EP3068451A1 - Implant doté de propriétés de surface améliorées - Google Patents

Implant doté de propriétés de surface améliorées

Info

Publication number
EP3068451A1
EP3068451A1 EP14796766.5A EP14796766A EP3068451A1 EP 3068451 A1 EP3068451 A1 EP 3068451A1 EP 14796766 A EP14796766 A EP 14796766A EP 3068451 A1 EP3068451 A1 EP 3068451A1
Authority
EP
European Patent Office
Prior art keywords
implant
state
proteins
hydration
metal
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP14796766.5A
Other languages
German (de)
English (en)
Inventor
Arik Zucker
Stefano BUZZI
Armin W. MÄDER
Vincent MILLERET
Martin Ehrbar
Algirdas ZIOGAS
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Qvanteq AG
Original Assignee
Qvanteq AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Qvanteq AG filed Critical Qvanteq AG
Publication of EP3068451A1 publication Critical patent/EP3068451A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
    • A61L31/00—Materials for other surgical articles, e.g. stents, stent-grafts, shunts, surgical drapes, guide wires, materials for adhesion prevention, occluding devices, surgical gloves, tissue fixation devices
    • A61L31/02—Inorganic materials
    • A61L31/022—Metals or alloys
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/82—Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/86—Stents in a form characterised by the wire-like elements; Stents in the form characterised by a net-like or mesh-like structure
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
    • A61L31/00—Materials for other surgical articles, e.g. stents, stent-grafts, shunts, surgical drapes, guide wires, materials for adhesion prevention, occluding devices, surgical gloves, tissue fixation devices
    • A61L31/14—Materials characterised by their function or physical properties, e.g. injectable or lubricating compositions, shape-memory materials, surface modified materials
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2310/00—Prostheses classified in A61F2/28 or A61F2/30 - A61F2/44 being constructed from or coated with a particular material
    • A61F2310/00005—The prosthesis being constructed from a particular material
    • A61F2310/00011—Metals or alloys
    • A61F2310/00023—Titanium or titanium-based alloys, e.g. Ti-Ni alloys
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
    • A61L2400/00—Materials characterised by their function or physical properties
    • A61L2400/18—Modification of implant surfaces in order to improve biocompatibility, cell growth, fixation of biomolecules, e.g. plasma treatment

