EP2295630A1 - Method for producing coated protein fibres - Google Patents

Abstract

Producing a coated protein fiber comprises preparing protein fibers with a diameter of 10 nm to 10 mu m from a solution or dispersion and contacting the fibers with 2-cyanoacrylic acid ester during or after their preparation. An independent claim is included for the coated protein fibers, prepared by the above process. ACTIVITY : Vulnerary. MECHANISM OF ACTION : None given.

Description

The present invention relates to processes for the production of coated protein fibers in which from a solution or dispersion of a protein fibers having a diameter in the range of 10 nm to 10 microns are produced. Furthermore, the invention relates to coated protein fibers, their use and fiber fabrics comprising the coated protein fibers.

Processes for the preparation of polymer fibers are described in the literature and known to the person skilled in the art (see, for example, US Pat A. Echte, Handbook of Technical Polymer Chemistry, VCH Verlagsgesellschaft mbH, Weinheim, 1993, Chap. 9.6 "Manufacture of man-made fibers", pp. 563-581 ). For example, synthetic polymers can be spun into fibers by forcing melts or solutions of the polymers through holes and then solidifying and drawing by cooling or evaporating the solvent.

The production of so-called nano- and mesofibers, ie fibers with a diameter of a few nm to a few microns, can be performed better in other ways, for example by electrospinning or centrifugal spinning process, to name just a few.
Methods for electrospinning are also known to those skilled in the art and described in the literature, for example in DH Reneker and HD Chun, Nanotechn. 7 (1996) 216 f , and A. Greiner and J. Wendorff, Angew. Chemistry Int. Ed. 119 (2007) 5770-5805 ,
Electrospinning processes for the production of protein fibers are described, for example, in the non-prepublished EP 09156540.8 (File reference) and EP 08162122.9 (File reference) described.
Centrifuge spinning processes suitable for the production of nanofibers are described, for example, in US Pat EP 624 665 A and the EP 1 088 918 A disclosed. In these centrifugal spinning processes, the polymer-containing solution or dispersion is placed in a rotating container and discharged by centrifugal forces from the container in the form of fibers.
As a rule, the fibers obtained by means of these electrospinning or centrifuge spinning processes can also be deposited and obtained directly, for example by deposition on a support, in the form of fibrous sheets, for example nonwovens.

One of the main fields of application for polymer and protein fibers is the production of fibrous webs such as fabrics or nonwovens. These are widely used, for example in mass applications such as textiles, as technical devices such as filters or, in the case of protein fibers, for special applications such as wound dressings in the medical sector. For most applications of this type, it is important that the polymer or protein fibers have good water and moisture stability, respectively. This is normally not the case when the fiber is made from water soluble polymers, eg polyvinyl alcohol. But also commonly referred to as water-insoluble polymers often have the disadvantage that fiber fabrics made from them can lose stability or strength, at least for prolonged exposure to water or moisture. For example, there are naturally occurring polymers based on protein or polysaccharide, which also do not dissolve under the action of water, but can absorb and incorporate water, so that produced from these polymers fibers or surface fiber structure, for example, swell and thus also in their mechanics or - in particular in filters - be changed in their permeability.

To improve the water or moisture resistance of polymer or protein fibers or fiber fabrics produced therefrom, various measures are described in the literature.

Thus, fibers from water-soluble polymers can be rendered insoluble by cross-linking or restructuring (post-crystallization). The stability of polyvinyl alcohol fibers against water could be achieved, for example, by treatment with methanol (see Yao L. et al., Chem. Mater. 15 (2003) 1860-1864 ), Crosslinking with polyacrylic acid (see Zeng J. et al., E-polymers 78 (2004 )) or UV crosslinking of modified polyvinyl alcohol (see Zeng J. et al., Macromol. Rapid Commun. 26 (2005) 1557-1562 ) increase. In these crosslinking methods, the crosslinker was already added to the polymer-containing spinning solution and co-spun. It is a thermal or radiation-induced treatment required, which is usually complex and expensive.

On the one hand, special proteins can be rendered more water-stable by means of physical methods such as solvent treatment or pressure treatment. This happens loudly Ishida et al. (Macromolecules 1990, 23, 88-94 ) thanks to the refolding of the protein molecules into another secondary structure, eg in β-sheet conformation. Furthermore, chemical cross-linking methods can be used to make protein structures more water-stable. A chemical cross-linker is understood to mean a molecule in which at least two chemically reactive groups are connected to one another via a linker. Examples of these are sulfhydryl-reactive groups (for example maleimides, pyridyl disulfides, α-haloacetyls, vinyl sulfones, sulfatoalkyl sulfones (preferably sulfatoethyl sulfones)), amine-reactive groups (for example succinimidyl esters, carbodiimde, hydroxymethyl phosphine, imido esters, PFP esters, aldehydes, isothiocyanates etc.). , carboxy-reactive groups (eg, amines, etc.), hydroxyl-reactive groups (eg, isocyanates, etc.), unselective groups (eg, aryl azides, etc.), and photoactivatable groups (eg, perfluorophenyl azide, etc.). These reactive groups can be used with forming amino, thiol, carboxyl or hydroxyl groups in covalent linkages.

The WO 2006/089522 A1 discloses methods of making polymer fibers wherein a dispersion of a water-insoluble polymer is electrospun in an aqueous medium. In this process, it has been possible for the first time to spin water-insoluble polymers without the use of organic solvents by means of an electrospinning process, polymer fibers, in particular nano- or mesofibres, being obtained. One way to improve the water stability of fibers obtained from aqueous dispersions by electrospinning of water-insoluble polymers consists in the interparticle crosslinking of the fibers according to WO 2009/074630 , another in the targeted tuning of glass transition temperature of the polymer and processing temperature in electrospinning according to WO 2009/010443 ,

The formation of poly-2-cyanoacrylate fibers has also been described, in that monomer vapors were deposited on a substrate and polymerized with initiator (see FIG. SV Doiphode et al., Polymer 47 (12) (2006) 4328-4332 ). The adhesion and adhesion of 2-cyanoacrylates or their polymers, as well as their relatively low water solubility are known in the art. Among other things, due to these properties, 2-cyanoacrylates or their polymers for bonding wounds, for improving the adhesion of polymer films (s. Dong YW et al., J. Adhesion Sci. Technol. 9 (4) (1995) 501-525 ) and used as so-called superglue. In the US 6,126,776 discloses a process in which a solid, UV or plasma pretreated polymeric substrate, such as films or nonwovens, is treated with 2-cyanoacrylate vapors to improve the adhesion of a post-applied organic material. In GB 2447933 there are disclosed specific cyanoacrylate monomers that can be converted to polymers with improved water stability. Nevertheless, polycyanoacrylates and adhesions with cyanoacrylate adhesives are not permanently moisture-stable, because under appropriate conditions the polymer can be split again (see http://de.wikipedia.org/wiki/Klebstoff from 17.07.2009, chapter 4.2, cyanoacrylate adhesives ).

