Method for imparting antimicrobial properties to a synthetic substrate

Abstract

This invention discloses a method for treating a synthetic substrate to provide antimicrobial properties.

Description

Technical Field

[0001] The present invention finds application in the biomedical field and particularly relates to imparting antimicrobial properties by treating synthetic substrates.

Background Art

[0002] As medical care and medical practices have evolved, the production of medical devices has also evolved. The most widely used material to date is plastic, and its use has been increasing over time due to its unique and desirable properties. Among the many advantages of using plastic are that it is significantly lighter compared to all other materials commonly used in medicine, it is easy to process and can be effectively made into very small and complex parts, and above all, its flexibility. Furthermore, it must not be forgotten that it also has resistance to chemical substances, lipids, sterilization methods, disinfectants, and finally, biocompatibility. Currently, various types of plastic materials are used in the manufacture of medical devices, ranging from polyethylene to polyamides and nylons. These vary according to their respective inherent properties and the uses of the devices, such as sutures, catheters for deep vein access or urology, and filters for embolism protection or hemodialysis. As the use of plastic in the clinical setting progresses, its properties have naturally been improved through the mixing of chemical agents and the research of new compounds to more effectively address the problems that have gradually arisen from daily use. Furthermore, in recent years, research on actual coatings for functionalizing these materials has also begun. These coatings can incorporate metals such as silver or copper, or antimicrobial agents such as antibiotics or antifungal agents, to further improve biocompatibility properties. However, despite many efforts, it is still impossible to obtain plastic materials, either coated or uncoated, that fully achieve the desired properties. The most representative categories of plastic medical devices will be described below, paying particular attention to their limitations and the approaches currently available on the market to overcome them.

[0003] catheter Catheters are made from a variety of materials, including polytetrafluoroethylene, polyurethane, polyethylene, and silicone. However, polyurethane remains the best choice, ensuring a high level of biocompatibility and optimized outer diameter and wall thickness to guarantee flow optimization in relation to the invasiveness of the device.

[0004] Vascular catheter The three most common causes of vascular catheter dysfunction and failure are biofilm formation, infection, and thrombus formation, which lead to the development of fibrin sheaths. Biofilm formation is a significant factor in both early and late catheter failure, as well as catheter failure associated with infection. A biofilm is a complex structure formed by bacteria adhering to an artificial surface. Bacterial adhesion and biofilm formation on the catheter surface begin immediately after catheter placement, and electron microscopy has shown bacterial adhesion to the surface of the indwelling vascular catheter as early as 24 hours after insertion. The bacteria proliferate and secrete a polysaccharide matrix, which serves as a culture medium for additional microorganisms to adhere. Catheters become infected through two main routes, depending on the length of time since the catheter placement procedure. Within the first 30 days after placement, catheters are infected primarily through external routes, from the patient's skin microbiome and the hands of healthcare workers. After the first 30 days, catheters become infected through internal routes, including contamination of the catheter hub, leading to hematogenous transmission and bacteremia. Typical microorganisms involved in these infections include coagulase-negative staphylococci, Staphylococcus aureus, Pseudomonas, enterococci, and Candida. Clinical infections of biofilms generally show resistance to antimicrobial treatment. This is because antibiotics are ineffective because they cannot penetrate the entire layer of the biofilm, and the involved microorganisms have a slow growth rate. The biofilm evolves into a more complex structure, namely a fibrin sheath, over several weeks to months. The fibrin sheath gradually extends along the length of the catheter, surrounding the catheter surface from the venipuncture site and eventually covering the catheter tip, thereby occluding the catheter lumen. Catheter malfunction rates due to fibrin sheath formation are reported to be 50%. Finally, catheter failure due to thrombosis is a common problem in hemodialysis patients. Hemodialysis patients have a unique blood physiology that makes them prone to thrombosis. These factors include both platelet abnormalities and plasma abnormalities.

[0005] Urethral catheter Urinary tract infections (UTIs) are one of the most common healthcare-associated infections reported to the CDC's National Healthcare Safety Network, with over 560,000 cases and over 13,000 deaths annually (mortality rate of 2.3%). UTIs are also a major cause of secondary hospital-acquired bloodstream infections, with approximately 17% of hospital-acquired bacteremias originating from the urinary tract and a mortality rate of up to 10%. Of hospital-acquired UTIs, 75% of cases are associated with urinary catheters, referred to as catheter-associated urinary tract infections (CAUTIs). With short-term catheterization (<3 days), most episodes of catheter-associated bacteriuria are asymptomatic, with a single organism isolated, and less than 5% of patients with catheter-associated bacteriuria are identified with bacteremia. However, with long-term catheterization (>28 days), almost all patients develop bacteriuria. Catheterization is associated with two phenomena: the occurrence of new episodes of bacteriuria due to various urinary tract pathogenic Gram-negative and Gram-positive bacterial species, and the presence of persistent bacterial strains in the catheterized urinary tract. Since prolonged use of urinary catheters increases the risk of UTIs, minimizing catheter use during hospitalization is recommended. Furthermore, it is well recognized that urinary catheter use promotes microbial adhesion and colonization, leading to infection, which is always associated with the formation of microbial biofilms. Biofilms are communities of surface-attached microorganisms embedded in a self-generated extracellular matrix. Bacteria isolated within biofilms are protected from host immune responses and antimicrobial agents, thus playing a crucial role in the pathogenesis of CAUTIs. Within biofilms, bacteria can transmit genes encoding antimicrobial resistance, and intercellular communication can occur through a process called quorum sensing.

[0006] Urinary tract infections that progress with biofilm formation are 1000 times more resistant to antibiotics than their floating counterparts, making treatment extremely difficult. Furthermore, urease-producing agents such as Proteus mirabilis are known to disintegrate elements like calcium, magnesium, and phosphate from urine during short-term catheterization. Obstruction occurs when a scab forms until the lumen is blocked. In patients with long-term catheterization, 48% developed catheter obstruction, and 37% required bypass surgery (where urine constantly passes outside the catheter). These complications are painful and can cause urinary incontinence (which is distressing for patients).

[0007] Encrusting stations occur as a result of ionic components in urine crystallizing and adhering to the surface of biological materials, where a bacterial biofilm layer forms. The most commonly detected bacterium in association with encrusting stations is Proteus mirabilis. Proteus produces an enzyme called urease, which breaks down urea to produce ammonia and carbon dioxide. Carbon dioxide dissolves to form carbonic acid. However, since more ammonia is formed than carbonic acid, the H+ ion concentration decreases, and the urine becomes more alkaline. This change in pH significantly affects the solubility of struvite and calcium phosphate.

[0008] Embolism protection filter When atherosclerotic lesions are manipulated using wires, catheters, balloons, stents, and other intravascular devices during invasive procedures, atherosclerotic plaque is released, resulting in distal embolism. This plaque fragment causes cessation or delay of blood flow due to numerous factors, including thrombosis resulting from mechanical occlusion of large and microvascular channels, local platelet adhesion, platelet activation, and tissue factor release, as well as microvasoconstriction due to thromboxane release.

