Synthesis and micro-/nanostructuring of surface-attached crosslinked antimicrobial and/or antibiofouling polymer networks

Abstract

The present invention relates to substrates comprising a crosslinked network of covalently attached antimicrobial and/or antibiofouling polymers. The crosslinked network of antimicrobial and/or antibiofouling polymers acts highly efficiently against pathogens, e.g. bacteria and fungi. Both the antimicrobial and the antibiofouling cross-linked polymer networks are preferably better resistant to mechanical damage than simple surface-immobilized polymer monolayers. The antimicrobial and/or antibiofouling polymers of the crosslinked network are preferably obtained by ring opening metathesis polymerization (ROMP) and exhibit a molecular weight of preferably more than 30,000 or even 100,000 g mol.sup.1. The crosslinked network of antimicrobial and/or antibiofouling polymers is preferably covalently attached to the surface of a substrate, e.g. an implant, a medical device, medical equipment or a (tissue-supporting) biomaterial, etc. The present invention is also directed to uses of crosslinked networks of antimicrobial and/or antibiofouling polymers as defined herein, e.g. for coating a surface of a substrate, and to methods therefore.

Claims

1. Substrate comprising covalently attached to the surface of the substrate a crosslinked network of antimicrobial or antibiofouling polymers, wherein covalent attachment to the surface of the substrate and crosslinking of the network has been carried out simultaneously, the antimicrobial or antibiofouling polymers comprising a molecular weight of more than 30,000 g mol.sup.1 and as a repeat unit a) for the antimicrobial polymer, a structure according to at least one of the following formulae: ##STR00032## or a combination thereof; wherein A is selected independent from each other from any of O, S, or NH; R is selected from (CH.sub.2).sub.pN.sup.+(R.sub.6).sub.3 wherein: R.sub.6 is selected from H or an uncharged hydrophobic or hydrophilic group; and p is an integer selected from a range of 1 to 10; R.sub.1 is a hydrophilic group and carries a positive charge; R.sub.2 is a hydrophobic group; X is selected from any of CH.sub.2, CH.sub.2CH.sub.2, O, S, NR.sub.3, PR.sub.3, or CC(R.sub.4R.sub.5); wherein R.sub.3, R.sub.4, and/or R.sub.5 is selected independent from each other from H or a hydrophobic or hydrophilic group; n is an integer selected from a range of 10 to 2500; m is an integer selected from a range of 0 to 20; and wherein a net charge of all positive and negative charges per repeat unit of any of formulae (Ia), (Ib), (Ic), (Id) and/or (Ie) in their deprotected form is greater than 0; b) for the antibiofouling polymer, a structure according to at least one of the following: ##STR00033## or a combination thereof; wherein A is selected independent from each other from any of O, S, or NH; W is selected from any of (CH.sub.2).sub.qN.sup.+(R.sub.11R.sub.12R.sub.13), or (CH.sub.2).sub.qOPO.sub.2.sup.(CH.sub.2).sub.rN.sup.+(R.sub.14R.sub.15R.sub.16), wherein R.sub.11, R.sub.12 is independent from each other an uncharged hydrophobic or hydrophilic group, and R.sub.13 is selected from any of (CH.sub.2).sub.rCO.sub.2.sup., (CH.sub.2).sub.rSO.sub.3.sup., (CH.sub.2).sub.rOSO.sub.3.sup., (CH.sub.2).sub.rOPO.sub.3.sup., (CH.sub.2).sub.rPO.sub.3.sup., R.sub.14, R.sub.15, R.sub.16, is independent from each other H or a hydrophobic or hydrophilic group, q, r are integers, each independently selected from a range of 1 to 10; X is selected from any of CH.sub.2; CH.sub.2CH.sub.2; O; S; NR.sub.9; NR.sub.10; NW; PR.sub.9; PR.sub.10; PW; N.sup.+(R.sub.9R.sub.9); N.sup.+(R.sub.9R.sub.10); N.sup.+(R.sub.9W); N.sup.+(R.sub.10W); N.sup.+(R.sub.10R.sub.10); N.sup.+(WW); CCH.sub.2; CC(R.sub.9R.sub.9); CC(R.sub.9R.sub.10), CC(R.sub.9W); CC(R.sub.10W), CC(R.sub.10R.sub.10), CC(WW), wherein: R.sub.9 is selected independent from each other from a hydrophobic or hydrophilic group, R.sub.10 is selected independent from each other from any of (CH.sub.2).sub.rCO.sub.2.sup., (CH.sub.2).sub.rSO.sub.3.sup., (CH.sub.2).sub.rOSO.sub.3.sup., (CH.sub.2).sub.rPO.sub.3.sup., (CH.sub.2).sub.rPO.sub.3.sup.; and r is an integer selected from a range of 1 to 10; Y is selected from W or any hydrophilic or hydrophobic group Z is selected from W or any hydrophilic or hydrophobic group n is an integer selected from a range of 10 to 2500; m is an integer selected from a range of 0 to 20; and wherein a net charge of all positive and negative charges per repeat unit of any of formulae (IIa), (IIb), (IIc), (IId) and/or (IIe) in their deprotected form is 0; wherein the surface of the substrate is selected from an inorganic surface, or an organic surface.