Despite these known methods, more favorable and more efficient methods are desirable in order to improve the water or moisture resistance of polymer or protein fibers, in particular the so-called nanofibers. Furthermore, it is desirable to influence the decomposition or degradation of protein fibers, as can be done for example by enzymes or microorganisms in the presence of moisture or water, ie either accelerate or slow down depending on the application of protein fibers; For example, it would be desirable to use protein fibers as wound coverings, whereby the decomposition or degradation rates of the protein fibers caused by the wound enzymes are specifically adjustable. It is therefore an object of the present invention to provide protein fibers, in particular so-called nanofibers, and fiber fabrics obtainable therefrom, which have improved resistance to water or moisture, ie a reduced solubility, swelling and / or change in the mechanical properties under the action of water or moisture Have properties and / or the flow properties and / or the fiber structure or an improved decomposition or degradation behavior. The use of organic solvents should, if possible, be largely avoided in the production of such water- or moisture-stable fibers and fibrous webs for toxicological, occupational safety and regulatory reasons.

This object is achieved by the method mentioned, wherein essential to the invention is that the fibers are contacted during or after their preparation with a 2-cyanoacrylic.

The coated protein fibers and fiber webs which can be produced by the process according to the invention have improved water or moisture resistance compared with known nanofibers, ie. they have a reduced solubility, swelling and / or change in the mechanical properties and / or the flow properties and / or the fiber structure and / or an improved decomposition or degradation behavior under the action of moisture or moisture. The use of organic solvents is largely avoided in the inventive method.

The articles, methods and uses of the invention are described below.

In principle, all proteins can be used in the method according to the invention, which are known from the solution or dispersion according to those skilled in the art and described in the literature to fibers having a diameter in the range of 10 nm to 10 .mu.m, preferably from 20 nm to 5 .mu.m, especially preferably from 50 nm to 2 microns, let process.

Suitable proteins in the context of the present invention are synthetic or natural proteins, including peptides, in particular amphiphilic self-assembling proteins, where the proteins may optionally additionally be chemically and / or enzymatically modified, for example by esterification, amidation, saponification, carboxylation, acetylation, acylation, Hydroxylation, glycosylation or farnesylation.

Preferred proteins for use in the processes according to the invention are those which are not water or moisture-resistant, in particular those which are water-soluble or water swellable. For the purposes of the present invention, "water-soluble" is understood as meaning all proteins whose solubility in water at 23 ° C. is higher than 0.1% by weight (based on the total weight of the solution). In the context of the present invention, all proteins are to be understood as "water-swellable" whose weight increase after 6 hours storage at 50 ° C. in a circulating air oven and subsequent storage in water at 23 ° C. for more than 30 minutes is more than 1% (based on the weight of the protein after 6 hours storage at 50 ° C).

The preferred amphiphilic self-assembling proteins are, for example, microbead-forming proteins as described in US Pat WO-A-20077082936 or in the WO-A-2008155304 which is hereby incorporated by reference, or intrinsically unfolded proteins.

For example, the amphiphilic self-assembling protein is a silk protein, such as, in particular, a spider silk protein, preferably a C16 protein (see SEQ ID NO: 2,); or a spinnable protein derived from these proteins having a sequence identity of at least about 50%, e.g. at least 60, 70, 80, 90, 95, 96, 97, 98 or 99%.

Other preferred intrinsically unfolded amphiphilic self-assembling proteins are the R16 protein comprising an amino acid sequence of SEQ ID NO: 4 or the S16 protein comprising an amino acid sequence of SEQ ID NO: 6; or a spinnable protein derived from these proteins having a sequence identity of at least about 60%, e.g. at least 70, 80, 90, 95, 96, 97, 98 or 99%.

"Silk proteins" are understood to mean those proteins which contain highly repetitive amino acid sequences and are stored in the animal in a liquid form and whose secretion by shearing or spinning results in fibers ( Craig, CL (1997) Evolution of arthropod silks. Annu. Rev. Entomol. 42: 231-67 ).

Particularly suitable proteins are spider silk proteins which could be isolated in their original form from spiders.

Especially suitable proteins are silk proteins that could be isolated from the spider's "major ampullate" gland.

Preferred silk proteins are ADF3 and ADF4 from the "major ampullate" gland of Araneus diadematus ( Guerette et al., Science 272, 5258: 112-5 (1996 )).

Also suitable proteins are natural or synthetic proteins derived from natural silk proteins and which, using genetic engineering techniques, are heterologous in prokaryotic or eukaryotic expression systems were manufactured. Nonlimiting examples of prokaryotic expression organisms are Escherichia coli, Bacillus subtilis, Bacillus megaterium, Corynebacterium glutamicum and others. Nonlimiting examples of eukaryotic expression organisms are yeasts such as Saccharomyces cerevisiae, Pichia pastoris and others, filamentous fungi such as Aspergillus niger, Aspergillus oryzae, Aspergillus nidulans, Trichoderma reesei, Acremonium chrysogenum and others, mammalian cells such as Hela cells, COS cells, CHO Cells, etc., insect cells, such as Sf9 cells, MEL cells and others.

Especially preferred are synthetic proteins based on repeating units of natural silk proteins. In addition to the synthetic repetitive silk protein sequences, these may additionally contain one or more natural non-repetitive silk protein sequences ( Winkler and Kaplan, J. Biotechnol 74: 85-93 (2000 )).

Among the synthetic silk proteins preferred for the formulation of drugs by means of spinning processes are synthetic spider silk proteins which are based on repeating units of natural spider silk proteins. In addition to the synthetic repetitive spider silk protein sequences, these may additionally contain one or more natural non-repetitive spider silk protein sequences.

Among the synthetic spider silk proteins, preference is given to the so-called C16 protein ( Huemmerich et al. Biochemistry, 43 (42): 13604-13612 (2004 )). This protein has the polypeptide sequence shown in SEQ ID NO: 2.

In addition to the polypeptide sequence shown in SEQ ID NO: 2, particularly functional equivalents, functional derivatives and salts of this sequence are also preferred.

