Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D1/00—Processes for applying liquids or other fluent materials
  • B05D1/62—Plasma-deposition of organic layers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D5/00—Processes for applying liquids or other fluent materials to surfaces to obtain special surface effects, finishes or structures
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D133/00—Coating compositions based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Coating compositions based on derivatives of such polymers
  • C09D133/04—Homopolymers or copolymers of esters
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D133/00—Coating compositions based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Coating compositions based on derivatives of such polymers
  • C09D133/24—Homopolymers or copolymers of amides or imides
  • C09D133/26—Homopolymers or copolymers of acrylamide or methacrylamide

Definitions

• Catechol-containing coatings have attracted a lot of attention since the discovery of the role of such groups in the adhesion of mussels.
• Catechol groups present in the 3,4-dihydroxyphenylalanine (DOPA) found in the Mytilus edulis foot protein or its dihydroxyphenyl derivates (DHPD), are well known to react and adhere to both inorganic and organic surfaces in a wet, turbulent and saline environment.
• DOPA 3,4-dihydroxyphenylalanine
• DHPD dihydroxyphenyl derivates
• Catechol/quinone functionalised layers are attracting more and more interest from materials scientists and companies due to the richness of the chemistry associated to these highly reactive functional groups.
• Macromolecules are synthetic or natural polymers, and bear at least one catechol group at the chain-end or along the chain as side chains. They are produced by different synthetic pathways that are summarized in the review by Faure et al.
• the deposition is carried out by the conventional wet deposition techniques such as dip-coating, spraying, roll-coating, etc.
• the second technique consists in the autopolymerization of dopamine in alkaline solution during 24h, or with use of oxidant, such as sodium periodate or an enzyme.
• US4693799 discloses a process for producing a plasma polymerised film having a low coefficient of friction, using a low temperature plasma.
• WO2007/022645 discloses a solvent based method to form an adlayer on a substrate which comprises dissolving the compounds to be adhered in water and placing the substrate in the solution for an hour at room temperature.
• Current strategies for the deposition of catechol/quinone functionalised layers are based on wet chemical techniques which generally require the use of solvents and are known to present low film deposition rates and are time-consuming. A way of ameliorating these problems has been sought.
• a method for adhering a catechol and/or quinone functionalised layer to a substrate comprising the steps of: (a) providing a substrate, (b) providing a precursor which comprises at least a quinone group; a protected or unprotected catechol group; a vinylic or non-vinylic molecule substituted by one or more quinone group and/or protected or unprotected catechol group; and/or a natural or synthetic derivative of a catechol group and/or a quinone group; wherein the quinone group is a 1,2-benzoquinone group and the catechol group is a 1,2-dihydroxybenzene group; (c) applying a plasma to the precursor and the substrate in order to form a coating comprising a catechol and/or quinone functionalised layer on the substrate.
• a substantially solvent-free coated substrate wherein the coating comprises a catechol and/or quinone functionalized layer.
• the present invention provides a chemical vapour deposition method assisted by plasma to obtain an adherent catechol/quinone functionalized layer.
• the catechol/quinone surface content, crosslinking and thickness of the layer as well as the synthesized organic layer molecular weight can be adjusted according to the plasma parameters.
• the highly chemically reactive coatings formed by the method of the invention are useful for various applications, due to: a. Their ability to promote adhesion between two dissimilar surfaces: e.g. ability to bind to or adhere to a dissimilar substrate, surface, compound or particle, both organic (such as proteins, enzymes, polymers (synthetic or natural) and inorganic (metal (oxide) (nano)particles, glass, silica, etc.), in an aqueous, humid, or non-aqueous environment; b. their ability to form irreversible (covalent bond) or reversible (hydrogen bond, electron ⁇ - ⁇ interaction) chemical crosslinks either with other catechol/quinone groups or other functional groups [e.g.
• amine, thiol, imidazoles, hydroxyl, or carboxyl groups or other reactive groups.
• suitable applications for the coated substrate according to the invention include
• a suitable substrate for an adhesive coating in some embodiments may be a tape, a bandage, a patch, a wound dressing and/or a medical device (such as an electrode).
• a medical device such as an electrode
• a suitable substrate for an antifouling coating in some embodiments may be a medical device, a contact and/or intraocular lens, a blood-contacting device, a medical implant, a surgical tool, a tissue scaffold implant.
• a plasma deposition method presents several advantages: a. it is a simple one-step procedure and is an all-dry solvent-free process; b. it is considered as a green process as it uses a minimal amount of substances, produces of minimal amount of effluent, no environmental remediation process required and is viable in industrial applications; c. it is considered as a non-substrate specific surface treatment method, d. the modification is limited to the top surface layer and does not affect the material bulk properties; e. in general, the modification is fairly uniform over the whole substrate; f. the chemistry of the deposited layer, notably the density of the functional groups which are useful for controlling molecule bonding, can be finely tuned by adjusting the process parameters; g.
• coatings presenting a broad range of common functional groups, such as anhydride, carboxylic acid, amines, epoxy, hydroxyl or bromine, can be deposited by using a suitable organic precursor. h. the deposited layer is free from impurities related to the solvents or plasticiser agents used in wet chemistry.
• the precursor comprises at least a vinylic or non-vinylic molecule substituted by one or more quinone group and/or protected or unprotected catechol and/or a natural or synthetic derivative of catechol and/or quinone.
• the quinone group is a 1,2- benzoquinone group.
• the precursor comprises at least a vinylic or non-vinylic molecule substituted by one or more compounds of formula (VII) and/or a natural or synthetic derivative of a compound of formula (VII), wherein the compound of formula (VII) is defined as follows:
• both substituents Rs either both represent an optionally protected hydroxyl group or a carbonyl group wherein the bond between each carbon atom which is substituted by a Rs substituent is a single bond when both Rs substituents represent a carbonyl group and wherein the bond between each carbon atom which is substituted by a 8 substituent is a double bond when both Rs substituents represent an optionally protected hydroxyl group.