2. Substrate according to claim 1, wherein the antimicrobial or antibiofouling polymers of the network are crosslinked using a di-, tri-, tetra- or higher functional crosslinker.

3. Substrate according to claim 2, wherein the antimicrobial or antibiofouling polymers of the network are crosslinked using a di-, tri-, tetra- or higher functional thiol crosslinker.

4. Substrate according to claim 1, wherein the antimicrobial or antibiofouling polymers of the network are further modified via grafting onto with an antimicrobial or antibiofouling polymer selected from ##STR00034## wherein A is selected independent from each other from any of O, S, or NH; R is selected from (CH.sub.2).sub.p N.sup.+(R.sub.6).sub.3 wherein: R.sub.6 is selected from H or an uncharged hydrophobic or hydrophilic group; and p is an integer selected from a range of 1 to 10; R.sub.1 is a hydrophilic group and carries a positive charge; R.sub.2 is a hydrophobic group; X is selected from any of CH.sub.2, CH.sub.2CH.sub.2, O, S, NR.sub.3, PR.sub.3, or CC(R.sub.4R.sub.5); wherein R.sub.3, R.sub.4, and/or R.sub.5 is selected independent from each other from H or a hydrophobic or hydrophilic group; n is an integer selected from a range of 10 to 2500; m is an integer selected from a range of 0 to 20; and wherein a net charge of all positive and negative charges per repeat unit of any of formulae (Ia), (Ib), (Ic), (Id) and/or (Ie) in their deprotected form is greater than 0; ##STR00035## wherein A is selected independent from each other from any of O, S, or NH; W is selected from any of (CH.sub.2).sub.qN.sup.+(R.sub.11R.sub.12R.sub.13), or (CH.sub.2).sub.qOPO.sub.2.sup.(CH.sub.2).sub.rN.sup.+(R.sub.14R.sub.15R.sub.16), wherein R.sub.11, R.sub.12 is independent from each other an uncharged hydrophobic or hydrophilic group, and R.sub.13 is selected from any of (CH.sub.2).sub.rCO.sub.2.sup., (CH.sub.2).sub.rSO.sub.3.sup., (CH.sub.2).sub.rOSO.sub.3.sup., (CH.sub.2).sub.rOPO.sub.3.sup., (CH.sub.2).sub.rPO.sub.3.sup., R.sub.14, R.sub.15, R.sub.16, is independent from each other H or a hydrophobic or hydrophilic group, q, r are integers, each independently selected from a range of 1 to 10; X is selected from any of CH.sub.2; CH.sub.2CH.sub.2; O; S; NR.sub.9; NR.sub.10; NW; PR.sub.9; PR.sub.10; PW; N.sup.+(R.sub.9R.sub.9); N.sup.+(R.sub.9R.sub.10); N.sup.+(R.sub.9W); N.sup.+(R.sub.10W); N.sup.+(R.sub.10R.sub.10); N.sup.+(WW); CCH.sub.2; CC(R.sub.9R.sub.9); CC(R.sub.9R.sub.10), CC(R.sub.9W); CC(R.sub.10W), CC(R.sub.10R.sub.10), CC(WW), wherein: R.sub.9 is selected independent from each other from a hydrophobic or hydrophilic group, R.sub.10 is selected independent from each other from any of (CH.sub.2).sub.rCO.sub.2.sup.; (CH.sub.2).sub.rSO.sub.3.sup., (CH.sub.2).sub.rOSO.sub.3.sup., (CH.sub.2).sub.rPO.sub.3.sup., (CH.sub.2).sub.rPO.sub.3.sup.; and r is an integer selected from a range of 1 to 10; Y is selected from W or any hydrophilic or hydrophobic group Z is selected from W or any hydrophilic or hydrophobic group n is an integer selected from a range of 10 to 2500; m is an integer selected from a range of 0 to 20; and wherein a net charge of all positive and negative charges per repeat unit of any of formulae (IIa), (IIb), (IIc), (IId) and/or (IIe) in their deprotected form is 0.