Furthermore, preference is given to synthetic proteins which are combined on repeating units of natural silk proteins with sequences of insect structural proteins such as the Resilin ( Elvin et al., 2005, Nature 437: 999-1002 ).

Particularly preferred among the combination proteins of silk proteins and resilins are the R16 and S16 proteins. These proteins have the polypeptide sequences shown in SEQ ID NO: 4 and SEQ ID NO: 6.

In addition to the polypeptide sequences shown in SEQ ID NO: 4 and SEQ ID NO: 6, particularly functional equivalents, functional derivatives and salts of these sequences are also preferred.

According to the invention, "functional equivalents" are understood in particular also to mean mutants which are present in at least one sequence position of the abovementioned amino acid sequences have another than the specifically mentioned amino acid but still has the property for packaging effect substances. "Functional equivalents" thus include the mutants obtainable by one or more amino acid additions, substitutions, deletions, and / or inversions, which changes can occur in any sequence position as long as they result in a mutant having the property profile of the invention. Functional equivalence is especially given when the reactivity patterns between mutant and unchanged polypeptide are qualitatively consistent.

"Functional equivalents" in the above sense are also "precursors" of the described polypeptides as well as "functional derivatives" and "salts" of the polypeptides.

"Precursors" are natural or synthetic precursors of the polypeptides with or without the desired biological activity.

Examples of suitable amino acid substitutions are shown in the following table: Original rest Examples of substitution Ala Ser bad Lys Asn Gln; His Asp Glu Cys Ser Gln Asn Glu Asp Gly Per His Asn; Gln Ile Leu; Val Leu Ile; Val Lys Arg; Gln; Glu mead Leu; Ile Phe Met; Leu; Tyr Ser Thr Thr Ser Trp Tyr Tyr Trp; Phe Val Ile; Leu

The term "salts" means both salts of carboxyl groups and acid addition salts of amino groups of the protein molecules according to the invention. Salts of carboxyl groups can be prepared in a manner known per se and include inorganic salts such as sodium, calcium, ammonium, iron and zinc salts, as well as salts with organic bases such as amines such as triethanolamine, arginine, lysine , Piperidine and the like. Acid addition salts, such as, for example, salts with mineral acids, such as hydrochloric acid or sulfuric acid, and salts with organic acids, such as acetic acid and oxalic acid, are likewise provided by the invention.

"Functional derivatives" of polypeptides of the invention may also be produced at functional amino acid side groups or at their N- or C-terminal end by known techniques. Such derivatives include, for example, aliphatic esters of carboxylic acid groups, amides of carboxylic acid groups, obtainable by reaction with ammonia or with a primary or secondary amine; N-acyl derivatives of free amino groups prepared by reaction with acyl groups; or O-acyl derivatives of free hydroxy groups prepared by reaction with acyl groups.

Included in the invention with "functional equivalents" are homologs to the specific proteins / polypeptides disclosed herein. These have at least 60%, e.g. 70, 80 or 85%, e.g. 90, 91, 92, 93, 94, 95, 96, 97, 98 or 99% identity to one of the specifically disclosed amino acid sequences.

By "identity" between two sequences is meant, in particular, the identity of the residues over the respective entire sequence length, in particular the identity which can be determined by comparison with Vector NTI Suite 7.1 (Vector NTI Advance 10.3.0, Invitrogen Corp.) (or Software The company Informax (USA) using the Clustal method (Higgins DG, Sharp PM, Fast and sensitive multiple sequence alignments on a microcomputer. Comput Appl. Biosci. 1989 Apr; 5 (2): 151-1 ) is calculated by setting the following parameters: Multiple alignment parameters: Gap opening penalty 10 Gap extension penalty 0.05 Gap separation penalty range 8th Gap separation penalty off % identity for alignment delay 40 Residue specific gaps off Hydrophilic residues gap off Transition weighing 0 Pairwise alignment parameter: FAST algorithm off K-tuple size 1 Gap penalty 3 Window size 5 Number of best diagonals 5

To produce the coated protein fibers according to the invention, the said proteins can also be used in admixture with one or more polymers, for. B as a dispersant or thickener for the spinnable solution. Provided the proteins are used in mixture with one or more polymers, the mixing ratios are basically no limits, but usually such mixtures include 10 to 99 wt .-%, preferably 50 to 99 wt .-%, particularly preferably 80 to 99 wt. -%, protein and 1 to 90 wt .-%, preferably 1 to 50 wt .-%, particularly preferably 1 to 20 wt .-%, of one or more polymers, wherein the wt .-% are each based on the total weight of Protein and polymer and together give 100 wt .-%.

The term "polymers" encompasses both homopolymers and copolymers, with the exception of proteins. Suitable copolymers are both random and alternating systems, block copolymers or graft copolymers. The term copolymers encompasses polymers which are made up of two or more different monomers or in which the incorporation of at least one monomer into the polymer chain can be realized in various ways, e.g. in the case of stereo block copolymers. Blends of homopolymers and copolymers can also be used. The homo- and copolymers may be miscible or immiscible with each other. The polymers which are suitable for the processes according to the invention can be of synthetic origin, but they can also be naturally occurring polymers, for example based on polysaccharides. Suitable polymers include, for example, polyvinyl alcohol, poly-N-vinylpyrrolidone, polyvinylformamide, polyethylene oxide, polyvinylamine, polyvinyl acetate, polyacrylic acid, polyacrylic acid esters, polyacrylamide, polyaccharides such as cellulose, cellulose ethers such as e.g. Methylcellulose (with a degree of substitution of from 3 to 40%), ethylcellulose, butylcellulose, hydroxymethylcelluloses; hydroxyethylcelluloses; Hydroxypropylcelluloses, isopropylcellulose, cellulose esters, e.g. Cellulose acetate, starches, modified starches, e.g. Methyl ether starch, alginate.

Suitable methods known to the person skilled in the art for producing protein fibers of the stated diameter from solution and dispersion are described, for example, in US Pat A. Echte, Handbook of Technical Polymer Chemistry, VCH Verlagsgesellschaft mbH, Weinheim, 1993, Chap. 9.6.3.2 "Dry Spinning" and 9.6.3.3 "Wet Spinning" p. 575-577 , described. Preferred methods of preparation of solutions are those in which water is used as the solvent, since thereby possible toxicological, labor-safety-related and approval-related difficulties can be avoided. So the authors of Adv. Mater. 2009, 21, 366-370 Produce the protein fibers from regenerated Bombyx mori Silk fibroin from aqueous LiBr solution with the addition of polyethylene glycol by the wet spinning method.
However, since the solubilities of the proteins in water are often insufficient and the methods for producing aqueous protein solutions contain several complex stages (inter alia dialysis), solutions in organic solvents, for example acetic acid or especially formic acid, are preferred in these cases for producing fibers , at.