• the precursor may be a vinylic or non-vinylic molecule substituted by a quinone group and/or a protected or unprotected catechol and/or a polymer substituted by at least a quinone group and/or a protected or unprotected catechol group.
• a precursor may be used with other vinylic- or non-vinylic co-monomer(s) in the present invention.
• the precursor is one or more of: a vinyl monomer substituted by a quinone group and/or a protected or unprotected catechol group; a non-vinylic molecule substituted by a quinone group and/or a protected or unprotected catechol group;
• non-vinylic molecule substituted by a quinone group and/or a protected or unprotected catechol quinone group with a vinylic or a non vinylic co-monomer;
• a natural or synthetic polymer substituted by at least a quinone group and/or a protected or unprotected catechol group with a vinylic or a non vinylic co-monomer.
• a vinyl monomer substituted by a catechol group suitable for use as a precursor in the present invention may be a compound of general formula (I):
• Y represents a covalent bond or a linking group such as an optionally substituted alkyl, amide or ester group and X represents an alkyl group or hydrogen.
• an optional substituent for Y is an alkyl, amide or ester group.
• an amide group represented by Y may be:
• an ester group represented by Y may be: wherein i represents an alkyi group.
• X represents methyl or hydrogen.
• an alkyi group is a straight or branched chain, substituted or unsubstituted alkyi group having from 1 to 6 carbon atoms.
• a vinyl monomer bearing a catechol group suitable for use as a precursor in the present invention may be a compound of formula:
• the vinyl-monomer substituted by a catechol group of formula (I) may be used alone or with an additional vinyl co-monomer.
• a suitable vinyl monomer is any vinyl monomer able to be (co)polymerized by plasma. Typical examples include an acrylate, methacrylate, styrene and derivatives, vinyl ester, vinyl amide, acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, unsaturated vegetable oil, fatty acid, acrylic acid, methacrylic acid, vinyl alkoxysilanes, vinyltrimethoxysilane, and/or ethylene.
• a liquid vinylic co-monomer can be used as both a co-monomer and a solvent to dissolve a solid vinyl- monomer substituted by a catechol group of formula (I).
• the vinyl monomer substituted by a catechol group of formula (I) may be used alone or with an additional non-vinylic co-monomer such as a siloxane-forming material, for example hexamethyldisiloxane, hexamethyldisilazane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, hexaethyldisiloxane, tetraethylorthosilicate, tetramethyldisiloxane, pentamethylcyclopentasiloxane, octamethylcyclooctasiloxane, and/or polydimethylsiloxane and its derivatives.
• a siloxane-forming material for example hexamethyldisiloxane, hexamethyldisilazane, octamethylcyclotet
• a liquid non-vinylic co-monomer can be used as both a co- monomer and a solvent to dissolve a solid vinyl-monomer substituted by a catechol group of formula (I).
• the use of a non-vinylic monomer may allow the formation of a matrix including the catechol/quinone functional groups. This matrix may ensure the film has mechanical and chemical stability, thus providing improved ageing properties.
• a vinyl monomer substituted by a quinone group suitable for use as a precursor in the present invention may be a compound of general formula (II):
• the vinyl-monomer substituted by a quinone group of formula (II) may be used alone or with an additional vinyl co-monomer.
• a suitable vinyl monomer is any vinyl monomer able to be (co)polymerized by plasma. Typical examples include an acrylate, methacrylate, styrene and derivatives, vinyl ester, vinyl amide, acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, unsaturated vegetable oil, fatty acid, acrylic acid, methacrylic acid, vinyl alkoxysilanes, vinyltrimethoxysilane, and/or ethylene.
• a liquid vinylic co-monomer can be used as both a co-monomer and a solvent to dissolve a solid vinyl- monomer substituted by a quinone group of formula (II).
• the vinyl monomer substituted by a quinone group of formula (II) may be used alone or with an additional non-vinylic co-monomer such as a siloxane-forming material, for example hexamethyldisiloxane, hexamethyldisilazane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, hexaethyldisiloxane, tetraethylorthosilicate, tetramethyldisiloxane, pentamethylcyclopentasiloxane, octamethylcyclooctasiloxane, and/or polydimethylsiloxane and its derivatives.
• a siloxane-forming material for example hexamethyldisiloxane, hexamethyldisilazane, octamethylcyclot
• non-vinylic co-monomer is a liquid
• a liquid non-vinylic co-monomer can be used as both a co- monomer and a solvent to dissolve a solid vinyl-monomer substituted by a quinone group of formula (II).
• the use of a non-vinylic monomer may allow the formation of a matrix including the catechol/quinone functional groups. This matrix may ensure the film has mechanical and chemical stability, thus providing improved ageing properties.
• a non-vinylic molecule substituted by a catechol group is a molecule bearing at least one catechol group with no polymerizable double bonds.
• a non-vinylic molecule substituted by a catechol group suitable for use in the present invention as a precursor may be a compound of general formula (III):
• Rg represents one or more optionally substituted alkyl, cycloalkyi, heterocycloalkyi, and/or aromatic groups or two or more Rs substituents in combination represent a polycyclic cycloalkyi, heterocycloalkyi and/or aromatic group.
• a suitable substituent is a hydrogen or halogen atom or a hydroxy, amine, amide, ester, ether and/or carboxylic acid group.
• a non-vinylic molecule substituted by a catechol group for use in the present invention as a precursor may be a compound of formula:
• the molecule substituted by catechol may be dopamine, 1,2-dihydroxybenzene, a dihydroxyphenyl derivative (DHPD) and/or a polyphenol such as a tannin.