5. Substrate according to claim 1, wherein a structure of the network of antimicrobial or antibiofouling polymers comprises pores having a width of about 50-500 nm.

6. Substrate according to claim 1, wherein the crosslinked network formed by the antimicrobial or antibiofouling polymers comprises a thickness of about 10 nm to about 1000 m.

7. Substrate according to claim 1, wherein the crosslinked network formed by the antimicrobial or antibiofouling polymers comprises predefined breaking points.

8. Substrate according to claim 1, wherein the crosslinked network of antimicrobial or antibiofouling polymers is micro- or nano-structured according to a defined pattern.

9. Substrate according to claim 1, wherein the surface of the substrate is a polymeric surface.

10. Substrate comprising covalently attached a cross-linked network of antibiofouling polyzwitterionic polymers, the antibiofouling polymers of the network comprising a molecular weight of more than 10,000 g mol.sup.1 and as a repeat unit a structure according to at least one formula (IIa): ##STR00036## wherein A is selected from O; X is selected from O; Y is selected from the group ##STR00037## wherein p is an integer selected from a range selected from 1-10; B is O.sup. or OH; n is an integer selected from a range of 10 to 2500; wherein a net charge of all positive and negative charges per repeat unit of formula (IIa) in its deprotected form is 0.

11. Substrate according to claim 10, wherein the antibiofouling polymer has as a repeat unit a structure according to the following formula: ##STR00038##

Description

FIGURES

(1) The FIGURES shown in the following are merely illustrative and shall describe the present invention in a further way. These FIGURES shall not be construed to limit the present invention thereto.

(2) FIG. 1: shows micrographs of the lithographically structured film as prepared according to Example 4.

(3) FIG. 2: shows an exemplary pretreated surface which includes benzophenone as a photocrosslinker, and an exemplary thiol-crosslinker as a tetrafunctional crosslinker, according to one embodiment.

(4) FIG. 3: shows a general scheme I of a concept for the preparation of antimicrobial or antibiofouling polymers, according to one embodiment.

EXAMPLES

(5) The examples shown in the following are merely illustrative and shall describe the present invention in a further way. These examples shall not be construed to limit the present invention thereto.

(6) General:

(7) All chemicals were obtained as reagent grade from Aldrich, Fluka or Acros and used as received. HPLC grade solvents were purchased from Aldrich or Acros and used as received. THF (HPLC grade, Fisher Scientific) was distilled from sodium/benzophenone under nitrogen. Dichloromethane (HPLC grade, Fisher Scientific) was distilled from CaH.sub.2 under nitrogen. Gel permeation chromatography (DMF/0.01 M LiCl, calibrated with polystyrene standards) was measured on a PSS GRAM column (PSS, Mainz, Germany). NMR spectra were recorded on a Bruker 250 MHz spectrometer (Bruker, Madison, Wis., USA).