In the context of the present invention, preferred methods known to the person skilled in the art for producing protein fibers of the mentioned diameter from solution are electrospinning or centrifuge spinning processes, in particular electrospinning processes. Methods for electrospinning are, for example, in DH Reneker and HD Chun, Nanotechn. 7 (1996) 216 f ., A. Greiner and J. Wendorff, Angew. Chemistry Int. Ed. 119 (2007) 5770-5805 . WO 2006/089522 A1 . WO 2009/074630 . WO 2009/010443 described. Centrifuge spinning processes in which the polymer-containing melt, solution or dispersion is placed in a rotating container and discharged by centrifugal forces from the container in the form of fibers, are described for example in EP 624 665 A and EP 1 088 918 A ,

The solution to be used in electrospinning can be electrospun in any manner known to those skilled in the art.
In a preferred embodiment of the electrospinning, the solution to be spun is placed in an electric field with a thickness of generally between 0.01 and 10 kV / cm, preferably between 1 and 6 kV / cm and particularly preferably between 2 and 4 kV / cm, introduced by being squeezed out of one or more cannulas under low pressure. As soon as the electrical forces exceed the surface tension of the drops at the cannula tip, the mass transport in the form of a jet takes place on the opposite electrode. The possibly present solvent evaporates in the interelectrode space and the proteinaceous solid is then present in the form of fibers on the counter electrode. Spinning can be done in both vertical directions (bottom to top and top to bottom) and in horizontal direction.
In a further preferred embodiment of the electrospinning process, a cylinder-based device, for example Nanospider from Elmarco (Czech Rep.), Is used. The solution used is in a container in which a metal roller rotates permanently or the spin formulation is metered onto the roller with a separate device. The roll can be smooth, structured or provided with metal wires. In this case, part of the formulation is resistant to the roll surface. The electric field between the roller and the counterelectrode (above the roller) causes only liquid jets to form from the formulation, which then lose any solvent present or solidify the melt on the way to the counterelectrode. A nanofiber nonwoven fabric (fibrous web) is formed on the substrate (eg polypropylene, polyester or cellulose), which is passed between the two electrodes. The electric field generally has a strength between 0.01 to 10 kV / cm, preferably between 1 and 6 kV / cm and more preferably between 2 and 4 kV / cm. In particular, in this embodiment, the electric field has a magnitude of 2.1 kV / cm (82 kV at 25 cm electrode spacing). Spinning can be done in both vertical directions (bottom to top and top to bottom) and in horizontal direction.

Additives may be added to the solution or dispersion of the protein to alter, for example, the viscosity or surface tension, resulting in e.g. selectively influence the fiber formation or fiber morphology. Preferred additives are thickeners and surfactants known to the person skilled in the art and described in the literature.

In a preferred embodiment of the invention, it is possible to add to the solution or dispersion of the protein one or more active substances which have a targeted effect on a living organism, in particular a pharmacological, agrochemical, medicinal or cosmetic effect. These active substances may be active pharmaceutical ingredients, cosmetic effect substances, agrochemical active substances (fungicides, herbicides, insecticides), food or feed additives, biological active substances (peptides, growth factors, bacteria) or a combination of several of these active substances. The type or formulation of the active ingredients, their amounts and concentrations to be used as well as the targeted specific action in the living organism are known to those skilled in the art as such and described in the literature (see, for example WO 2001/54667 . WO 2004/014304 . WO 2007/082936 . WO 2007/093232 , and the unpublished EP 09156540.8 (File reference) and EP 08162122.9 (File number)). As a rule, in this embodiment of the invention, amounts of active substance of from 0.01 to 80% by weight, preferably from 1 to 70% by weight, particularly preferably from 10 to 50% by weight, based in each case on the total weight of protein and active ingredient, used.
The aim of the addition of the active substances mentioned is that they are released or released after the application of the coated protein fibers or fiber fabrics according to the invention on or on living organisms, and specifically develop a desired specific action on or in the living organism.

The fibers which can be prepared from the solution or dispersion of a protein by the abovementioned processes generally have a diameter in the range from 10 nm to 10 .mu.m, preferably from 20 nm to 5 .mu.m, particularly preferably from 50 nm to 2 .mu.m.

Essential to the invention is that these fibers are contacted during or after their preparation with a 2-cyanoacrylic acid ester.

Suitable 2-cyanoacrylic acid esters, which are generally known to the person skilled in the art and are described in the literature, are, for example, methyl, ethyl, n-butyl, octyl, allyl or methoxyethyl esters of 2-cyanoacrylic acid, in particular ethyl 2-cyanoacrylate.

The contacting of the protein fibers can be carried out according to the invention by exposing the fibers to an atmosphere containing gaseous 2-cyanoacrylates during their production. The partial pressure of 2-cyanoacrylates in the gas phase is equal to or less than the vapor pressure of the 2-cyanoacrylic ester used at the respective processing temperature. In non-pressurized process control, the partial pressure of the 2-cyanoacrylic esters used is generally in the range of 1 mbar to 1 bar, preferably in the range of 50 mbar to 800 mbar, more preferably in the range of 100 mbar to 500 mbar. In a printing procedure, the partial pressures of the 2-cyanoacrylic acid esters used can also be significantly higher than these values.

The contacting of the protein fibers with gaseous 2-cyanoacrylic acid ester is preferably carried out by exposing the fibers to an atmosphere containing gaseous 2-cyanoacrylic acid esters after their preparation. That In a first step, the protein fibers are prepared according to the methods described above, and only in a second separate step is the contacting of the protein fibers with gaseous 2-cyanoacrylic acid ester. The advantage of this variant is that the temperature-dependent vapor pressures of 2-cyanoacrylates can be chosen independently of the temperature of the protein fiber production. In non-pressurized process control, the partial pressure of the 2-cyanoacrylic esters used is generally in the range of 1 mbar to 1 bar, preferably in the range of 50 mbar to 800 mbar, more preferably in the range of 100 mbar to 500 mbar. In a printing procedure, the partial pressures of the 2-cyanoacrylic acid esters used can also be significantly higher than these values.