• DHPD dihydroxyphenyl derivative
• DH PD molecules suitable for use in the present invention are known from WO2008019352.
• a suitable DH PD molecule may be a compound of general formula (IV):
• 2 and 3 may be the same or different and may independently represent a hydrogen atom or a saturated or unsaturated, branched or unbranched, substituted or unsubstituted C 1 -4 hydrocarbon group;
• Pi represents separately and independently -NH2, -COOH, -OH, -SH,
• R2 and R3 are defined above, a single bond, halogen,
• each of Ai and A2 independently represents a hydrogen atom; a protecting group, substantially poly(alkyleneoxide),
• n an integer from 1 to 3
• Ag represents a hydrogen atom or an alkyl, ester, ether or amide group
• A3 represents
• R 5 represents a hydrogen atom or a saturated or unsaturated, branched or unbranched, substituted or unsubstituted C 1 -4 hydrocarbon group, and D has a value of from 1 to 50.
• D has a value of from 1 to 25. In some embodiments, D represents a number which is an integer. In some embodiments, the poly(alkylene oxide) substituent has the structure
• R 7 separately and independently represent a hydrogen atom or -CH3 and m has a value in the range of from 1 to 250
• a 4 represents -NH2, -COOH, -OH, -SH, -H or a protecting group.
• a suitable compound of formula (IV) is
• R3 and Pi are as defined above.
• a suitable compound of formula (IV) is:
• LG represents a linking group and is chosen from oligomers of substantially poly(alkylene oxide), acrylate, methacrylate, vinyl groups, and their derivatives, or having chemical structure - [C(R2)(R3)]x- 2 wherein R2 and R3 are as defined above.
• P2 represents -N H2, -COOH, -OH, -SH, a single bond, halogen, -N H-A5-, -C(0)A 6 , -CH(N HA 5 )-C(0)-A 6 wherein A 5 - represents -H, -C, a single bond, a protecting group, substantially alkyl, poly(alkylene oxide), a peptidal, acrylated, and/or methacrylated group, or is as defined for Ai and A 2 ; and wherein ⁇ represents -OH, -NH 2 or is as defined for Ai and A 2 .
• a suitable compound of formula (IV) is:
• LG is defined above.
• DHPD for use as the derivative of catechol and/or quinone may be 3,4- dihydroxyphenylalanine (DOPA), dopamine, or 3,4-dihydroxyhydrocinnamic acid (DOHA), as well as precursors and further derivatized forms of said compounds.
• precursors include but are not limited to tyrosine, tyramine, hydrocinnamic acid, phenylalanine, benzenepropanoic acid, benzylethamine, 2,4,5-trihydroxyphenylalanine and other phenolic or benzyl compounds that can be hydroxylated or dehydroxylated to form DHPD.
• DHPD examples include DHPD with protecting group(s), DHPD bound to a metal ion on the hydroxyl group(s), or DHPD modified with acrylate, methacrylate, substantially poly(alkylene oxide), peptide or oligomer containing DHPD and its precursors, and the combination thereof.
• non-vinylic molecule bearing catechol groups such as the compound of general formula (III) or the compound of general formula (IV) as defined above may be used alone or with a vinyl-co-monomer.
• a suitable vinyl monomer is any vinyl monomer able to be (co)polymerized by plasma.
• Typical examples include an acrylate, methacrylate, styrene and derivatives, vinyl ester, vinyl amide, acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, unsaturated vegetable oil, fatty acid, acrylic acid, methacrylic acid, vinyl alkoxysilanes, vinyltrimethoxysilane, and/or ethylene.
• the vinylic co-monomer is a liquid
• a liquid vinylic co-monomer can be used as both a co-monomer and a solvent to dissolve a solid compound of formula (III) or of formula (IV).
• non-vinylic molecule bearing catechol groups such as the compound of general formula (III) or the compound of general formula (IV) as defined above may be used alone or with an additional non-vinylic co-monomer such as a siloxane-forming material, for example hexamethyldisiloxane, hexamethyldisilazane, octamethylcyclotetrasiloxane, decamethylcyclopenti dodecamethylcyclohexas hexaethyldisiloxane, tetraethylorthosilicate, tetramethyldisiloxane, pentamethylcyclopenti octamethylcyclooctasiloxane, and/or polydimethylsiloxane and its derivatives.
• a siloxane-forming material for example hexamethyldisiloxane, hexamethyldisilazane, octamethylcyclotetrasi
• a liquid non-vinylic co-monomer can be used as both a co- monomer and a solvent to dissolve a compound of general formula (III) or compound of general formula (IV).
• the use of a non-vinylic monomer may allow the formation of a matrix including the catechol/quinone functional groups. This matrix may ensure the film has mechanical and chemical stability, thus providing improved ageing properties.
• a non-vinylic molecule substituted by a quinone group is any molecule bearing at least one quinone group with no polymerizable carbon-carbon double bonds.
• a non-vinylic molecule substituted by a quinone group suitable for use in the present invention as a precursor is a compound of general formula (V):
• the non-vinylic compound of general formula (V) may be used alone or with a vinylic co-monomer.
• a suitable vinyl monomer is any vinyl monomer able to be (co)polymerized by plasma. Typical examples include an acrylate, methacrylate, styrene and derivatives, vinyl ester, vinyl amide, acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, unsaturated vegetable oil, fatty acid, acrylic acid, methacrylic acid, vinyl alkoxysilanes, vinyltrimethoxysilane, and/or ethylene.
• the vinylic co-monomer is a liquid
• a liquid vinylic co-monomer can be used as both a co-monomer and a solvent to dissolve a solid compound of formula (V).