(8) Synthesis of a Variation of Grubbs 3.sup.rd Generation Catalyst:

(9) A variation of Grubbs 3.sup.rd generation catalyst (original Grubbs 3.sup.rd generation catalyst=Dichloro-di(3-bromopyridino)-N,N-Dimesitylenoimidazolino-RuCHPh; G3) was specifically synthesized similar as described previously by Grubbs and colleagues (see J. A. Love, J. P. Morgan, T. M. Trnka, R. H. Grubbs, Angewandte Chemie International Edition 2002, 41, 4035-4037). For this variation of Grubbs 3.sup.rd generation catalyst pyridine was taken instead of 3-bromo pyridine to yield the corresponding catalyst with two pyridine ligands.

(10) Silanization of a Silicon Wafer as Substrate for Polymer Immobilization:

(11) The crosslinking agent 4-(3-triethoxysilyl)propoxybenzophenone (=3EBP-silane) was synthesized as described in the literature (Gianelli et al., Soft Matter 2008, 4, 1443). A solution of 3EBP-silane (20 mg mL.sup.1 in toluene) was spin coated on a (52525) m thick one-side-polished 100 mm standard Si (CZ) wafer ([100] orientation, 1000 rpm, 120 s). The wafer was cured for 30 min at 100 C. on a preheated hot plate, washed with toluene and dried under a continuous nitrogen flow.

Example 1

Surface-Bound Antibiofouling Polymer (Monolayer)

(12) 1.1Monomer Synthesis:

(13) The monomer was obtained from exo-7-oxabicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid anhydride (5 g, 30.0 mmol), which was dissolved in CH.sub.2Cl.sub.2. 1.1 eq of N-(tert-butoxycarbonyl)ethanolamine (5.32 g, 33 mmol) and 10 mol % 4-dimethylaminopyridine (DMAP) were added. After stirring over night, the solution was concentrated. Ether was added to precipitate DMAP salt, and the solution was filtered. This step was repeated until no more DMAP salts precipitated and the pure zwitterion was obtained. The isolated yield was 60-70%.

(14) ##STR00022##

(15) .sup.1H-NMR (300 MHz, CDCl.sub.3): =1.41 (s, 9H, H9), 2.83 (m, 2H, H3 & H3), 3.37 (m, 2H, H6), 4.18 (m, 2H, H5), 5.24 & 5.32 (s, 2H, H2 & H2), 6.46 (m, 2H, H1 & H1), 7.5-8.2 (br s, 1H, OH). HR-MS (FAB): calc. 299.31 g/mol. found 272.1 g/mol (M t-Butyl).

(16) 1.2Polymer Synthesis:

(17) The monomer was dissolved in 4 mL dichloromethane, and the respective amount of G3-catalyst (see Table 1 below for details) was dissolved in 1 mL dichloromethane tetrahydrofurane each and subject to three freeze-thaw cycles. The catalyst was added in one shot to the vigorously stirring monomer solution at room temperature under N.sub.2. After 30 min, the living polymer chain was end-capped with an excess of ethylvinyl ether (1 mL). The solution was allowed to stir for 2 hours. After evaporation of the solvent and drying, an aliquot of each polymer was taken for GPC and NMR analysis. The product was a brown solid. GPC was performed in THF (polystyrene standards).

(18) ##STR00023##

(19) .sup.1H-NMR (300 MHz, THF-d.sub.8): 1.40 (s, 9H, H9), 3.10 (br m, 2H, H3 & H3), 3.28 (br m, 2H, H6), 4.07 (br m, 2H, H5), 4.71 (m, 1H, H2 trans), 5.09 (br s, 1H, H2 cis), 5.59 (br s, 1H, NH), 5.91 (br m, 1H, H1 cis) and 6.12 (br m, 1H, H1 trans).