The contacting of the protein fibers with gaseous 2-cyanoacrylic acid both during and after their preparation is usually carried out over a period of 1 s to 60 min, preferably from 10 s to 30 min, more preferably from 1 min to 10 min.

In a further embodiment of the invention, the contacting of the protein fibers with 2-cyanoacrylic esters can also be effected by adding the 2-cyanoacrylic acid esters already to the solution or dispersion of the protein from which the protein fibers are produced (of course, this embodiment is not possible if the ingredients the solution or dispersion chemically react with the 2-cyanoacrylates or cause their polymerization, which is the case for example with aqueous solutions). The concentration of 2-cyanoacrylic acid ester in the solution or dispersion in this embodiment of the invention is usually in the range of 0.1 to 10 wt .-%, preferably from 0.5 to 5 wt .-%, particularly preferably from 1 to 5 wt. -%, in each case based on the total weight of the solution or dispersion.

In a further embodiment of the invention, the contacting of the protein fibers with 2-cyanoacrylic acid ester can also be effected by treating the fibers after their preparation with a solution containing the 2-cyanoacrylic acid esters. suitable Solvents for 2-cyanoacrylic acid esters are, for example, acetone or 2-butanone. The concentration of 2-cyanoacrylic acid esters in this solution is usually in the range from 0.1 to 10% by weight, preferably from 0.5 to 5% by weight, particularly preferably from 1 to 5% by weight, in this embodiment of the invention. , in each case based on the total weight of the solution. The temperature at which the contacting takes place is usually in the range from 5 to 90 ° C., preferably from 15 to 50 ° C., particularly preferably from 18 to 30 ° C. The contacting of the protein fibers with the solution of the 2-cyanoacrylic esters is generally carried out over a period of 1 s to 60 min, preferably from 10 s to 30 min, more preferably from 1 min to 10 min.

Of the described embodiments of the method according to the invention, the contacting of the protein fibers with 2-cyanoacrylic acid ester is preferred, in which the fibers are exposed after or during their production to an atmosphere containing gaseous 2-cyanoacrylic acid esters.

The described coatings of the protein fibers with 2-cyanoacrylic acid ester are not limited to the fibers as such, but can also be carried out accordingly on the fibrous webs formed from the protein fibers.

The protein fibers which can be produced in the course of the process according to the invention have a diameter in the range from 10 nm to 10 .mu.m, preferably from 20 nm to 5 .mu.m, particularly preferably from 50 nm to 2 .mu.m. The length of the fibers depends on the purpose and is usually 50 microns to several kilometers.

By contacting the protein fibers or the fiber fabrics with 2-cyanoacrylic ester, monomeric 2-cyanoacrylate precipitates and is polymerized to poly-2-cyanoacrylates. The deposition is usually carried out in the form of an adhering to the protein fiber, particularly preferably complete, coating. The coating can also be partial, i. E. the surface of the protein fibers is not completely coated. Depending on the morphology of the fibers, it is also possible that the poly-2-cyanoacrylates formed are not or only partially adhere to the fiber in the form of a coating, but instead adhere to or in the fiber or on the fiber.

The coated protein fibers according to the invention can be prepared by the processes according to the invention. Preferred inventive coated protein fibers comprising protein fibers having a diameter in the range of 10 nm to 10 .mu.m, preferably from 20 nm to 5 .mu.m, more preferably from 50 nm to 2 .mu.m, and a coating of poly-2-cyanoacrylic acid ester adhering to the protein fibers the thickness of the coating is particularly preferably in the range from 1 to 200 nm, in particular from 10 to 100 nm.

The coated protein fibers according to the invention are particularly suitable for the production of fibrous sheets. The preparation of the fiber fabrics can be carried out either in the same process step as the production of protein fibers, for example as described above in the direct production of fiber fabrics by electrospinning, or in a separate process step known in the art and described in the literature following the preparation the coated protein fibers of the invention.

These fibrous sheets according to the invention can be used in numerous different fields of application, for example for the production of nonwovens or nonwovens, in particular nonwovens for use in cosmetic products, textiles, in particular household textiles, cleaning products, medical products (such as wound dressings or face masks), hygiene products such as diapers, incontinence products , Panty liners, sanitary napkins, tampons, skin and facial pads, and the like, cell culture carriers. The objects mentioned may consist wholly or only partially of the fiber fabrics, z. B in the form of coatings and / or components. The fibrous sheets according to the invention are preferably used as filters and medical carriers.
Particularly preferred fiber sheets are used as wound care and wound care products, wound dressings, plasters, tamponades, wound dressings, bandages, dressings. For example, they can be used to superficially cover minor wounds such as cuts or larger wounds such as diabetic wounds, ulcers such as pressure sores, surgical wounds, burns, eczema, and the like. For example, fibrous sheets according to the invention can be used in the treatment of bleeding or non-bleeding wounds or injuries in the area of the skin, the eyes, the ears, the nose, the oral cavity, the teeth, as well as in the interior of the body, such as surgery in the intestinal region (stomach, intestine, Liver, kidneys, urinary tract), thorax (heart, lungs), genital area, skull, musculature; in the treatment and aftercare of wounds related to the transplantation of tissues, vessels or organs.

The coated protein fibers and fiber fabrics produced by the process according to the invention have improved water or moisture resistance compared with known nanofibers, ie they have reduced solubility, swelling and / or change in mechanical properties and / or flow properties under water or moisture. or the fiber structure and / or an improved decomposition or degradation behavior. The use of organic solvents is largely avoided in the inventive process if possible. A further advantage of the coated protein fibers according to the invention is that polymerized 2-cyanoacrylic acid esters are harmless from a medical or toxicological point of view (see, for example, US Pat Handbook of Adhesive Technology, 2nd Ed., A. Pizzi, K. Mittal, Marcel Decker (Ed.), 2003, p. 809 ) and for many applications, for example in the medical sector.

The invention will be explained in more detail below with reference to examples.