• the non-vinylic compound of general formula (V) may be used alone or with a non-vinylic co-monomer such as a siloxane-forming material, for example hexamethyldisiloxane, hexamethyldisilazane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, hexaethyldisiloxane, tetraethylorthosilicate, tetramethyldisiloxane, pentamethylcyclopentasiloxane, octamethylcyclooctasiloxane, and/or polydimethylsiloxane and its derivatives.
• a siloxane-forming material for example hexamethyldisiloxane, hexamethyldisilazane, octamethylcyclotetrasiloxane
• non-vinylic co-monomer is a liquid
• a liquid non-vinylic co- monomer can be used as both a co-monomer and a solvent to dissolve a compound of general formula (V).
• the use of a non-vinylic monomer may allow the formation of a matrix including the catechol/quinone functional groups. This matrix may ensure the film has mechanical and chemical stability, thus providing improved ageing properties.
• a polymer bearing catechol for use in the invention may be any polymer, synthetic or not, that is substituted by at least one catechol group at the chain end and/or along the chain.
• a polymer bearing catechol that may be used in the present invention include a poly(dopamine) of formula (Via), a polymer of formula (VIb) which is a poly(caffeic acid), a polymer of formula (Vic) wherein R represents an alkyl group or hydrogen (generally R represents methyl or hydrogen) and > ⁇ represents a linker between the main polymer backbone and the catechol group, a poly(dopamine acrylamide) of formula (VId) which is a poly(dopamine acrylamide), a polymer of formula (Vie) which is oxidized poly(dopamine acrylamide) and a polymer of formula (Vlf) which is a tannin:
• a polymer bearing catechol as defined above can be used alone deposited from an aqueous solution or from an organic solution or used in mixture with an additional vinyl-co-monomer such as any vinyl monomer able to be (co)polymerized by plasma.
• Typical examples include an acrylate, methacrylate, styrene and derivatives, vinyl ester, vinyl amide, acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, unsaturated vegetable oil, fatty acid, acrylic acid, methacrylic acid, vinyl alkoxysilanes, vinyltrimethoxysilane, and/or ethylene.
• a polymer bearing catechol as defined above can be used alone or in mixture with an additional non-vinylic-co-monomer such as a siloxane-forming material, for example hexamethyldisiloxane, hexamethyldisilazane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, hexaethyldisiloxane, tetraethylorthosilicate, tetramethyldisiloxane, pentamethylcyclopentasiloxane, octamethylcyclooctasiloxane, and/or polydimethylsiloxane and its derivatives.
• a siloxane-forming material for example hexamethyldisiloxane, hexamethyldisilazane, octamethylcyclotetrasiloxane
• a polymer bearing quinone for use in the invention may be any polymer, synthetic or not, that is substituted by at least one quinone group at the chain end and/or along the chain.
• a polymer bearing quinone for use in the present invention may be poly(caffeic acid) of formula Vie and/or oxidized poly(dopamine acrylamide) of formula Vlf.
• a polymer bearing quinone as defined above of formula (Vie) or of formula (Vlf) can be used alone deposited from an aqueous solution or from an organic solution or used in mixture with an additional vinyl-co-monomer such as any vinyl monomer able to be (co)polymerized by plasma.
• Typical examples include an acrylate, methacrylate, styrene and derivatives, vinyl ester, vinyl amide, acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, unsaturated vegetable oil, fatty acid, acrylic acid, methacrylic acid, vinyl alkoxysilanes, vinyltrimethoxysilane, and/or ethylene.
• a polymer bearing quinone as defined above of formula (Vie) or of formula (Vlf) can be used alone or in mixture with an additional non-vinylic-co-monomer such as a siloxane-forming material, for example hexamethyldisiloxane, hexamethyldisilazane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, hexaethyldisiloxane, tetraethylorthosilicate, tetramethyldisiloxane, pentamethylcyclopentasiloxane, octamethylcyclooctasiloxane, and/or polydimethylsiloxane and its derivatives.
• a siloxane-forming material for example hexamethyldisiloxane, hexamethyldisilazane
• the molar mass of the polymer bearing catechol or quinone for use as the precursor may be from 1000 g/mol to 10x10 s g/mol, preferably from 2000 g/mol to 5x10 s g/mol.
• a polymer substituted by a catechol and/or quinone group for use in the invention may be linear, branched, (hyper)branched, star-like, etc.
• a polymer substituted by a catechol and/or quinone group for use in the invention may be a random, alternative or block(-like) structure.
• the polymer can be a synthetic copolymer such as described in the scheme below or a peptide bearing catechol.
• the (co)polymer can be neutral or negatively or positively charged.
• a catechol substituted molecule or polymer may be protected.
• a protected catechol substituted molecule or polymer may be used alone or in mixture with vinylic or non-vinylic co-monomers in the present invention.
• suitable protecting groups include an alkyl group or a silane group.
• An alternative protecting group would be well known to a person of skill in the art, for example, examples of suitable protecting groups can be found in "Greene's protective groups in organic synthesis", 4th edition, P.G.M. Wuts, T.W. Greene; Wiley-lnterscience, 2007, John Wiley & Sons, Inc.
• Examples of vinyl monomers bearing protected catechol include:
• an organic and/or inorganic (nano) particles such as metallic (nano) particles for example elemental metals (Ag or Au), metal oxides (AI2O3, ZnO, Fe2C>3 and/or Fe30 4 ), metal halides (AgCI or AgBr), metal sulfides (PbS, CdS and/or Ag2S), can be added to the precursor to be used for plasma polymerization (step (c)) of the method of the invention.
• the method of the invention comprises a step (bl) wherein a polymerization initiator agent is injected into the precursor before step (c).
• the polymerization initiator agent may be injected into the deposition chamber at the beginning of step (c) or during all the duration of step (c)
• the polymerization initiator agent can be a free radical initiator.