(20) TABLE-US-00001 TABLE 1 Experimental parameters for the polymer synthesis M.sub.n Target M.sub.Monomer n.sub.Monomer m.sub.Monomer M.sub.Catalyst n.sub.Catalyst m.sub.Catalyst Sample N.sub.repeat units g mol.sup.1 g mol.sup.1 mmol mg g mol.sup.1 mmol mg 1a 306 100.000 327.3 1.53 500 726.6 0.0051 3.7 1b 612 200.000 0.010 1.9
1.3Polymer Deprotection for Solution Testing:

(21) The crude polymer was dissolved in 2 mL dichloromethane. An excess of TFA (2 mL, 2.97 g, 26.0 mmol) was added and the solution was stirred at room temperature over night. The excess acid was removed by azeotropic distillation with dichloromethane (215 mL) and methanol (115 mL) at the rotary evaporator. The samples were dried in vacuo over night and dissolved in 30 mL Milli-Q water or DMSO depending on solubility. They were dialyzed against Milli-Q water until the conductivity of the water was 0.1 S after 12 h of dialysis (total dialysis time 4-7 days). The hydrolyzed polymer was then freeze dried.

(22) ##STR00024##

(23) .sup.1H-NMR (300 MHz, DMSO-d.sub.6+D.sub.2O): 3.02 (br m, 2H, H3 & H3), 3.21 (br m, 2H, H6), 3.70 (br m, 2H, H5), 4.28 (m, 1H, H2 trans), 4.42 (br s, 1H, H2 cis), 5.60 (br m, 1H, H1 cis) and 5.83 (br m, 1H, H1 trans).

(24) 1.4Immobilization of the Antibiofouling Polymer on the Si-Wafer (Silanized as Described Above) as a Monolayer:

(25) i. 50 mg of polymer 1 was dissolved in 2.5 mL of THF yielding a 20 mg mL.sup.1 solution. 0.5 mL of polymer solution was filtered through a 0.45 m syringe filter and added dropwise to the center of the silanized silicon wafer. It was then spin-coated at 3000 rpm for 120 sec, yielding a 705 nm thick polymer film. ii. The polymer-coated silicon wafer was covalently cross-linked at a wavelength of 250 nm for 30 min using a Strata-linker device (Stratagene). The coated silicon wafer was then rinsed with THF (3) to remove the excess polymer, and dried under N.sub.2. iii. The polymer-coated silicon wafer was immersed into a 4 M solution of HCl in dioxane over night. It was the rinsed with isopropanol and ethanol (2) to remove reaction byproducts, and subject to further characterization.
1.5Deprotection of Polymer Monolayer.

(26) The functionalized wafer was immersed into 4 M HCl in dioxane for 4-12 hours. It was then washed with diethyl ether, dichloromethane and ethanol and blow dried under a stream of nitrogen.

(27) Characterization:

(28) Film thickness (measured by Ellipsometry): before deprotection: 101 nm after deprotection: 41 nm Contact angle (static/advancing/receding): before deprotection: 712/732/142 after deprotection: 542/582/72

Example 2

Surface-Bound Antibiofouling and Antimicrobial Polymer Network

(29) 2.1Polymer Synthesis:

(30) All solvents and reagents were obtained in p.a. or reagent quality from the usual suppliers, unless otherwise specified. The crosslinking agent 3EBP-silane was synthesized as described in the literature (see Example 1) The monomers 2 (R=Methyl to Hexyl or H) were synthesized as described previously (see Lienkamp et al., Journal of the American Chemical Society 2008, 130 (30), 9836-9843; Lienkamp et al., Chemistrya European Journal 2009, 15 (44), 11784-11800). The antibiofouling polymer was synthesized as described in example 1. The antimicrobial polymer was synthesized as described in the literature polymer was synthesized as described in the literature (see Lienkamp et al., Journal of the American Chemical Society 2008, 130 (30), 9836-9843).

(31) ##STR00025##

(32) A typical polymerization was performed as follows, where all manipulations were performed under nitrogen using standard Schlenk technique.1 (R=Propyl, 500 mg, 1.35 mmol) was dissolved in 2 mL CH.sub.2Cl.sub.2. Grubbs third generation catalyst (G3, 3.6 mg, 5 mol) was dissolved in 2 mL CH.sub.2Cl.sub.2 in a second flask and added to the monomer solution. After 30 min, excess ethylvinyl ether (1 mL) was added. The mixture was stirred for 2 hours. The solvent was then evaporated under reduced pressure. The NMR signals of the polymer matched those in the literature. GPC analysis (PSS SDV column, Chloroform, r.t., 1 mL/min) indicated that a polymer with a molecular weight of 120 000 g mol.sup.1 and a polydispersity of 1.24 was obtained.