Fig. 1

eine rasterelektronenmikroskopische Aufnahme der in Beispiel V-1 erhaltenen Proteinfasern (Protein S16, nicht kontaktiert, vor Wasserbehandlung)

Fig. 2

eine rasterelektronenmikroskopische Aufnahme der in Beispiel V-1 erhaltenen Proteinfasern (Protein S16, nicht kontaktiert, nach Wasserbehandlung)

Fig. 3

eine rasterelektronenmikroskopische Aufnahme der in Beispiel 1 erhaltenen Proteinfasern (Protein S16, kontaktiert mit Ethyl-2-cyanacrylat, vor Wasserbe- handlung)

Fig. 4

eine rasterelektronenmikroskopische Aufnahme der in Beispiel 1 erhaltenen Proteinfasern (Protein S16, kontaktiert mit Ethyl-2-cyanacrylat, nach Wasserbe- handlung)

Fig. 5

eine rasterelektronenmikroskopische Aufnahme der in Beispiel 2 erhaltenen Proteinfasern (Protein S16, kontaktiert mit einer Lösung von Ethyl-2- cyanacrylat, vor Wasserbehandlung)

Fig. 6

eine rasterelektronenmikroskopische Aufnahme der in Beispiel 2 erhaltenen Proteinfasern (Protein S16, kontaktiert mit einer Lösung von Ethyl-2- cyanacrylat, nach Wasserbehandlung)

Fig. 7

eine rasterelektronenmikroskopische Aufnahme der in Beispiel V-3 erhaltenen Proteinfasern (Protein R16, nicht kontaktiert, vor Wasserbehandlung)

Fig. 8

eine rasterelektronenmikroskopische Aufnahme der in Beispiel V-3 erhaltenen Proteinfasern (Protein R16, nicht kontaktiert, nach Wasserbehandlung)

Fig. 9

eine rasterelektronenmikroskopische Aufnahme der in Beispiel 3 erhaltenen Proteinfasern (Protein R16, kontaktiert mit Ethyl-2-cyanacrylat, vor Wasserbe- handlung)

Fig. 10

eine rasterelektronenmikroskopische Aufnahme der in Beispiel 3 erhaltenen Proteinfasern (Protein R16, kontaktiert mit Ethyl-2-cyanacrylat, nach Wasserbe- handlung)

Fig. 11 A-D

Photographische Widergabe der R16-Proteinfasern, wie sie in Vergleichs- beispiel V-4a und Beispielen 4 b-d nach 24-stündiger Inkubation im Protei- nase K enthaltenden Puffer anfielen (Fig. 11A: nicht mit Ethyl-2- cyanacrylat kontaktierte R16-Proteinfasern; Fig. 11 B: 20 Sekunden mit Ethyl-2-cyanacrylat behandelte R16-Proteinfasern; Fig. 11 C: 60 Sekunden mit Ethyl-2-cyanacrylat behandelte R16-Proteinfasern; Fig. 11 D: 120 Se- kunden mit Ethyl-2-cyanacrylat behandelte R16-Proteinfasern)

Fig. 12

Absorptionsphotometrische Bestimmung der Proteinfaser-Abbauprodukte in den nach enzymatischem Abbau gemäß Beispielen V-4a und 4 b-d er- haltenen Überständen

Show it:

Fig. 1

a scanning electron micrograph of the protein fibers obtained in Example V-1 (protein S16, not contacted, before water treatment)

Fig. 2

a scanning electron micrograph of the protein fibers obtained in Example V-1 (protein S16, not contacted, after water treatment)

Fig. 3

a scanning electron micrograph of the protein fibers obtained in Example 1 (protein S16, contacted with ethyl 2-cyanoacrylate, before water treatment)

Fig. 4

a scanning electron micrograph of the protein fibers obtained in Example 1 (protein S16, contacted with ethyl 2-cyanoacrylate, after water treatment)

Fig. 5

a scanning electron micrograph of the protein fibers obtained in Example 2 (protein S16, contacted with a solution of ethyl 2-cyanoacrylate, before water treatment)

Fig. 6

a scanning electron micrograph of the protein fibers obtained in Example 2 (protein S16, contacted with a solution of ethyl 2-cyanoacrylate, after water treatment)

Fig. 7

a scanning electron micrograph of the protein fibers obtained in Example V-3 (protein R16, not contacted, before water treatment)

Fig. 8

a scanning electron micrograph of the protein fibers obtained in Example V-3 (protein R16, not contacted, after water treatment)

Fig. 9

a scanning electron micrograph of the protein fibers obtained in Example 3 (protein R16, contacted with ethyl 2-cyanoacrylate, before water treatment)

Fig. 10

a scanning electron micrograph of the protein fibers obtained in Example 3 (protein R16, contacted with ethyl 2-cyanoacrylate, after water treatment)

Fig. 11 AD

Photographic reproduction of the R16 protein fibers, as obtained in Comparative Example V-4a and Examples 4 bd after incubation in the proteinase K incubation for 24 hours ( Fig. 11A non-ethyl cyanoacrylate contacted R16 protein fibers; Fig. 11 B: ethyl 2-cyanoacrylate treated R16 protein fibers for 20 seconds; Fig. 11 C: Ethyl 2-cyanoacrylate-treated R16 protein fibers for 60 seconds; Fig. 11 D: 120 seconds with ethyl 2-cyanoacrylate treated R16 protein fibers)

Fig. 12

Absorption photometric determination of the protein fiber degradation products in the supernatants obtained after enzymatic degradation according to Examples V-4a and 4 bd

Examples: Noninventive examples which serve for comparison are marked with the preceding "V-". Protein fiber production:

The protein fibers described in the Examples were prepared by the following either tip-based or roller-based electrospinning techniques. Further specific details are given in the individual examples.

Tip-based electrospinning process:

To prepare the protein fibers by the tip-based electrospinning method, an apparatus has been used in which a capillary nozzle connected to one pole of a power source is used to atomize the protein dispersion or solution. Opposite the outlet of the capillary nozzle, a square counterelectrode connected to the other pole of the voltage source is arranged at a distance of about 20 cm, which acts as a collector for the fibers formed. During operation of the device, a voltage between 15 kV and 35 kV is set at the electrodes and the protein dispersion or solution is discharged through the capillary nozzle under a low pressure. Due to the electrostatic charge of the protein dispersion or solution due to the strong electric field of 0.9 to 2 kV / cm, a material flow directed towards the counterelectrode solidifies on the way to the counterelectrode with fiber formation, resulting in fibers on the counterelectrode with diameters in the micron and nanometer range.

Roller-based electrospinning process:

To prepare the protein fibers by the roll-based electrospinning method, an apparatus has been used in which a serrated roller connected as an electrode rotates in a protein dispersion or solution container (Nanospider Elmarco apparatus). The counter electrode is located above the roller. The protein dispersion or solution got into the strong electric field with each rotation of the roll and several streams of material were formed. The fibers were deposited on a resting carrier fleece.

Contacting with 2-cyanoacrylates:

The coated protein fibers according to the invention were contacted either with gaseous or dissolved in a solvent 2-Cyanacrylsäureestern. Further specific details are given in the individual examples.