• the latter is an agent which produces free radicals, for example a precursor such as an azo compound, peroxide or peroxy ester, which generate radicals by thermolysis, photolysis or upon exposure to plasma. It is also possible to generate a free radical by a photochemical system and/or by high energy radiation such as beam or X- or ⁇ - radiation.
• Suitable free radical initiators include 4,4'-azobis(4-cyanopentano acid), 2,2'- azobis[2-methyl-N-(l,l-bis-(hydroxymethyl)-hydroxyethylpropionamide], 2,2'-azobis(2- methylpropionamidine)dihydrochloride, 2,2'-azobis[2-methyl-N-(2-hydroxyethyl)propionamide], 2,2'- azobis(isobutyramidine hydrochloride), 2,2'-azobis[2-methyl-N-(l,l-bis(hydroxymethyl)-2-ethyl)- propionamide], 2,2'-azobis[2-(2-imidazolin-2-yl)propane]dihydrochloride, 2,2'-Azobis[N-(2- carboxyethyl)-2-methylpropionamidine] hydrate, 2,2'-Azobis ⁇ 2-[l-(2-hydroxyethyl)-2-imidazolin-2- y
• an initiator generating radicals by photolysis may be used in step (b), for example a benzoin derivative, benzophenone, an acyl phosphine oxide and/or a photoredox system.
• an initiator generating radicals as a result of a redox reaction may be used in step (b), for example a combination of an oxidant and a reducing agent.
• a suitable oxidant is, for example, potassium peroxydisulfate, ammonium peroxy disulfate, hydrogen peroxide, tert-butyl hydroperoxide.
• a suitable reducing agent is, for example, a Fe(ll) salt, Ti (III) salt, potassium thiosulfate, potassium bisulfite, ascorbic acid and salts thereof, oxalic acid and salts thereof, dextrose and ongalite (Registered Trademark) (sodium formaldehyde sulfoxylate, BASF AG, Ludwigshafen, Germany).
• the reducing agent should be carefully chosen in order to limit oxidation of the dihydroxyphenyl moieties by the oxidant.
• the plasma used in step (c) of the method of the invention may be a non-equilibrium plasma process operating at a low, medium or atmospheric pressure.
• the method of the invention is performed in a plasma deposition chamber.
• step (a) of the method of the invention comprises providing a plasma deposition chamber.
• step (c) of the method of the invention comprises forming a functionalised layer on a surface portion of the substrate which is contacted by the precursor.
• an electrical excitation may be used in step (c) for the generation of the plasma.
• the electrical excitation may comprise an electrical signal having a frequency in the following ranges: from 1 to 500KHz (low frequency) and from 0.1 to 2.45 GHz (Microwave).
• the electrical excitation may comprise a radiofrequency signal, equalled to 13.56 MHz, 27.12 MHz, 40.68 MHz or 81.36 MHz.
• the electrical signal can be delivered in a continuous or pulsed wave form.
• the plasma discharge can be run in pulsed mode alternating ON period (ton) burst with OFF period (toff).
• step (c) of the method according to the invention may have a low or extremely low Duty Cycle (DC).
• the Duty Cycle may depend upon the type of electrical generator used. For example, for a sinusoidal chopped electrical generator, the Duty Cycle may be from 1 to 50% with a ON period that can vary, for example, from 1ms to 30ms. For a short square pulsed electrical generator, the Duty Cycle may be from 0.01 to 1% with ON periods varying in a range of from 1 to 50 ⁇ and/or from 100 to 500ns.
• step (c) of the method of the invention comprises the use of a gas.
• a gas such as nitrogen
• a noble gas such as argon or helium
• a gas mixture is used such as an inert or noble gas with an oxidant gas (such as O2, H2O vapour) or reducing gas (such as H2 or ammonia).
• step (c) in the method of the invention requires the use of a precursor injection system in order to introduce the precursor (step b) in the deposition chamber, thus placing it in contact with the substrate (step a) and the plasma.
• different kinds of precursor injection systems can be used.
• step (c) of the method of the invention operates by using an atmospheric plasma process
• the precursor is a liquid having a high vapour pressure
• the injection of precursor into the deposition chamber can be carried out by using a bubbler system.
• the introduction of precursor vapours into the deposition chamber can be improved by using a heated bubbler system.
• step (c) of the method of the invention operates by using an atmospheric plasma process, and where the precursor is a liquid having a low vapour pressure
• the injection of precursor into the deposition chamber can be carried out by nebulizer/spraying systems.
• step (c) of the method of the invention operates by using an atmospheric plasma process, and where the precursor is a non-heat sensitive solid
• the injection of precursor into the deposition chamber can be carried out by first melting the precursor and then by using a nebulizer system or an ultrasonic atomizer spray nozzle.
• the precursor injection can be carried out and controlled by heating and by using a vapour flow controller system, respectively.
• step (c) of the method of the invention operates by using a low pressure plasma process
• the precursor is a solid placed in a container
• the injection of precursor into the deposition chamber can be controlled by using a mass flow controller or a micro- leak valve installed in the precursor line to control the flux of the sublimated precursors.
• step (c) of the method of the invention operates by using a low pressure plasma process
• the precursor is a liquid placed in a container
• the injection of precursor into the deposition chamber can be done by using a nebulizer system or an ultrasonic atomizer spray nozzle.
• the precursor injection systems described above are given as examples without restricting the possibility to use other kinds of precursor injection systems.
• the above precursor injection systems can also be used for the plasma deposition of a polymer bearing catechol and/or quinone group.
• the injection position of the precursor(s) in the plasma deposition chamber may be selected. In some embodiments, one of three different injection positions of the precursors may be used: a. injection in the plasma discharge zone, b. injection in the plasma post-discharge zone, c. deposition on the substrate surface before contact with the plasma discharge or post- discharge zone.