(33) 2.2Surface-Bound Polymer Network Formation:

(34) A solution of polymer 3 (10 mg/ml), tetrathiol (0.04 mg/ml) and DMPAP (0.01 ml/ml) in a mixture of dichloromethan and toluene (1:1) was produced. This solution was spin-cast on a 3-EBP treated silicon wafer (see 0.3) by spin-coating at 3000 rpm for 2 minutes to yield a thin polymer film. The film was cross-linked at 250 nm for 30 min using a Stratalinker. It was then washed with dichloromethane to remove unattached polymer chains and dried over night under N.sub.2-flow. To activate the antimicrobial function, the film was immersed in HCl (4 M in dioxane) for 12 hours and washed twice with ethanol. It was then dried over night under N.sub.2-flow.

(35) Characterization:

(36) The surface-bound polymer networks in the protected and deprotected form were analyzed using ellipsometry to obtain the layer thickness, contact angle measurement, and atomic force microscopy.

(37) TABLE-US-00002 SMAMP Poly(zwitterion) protected deprotected protected deprotected Thickness nm 70 2 60 2 65 2 57 2 Contact static 88 3 56 2 72 2 54 2 angle advancing 90 2 59 2 73 2 59 2 receding 38 2 14 2 14 2 7 2
2.3Control Experiment with Low Molecular Weight Polymer.

(38) When a propyl homopolymer with a molecular weight of 50 000 g mol.sup.1 was treated similarly to example 2.2, the films obtained could be partially washed away with dichloromethane. This emphasizes the need for high molecular weight for making surface bound monolayers and networks.

Example 3

Self-Patterning Surface-Bound Antibiofouling and Antimicrobial Polymer Networks

(39) 3.1Cross-Linking Solutions:

(40) A propyl homopolymer with a molecular weight of 500 000 g mol.sup.1 was synthesized analogously to the description in example 2.1. Monomer 2 (R=Propyl; 1.33 g, 3.59 mmol) was dissolved in 30 mL CH.sub.2Cl.sub.2. In a second flask, a solution of Grubbs catalyst (4.7 mg, 6.5 mmol) dissolved in 3 mL CH.sub.2Cl.sub.2 was produced. This solution was added to the first flask. After 30 min, 1 mL ethylvinylether (0.75 g, 10.4 mmol) was added. The mixture was stirred over night. The product was dried under reduced pressure. The respective amount of this polymer was dissolved in the specified amount of dichloromethane; for the cross-linker solutions, the respective amount of 2,2-dimethoxy,2-phenyl-acetophenone (DMPAP), and pentaerythritoltetrakis(3-mercaptopropionate) (tetrathiol) were dissolved in the specified amount of dichloromethane. This yielded solutions 1-4, respectively.

(41) TABLE-US-00003 Solu- m (solute)/ n (solute)/ V (solvent)/ c (solute)/ tion Solute mg mmol mL mol L.sup.1 1 Polymer 2 101.9 0.28 5.0 0.055 (repeat units) (repeat units) 2 DMPAP 2.7 0.011 10.0 0.001 Tetrathiol 128.0 0.26 0.026 3 Polymer 2 102.1 0.28 5.0 0.055 (repeat units) (repeat units) 4 DMPAP 0.9 0.004 10.0 0.0004 Tetrathiol 128.0 0.26 0.026
3.2Polymer Network Formation:

(42) In a typical cross-linking experiment, solutions A-K were prepared according to the recipes below. They were dispensed on the stationary silicon wafer, which had been pre-treated as described above. Immediately afterwards, the wafer was spun with a rotation speed of 2000 rpm for 60 s. The resulting layer was cross-linked by flood exposure at 250 nm for 45 min using a Newport Oriel NUV illumination system MODEL 97000STD4. The wafers were then immersed in dichloromethane for 1 h and dried over night under continuous N.sub.2-flow. The resulting layer was characterized by ellipsometry and atomic force microscopy as detailed below.

