
the number of the bacteria adhering to the foil. The
conversion factor between the RLU value and the bacteria count
is determined in that an aliquot of 0.1 ml of the bacterial
suspension with l08 cells /ml is extracted in 10 ml hot
TRIS/EDTA and then the ATP content is determined. In Table 6,
the bacterial adhesion on the untreated substrates is set at
100% (= 0% reduction of the bacterial adhesion).
Tests conducted with other bacterial strains such as
staphylococcus aureus, Staphylococcus epidermis, Streptococcus
pyogenes, Pseudomonas aeroginosa, and Escherichia coli proceed
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in the same way, and provide similar results.
Test results
Examples 1 to 30.
The test conditions and the results obtained are set out in
the following Table 5.
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Ex. Foil/ Acti- Polymin CoatingDip ESCA CoeFf. Red'n
No. Tube nation SolutionPolymercycles(atom-%)Frictionbacterial
(%_~) O S ~ adhesion
Waters
min
1 Foil A 1, P I B 2 3 - - 5 0.36 89%
1
5 min (2.5lo) LO 0.31
bilateral
2 Foil A l P 1 B l 1 - - l 0.31 97%
1
5 min (2.5%) 5 0.Z9
bilateral l0 D.29
3 Tube A 1 P 1 B 2 1 - - - 73"0
3
40 s (2.5%)
@
40 rpm
4 Tube A 2 P 1 B 2 l - - - 93%
2
60 s (2.5%)
Tube A l P t B 2 3 _ _ _ _ 95%
2
4U s (2.5%)
C.~
40 rpm
6 Tube A t P I B 1 l _ _ _ _ 95%
2
40 s (2.5%)
@
40 rpm
7 Tube A 1 P 1 B l 3 - - - - 86%
2
40 s (2.5%)
@
40 rpm
8 Foil A 1 P l B 2 1 - - l 0.04 82%
1
5 min (2.5%) 5 0.0:l
once 10 0.03
I 5
0.03
9 Foil A 1 P I B 2 3 - - 1 0.06 95%
l
5 min (2.5%) 5 U.05
once 10 0.l5
l5 0.21
Foil4 A 6 P 1 B 3 3 2-l.a 1 0.25 94%
-
Q2.5%) 5 0.27
t 0.28
ll FoilS r1 -t P l B -4 l 3?.0 1 0.04 9l%
7.0
(2.5%) 5 d.04
t o
0.04
12 Foil6 A 5 P 1 B 4 3 34.0 1 0.05 93%
6.8
(2.p%a)
5 0.05
10 0.05
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Table 5 (cont)
Ex. FoiU Acti- Polymin CoatingDip ESCA Coetf. Red'n
No. Tube vation Solution Polymercycles(atom-%)Frictionbacterial
(%-wt) O S Waters adhesion
,cc
min
13 Foil7 - P 1 B ~ 3 - - 84%
(2.~%)
14 Foil A 6 P 1 B 2 1 - - 88'7
8
(2.5%)
15 Foil A 1 P I B 4 1 - - - 75%
9
3 min (?.~%)
16 Foil A 4 P 1 B ~ 3 - - 1 0.09 96%
10
(2.5%) 5 0.1l
10 0.15
17 Foil A I P 1 B -1 3 36.l 1 0.03 93%
i 6.9
min (2.6%) ~ 0.04
once IO 0.04
18 Foil A 1 P ? B 6 ~ I9.9 - 93%
1 4.0
5 min ( I %)
once
19 Tube A 1 P 2 H 6 3 l8.1 - 67%
2 2.7
40 s (5%)
@
40 rpm
20* Foil 6.9 1 0.36 0%
l -
5 0.36
10 0.36
21 * Tube 6.5 0%
2 -
22* Foil 1 1. I 0.36 0%
-l f -
5 0.36
10 0.36
23* Iuil 2 - l 0.36 0%
~
5 0.36
l0 0.36
24* Foil I - 1 0.36 0%
~
5 0.36
10 0.36
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Table 5 (conclusion)
Ex. Foil/ Acti- Polymin CoatingDip ESCA Coeff. Red'n
No. Tube vation SolutionPolymercycles(atom-%)Frictionbacterial
(%-wt) O S Ec adhesion
Watecs
min
25 Foil A 8 - B 4 l 25.9 1 0.07 62%
1 1.7
3 min - 5 0.07
10 0.05
26 Tube A l P 2 B -1 1 - - l 0.05 30%
11
30 sec (2.5%)
27 Tube A 8 - B -4 l 24.0 - ~5%
12 2.2
t min
28 Tube A 7 B -1~ l3 23.7 67%
l3 3.
I
l min -
29 Tube: A 1 P 1 B -t 1 - - 1 0.04 -
t-l
30 sec (2.5%) 5 0.04
once t0 0.04
30 Tube A 7 - B -1 t 23.3 - 43%
15 =4.3
l0 min
once
Comparitive example
It was impossible to measure a contact angle in Examples 1 to 19 and
25 to 30.
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Example 31
A polyamide 12-foil (L2101F, Huls AG) was irradiated
for 5 minutes at 1 Torr, using a 172 nm excimer lamp, and then
immersed in a 2.5%-wt solution of Lupasol P (BASF
Aktiengesell-schaft) (P 1 in Table 3) and dried for 5 minutes
at 60~C. The dried foil is immersed for 20 seconds in a 5%-wt
solution of the coating polymer B 5 and then dried for 72
hours at 60~C. The coefficient of friction ~, was between 0.07
and 0.1, as compared to 0.36 for the uncoated material. The
angle of contact could not be measured because the droplets
spread.
Example 32
A foil of an thermoplastic elastomer was dipped 3
times for 10 seconds on each occasion in acetone for
hydrophilization, dried at room temperature, and then immersed
for 30 seconds in a 2.5%-wt aqueous solution of Lupasol P
(BASF AG) (P 1 in Table 3). It was then dried for 5 minutes
at room temperature and for 30 minutes in a drying cabinet at
60~C. The dried foil was then immersed for 30 seconds in the
solution of a sugar polymer of formula
- [CH-CH2-CH- CH2]n _
4 p-06H4
CHOR COONa
RO OR
OR
OR
OR
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CA 02259073 1999-O1-12
R = H, -S03Na; p-C H4 = p-phenylene
(copolymer 1:1, gm~molecular weight Mn = 570,000, degree of
sulfation 3.09 radicals -S03Na/molecule, produced as described
in Patent Application 195 20 369.8 (O.Z. 5195), used as a 5%-
wt aqueous solution) and dried for 5 minutes at room
temperature and for 30 minutes in a drying cabinet at 60~C.
The coefficient of friction was 0.02. It was not possible to
measure an angle of contact because the water droplets spread.
In a finger test, abrasion of the coating was perceptible
after 58 strokes.
Example 33
As in Example 32, although instead of an acetone
wash, the foil was irradiated for 10 seconds at 1 Torr, using
an 172 nm excimer radiator. In a finger test, the coating
could be abraded after 120 strokes.
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