Test of water or moisture resistance:

The protein fibers and coated protein fibers according to the invention prepared according to the examples and comparative examples were introduced into quiescent water at a temperature of 23 ° C. for a period of 24 hours to determine the resistance to water or moisture. After subsequent drying, electron or light micrographs were taken. By comparing them visually with corresponding electron or light micrographs of the identical protein fiber samples prior to water treatment, it can be seen whether and how much the fibers, their morphology or microstructure has changed under the action of water, i. how water- or moisture-resistant the fibers are.

Example V-1 and 1: The protein used was a protein S16.

S16 protein microbeads were used to prepare spinnable S16 protein solutions. These can be like in WO 2008/155304 be prepared described. Alternatively, a production may be carried out as follows.
The production of the S16 protein is carried out biotechnologically using plasmid-containing Escherichia coli expression strains (plasmid vectors or E. coli production strains were used which contained coding DNA sequences for the S16 protein). Design and cloning of the S16 protein are analogous to Hümmerich et al. (Biochemistry 43, 2004, 13604-13012 ) feasible. In contrast to the method described there, S16 protein was produced in E. coli strain BL21 Gold (DE3) (Stratagene). Cultivation is carried out in Techfors fermenters (Infors HAT, Switzerland) using a minimal medium and fed-batch techniques. Minimal medium: 2.5 g / l citric acid monohydrate 4 g / l glycerol 12.5 g / l potassium dihydrogen phosphate 6.25 g / l ammonium sulfate 1.88 g / l of magnesium sulfate heptahydrate 0.13 g / l calcium chloride dihydrate 15.5 ml / l of trace element solution (40 g / l citric acid monohydrate; 11 g / l zinc (II) sulphate heptahydrate; 8.5 g / l diammonium iron (II) sulphate heptahydrate; 3 g / l manganese (II) sulphate monohydrate; 0.8 g / l copper (II) sulphate pentahydrate; 0.25 g / l cobalt (II) sulphate hepta hydrate) 3 ml / l vitamin solution (6.3 mg / ml thiamine hydrochloride, 0.67 mg / ml vitamin B12) pH 6.3 Feed Solution: 790 g / l glycerol 6.9 g / l citric acid monohydrate 13.6 g / l sodium sulfate 1.05 g / l diammonium iron (II) sulphate heptahydrate 13 mg / l thiamine hydrochloride The cells were grown at 37 ° C to an OD600 of 100, followed by the induction of protein expression with 0.1 mM isopropyl β-D-1-thiogalactopyranoside (IPTG). At the end of the fermentation (8 to 12 hours after induction), the cultures were harvested. The main part of the protein was in "inclusion bodies".

After cell harvesting, the pellet was resuspended in 20 mM 3 - (- N-morpholino) propanesulfonic acid (MOPS) pH 7.0 (5 L buffer per kilogram wet weight). Subsequently, cell digestion was carried out using a Micofluidizer M-110EH (Microfluidics, US) at pressures of 1200 to 1300 bar. After sedimentation, the pellet contained after digestion in addition to the "inclusion bodies" cell debris and membrane components, which were removed by two washing steps. In a first washing step, the pellet was resuspended in 2.5 volumes Tris buffer (50 mM Tris / HCl, 0.1% Triton X-100, pH 8.0), and then the remaining solid was sedimented by centrifugation. A second wash was performed using Tris buffer (50 mM Tris / HCl, 5 mM EDTA, pH 8.0). The pellet, once again obtained after sedimentation, was almost free of membrane and cell debris.

The purified "inclusion bodies" were dissolved in guanidinium thiocyanate (Roth, Germany), 1.6 g guanidinium thiocyanate being added per 1 g pellet (wet mass). The inclusion bodies were dissolved with gentle heating (50 ° C.) with stirring. To separate off any non-soluble constituents, a centrifugation was then carried out. In order to obtain an aqueous S16 protein solution, dialysis was then carried out for 16 hours against 5 mM potassium phosphate buffer (pH 8.0) (dilution factor of dialysis: 200).

Contaminating E. coli proteins formed aggregates on dialysis, which could be separated by centrifugation. The resulting protein solution had a purity of ~95% S16 protein.

To prepare a storable form of the protein, the aqueous protein solution was processed by precipitation to protein microbeads. To prepare S16 protein microbeads, the aqueous S16 protein solution was admixed with 0.25 parts by volume of a 4 molar ammonium sulfate solution. Under the action of the ammonium sulfate, the protein monomers assemble into spherical structures, which are referred to here as microbeads. The microbeads were separated by centrifugation, washed three times with distilled water and then freeze-dried.

For the production of a spinnable solution, 10 parts by weight of S16 protein microbeads were dissolved in 90 parts by weight of anhydrous formic acid (purity 99.9% by weight).

This protein solution was processed into protein fibers by the roll-based electrospinning method, with the following process parameters chosen: Tension: 70-82 kV Electrode gap: 25 cm relative humidity: 22% Temperature: 24 ° C

The protein fibers thus obtained (Example V-1) are in Fig. 1 shown.

A part of the protein fibers obtained in Example V-1 was tested for water and moisture resistance as described above. Fig. 2 shows these protein fibers after the test.

Another portion of the protein fibers obtained in Example V-1 was contacted with ethyl 2-cyanoacrylate as follows:

0.2 g of ethyl-2-cyanoacrylate from Sigma Aldrich were placed in a glass vial with a volume of 10 ml and then brought into the gas phase at a temperature of 150-170 ° C, ie evaporated. Subsequently, the substrate with the protein fibers obtained in Example V-1 was left in this for a period of 1 minute Gas phase contacted. The coated protein fibers (Example 1) thus obtained are described in Fig. 3 shown.

A part of the coated protein fibers obtained in Example 1 was tested for water and moisture resistance as described above. Fig. 4 shows these coated protein fibers after the test.

Result: While the non-2-cyanoacrylate-contacted protein fibers changed significantly in their fiber structure, the fiber structure of the 2-cyanoacrylate contacted coated protein fibers remained largely intact.

Example V-2 and 2:

The protein S16 described in Examples V-1 and 1 was used as the protein and processed into protein fibers in the manner also described in Examples V-1 and 1.

The protein fibers thus obtained were contacted with ethyl 2-cyanoacrylate as follows:

0.1 g of ethyl 2-cyanoacrylate was dissolved in 9.9 g of toluene. Subsequently, the substrate was contacted with the protein fibers obtained in Example 2 for a period of 10 seconds with this toluenic ethyl-2-cyanoacrylate solution and finally dried. The coated protein fibers (Example 2) thus obtained are described in Fig. 5 shown.