(43) Solution Recipes:

(44) TABLE-US-00004 m (solute)/ n (solute)/ V (total)/ c (solute)/ Solution Component V/mL mg mmol mL mol L.sup.1 A Solution 1 0.4 8.12 0.022 0.8 0.028 Solution 2 0.4 Tetrathiol: 5.12 Tetrathiol: 0.010 Tetrathiol: 0.013 DMPAP: 0.108 DMPAP: 0.0004 DMPAP: 0.0005 DCM 0.0 B Solution 1 0.4 8.12 0.022 0.8 0.028 Solution 2 0.3 Tetrathiol: 3.84 Tetrathiol: 0.008 Tetrathiol: 0.010 DMPAP: 0.081 DMPAP: 0.0003 DMPAP: 0.0004 DCM 0.1 C Solution 1 0.4 8.12 0.022 0.8 0.028 Solution 2 0.2 Tetrathiol: 2.56 Tetrathiol: 0.005 Tetrathiol: 0.007 DMPAP: 0.054 DMPAP: 0.0002 DMPAP: 0.0003 DCM 0.2 D Solution 1 0.4 8.12 0.022 0.8 0.028 Solution 2 0.1 Tetrathiol: 1.28 Tetrathiol: 0.003 Tetrathiol: 0.003 DMPAP: 0.027 DMPAP: 0.0001 DMPAP: 0.0001 DCM 0.3
Molar Ratios of the Reaction Solutions:

(45) TABLE-US-00005 n (1, repeat Ratio of polymer units)/ n (tetrathiol)/ n (DMPAP)/ repeat units: Solution mmol mmol mmol SH units:DMPAP A 0.022 0.010 0.0004 1:1.9:0.019 B 0.022 0.008 0.0003 1:1.4:0.014 C 0.022 0.005 0.0002 1:1.0:0.010 D 0.022 0.003 0.0001 1:0.5:0.005
Characterization:

(46) AFM investigation revealed that instead of a homogeneous film, a porous film with pores of defined size distribution were obtained. The results are summarized below. It is believed that a phase separation of the polymer and the cross-linking solution occurs, combined with dewetting, which leads to a templating effect.

Example 4

Photolithographic Structuring of Surface-Bound Antibiofouling and/or Antimicrobial Polymer Networks

(47) 4.1Polymer 3, with a molecular weight of M=500 000 g mol.sup.1, was dissolved in dichloromethane to yield a 40 mg mL.sup.1 solution. A stock solution of 120 mg tetrathiol and 2 mg DMPAP in 5 mL dichloromethane was prepared. 0.5 mL of this solution was mixed with 0.5 mL polymer solution.

(48) 4.2Wafer pieces were cleaned with acetone and isopropanol and spun at 3000 rpm. The solution mixture of example 6.1 was added to the rotating sample and spun for 60 sec. The resulting films were covered with a lithographic test mask and flood exposed to UV light using a Newport Oriel NUV illumination system MODEL 97000STD4 without filter. A control film was produced similarly, but without the test mask. Both samples were washed carefully with dichloromethane. The control film had a thickness of 308 nm (determined by ellipsometry). The micrographs of the lithographically structured film are shown in FIG. 1.

Example 5

Surface-Modification of Antimicrobial and/or Antibiofouling Networks by Grafting onto

(49) A silicon wafer that has been treated as described in example 2.2 was placed into an oven-dried vial under nitrogen atmosphere. The wafer was then covered with a solution zwitterionic polymer with pentafluorophenol endgroup (6 mg, 1.Math.10.sup.3 mmol, M=6000 g/mol, in 4 mL dichloromethan) that had been prepared analogously to the endfunctionalized SMAMP in Madkour et al., Macromolecules 2010, 43 (10), 4557-4561. A solution of N,N-dimethylaminopyridine in dichloromethane (1 mL, 0.2 mg/mL, 2 eq.) was added, followed after 2 h by a solution of dicyclohexylcarbodiimid in dichlormethane (1 mL, 0.8 mg/mL, 4 eq.). After 3 days, the wafer was taken out and washed with hexane, DCM, water and ethanol. For deprotection of the Boc-group on the zwitterionic polymer, the wafer was immersed in HCl (4 M in dioxane) for 5 hours and washed twice with ethanol. Finally, the film was dried under N.sub.2-flow over night.