• the coating may be a highly functionalised coating having a high number of catechol and/or quinone substituent groups, for example from 1 x 10 11 to 1 x 10 18 functional groups per cm 2 . In some embodiments, the coating may be on the whole or part of a surface of a substrate.
• the substantially solvent-free coating on the substrate according to the invention may have no detectable amount of a solvent which is not a compound described herein as being suitable for use in the method of the present invention.
• the substrate used in the invention may be an inorganic or organic substrate.
• a suitable inorganic substrate may be or a metal substrate, for example a nickel, titanium, steel, stainless steel or aluminium substrate or a ceramic substrate, for example a glass or silicon wafer.
• a suitable organic substrate is a polymeric substrate, for example nylon, polyamide, polyurethane, polyester, polytetrafluoroethylene, polystyrene, polypropylene, polyethylene substrate.
• the substrate may be in the form of a mesh.
• the substrate may be a pre-coated substrate; for example a metallized polymer, metallized glass, painted polymer or painted metal.
• the catechol and/or quinone functionalized surface can have the ability to form irreversible (covalent bond) or reversible (hydrogen bond, electron ⁇ - ⁇ interaction) chemical crosslinks either with other catechol/quinone groups or other functional groups (e.g. amine, thiol, imidazoles, hydroxyl, or carboxyl groups), or other reactive groups.
• the adherent coating obtained by the method of the invention is a catechol and/or quinone functionalized layer.
• the coated su bstrate according to the invention is useful for interaction with a biomolecule. This is because the coating is believed to act as an interfacial adhesive.
• the coated substrate according to the invention comprises a biomolecule.
• the biomolecule may be a bioactive molecule and/or a natural or synthetic peptide or protein, for example an enzyme.
• the biomolecule in its free form (i.e. before immobilization onto the coated substrate) contains at least functional group which may be at least one amino group and/or at least one thiol group. This functional group is believed to allow a convenient reaction with a quinone form of the oxidized dihydroxyphenyl group contained in the coated substrate according to the invention and in very mild reaction conditions (such as ambient temperature and aqueous solution).
• a biomolecule may be chemically, generally covalently, grafted to the coated substrate by the reaction of one or more of its amino groups and/or thiol groups with quinone functions of the coating.
• the biomolecule may be selected to impart additional functionality to the coating. For instance, when antimicrobial activity is desired, an antimicrobial peptide and/or protein from a bacterial, fungal, vegetal, animal, human origin or any analogous chemical structures obtained by de novo design and chemical synthesis can be used. Similarly, an antibacterial substance can be used. Examples include: nisin, lysozyme, natamycine and/or melimine peptides.
• organic antibacterial molecules are chitosan or other antibacterial molecules well-known in the art like triclosan, isothiazolinones, etc.
• biomolecules of interest are polysaccharides; an example of an antimicrobial polysaccharide is chitosan.
• an antibiofilm biomolecule or synthetic substance can be used such as dispersine B.
• a coated substrate may comprise an antibacterial metal nanoparticle such that catechol groups of the coating of the coated substrate can be exploited to form and stabilize to the surface antibacterial metal nanoparticles such as silver nanoparticles.
• a biomolecule may be an enzyme including but not limited to beta-lactamase. Other biomolecules may also be selected depending upon the intended use of the coated substrate.
• Figure 1 shows a schematic cross-sectional view of a first atmospheric pressure plasma deposition chamber to be used in the invention
• Figure 2 shows FT-IR spectra of: a sprayed DOA-VTMOS solution (a) and plasma deposited layers from sprayed VTMOS (b) and sprayed DOA-VTMOS solution (c);
• Figure 3 shows UV-Visible spectra of: 0.5 mg/mL Dopamine acrylamide (DOA) in Vinyltrimethoxysilane (VTMOS) solution (a), sprayed solution “a” on a metallic substrate (b) and plasma deposited layer from sprayed solution "a”(c);
• DOA Dopamine acrylamide
• VTMOS Vinyltrimethoxysilane
• Figure 4 shows a degradation assay of amoxicillin by free and immobilized beta-lactamase
• Figure 5 shows a schematic cross-sectional view of a second atmospheric pressure plasma deposition chamber to be used in the invention
• Figure 6 shows a schematic cross-sectional view of a low pressure plasma deposition chamber to be used in the invention
• Figure 7 shows a schematic cross-sectional view of a first embodiment of a coated substrate according to the invention.
• Figure 8 shows a schematic cross-sectional view of a second embodiment of a partially coated substrate according to the invention.
• a first atmospheric pressure plasma deposition chamber is indicated generally at 100 on Figure 1 of the drawings.
• Chamber 100 comprises a spray system indicated generally at 105, a plasma generation system indicated generally at 107, a moving table 110 and an inorganic or organic substrate 120.
• the spray system 105 has a precursor inlet 130 and an ultrasonic spray system 140 which generates microdroplets 150 which when directed against the substrate 120 in step 200 forms an initial coating layer 152.
• the ultrasonic spray system 140 may be a 48 kHz ultrasonic atomising nozzle (Sono-Tek Corporation).
• the plasma generation system 107 has a pair of electrodes 160, a gas flux inlet 170, a high voltage circuit 180 and a gas outlet 190.
• a second atmospheric pressure plasma deposition chamber is indicated generally at 500 on Figure 5 of the drawings.
• Chamber 500 comprises a plasma generation system indicated generally at 507, a moving table 510 and an inorganic or organic substrate 520.
• the plasma generation system 507 has a pair of electrodes 560, a gas and precursor inlet 570, a high voltage circuit 580 and a gas and precursor outlet 590.
• the plasma generation system 507 is arranged vertically above the moving table 510 and is spaced from the substrate 520.