[0009] Embolism protection devices can prevent or reduce plaque fragments from reaching the distal bed, thereby potentially reducing adverse clinical events. The Embrella deflector device (Edwards Lifesciences) is an umbrella-shaped device with two heparin-coated polyurethane membranes attached to an elliptical nitinol frame. The Sentinel (Claret Medical) device consists of two polyurethane filters positioned on a flexible nitinol radiopaque frame attached to a 100 cm long delivery catheter. The TriGuard embolism protection device (Keystone Heart) features a nitinol mesh coated with chemical and physical materials (Applause™ Heparin Coating SurModics, Inc., Eden Prairie, MN, USA) to reduce the likelihood of thrombus formation. The Embol-X EPD (Edwards Life Sciences) features a heparin-coated polyester mesh on a flexible nitinol frame. Generally, these filter problems stem not only from platelet activation and the resulting thrombus formation, but also from potential clogging by serum protein clumps that can alter their porosity.

[0010] Mesh for abdominal wall repair Until 1958, the treatment of abdominal wall hernias was based on suturing, and the main problem faced by surgeons at the time was the increasing recurrence of hernias. To overcome this, the concept of using mesh was introduced by Usher. Synthetic meshes include permanent meshes and absorbable meshes. Permanent materials are generally composed of polypropylene, polyester, or stretched polytetrafluoroethylene (ePTFE). Each of these materials has its advantages and limitations. These meshes are often used in combination or with the addition of other materials to be designed as composite meshes that leverage the advantages of each while compensating for their disadvantages. Many of these composite meshes are already approved for clinical use. Permanent synthetic meshes are susceptible to infection and their use in contaminated environments is limited. According to a recent meta-analysis, the overall infection rate was 5%. Mesh removal was performed in 70% of cases and in 100% of cases with ePTFE grafts.

[0011] polypropylene Polypropylene is widely used in various surgical procedures and is relatively inexpensive. Experimental studies have shown that polypropylene mesh integrates well into the anterior abdominal wall within two weeks of implantation. However, inflammatory responses can contribute to adhesion formation and lead to contraction of the mesh and surrounding tissues.

[0012] The inflammatory response caused by polypropylene limits its durability, and when the mesh is used adjacent to the intestines, adhesion formation also increases. As a result, polypropylene is rarely used alone in the abdominal cavity. Polypropylene can be used in combination with temporary or permanent materials (i.e., polyglecapron, carboxymethylcellulose, and omega-3 fatty acids) to reduce adhesion formation or prevent contact with the intestines. The inflammatory response to polypropylene causes the material to shrink by 30-50%. This shrinkage can not only cause detachment from the original tissue but also lead to the involvement of the composite mesh, potentially exposing the polypropylene component to the intestinal surface.

[0013] polyester Polyester is a carbon-based polymer commonly used in textiles. Early studies raised concerns about its higher incidence of infection, small bowel obstruction, recurrence, and fistula compared to other synthetic materials. Polyester meshes remain clinically available, but with the caveat that they must be isolated from the intestinal surface. Polyester can offer several advantages over polypropylene. In an animal model of abdominal hernia repair, polyester mesh coated with a collagen hydrogel matrix showed superior tissue uptake compared to a composite mesh of polypropylene and sodium hyaluronate / carboxymethylcellulose (Sepramesh, Bard, Davol, Inc., Warwick, RI).

[0014] Extended polytetrafluoroethylene (ePTFE) ePTFE is a microporous woven mesh originally used for vascular grafts. The material used in abdominal cases generally has two sides: one smooth side with small pores and the other with larger pores with ridges and grooves. The material is designed so that the smooth side faces the intestine to minimize adhesion and the rough side faces the fascia to allow for internal tissue growth. However, experimental studies have shown limited inward growth of fibers around ePTFE grafts and minimal inflammatory changes. This may be a result of the small pore size, hydrophobicity, or electronegative charge of the mesh. In animal models of abdominal hernia, grafts constructed with ePTFE were compared to polypropylene grafts. While ePTFE grafts showed less evidence of adhesion, there was no inward proliferation of fibrous-collagen tissue into the ePTFE grafts. The polypropylene mesh was fully integrated. Furthermore, hernia recurrence was 60% in the ePTFE group compared to 0% in the polypropylene group. All recurrent hernias were located at the junction of the mesh and the intrinsic tissue, suggesting that a lack of inward growth to the ePTFE leads to inadequate fixation of the mesh to the fascia.

[0015] To overcome the limitations of the various devices exemplified, novel coatings, materials, and designs have been extensively studied. Engineering approaches fall into three main categories: (i) antimicrobial properties; (ii) antifouling properties; and (iii) antithrombotic properties. Antimicrobial strategies include passive antimicrobial release (typically by impregnation into plastic surfaces) and non-release contact bactericidal (by incorporation of antimicrobial compounds covalently immobilized on plastic materials or hydrogel coatings). Antifouling materials or designs prevent bacterial adhesion using non-antimicrobial approaches such as mechanical methods or undesirable surface topography or chemical methods. Finally, heparinized coatings are widely applied due to heparin's ability to bind to antithrombin and induce allosteric structural changes, thereby dramatically accelerating its ability to inhibit FXa, thrombin, and other proteases that contribute to thrombus formation.

[0016] i) Antimicrobial strategies Silver coating Silver is one of the most common antimicrobial agents for medical device coatings and is one of the few antimicrobial agents approved by the FDA for urinary catheter applications. Silver coatings can be applied to both internal and external surfaces, slowly releasing ionic silver particles over the first five days and providing consistent elution over time. Silver-coated synthetic materials reduce pathogen colonization by releasing silver ions that target bacteria into the surrounding environment through three mechanisms: (1) impaired membrane function due to loss of membrane potential, (2) impaired protein function due to disruption of Fe-S clusters, and (3) oxidative stress due to antioxidant depletion.

[0017] Antibiotic coating Antibiotics selectively inhibit the biological activity of microorganisms at low concentrations, which is crucial for the prevention and control of infections. Antibiotic coatings are perhaps the most direct method for preventing bacterial infections, designed to inhibit or delay the initiation of biofilm formation by controlling the release of high local concentrations of antibiotics to sites of potential colonization. Compared to silver coatings, antibiotic coatings have higher activity in targeting pathogens. To date, many antibiotics have been impregnated into plastic medical devices. These include nitrofurazone, gentamicin, norfloxacin, sparfloxacin, vancomycin, and rifampin.

[0018] Notably, nitrofurazone is listed by the FDA as a Group I banned substance for food animals because it can cause mammary and ovarian tumors in animal subjects. This side effect of nitrofurazone has led to a stagnation in research in this field. Catheters coated with antimicrobial agents are beneficial in preventing catheter-associated urinary tract infections, but the costs associated with these catheters, patient convenience, and complications should also be considered. The greatest concern with all antimicrobial-treated medical devices is the development of resistance to the active substance / coating. Therefore, their use may be losing support due to their limited efficacy and the potential for resistance development.

[0019] bactericidal enzyme coating Bactericidal enzymes inhibit bacteria through the production of antimicrobial substances (i.e., oxidases). Specifically, hydrogen peroxide (H2O2) produced by peroxidases is used to attack bacterial cells or to oxidize halides into more potent antimicrobial substances. Recently, bactericidal enzymes have been used as highly active antibacterial materials for experimental catheter coatings. Bactericidal enzymes have several advantages over other conventional antibacterial materials as catheter coatings: (1) They are more specific to selected pathogens without disturbing other beneficial microorganisms in the host; (2) It is very difficult for pathogens to develop resistance to bactericidal enzymes; and (3) Bactericidal enzymes are considered to be natural, non-reactive, and non-toxic to the host. However, the production and purification of bactericidal enzymes are far more expensive compared to conventional antimicrobial agents such as silver and antibiotics. Furthermore, bactericidal enzymes are susceptible to denaturation under extreme conditions during device sterilization, storage, and transport.