A part of the coated protein fibers obtained in Example 2 was tested for water and moisture resistance as described above. Fig. 6 shows these coated protein fibers after the test.

Result: While the non-2-cyanoacrylate-contacted protein fibers changed significantly in their fiber structure, the fiber structure of the 2-cyanoacrylate contacted coated protein fibers remained largely intact.

Example V-3 and 3: The protein used was a protein R16.

The preparation of spinnable R16 protein solutions was carried out analogously to the preparation of the S16 protein solutions described in Examples V-1 and 1.

This R16 protein solution was processed into protein fibers by the roll-based electrospinning method, with the following process parameters chosen: Tension: 82 kV Electrode gap: 25 cm relative humidity: 33% Temperature: 24 ° C

The protein fibers thus obtained (Example V-3) are described in Fig. 7 shown.

A part of the protein fibers obtained in Example V-3 was tested for water and moisture resistance as described above. Fig. 8 shows these protein fibers after the test.

Another portion of the protein fibers obtained in Example V-3 was contacted with ethyl 2-cyanoacrylate as follows:

0.2 g of ethyl-2-cyanoacrylate from Sigma Aldrich were placed in a glass vial with a volume of 10 ml and then brought into the gas phase at a temperature of 150-170 ° C, ie evaporated. Subsequently, the substrate was contacted with the protein fibers obtained in Example V-3 for a period of 1 minute in this gas phase. The coated protein fibers (Example 3) thus obtained are described in Fig. 9 shown.

A part of the coated protein fibers obtained in Example 3 was tested for water and moisture resistance as described above. Fig. 10 shows these coated protein fibers after the test.

Result: While the fiber structure of the non-2-cyanoacrylate-contacted protein fibers was completely destroyed, the fiber structure of the 2-cyanoacrylate-contacted coated protein fibers remained largely intact.

Example V-4a and 4b-d: Enzymatic degradation of protein fibers

R16 protein fibers were prepared as described in Example V-3.

Subsequently, some of these protein fibers were contacted with ethyl 2-cyanoacrylate as described in Example 3, but with three separate batches having contact times of 20 seconds, 60 seconds and 120 seconds, respectively.

Subsequently, of the protein fibers not contacted with ethyl 2-cyanoacrylate (Example V-4a) and each of the protein fiber structures obtained in the three ethyl 2-cyanoacrylate contacted approaches (Examples 4 bd) were each 2-3 cm ² pieces in FIG , Transferred 5 ml Eppendorf tubes and mixed with 1 ml of 5 mM potassium phosphate buffer. The potassium phosphate buffer contained 1.2 AU proteinase K. (Quiagen, Germany). The mixtures were incubated at 23 ° C. and 700 rpm in a thermomixer (Eppendorf).
After defined time intervals, in each case 20 .mu.l of sample were taken from the batch according to Example V-4a and the three batches according to Examples 4 bd and any solid matter collected was centrifuged off. By absorption photometric measurement (280 nm) on the supernatant (ie on the obtained after centrifugation clear liquid phase), the proportion of protein degradation products (peptides) was then determined.

The R16 protein fibers not contacted with ethyl 2-cyanoacrylate (Example V-4a) showed clearly visible degradation or dissolution phenomena in the proteinase K mixtures even after 120 min. After 24 h, the non-ethyl 2-cyanoacrylate contacted R16 protein fibers (Example V-4a) were visually almost completely degraded ( Figure 11A ). The ethyl 2-cyanoacrylate contacted R16 protein fibers (Examples 4c and d) were still intact in the proteinase K inserts even after 24 h and had not dissolved ( FIGS. 11C and D ), or in the case of the 20 s ethyl 2-cyanoacrylate contacted R16 protein fibers (Example 4 b) showed relatively low signs of degradation after 24 h ( FIG. 11B ).

The abovementioned absorption photometric determination of the supernatants also showed that ethyl-2-cyanoacrylate-contacted R16 protein fibers are degraded much more slowly by proteinase K than non-contacted ones. Supernatants from the proteinase K-containing mixtures according to Examples 4 bd showed significantly lower absorption in the course of time considered for degradation kinetics up to 480 min than the supernatant obtained according to Example V-4a with proteinase K of the non-ethyl 2-cyanoacrylate contacted R16 protein fibers ( Fig. 12 ). Furthermore, it was clearly demonstrated that the proteolytic degradation of the ethyl 2-cyanoacrylate contacted protein fibers according to Examples 4 bd depends on the duration of the contacting. Thus, a lower absorption and thus a reduced protein fiber degradation was observed over the entire time period considered in the 120 seconds with ethyl-2-cyanoacrylate-contacted protein fibers than in the 60 or 20 seconds contacted protein fibers ( Fig. 12 ).

The examples show that the coated protein fibers and fiber fabrics produced by the process according to the invention have improved water or moisture resistance compared to known nanofibers, ie they have a reduced solubility, swelling and / or change in the mechanical properties under water or moisture. or the flow properties and / or the fiber structure and / or an improved decomposition or degradation behavior.

Claims (12)

Process for the production of coated protein fibers, in which from a solution or dispersion of a protein fibers with a diameter in the range of 10 nm to 10 microns are produced, characterized in that the fibers are contacted during or after their preparation with a 2-cyanoacrylic acid ester. Process according to Claim 1, characterized in that the fibers are produced by an electrospinning or centrifuge spinning process. Method according to one of claims 1 to 2, characterized in that the protein is a water-soluble or water-swellable protein. Method according to one of claims 1 to 3, characterized in that the active ingredient is added to the solution or dispersion of the protein, which specifically develops a specific action on a living organism. Method according to one of claims 1 to 4, characterized in that the fibers are prepared from a solution of the protein in an organic solvent. Method according to one of claims 1 to 4, characterized in that the fibers are produced from a dispersion of the protein. Method according to one of claims 1 to 6, characterized in that the protein fibers are contacted during or after their preparation with gaseous 2-cyanoacrylic acid ester. Coated protein fibers producible according to one of the methods according to claims 1 to 7. Use of the coated protein fibers according to claim 8 for the production of fibrous sheets. Fibrous sheet comprising coated protein fibers according to claim 8. Use of fibrous sheets according to claim 10 for the production of nonwovens, cosmetic products, medical devices, hygiene products, cell culture carriers. Use of 2-cyanoacrylates to influence the degradation behavior of protein fibers.

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