(50) Characterization: The surface-bound polymer networks in the protected and deprotected form were analyzed using ellipsometry to obtain the layer thickness, contact angle measurement, and atomic force microscopy.

(51) TABLE-US-00006 Poly(zwitterion)@ SMAMP@ SMAMP Poly(zwitterion) protected deprotected protected deprotected Thickness nm 48 2 37 2 Contact static 74 2 54 3 angle: advancing 73 2 58 2 receding 16 2 9 2

Example 6

Blending of SMAMPs with Polymers Bearing UV-Crosslinkable Groups and Thermo-Crosslinkable Groups

(52) 6.1. SMAMP 3 was mixed in 1:1 weight ratio with polymer 4, a copolymer of N,N-dimethylacrylamide and the UV crosslinker benzophenyl methyl methyacryate (95:5, M.sub.n=150 000 g mol.sup.1). It was then dissolved in dichloromethane and spin cast onto a 3EBP-functionalized silicon wafer at 3000 rpm for 60 seconds. It was UV irradiated using a stratalinker at 250 nm for 30 min. The resulting polymer film had a thickness of 100 nm, as determined by ellipsometry.

(53) ##STR00026##

(54) 6.2. The solution described in example 6.1 was solvent cast into a Teflon mold and irradiated for 45 min using a stratalinker at 250 nm. It was then allowed to dry over night. A copolymer blend of SMAMP and polymer 4 was thus obtained.

(55) 6.3. SMAMP 3 was mixed in 1:1 weight ratio with polymer 5, a copolymer of N,N-dimethylacrylamide and the thermo crosslinker styrene sulfonic acid azide (95:5, M.sub.n=150 000 g mol.sup.1). It was then dissolved in dichloromethane and spin cast onto a 3EBP-functionalized silicon wafer at 3000 rpm for 60 seconds. It was heated for 60 min to 120 C. on a hot plate. The resulting polymer film had a thickness of 89 nm, as determined by ellipsometry.

(56) ##STR00027##

(57) 6.4. The solution described in example 6.3 was solvent cast into a Teflon mold and heated for 60 min at 120 C. It was then allowed to dry over night. A copolymer blend of SMAMP and polymer 5 was thus obtained.

(58) 6.5. SMAMP 3 and polymer 5 were co-extruded at 250 C. yielding a granular copolymer blend.

Example 7

Synthesis of Antimicrobial Polymers with Predetermined Break Points (R) for Triggered Release of Active Antimicrobial Agents

(59) Monomer 2 with R=propyl (500 mg, 1.53 mmol) was dissolved in 4 mL dichloromethane. 123.3 mg (0.17 mmol) of G3-catalyst were dissolved in 1 mL tetrahydrofurane. Both were subject to three freeze-thaw cycles. The catalyst was added in one shot to the vigorously stirring monomer solution at room temperature under N.sub.2. After 10 min, 1.53 mmol of comonomer were added

(60) ##STR00028##
Q=O, S, NH, CH2

(61) ##STR00029##
m, n=0, 1, 2, 3 . . .

(62) ##STR00030##
A=H, any aliphatic group, any aromatic group . . . .

(63) The process was repeated 3 times, then 500 mg of monomer 2 where added, and the living polymer chain was quenched with ethyl vinyl ether, yielding a polymer with the sequence (SMAMP-X).sub.n-SMAMP, where n=3.

(64) The thus created polymer with intended break points (R) at X can then be used in either of the formulations described above (examples 2-5). It is then treated with trifluoroacetic acid, HCl, or thermally, to yield the active antimicrobial function.

(65) Upon addition of 6 N HCl or an esterase, the comonomer is hydrolyzed, and low molecular weight SMAMPs are released into any solution surrounding the material.

(66) ##STR00031##