[0020] Antimicrobial peptide (AMP) coating. AMP, or so-called host defense peptide, is a broad-spectrum antimicrobial agent effective against both Gram-negative and Gram-positive strains, viruses, and fungi. AMP targets pathogens through multiple pathways: (1) cytoplasmic membrane alteration; (2) membrane permeation; (3) activation of autodigestives; (4) inhibition of DNA, RNA, and protein synthesis; (5) inhibition of specific enzymes; and (6) enhancement of immunomodulation. These AMP-coated catheters exhibited excellent antimicrobial and antibiofilm activity against pathogens and showed no toxicity to mammalian cells.

[0021] ii) Anti-fouling strategy Antifouling materials or designs are inherently resistant to bacterial adhesion and subsequent biofilm formation solely through their structure, without the need for antimicrobial additives. Antifouling mechanisms include hydration forces, steric repulsion, electrostatic repulsion, and low surface energy. The field of antifouling polymers is rapidly growing and holds promise as an exciting new approach to combating bacterial infections that are unlikely to exacerbate antibiotic resistance.

[0022] PEG coating PEG is a hydrated layer with a steric repulsive force against large energy barriers and non-specific protein adsorption. The PEG coating on the substrate is designed to prevent bacterial adhesion. This coating showed excellent antibacterial and antifouling activities against both Gram-positive (Staphylococcus aureus (S. aureus)) and Gram-negative (Escherichia coli (E. coli)) bacteria. PEG-based coatings have historically been regarded as the gold standard for protein-resistant surfaces, but there are still drawbacks to the use of PEG. Recent studies have shown that PEG causes an immune response in approximately 25% of the population. Furthermore, the long-term stability of the PEG coating is impaired by oxidative degradation of the polyether backbone.

[0023] Hydrogel hydrogel coating The formation of the hydrogel layer is another strategy for achieving protein resistance. A hydrogel is a lightly cross-linked polymer network that can swell and retain large amounts of water. Similar to the surface of a PEG graft, the hydrogel forms a hydrated layer, increases surface hydrophilicity, and establishes a barrier that inhibits non-specific protein adsorption. In many cases, the hydrogel coating approach is combined with silver-based treatments. However, it has been reported that the hydrogel layer increases the aggregation of floating cells and newly nucleated crystals, resulting in faster catheter occlusion than in the case of uncoated silicone.

[0024] Poly zwitterionic coating Polyzwitterions have both cationic and anionic groups along the polymer backbone and are overall charge-neutral. Polyzwitterions are highly hydrophilic and form a hydration layer on the surface. Polyzwitterions also repel non-specific protein absorption via electrostatic and steric repulsion. The polyzwitterion surface has been demonstrated to be a strong alternative to conventional antifouling PEGylated surfaces. The most common zwitterionic polymers are phosphorylcholine (PC), sulfobetaine, and carboxybetaine. Unlike permanently charged polymers, zwitterionic polymers can switch between anionic and cationic forms by a controlled hydrolysis process, where the release of dead bacteria and antifouling occur on the same substrate. However, the long-term stability of zwitterionic surfaces remains a concern. The surface hydration layer of the polyzwitterion is disrupted, losing its antibacterial activity, and bacteria adhere to the surface of the modified coating.

[0025] Nitric oxide-releasing coating Nitric oxide (NO) is a chemically unstable lipophilic gas and is one of the smallest endogenous produced molecules against infection. NO has shown local bactericidal / biofilm dispersal effects by amino and sulfhydryl nitrosation, lipid peroxidation, tyrosine nitration, DNA degradation, and regulation of motility stimulation and dispersion. When produced by activated immune cells, NO can diffuse through bacterial cell membranes and destroy microorganisms by exerting nitrosation and oxidative stress. Common NO donors are S-nitrosothiols, such as S-nitroso-N-acetyl-DL-penicillamine (SNAP) and S-nitrosoglutathione (GSNO), which can be mixed into polymer materials for slow release of NO. NO-releasing polymer coatings have been widely applied to prevent biofilm-related infections on implanted biomedical devices. However, few studies have been conducted using NO or NO donor-impregnated urethral catheters. The long-term storage stability of the material, NO donor diffusion in the physiological environment, and toxicity are the major concerns requiring further research.

[0026] iii) Antithrombotic coating Tunnel-type hemodialysis catheters have two types of antithrombotic coatings: Carmeda BioActive Surface (CBAS), used in Spire Biomedical catheter products, and Trillium Biosurface, developed by BioInteractions Ltd. (Reading, Burks, UK), used in Tyco-Kendall products. Both surfaces use heparin bound to the catheter as an anticoagulant. Heparin is not only a potent anticoagulant, but many studies have shown that it reduces both thrombin activator and smooth muscle cell proliferation. However, the initial clinical benefits observed for blood contact devices with heparinized coatings are typically not maintained because heparin surface activity cannot be preserved, possibly as a result of enzymatic or chemical degradation, which involves a decrease in the availability of high-affinity antithrombin binding sites. In particular, heparin and heparan sulfate are depolymerized and degraded by heparanase, an endo-β-D-glucuronidase produced by various cells and tissues, including fibroblasts, endothelial cells, platelets, activated immune cells, hepatocytes, and cancer cells. Plasma heparanase activity is significantly elevated in patients with atherosclerosis, renal failure, and type 2 diabetes, as well as in postoperative patients, which may further contribute to the early decline in clinical benefit from heparin-binding prostheses. Importantly, unfractionated and low molecular weight heparins are susceptible to cleavage by heparanase, resulting in reduced local concentrations of high-affinity antithrombin binding sites and neutralization of anticoagulant properties.

[0027] Polyphenols are widely found in many plant products, including green tea, red wine, cocoa, and fruits. They are readily available, inexpensive, and generally considered safe by the U.S. Food and Drug Administration.

[0028] Yang L et al. [6] Fe 3+The procedure describes how to obtain a coating on a quartz or silicone slide using tannic acid coordinated by metallic bonding. Fe-TA films are effective in preventing platelet adhesion, but the procedure is long and complex, involving pretreatment in a very strong boiling solution (98% H2SO4:30% H2O2 = 3:1) followed by 4 hours of passage in trimethylchlorosilane (4% dichloromethane).

[0029] The approach described above involves complex procedures and critical processing conditions, and is specific to only certain types of plastic substrates.