• the gas and precursor introduced by outlet 590 and the substrate 520 are then submitted to a plasma polymerization step 300.
• a substrate 520A of organic or inorganic material having an adhered coating 552B is generated.
• the coating 552B is an organic functionalised layer with quinone groups 554 and catechol groups 555
• a low pressure plasma deposition chamber is indicated generally at 600 on Figure 6 of the drawings.
• Chamber 600 comprises a deposition chamber 605, a high voltage electrode 602, a grounded electrode 601, a generated plasma 603, a plasma gas and precursor inlet 604, an outlet 606 connected to a pump, a substrate 620 and a functionalised layer 652.
• a coated substrate according to a first embodiment of the invention is indicated generally at 700 in Figure 7.
• the coated substrate has a substrate 704 and a solvent-free adhered coating 702.
• a coated substrate according to a first embodiment of the invention is indicated generally at 800 in Figure 8.
• the coated substrate has a substrate 804 and solvent-free adhered coating portions 802A and 802B which partly cover substrate 804.
• This basic aqueous solution was degassed in sonicator bath (Branson 2510, 100 W, 42 KHz) for 1 h, applying light vacuum followed by, bubbling with argon for another 2 h.
• 3 g (15.8 mmol) of Dopamine hydrochloride (molecule 1) was added under argon atmosphere and continued stirring for 30 minutes.
• the flask was then cooled at 0°C before drop- wise addition of 5.1 mL (63.2 mmol) of acryloyl chloride with stirring.
• Another 9.0 g Na2CC>3 was added to maintain the pH of the solution above 9 during the reaction. After stirring for 12 h at room temperature, the solution was acidified to pH 1-2 with 6N HCI and continued stirring for 1 h in an open vessel.
• the substrates used for deposition are 1 mm thick mirror polished 304 stainless steel disks or aluminium foils. Stainless steel disks were first cleaned by successive ultrasonic washings in butanone (5 min.), acetone (1 min.) and absolute ethanol (lmin) and further dried under a nitrogen flux. Lysozyme from chicken egg, white egg (lyophilized powder, protein >90 %, >40,000 units/mg protein, Aldrich) was used as received. [081] Before plasma deposition, the metallic substrates were plasma cleaned and activated through an Ar/0 2 plasma treatment (19 slm/ 1 slm (standard litre per minute)) in continuous (CW) discharge mode at 1.6W/cm 2 during 30 sec.
• VTMOS vinyltrimethoxysilane
• the prepared solution was sprayed by a 48 kHz ultrasonic atomising nozzle 140 (Sono-Tek Corporation) using the apparatus illustrated in Figure 1.
• the created mist 150 was composed of droplets of median diameter of 40 microns and the range of size is 5 to 200 microns. 0.25 mL/min of solution was injected in the nozzle 140 by using a syringe driver.
• the Sonotek generator 140 was set up to 2W to generate the mist 150, while at the output of the nozzle 140, a nitrogen flow was used in order to shape the mist 150, and entrain it on the substrate 120.
• Plasma curing in argon was then performed with a dielectric barrier discharge reactor 107 composed of two flat alumina covered electrodes 160 connected to high voltage 180 and ensuring an efficient plasma surface zone of 18.72 cm 2 .
• the samples were placed on the moving table 110 (i.e, grounded electrode) ensuring a dynamic deposition mode.
• the table 110 speed and the gap between the electrodes 160 were fixed at 100 mm.s 1 and 1 mm, respectively.
• the plasma discharge was ignited with a sinusoidal signal at 10 kHz chopped by a 1667 Hz rectangular signal.
• the power density was set up to 1.6 W/cm 2 .
• a biomolecule in the form of lysozyme (antibacterial peptide) was then immobilised on the coated surface as follows. Substrates coated with the catechol/quinone functionalized layer were immersed in a lOmM phosphate buffer solution containing lysozyme at 5 mg/ml, at pH 11 during lh at room temperature under gentle mechanical agitations. The samples were then washed 5 times during 5 minutes with MilliQ purified water.
• FT-IR analysis was performed on a Bruker Hyperion 2000 spectrometer equipped a with MCT detector. A grazing angle or AT objectives were used for the coated stainless steel or aluminium substrates analyses, respectively.
• PerkinElmer Lambda 950 UV-vis-NI (InGaAs) spectrophotometer equipped with an integrating sphere was used for UV-visible spectroscopy.
• the deposition rate measured with a contact profilometer, was estimated to be around 5 to 10 nm/s, 29 .
• catechol/quinone functionalized layers can be deposited according to the present invention with a deposition rate that is at least 200 times faster than the conventional wet chemical methods already reported.
• a peak at 1450 cm “1 is ascribed to CN stretching.
• the absence of the vinylic peak 1600 cm “1 from DOA and VTMOS suggests that a plasma polymerisation through the vinyl monomer group occurred.
• Catechols are chromophore compounds that absorb in the UV zone.
• dopamine acrylamide in VTMOS solution shows an absorbance peak at around 290 nm ( Figure 3. a).
• UV-Visible analyses of plasma deposited layer confirm the presence of free catechol groups with a small shift of this peak toward 276 nm. The same shift was observed in the UV-analyse of a sprayed DOA/VTMOS solution onto a surface ( Figure 3b).
• the plasma deposited layer one can also notice the formation of a band at 320 nm and the emergence of a peak at 420 nm.
• the former peak might be due to the formation of a polymer of higher molecular mass, a dopamine derivative intermediate.
• the peak at 420 nm is sometimes assigned to catechol oxidation and accumulation of phenol coupling products.
• JISZ2801 antimicrobial tests were performed on plasma deposited layers after the lysozyme immobilization step. Metallic grafted samples exhibited a total reduction of the bacteria population. Log reduction of the bacteria of 6.9 was achieved, which is far above the 2 log reduction efficacy limit set by the test.