[0030] The inventors of this application disclose the use of polyphenols for the functionalization of animal-derived tissues for the production of biological prostheses [1-6]. [Overview of the project]

[0031] The inventors of this patent application have surprisingly found that synthetic substrates can be treated to impart antimicrobial properties, and these substrates can then be used in the manufacture of medical devices. [Brief explanation of the drawing]

[0032] [Figure 1] Figure 1: Scanning electron microscope (SEM) evaluation of the inner and outer surfaces of the original polyurethane sample (untreated) and after treatment with two variants of a caffeic acid solution (CA treatment 1 and CA treatment 2). [Figure 2] Figure 2: Scanning electron microscopy (SEM) evaluation of the original polyamide mesh sample (untreated) and the samples after treatment with two variants of caffeic acid solution (CA treatment 1 and CA treatment 2). The lower part of the figure shows the results of EDX evaluation comparing the untreated sample and the variant treated with CA treatment 1. A significant increase in the amount of C and O atoms was observed in the treated samples, which supports stable interaction with the polyphenol mixture (rich in C and O). [Figure 3]Figure 3: Scanning electron microscope (SEM) evaluation of the original silicone sample (untreated) and the samples after treatment with two variants of caffeic acid-based solution (CA treatment 1 and CA treatment 2). [Figure 4] Figure 4: Proton nuclear magnetic resonance analysis of polyurethane samples after treatment with two variants (P1 and P2) of a caffeic acid-based solution. [Figure 5] Figure 5: Carbon-13 nuclear magnetic resonance analysis of untreated (NT) and treated (P2) polyurethane samples. [Figure 6] Figure 6: Carbon-13 nuclear magnetic resonance analysis of polyamide samples after treatment with untreated (CTRL) and two variants of caffeic acid-based solution (P1 and P2). [Figure 7] Figure 7: Proton nuclear magnetic resonance analysis of the untreated (CTRL) silicone sample and two variants treated with a caffeic acid solution (Sample 1 and Sample 2). [Figure 8] Figure 8: Carbon-13 nuclear magnetic resonance analysis of the untreated (CTRL) and treated (sample 2) silicone sample. [Figure 9] Figure 9: Percentage reduction in protein adhesion on different plastic substrates, as evaluated using bovine serum albumin and bovine thyroglobulin. [Figure 10] Figure 10: Degree of reduction in adhesion of different bacterial strains to different types of plastic substrates. [Figure 11] Figure 11: Thrombin generation assays performed on polyurethane (PU), silicone (SI), polyamide (PA), and polyester (PE) samples before (NT) and after treatment with a caffeic acid-based solution. The samples were compared to reference materials consisting of medical-grade steel (MS, high thrombin generation ability) and low-density polyethylene (LDPE, low thrombin generation ability).

[0033] (Purpose of the present invention) In its first objective, the present invention discloses a method for imparting antimicrobial properties to a synthetic substrate.

[0034] In a particular embodiment, the synthetic substrate is selected from the group including polyurethane, polyester, polyamide, silicone, PEEK, polytetrafluoroethylene, and stretched polytetrafluoroethylene.

[0035] In certain embodiments, the method of the present invention can also impart to the synthetic substrate one or more properties selected from the group including inhibition of surface adhesion to serum proteins, resistance to tissue bacterial adhesion, and inhibition of thrombin production.

[0036] In a second object, the present invention discloses synthetic substrates obtained according to the described method and medical devices comprising such substrates.

[0037] In a particular embodiment, the medical device is selected from the group including catheters, such as vascular catheters, urinary catheters, embolic protection filters, and abdominal wall repair meshes.

[0038] (Detailed description of the present invention) According to the first object of the present invention, a method for imparting antimicrobial properties to a synthetic substrate is disclosed.

[0039] In particular, the synthetic substrate is represented by a plastic substrate.

[0040] In a preferred embodiment, the plastic substrate is made of a material selected from the group including polyurethane, polyester, polyamide, polyethylene, silicone, PEEK, polyacrylate, acrylic hydrogel, Teflon, polysiloxane, and fluorinated polymer.

[0041] In particular, polyesters include, for example, polyethylene terephthalate, nylon, dacron, polyglycolic acid, polylactic acid, and polycaprolactone.

[0042] Polyamides, in particular, include Kevlar.

[0043] In particular, polyethylene includes low molecular weight polyethylene, high molecular weight polyethylene, and very high molecular weight polyethylene.

[0044] In particular, polyacrylates include polymethyl methacrylate and polymethyl acrylate.

[0045] In particular, polysiloxanes contain silastic compounds.

[0046] In particular, fluorinated polymers include polytetrafluoroethylene and stretched polytetrafluoroethylene.

[0047] According to the present invention, the method of the present disclosure may include a preliminary step of pre-treating the substrate.

[0048] In particular, the pretreatment includes incubation of the substrate in an alcohol pretreatment solution.

[0049] More specifically, the concentration of the alcohol is approximately 10-100% (v / v), preferably 100% (v / v).

[0050] In one embodiment, the pretreatment incubation is continued for a period of 2 minutes to 24 hours.

[0051] In a preferred embodiment, the pretreatment incubation is performed for approximately 10 minutes.

[0052] According to a preferred embodiment of the present invention, prior to the pretreatment step, the pretreatment solution is maintained at a temperature of approximately -25°C to -15°C.

[0053] In a preferred embodiment, the pretreatment solution is maintained at a temperature of approximately -20°C.

[0054] In a preferred embodiment, the pretreatment solution is maintained at the temperature of the Disclosure for about 10 minutes to 5 hours.

[0055] Regarding the object of the present invention, the method of the present invention includes the step of contacting the substrate with a coffee acid-based treatment solution.

[0056] In particular, the caffeic acid-based treatment solution has a caffeic acid concentration of 0.1 to 10 mg / ml.

[0057] In a preferred embodiment, the treatment solution has a caffeic acid concentration of approximately 2-4 mg / ml.

[0058] The treatment solution of the present invention is prepared by dissolving caffeic acid in alcohol at a final volume of 70% (v / v).

[0059] In particular, to prepare the treatment solution, caffeic acid is dissolved in a C1-C4 alcohol.

[0060] In a preferred embodiment, the C1-C4 alcohol is selected from the group comprising methanol, ethanol, isopropanol, or butanol.

[0061] Next, the pH of the treatment solution is adjusted to a range of 2.5 to 9.0, preferably a range of pH 5.5 to 8.0.

[0062] According to one embodiment of the present invention, the treatment solution contains a second component.

[0063] For the purposes of the present invention, the second component is selected from the group comprising polyphenols and their salts or esters, phenolic compounds and their salts and derivatives, antibiotics or antimicrobial agents, methylated phenols, fatty acids and their esters and metal-based solutions.

[0064] In particular, the polyphenols include resveratrol, aloin, cyanarin, epigallocatechin, tannic acid, chlorogenic acid, hydroxytyrosol, rosmarinic acid, narigenin, gallic acid, hesperidin, quinic acid, and eleonolic acid. The group includes (acid), pinoresinol, luteolin, apigenin, tangeritin, isorhamnetin, kaempferol, myricetin, eriodictyol, theaflavin, thearubigin, daidzein, genistein, glycitein, pterostilbene, delphinidin, malvidin, pelargonidine, peonidine, chicory acid, ferulic acid, salicylic acid, baicalein, 5,7-dihydroxy-4-phenylcoumarin, rutin hydrate, 5,8-dihydroxy-1,4-naphthoquinone, 2,3-dichloro-5,8-dihydroxy-1,4-naphthoquinone, ethyl-3,4-dihydroxy-cinnamate, butyl gallate, 4-hydroxyl-4-biphenyl carboxylic acid, oleuropein, garlic acid, magnolol, curcumin, and ethyl-3,5-dihydroxy-benzoate.

[0065] In particular, the phenol compound is selected from the group including vanillin, cinnamic acid, phenylalanine, coumarin, xanthones, catechins, flavonoids, flavones, chalcones, flavanonols, flavanols, leucoanthocyanidins, anthocyanidins, hydroxycinnamic acid, and phenylpropanoids.

[0066] This includes derivatives of such phenolic compounds, some of which are expressed as salts or esters.

[0067] In particular, the antibiotic or antimicrobial agent is selected from the group comprising penicillin, aminoglycosides, carbapenems, glycopeptides, and lipoglycopeptides, such as vancomycin, monobactam, aztreonam, oxazolidinone, such as linezolid and tedizolid, rifamycin, streptogramin, such as quinupristin and dalfopristin, cephalosporins, tetracyclines, macrolides, fluoroquinolones, and sulfonamides.

[0068] In particular, the methylated phenol is selected from the group comprising α-tocopherol, β-tocopherol, γ-tocopherol, δ-tocopherol, and tocotrienol.

[0069] In particular, the metal-based solution is selected from the group comprising acetates, sulfates, phosphates, chlorides, nitrites, nitrates, or carbonates.

[0070] The metal may be selected from the group including iron, silver, gold, zinc, copper, barium, magnesium, and aluminum.

[0071] For example, barium carbonate, iron(II) chloride, iron(III) chloride, iron(II) nitrate, iron(III) nitrate, aluminum chloride, calcium chloride, calcium carbonate, calcium nitrate, copper sulfate, and copper nitrate can be used.

[0072] For the purposes of the present invention, the concentration of the second component is approximately 0.1 to 20 mg / ml.

[0073] The treatment solution of the present invention is prepared by mixing a solution of caffeic acid with a solution of a second component.

[0074] In particular, the caffeic acid solution is preferably represented by an alcoholic solution of caffeic acid.

[0075] In a preferred embodiment, a caffeic acid solution is prepared by dissolving caffeic acid in alcohol at a final volume of 70% (v / v).

[0076] In particular, to prepare the treatment solution, caffeic acid is dissolved in a C1-C4 alcohol.

[0077] In a preferred embodiment, the C1-C4 alcohol is selected from the group comprising methanol, ethanol, isopropanol, or butanol.

[0078] In a preferred embodiment, a solution of the second component is prepared by dissolving the second component in an aqueous buffer solution.

[0079] For the purposes of the present invention, suitable buffers can be selected from the group including PBS (phosphate buffer), bicarbonate buffer, Dulbecco's phosphate-buffered saline, TBE (Tris / boric acid / EDTA buffer), TE (Tris / EDTA) buffer, Tris-buffered saline (TBS), SSC (sodium chloride / sodium citrate), and SSPE (sodium chloride / sodium phosphate / EDTA).

[0080] Finally, the two solutions are mixed and the pH is adjusted to a range of 2.5 to 9.0, preferably pH 5.5 to pH 8.0.

[0081] For the purposes of the present invention, the method of the present invention comprises at least one processing cycle, the processing cycle comprising the following steps: i) The synthetic substrate is incubated in the processing solution, and then ii) Wash the incubated synthetic substrate.

[0082] In particular, the incubation in step i) is carried out for about 5 to 25 minutes, preferably about 15 minutes.

[0083] In particular, the cleaning step ii) is performed for about 2 to 120 minutes, preferably about 20 minutes.

[0084] For the purposes of the present invention, processing step i) includes at least one cycle performed at pH 5.5.

[0085] For the purposes of the present invention, the processing step i) further includes at least one cycle performed at pH 8.0 after a washing treatment at pH 5.5.

[0086] In one embodiment of the present invention, processing step i) includes one to five processing cycles performed at pH 5.5.

[0087] Preferably, processing step i) includes three processing cycles performed at pH 5.5.

[0088] In one embodiment of the present invention, processing step i) further comprises one to five processing cycles performed at pH 8.0, where each step at pH 8.0 follows each step at pH 5.5.

[0089] Preferably, the treatment step i) includes three treatment cycles performed at pH 8.0, where each step at pH 8.0 follows each step at pH 5.5.

[0090] For the purposes of the present invention, processing step i) is carried out in the dark.

[0091] Regarding step ii), washing is performed with a washing solution represented by a buffer.

[0092] In particular, the buffer solution is selected from the group including PBS (phosphate buffer), bicarbonate buffer, Dulbecco's phosphate-buffered saline, TBE (Tris / boric acid / EDTA buffer), TE (Tris / EDTA) buffer, Tris-buffered saline (TBS), SSC (sodium chloride / sodium citrate), and SSPE (sodium chloride / sodium phosphate / EDTA).

[0093] For the purposes of the present invention, a drying step is performed after the processing step.

[0094] In particular, the drying process is carried out at a temperature of approximately 30 to 45°C.

[0095] In particular, the drying process is carried out for about 1 minute to 5 hours, preferably for about 30 minutes.

[0096] According to the present invention, the method disclosed above imparts antimicrobial properties to the treated synthetic substrate.

[0097] In particular, the aforementioned antimicrobial properties are effective against Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Proteus mirabilis, Enterococcus faecalis, Listeria monocytogenes, Salmonella enterica typhimurium, Streptococcus viridans, nontuberculous mycobacteria (e.g., Mycobacterium chelonae), yeast (e.g., Candida albicans) This refers to albicans, and fungi, such as Aspergillus brasiliensis.

[0098] In a preferred embodiment, the antimicrobial properties are against Staphylococcus aureus, Escherichia coli, and Proteus mirabilis.

[0099] Furthermore, the method of the present invention provides one or more properties, such as inhibition of surface adhesion to serum proteins, resistance to bacterial adhesion to tissues, and inhibition of thrombin production.

[0100] In particular, the resistance to bacterial adhesion of the tissue is due to the presence of Staphylococcus aureus, Escherichia coli, Proteus mirabilis, Pseudomonas aeruginosa, Enterococcus faecalis, Listeria monocytogenes, Salmonella enterica typhimurium, Streptococcus viridans, nontuberculous mycobacteria (such as Mycobacterium chelonae), yeast (such as Candida albicans), and other bacteria. This refers to albicans, and fungi, such as Aspergillus brasiliensis.

[0101] In a preferred embodiment, the resistance to bacterial adhesion of the tissue is to Staphylococcus aureus, Escherichia coli, and Proteus mirabilis.

[0102] A second object of the present invention is disclosed, which is a synthetic substrate obtained according to the method of the present invention.

[0103] In particular, the synthetic substrate is a material selected from the group including polyurethane, polyester, polyamide, polyethylene, silicone, PEEK, polyacrylate, acrylic hydrogel, Teflon, polysiloxane, and fluorinated polymer, as disclosed above.

[0104] Furthermore, medical devices containing such substrates are disclosed.

[0105] For the purposes of the present invention, medical devices are selected from the group including catheters, such as vascular catheters, urinary catheters, embolic protection filters, abdominal wall repair meshes, syringes, kits for various applications, laboratory tubes, blood bags, tools, gloves, trays, thermometers, and sutures.

[0106] The present invention is further disclosed by the following experimental section.

[0107] Experiment Section (Polyurethane (PU)) The polyurethane samples were incubated in a 100% (v / v) isopropanol solution for 10 minutes. Before use, the alcohol solution was left at -20°C for 10 minutes to 5 hours.

[0108] Next, the samples were incubated in two different mixtures of caffeic acid-based polyphenols: Variant 1 (P1 in Figure 4), consisting of caffeic acid at a concentration of 2 mg / ml and tannic acid at a concentration of 4 mg / ml, and Variant 2 (P2 in Figure 4), consisting of caffeic acid at a concentration of 2 mg / ml and rutin hydrate at a concentration of 1 mg / ml.

[0109] In both variants, caffeic acid was dissolved in isopropanol at 70% of the final volume.

[0110] The second polyphenol was dissolved in PBS (phosphate buffer) at 30% of its final volume.

[0111] Finally, mix the two solutions and adjust the pH to a range of pH 5.5 to pH 8.0.

[0112] Next, the polyurethane samples are incubated in these caffeic acid-based solutions for three cycles at pH 5.5, and then for three cycles at pH 8.0.