• Example 3
• the substrate used for deposition is 1 mm thick mirror polished 304 stainless steel disks. Prior to plasma deposition, stainless steel disks were cleaned by successive ultrasonic washings in butanone (5 min.), acetone (1 min.) and absolute ethanol (lmin) and further dried under a nitrogen flux. Metallic substrates were then plasma activated through an Ar/02 plasma treatment (19 slm/ 1 slm (standard litre per minute)) in continuous (CW) discharge mode at 1.6W/cm2 during 30 sec.
• Catechol molecule (1,2-dihydroxybenzene, Sigma-Aldrich, >99%) was dissolved at final concentration of 5 mg/mL in vinyltrimethoxysilane (VTMOS, 98%, Sigma-Aldrich) at ambient temperature.
• VTMOS vinyltrimethoxysilane
• nisin antibacterial peptide
• the conditions for nisin antibacterial peptide immobilization were as follows. The catechol/quinone plasma functionalized layers were immersed in a 1 mL solution containing 5 mg of nisin and left to react under constant agitation during 1 hour at ambient temperature. Nisin immobilisation was performed in a 10 mM phosphate buffer solution at pH 6.8. The surfaces were then rinsed with deionized water 4 times during 5 minutes under 500 rpm stirring to remove unreacted peptides.
• Example 4 preparation of bio-inspired antibiofilm surfaces is described.
• the materials were the same as for Example 2 except that the biomolecule used is DispersinB (antibiofilm), which has been produced according to the protocol published by Kaplan et al. (Kaplan, J.B. agunath, C. Ramasubbu N. Fine D.H, J. Bacteriol. 2005, 185, 4693).
• the plasma deposition method was the same as for Example 2.
• DispersinB Antibio-film enzyme
• the DispersinB immobilization conditions were as follows. Substrates coated with the catechol/quinone functionalized layer were immersed in a lOmM phosphate buffer solution containing Dispersin B at 1 mg/ml, at pH 7 during lh at room temperature under gentle mechanical agitations. The samples were then washed 5 times during 5 minutes with MilliQ purified water.
• DspB Dispersin B
• pET- 28a/DspB-expressing Escherichia coli was grown overnight at 37°C with shaking in 50 ml LB medium supplemented with 50 ⁇ g/ml kanamycin.
• the bacterial suspension was diluted 100-fold in a total of 2 liters of LB supplemented with kanamycin (50 ⁇ g/ml), and the expression of DspB was induced with isopropyl- -D-thiogalactopyranoside (final concentration, 0.5 mM) when the culture reached an A600 of 0.6.
• the induced culture was incubated for further 4 h at 37°C with shaking.
• DspB was purified by nickel affinity chromatography as previously described [Faure et al., Adv. Funct. Mater. 2012, 22, 5271- 5282]. Fractions were analyzed by SDS-PAGE and by the ability to hydrolyze the chromogenic substrate 4-nitrophenyl-N-acetyl- ⁇ -D-galactosaminide (Sigma Aldrich). Those fractions containing Dispersin B were pooled and dialyzed against 10 mM P04 pH 5.9, 100 mM NaCI overnight at 4°C. Proteins were quantified using the BCA kit (Pierce).
• test in-vitro anti-adhesion test was performed as follows. A preculture of biofilm forming S. epidermidis ATCC35984 was grown overnight at 37°C in LB (3 mL) and used the next morning to seed a fresh culture in LB (50 mL). The bacterial concentration of test inoculum was adjusted to about 107 cells mL "1 in M63 medium supplemented with glucose and casamino acids. Metallic substrates coated with anti-adhesive films were placed in Petri dishes containing damp blotting paper. Test inoculum (200 ⁇ ) was pipetted onto each substrate. The Petri dishes containing the inoculated coupons were closed and incubated at 37°C for 24 h.
• Example 5 [0109] In this example, the preparation of bio-inspired surfaces for water depollution, hereafter for antibiotic degradation is described.
• Enzymatic activity was estimated through the amoxicillin degradation monitoring over time. Enzymes were incubated in a 2 mL degradation medium composed of tap water filtered through 0.22 ⁇ , HEPES (12.5 mM) , BSA (10 ⁇ g.mL 1 ) and amoxicillin (100 ⁇ g.mL 1 ). Each 24h, the degraded amoxicillin concentration was estimated by absorbance measurements at 210 nm with a 2 Synergy microplate reader (Biotek). The medium was removed every 24 hours, wells were washed 3 times with filtered tap water and a new volume of the degradation medium was put in wells.
• the substrates used for deposition were 1 mm thick mirror polished 304 stainless steel disks or aluminium foils. Stainless steel disks were first cleaned by successive ultrasonic washings in butanone (5 min.), acetone (1 min.) and absolute ethanol (lmin) and further dried under a nitrogen flux. Before plasma deposition, the metallic substrates were plasma cleaned and activated through an Ar/0 2 plasma treatment (19 slm/ 1 slm (standard litre per minute)) in continuous (CW) discharge mode at 1.6W/cm2 during 30 sec.
• a homopolymer of methacrylamide bearing 3,4-dihydroxy-L-phenylalanine, noted P(mDOPA) (molecule (1)), was prepared and oxidized in basic media according to a procedure described in J. Mater. Chem. 2011, 21, 7901-7904. For that, 20mg of P(mDOPA) was dispersed in a lOmL distilled water solution and a NaOH solution (0.1 M) was slowly added in order to raise the pH above 10. The oxidation step lasted at least one night under air. At the end of the reaction, polymer solution presents a pink colour characteristics confirming that the oxidized Pox(mDOPA) polymer had been obtained, (molecule (2)).
• DspB DispersinB

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