[0113] In each cycle, the incubation time in the caffeic acid-based polyphenol solution was 15 minutes, and after the completion of each cycle, washing with TBE (Tris / boric acid / EDTA buffer) was performed for 20 minutes.

[0114] After the processing cycle, the sample was placed in a 37°C stove for 30 minutes.

[0115] (Polyamide (PA)) The polyamide sample was incubated in a 100% (v / v) ethanol solution for 10 minutes. The incubation time can be varied from 2 minutes to 24 minutes.

[0116] Before use, the alcohol solution was left at -20°C for 10 minutes to 5 hours.

[0117] Subsequently, the samples were incubated in two different mixtures of caffeic acid-based polyphenols: Variant 1 (P1 in Figure 6), consisting of caffeic acid at a concentration of 4 mg / ml and tannic acid at a concentration of 8 mg / ml, and Variant 2 (P2 in Figure 6), consisting of caffeic acid at a concentration of 4 mg / ml and barium carbonate at a concentration of 1 mg / ml.

[0118] In both variants, caffeic acid was dissolved in isopropanol at 70% of the final volume.

[0119] The metal salt was dissolved in PBS (phosphate buffer) at 30% of its final volume.

[0120] Finally, the two solutions are mixed and the pH is adjusted to a range of 2.5 to 9.0 (pH 5.5 and pH 8.0 in this example).

[0121] Next, the polyamide samples are incubated in these caffeic acid-based solutions for three cycles at pH 5.5, and then for three cycles at pH 8.0.

[0122] In each cycle, the incubation time in the caffeic acid-based polyphenol solution was 15 minutes, followed by a 20-minute wash with TBE (Tris / boric acid / EDTA buffer).

[0123] After the processing cycle, the sample was placed in a 37°C stove for 30 minutes.

[0124] (silicone) The silicone sample was incubated in 100% (v / v) isopropanol solution for 10 minutes. The incubation time can be varied from 2 minutes to 24 minutes.

[0125] Before use, the alcohol solution was left at -20°C for 10 minutes to 5 hours.

[0126] Subsequently, the samples were incubated in two different mixtures of caffeic acid-based polyphenols: Variant 1 (Sample 1 in Figure 7), consisting of caffeic acid at a concentration of 2 mg / ml and tannic acid at a concentration of 4 mg / ml, and Variant 2 (Sample 2 in Figure 7), consisting of caffeic acid at a concentration of 2 mg / ml and ganodelic acid at a concentration of 5 mg / ml.

[0127] In both variants, caffeic acid was dissolved in isopropanol at 70% of the final volume. The second polyphenol was dissolved in PBS (phosphate buffer) at 30% of the final volume.

[0128] Finally, mix the two solutions and adjust the pH to a range of pH 5.5 to pH 8.0.

[0129] Next, the silicone sample is incubated in a caffeic acid solution for three cycles at pH 5.5, and then for three cycles at pH 8.0.

[0130] In each cycle, the incubation time in the caffeic acid-based polyphenol solution was 15 minutes, and after the completion of each cycle, washing with TBE (Tris / boric acid / EDTA buffer) was performed for 20 minutes.

[0131] After the processing cycle, the sample was placed in a 37°C stove for 30 minutes.

[0132] (Polyester (PE)) The polyester sample was incubated in 100% (v / v) isopropanol solution for 10 minutes. The incubation time can be varied from 2 minutes to 24 hours.

[0133] The alcohol solution was left at -20°C for a period ranging from 10 minutes to 5 hours.

[0134] Subsequently, the samples were incubated in a mixture of caffeic acid-based polyphenols consisting of caffeic acid (4 mg / ml selected), tannic acid at a concentration of 8 mg / ml, and a mixture of penicillin (150 μg / ml) / streptomycin (150 μg / mg) / neomycin (100 μg / ml).

[0135] Caffeic acid was dissolved in isopropanol at 70% of its final volume.

[0136] Polyphenols and antibiotics were dissolved in PBS (phosphate buffer) at 30% of the final volume.

[0137] Finally, mix the two solutions and adjust the pH to a range of 5.5 to 8.0.

[0138] Next, the polyester samples are incubated in these caffeic acid-based solutions for three cycles at pH 5.5, and then for three cycles at pH 8.0.

[0139] In each cycle, the incubation time in the caffeic acid-based polyphenol solution was 15 minutes, followed by a 20-minute wash with TBE (Tris / boric acid / EDTA buffer).

[0140] After the processing cycle, the sample was placed in a 37°C stove for 30 minutes.

[0141] Treated and untreated plastic samples were subjected to scanning electron microscopy (SEM) for surface evaluation, nuclear magnetic resonance (H-NMR and C-NMR) for characterizing interactions with the support, testing for anti-adhesion of several bacterial strains and serum proteins, and evaluation of thrombosis formation.

[0142] result (Scanning electron microscope (SEM)) Polyurethane sample Figure 1 highlights that, when compared at low magnification (50X), the samples treated with caffeic acid (CA) solutions appear indistinguishable from the untreated sample (NT) visually. By increasing the magnification, it is possible to recognize homogeneous coatings whose thickness and texture can be adjusted based on specific variations in the caffeic acid solutions (CA-1 and CA-2).

[0143] Polyamide sample Figure 2 highlights that, when compared at low magnification (400X), the sample treated with a caffeic acid solution (CA-treatment 1) is visually indistinguishable from the untreated sample (NT). The presence of a polyphenol coating was confirmed by EDX analysis. This analysis revealed an increased presence of C and O atoms compared to the NT sample. Energy-dispersive X-ray spectroscopy (EDX) is an analytical technique that enables the chemical characterization / elemental analysis of materials. A sample excited by an energy source (such as an electron beam from an electron microscope) dissipates some of the absorbed energy by emitting core-shell electrons. High-energy outer-shell electrons fill these spaces, and the energy difference is emitted as X-rays with a characteristic spectrum based on the originating atoms. This makes it possible to analyze the composition of a given volume of sample excited by the energy source. Elements are identified by the position of the peaks in the spectrum, and the intensity of the signal corresponds to the concentration of the element. However, by increasing the magnification, it is possible to recognize a homogeneous coating whose thickness and texture can be adjusted based on specific variations in the caffeic acid-based solutions (CA-1 and CA-2).

[0144] Silicone sample The silicone sample exhibited different behavior compared to other types of materials analyzed. As shown in Figure 3, treatment with a caffeic acid-based solution ensured the formation of a coating, which was only visible at high magnification (starting from 6000X). This coating became observable as a result of crack formation by prolonged irradiation with the electron beam of the SEM. This feature makes the coating particularly interesting, as it is undetectable to the naked eye.

[0145] Nuclear Magnetic Resonance (NMR) Evaluation Polyurethane sample ¹H-NMR analysis showed no substantial difference in the peaks of the polyurethane samples treated with various caffeic acid-based solutions. The P1 and P2 spectra were virtually identical (Figure 4), indicating no release of caffeic acid and supporting the stability of the treatment. In particular, the P2 treatment showed a decrease in the ¹¹C-NMR spectrum, with a peak of approximately 68 ppm corresponding to the formation of covalent bonds with the terminal hydroxyl groups of the polyurethane chain (Figure 5).

[0146] Polyamide sample ¹H-NMR analysis (Figure 6) confirmed the stability of the interaction between the caffeic acid-based polyphenol solution and the polyamide sample. Furthermore, the disappearance of the peak at 3.7 ppm, which was observable in the control (CTRL) sample, indicates the formation of a covalent chemical bond between the terminal amino group of the polyamide and the caffeic acid-based solution used for coating (the signal highlighted in yellow corresponds to the signal of the proton at position 1 of the chain).

[0147] Silicone sample ¹H-NMR analysis confirmed the stability of the interaction between the caffeic acid-based polyphenol solution and the silicone sample. In particular, significant ¹H-mediated interactions were demonstrated, confirmed by the presence of several peaks in the 1.4–0.6 ppm region (Figure 7). Furthermore, the disappearance of peaks at 60 ppm and 185 ppm, observable in the control (CTRL) sample (Figure 8), indicates the formation of covalent bonds between the polyphenol surface and the silicone surface.

[0148] Inhibition of surface adhesion to serum proteins Samples of different plastic substrates, treated with and untreated with the caffeic acid-based polyphenol solution according to the present invention, were incubated at 37°C for 24 hours in a phosphate buffer containing 50 μg / ml bovine serum albumin (66 kDa) or bovine tyroglobulin (330 kDa) with moderate but constant stirring. Afterward, all samples were washed three times with phosphate buffer for 3 minutes each to remove any protein residue that was not firmly bound to the surface. The amount of protein attached to the surface was measured, and the reduction rate for each treated sample was calculated, with the amount of protein quantified in the untreated sample set to 100. As shown in Figure 9, treatment with the caffeic acid-based solution of the present invention can generally guarantee a reduction of over 90% in protein adhesion.

[0149] Resistance to bacterial adhesion in tissues Antifouling bacterial activity was evaluated for Staphylococcus aureus (S. aureus), Escherichia coli (E. coli), and Proteus mirabilis (P. mirabilis). Bacteria were grown overnight in trypsin-containing soy broth (TSB) at 37°C. The total bacterial load was measured using 10-factor serial dilutions (10) of TSB. -1 ~10 -7 The microorganisms were evaluated using a suitable selective medium, seeded in a Petri dish, and kept in an incubator overnight. After incubation, the effective microbial concentration was measured by counting the CFU. Furthermore, the optical density at 600 nm was measured for each serial dilution, and the linearity between the latter and the effective microbial load of the broth was verified.

[0150] Polyurethane (PU), polyamide (PA), silicone (SI), and polyester (PE) samples were prepared using a biopsipunch (3 mm diameter) before and after treatment with a caffeic acid solution (CA, n=5 for each treatment) to obtain the same effective surface area against bacterial adhesion. To remove bacterial load before the adhesion test, the samples were washed with PBS and incubated overnight at room temperature in PBS supplemented with gentamicin (300 μg / mL) under moderate but constant stirring. After overnight incubation, the samples were thoroughly washed in PBS to remove any residual antibiotics that could distort the test results. Subsequently, treated and untreated samples were subjected to single exposure to Staphylococcus aureus (S. aureus), Escherichia coli (E. coli), and Proteus mirabilis (P. mirabilis) for 90 minutes at room temperature under moderate but constant stirring.

[0151] Subsequently, the samples were subjected to three moderate vortex passes to facilitate the isolation of loosely bound bacteria, serially diluted with washing solutions, and seeded into petri dishes containing appropriate selective growth media. Finally, after incubation at 37°C for 24 hours, CFUs were counted for each sample.

[0152] The number of colonies found in the untreated sample was set as 100%, and the percentage of adhesion inhibition was calculated for each single sample treated with a caffeic acid solution.

[0153] As shown in Figure 10, the coffee acid-based solution of the present invention has been proven effective in inhibiting surface adhesion of all bacteria considered by at least 80%, regardless of the type of plastic support. The only exception is polyurethane, which already has excellent anti-adhesion activity against Escherichia coli (E. coli). In this particular case, the inhibition rate of bacterial adhesion was lower (23.2%) compared to other materials.

[0154] Thrombin generation test (TGA) Samples of polyurethane (PU), polyamide (PA), silicone (SI), and polyester (PE) were subjected to a thrombin formation assay (Haemoscan, Groningen, Netherlands) before (NT) and after treatment with a caffeic acid solution (CA, n=5 for each treatment). Thrombin is a key enzyme in the coagulation cascade. Its measurement provides direct information about the thrombogenicity of biomaterials (i.e., their ability to form thrombi). In normal plasma, thrombin is incorporated into the fibrin network and rapidly inactivated by antithrombin III or other antiproteases. Thrombin's short half-life hinders accurate enzyme quantification. The thrombin formation assay is based on a special plasma product that allows for the measurement of thrombin activity in incubation medium after exposure to biomaterials. This method is suitable for evaluating the blood compatibility of biomaterials and medical devices according to the international standard ISO 10993-4:2002. Samples were processed according to the manufacturer's instructions. In short, samples were incubated in modified human plasma (plasma provided by the manufacturer) and then collected at different time points. The thrombin concentration of the samples was determined from the optical density calibration curve at 405 nm. The thrombin generation curve for each sample was constructed by plotting the thrombin concentration against the time at which the sample was collected. This curve was used to measure the thrombin generation rate, and the sample was measured in 1 cm³. 2 The results are represented by a hit. Reference materials, particularly low-density polyethylene (LDPE, with a low tendency to form thrombin) and medical-grade steel (LDPE, with a high tendency to form thrombin), were provided by the manufacturers. As shown in Figure 11, the materials generally exhibit good resistance to thrombus formation by the original materials (NT), with the exception of polyester, which tends to behave more similarly to medical-grade steel. Surprisingly, treatment with a caffeic acid solution (CA) can significantly reduce the thrombotic tendency in all treated materials, inhibiting it by up to approximately 60% (for polyurethane and polyester).

[0155] From the above disclosure, the advantages provided by the present invention will be immediately apparent to those skilled in the art.

[0156] For example, the present invention can limit the adhesion of proteins and several bacterial strains to different plastic supports used in the manufacture of medical devices, and thus can prevent bacterial colonization and infection.

[0157] Furthermore, the present invention has been shown to protect treated plastic supports from the formation of thrombi and structured thrombi.

[0158] Such treatments demonstrate high chemical stability with plastic substrates and have proven effective in modifying the surface interaction properties of plastic polymers, thereby enabling them to adjust the degree of hydrophilicity.

[0159] The present invention has been proven to be extremely stable and safe, as confirmed by SEM and NMR analysis.

[0160] Finally, the present invention provides a method that can be implemented using conventional equipment and machinery.

[0161] The present invention is subject to numerous modifications and variations, all of which fall within the scope of the appended claims. Furthermore, all elements may be replaced with other technically equivalent elements.

[0162] References 1. EP3972659 - Method for preventing the formation of calcified deposits and for inactivating xenoantigens in biologicals matrices; 2. EP3383446 - Method for inactivating xenoantigens in biological tissues; 3. Eur J Cardiothorac Surg 2022; ezac583. doi: 10.1093 / ejcts / ezac583. Online ahead of print. 4. Cardiol Cardiovasc Med 2022;6(5):487-492. doi: 10.26502 / fccm.92920287. 5. Tissue Eng Part A 2017;23(19-20):1181-1195. doi: 10.1089 / ten.tea.2016.0474. 6. ACS Appl Mater Interfaces 2016;8(40):26570-26577. doi: 10.1021 / acsami.6b08930. 7. Chem Commun (Camb) 2016;52(2):312-315. doi: 10.1039 / c5cc07090b. 8. Polymers (Basel) 2019;11(7):1200. doi: 10.3390 / polym11071200. 9. Biomater Sci 2019;7(12):5035-5043. doi: 10.1039 / c9bm01223k.

Claims

1. A method for imparting antimicrobial properties to a synthetic substrate, comprising the step of contacting the substrate with a caffeic acid-based treatment solution.

2. A method for imparting antimicrobial properties to a synthetic substrate according to the claim, wherein the synthetic substrate is made of a material selected from the group including polyurethane, polyester, polyamide, polyethylene, silicone, PEEK, polyacrylate, acrylic hydrogel, Teflon, polysiloxane, and fluorinated polymer.

3. The method according to claim 1 or 2, wherein the method includes a step of pre-treating the surface, wherein the surface is incubated in a pre-treatment solution of C1-C4 alcohol.

4. The method according to the claim, characterized in that the pretreatment solution comprises methanol, ethanol, isopropanol, or butanol.

5. The method according to claim 3 or 4, wherein the incubation is continued for a period of 2 minutes to 24 hours.

6. The method according to any one of claims 3 to 5, characterized in that the pretreatment solution contains the C1-C4 alcohol at a concentration of about 10 to 100% (v / v).

7. The method according to any one of claims 3 to 6, characterized in that, prior to the pretreatment step, the pretreatment solution is maintained at a temperature of -25°C to -15°C for about 10 minutes to 5 hours.

8. The method according to any one of the claims, characterized in that the concentration of caffeic acid in the processing solution is about 1 to 10 mg / ml.

9. The method according to any one of the claims, characterized in that the processing solution is a C1-C4 alcohol solution.

10. The method according to any one of the claims, characterized in that the treatment solution comprises methanol, ethanol, isopropanol, or butanol.

11. The method according to any one of the claims, characterized in that the processing solution further comprises a second component.

12. The method according to the claim, characterized in that the concentration of the second component is about 0.1 to 20 mg / ml.

13. The method according to any one of claims 11 or 12, wherein the second component is selected from the group comprising polyphenols and salts or esters thereof, phenolic compounds and salts and derivatives thereof, antibiotics or antimicrobial agents, methylated phenols, fatty acids and esters thereof, and metal-based solutions.

14. The aforementioned polyphenols include resveratrol, aloin, cyanarin, epigallocatechin, tannic acid, chlorogenic acid, hydroxytyrosol, rosmarinic acid, narigenin, gallic acid, hesperidin, quinic acid, and eleonolic acid. Garlic acid, pinoresinol, luteolin, apigenin, tangeritin, isorhamnetin, kaempferol, myricetin, eriodictiol, theaflavin, thearubigin, daidzein, genistein, glycitein, pterostilbene, delphinidin, malvidin, pelargonidine, peonidine, chicory acid, ferulic acid, salicylic acid, baicalein, 5,7-dihydroxy-4-phenylcoumarin, rutin hydrate, 5,8-dihydroxy-1,4-naphthoquinone, 2,3-dichloro-5,8-dihydroxy-1,4-naphthoquinone, ethyl-3,4-dihydroxy-cinnamate, butyl gallate, 4-hydroxyl-4-biphenyl carboxylic acid, oleuropein, garlic acid The method according to any one of claims 11 to 13, characterized in that it is selected from the group comprising (acid), magnolol, curcumin, and ethyl-3,5-dihydroxy-benzoate.

15. The method according to claim 13, characterized in that the phenol compound is selected from the group comprising vanillin, cinnamic acid, phenylalanine, coumarin, xanthones, catechins, flavonoids, flavones, chalcones, flavanonols, flavanols, leucoanthocyanidins, anthocyanidins, hydroxycinnamic acid, phenylpropanoids; and salts or esters thereof.

16. The method according to claim 13, characterized in that the antibiotic or antimicrobial agent is selected from the group comprising penicillin, aminoglycosides, carbapenems, glycopeptides, and lipoglycopeptides, such as vancomycin, monobactam, aztreonam, oxazolidinone, such as linezolid and tedizolid, rifamycin, streptogramin, such as quinupristin and dalfopristin, cephalosporins, tetracyclines, macrolides, fluoroquinolones, and sulfonamides.

17. The method according to claim 13, characterized in that the methylated phenol is selected from the group comprising α-tocopherol, β-tocopherol, γ-tocopherol, δ-tocopherol, and tocotrienol.

18. The method according to claim 13, characterized in that the metal-based solution is selected from the group comprising an acetate, sulfate, phosphate, chloride, nitrite, nitrate, or carbonate of any one of the groups including iron, silver, gold, zinc, copper, barium, magnesium, and aluminum.

19. The method according to any one of the claims, characterized in that the pH of the treatment solution is adjusted to about 2.5 to 9.0, preferably about 5.5 to 8.

0.

20. The above process constitutes at least one processing cycle: i) The synthetic substrate is incubated in the processing solution, and then ii) Washing the synthetic substrate. The method according to any one of the claims, characterized by including

21. The method according to the claim, characterized in that the treatment comprises at least one cycle performed at pH 5.

5.

22. The method according to the claim, characterized in that the treatment further comprises at least one cycle performed at pH 8.

0.

23. The method according to any one of claims 20 to 22, characterized in that the treatment includes one to five treatment cycles performed at pH 5.

5.

24. The method according to any one of claims 20 to 23, characterized in that the treatment includes one to five treatment cycles performed at pH 8.

0.

25. The method according to any one of claims 20 to 24, characterized in that the processing is carried out in the dark.

26. The method according to any one of claims 20 to 25, characterized in that step i) is performed for approximately 5 to 25 minutes.

27. The method according to any one of claims 20 to 26, characterized in that the washing is performed in a buffer solution.

28. The method according to any one of claims 20 to 27, characterized in that step ii) is performed for a period of about 2 to 120 minutes.

29. The method according to any one of claims 20 to 28, characterized in that the washing is performed with a washing solution selected from the group comprising PBS (phosphate buffer), bicarbonate buffer, Dulbecco's phosphate-buffered saline, TBE (Tris / boric acid / EDTA buffer), TE (Tris / EDTA) buffer, Tris-buffered saline (TBS), SSC (sodium chloride / sodium citrate), and SSPE (sodium chloride / sodium phosphate / EDTA).

30. The method according to any one of claims 20 to 29, characterized in that the method further comprises a drying step.

31. The method according to the claim, characterized in that the drying step is carried out at a temperature of approximately 30 to 45°C.

32. The method according to claim 30 or 31, characterized in that the drying step is performed for a period of about 1 minute to 5 hours.

33. The method according to any one of claims 1 to 32, wherein the synthetic substrate can also be given one or more properties selected from the group including inhibition of surface adhesion to serum proteins, resistance to tissue bacterial adhesion, and inhibition of thrombin production.

34. The method according to any one of claims 1 to 33, characterized in that the antimicrobial properties are against Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Proteus mirabilis, Enterococcus faecalis, Listeria monocytogenes, Salmonella enterica typhimurium, Streptococcus viridans, Mycobacterium chelonae, Candida, and Aspergillus brasiliensis.

35. A synthetic substrate obtained by the method described in any one of the above claims.

36. A medical device comprising the synthetic substrate described in the above claim.

37. The medical device according to the claim, selected from the group including catheters, such as vascular catheters, urinary catheters, embolic protection filters, abdominal wall repair meshes, syringes, kits for various applications, laboratory tubes, blood bags, tools, gloves, trays, thermometers, and sutures.

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