Definitions

  • the present invention relates to an implant for vascular implantation in a body, in particular a vascular prosthesis z.
  • a vascular prosthesis z In the form of a stent and a use of the implant for regulating a
  • Implants such. B. stents used in blood vessels pose certain risks for the patient. Among other inflammatory reactions can occur and it can lead to a renewed stenosis in the blood vessels z.
  • thrombosis formation on the surface of the implant or by neointimal hyperplasia By thrombosis formation on the surface of the implant or by neointimal hyperplasia.
  • contaminants on the surface of the implant such as may result from conventional handling and cleaning of the implant or transfer of the implant, can affect the body's response to the implant. Complications can be caused by the
  • Adsorption of proteins on the surface of the implant are triggered as soon as they come into contact with the body or with blood.
  • the amount and type of adherent proteins determine the further biological reactions between the body and the implant.
  • the adsorption of certain blood components is promoted or reduced and their effects activated or inhibited. This implant-body interaction determines the success or failure of the implant to grow into the body.
  • the successful ingrowth of an implant thus depends on the properties and the nature of the surface of the implant. Implants with various surface coatings are known from the prior art, wherein the individual coatings are intended to assist and influence the ingrowth of the implant in one way or another.
  • a stent with a nanoporous surface layer is known to improve ingrowth of the stent and its reendothelialization and to reduce inflammation and intimal proliferation.
  • the nanoporous surface layer may be provided with one or more therapeutic agents.
  • Experimental results for stents with a controllable elution system disclosed in US 2008/0086198 A1 show in comparison to bare stents Metal surface (bare metal stents) a lower restenosis. In a stent with a simple metal surface, a chronic irritation of the tissue surrounding the stent is suspected.
  • EP 1254673 B1 shows a stent whose surface should be such that a recognition of the stent as a foreign body is minimized.
  • the surface structure of the stent is intended to mimic the surface structure of the body's own cells. This is realized by spaced-apart microstructures on the stent surface which have an extension in the
  • Stent surface reduced. This should lead to a reduced inflammatory response and thus reduce the immune response.
  • Implants with coated surfaces or with surfaces which are provided with structures or a defined roughness are expensive to produce. Furthermore, such surfaces complicate the cleaning and
  • an implant for vascular implantation in a body has a surface which is provided in an implanted state for contact with the body or a body fluid and which is hydrated at least for the most part.
  • the surface thus has a hydration which covers at least the majority of the surface.
  • the surface is completely covered with the hydration.
  • the invention includes vascular implants of any kind, in particular implants that come into contact with body fluids and are used in the field of fluid dynamics of the body.
  • an implant with the features according to the present invention may advantageously be designed as a vascular prosthesis, such. Stents, grafts, heart valves, pacemaker elements, etc.
  • the invention particularly relates to cardiovascular implants used in soft tissue of the body, such as stents.
  • stents In contrast to bone implants such implants should not absorb or absorb the body fluid, such as blood.
  • Stents are usually tubular and constructed from a plurality of webs, which together form a kind of grid. The surface of a stent is formed by the surface of the webs or of the grid.
  • the implant is in a first state in which there is little or no hydration of the surface.
  • the surface is then subjected to a treatment for hydration so that the surface is at least largely hydrated in a second state in which the implant is inserted into the body or body lumen.
  • the characteristic of the implant surface in the first state can be the characteristics of a
  • the first state may also be referred to as a state of a conventionally manufactured and
  • Implantation provided implant can be considered.
  • the first state can thus be regarded as the initial state of the implant, in which the implant z. B. after molding or a first cleaning is present. Also, in the initial state, the implant may already be mounted in or on an insertion system.
  • the implant surface is fully hydrated during implantation. This includes the inner and outer surfaces, but also the lateral surfaces, as with a stent through his
  • Hydration can be achieved by hydroxide groups attached to the surface to which
  • Water molecules are adsorbed.
  • the hydration preferably comprises at least one water monolayer on the surface.
  • more water molecules are bound to the water monolayer, so that a
  • Hydration layer is present with a greater thickness than in the water monolayer. It can also be several monolayers stacked on each other. The water monolayer is by hydrogen bonds (H-bridges) strongly to the
  • Hydroxide groups bound to the surface can be bound by dipole-dipole bonds and / or by Van der Waals forces and / or H-bridges weaker to the water monolayer and thus form further molecule layers.
  • Contamination provides e.g. a suitable inert wrapping or packaging.
  • handling and storage of the implant can take place, as described in applicant's co-pending patent application (application number CH 00048/12).
  • the metal surface for hydration may have a first surface charge in a first state and take a second state with a second surface charge having a lower positive surface charge or a higher negative surface charge compared to the first
  • Embodiments of the present invention are referred to.
  • Implant inserted into the body or a body lumen overall a more negative surface charge than in the first state.
  • the second surface charge of the surface is negative. This can be done by the
  • an implant according to the present invention is intended to regulate adsorption of proteins on the surface of the implant with respect to the type, amount and / or conformation of particular proteins through a defined surface that is at least largely hydrated.
  • the defined surface may also have a defined surface charge and / or a defined predetermined composition of an oxide layer of the surface. The defined state becomes a desired one
  • implantation of the implant can change the amount of surface-adhering proteins and other elements, for example, reducing unwanted proteins and increasing the location of desired proteins.
  • Neutrophils can be increasingly located on the implant surface, which secrete cathelicidin and are therefore responsible for a reduction of restenosis.
  • the adsorption of platelets can be reduced.
  • the risk of complications in the implantation of an implant is significantly reduced and the ingrowth of the implant is improved.
  • a zeta potential value of the surface should be below the zeta potential value in the first state.
  • a pH of about 7.4 which corresponds to the pH of blood
  • a zeta potential value of less than -60 mV, in particular less than -70 mV is advantageous.
  • the zeta potential can z. B. serve to determine a defined state of the implant surface.
  • the mentioned potential values refer to a determination method by means of electrokinetic analysis. When using other methods of determination, the values of potential values may need to be in accordance with the
  • the surface of the implant can be characterized by the isoelectric point on the surface.
  • the isoelectric point is defined as the pH at which the surface charge is zero.
  • the surface in the second state has an isoelectric point which is lower than in the first state of the surface.
  • the isoelectric point is below 5.0 for a hydrated metal surface.
  • the isoelectric point can serve to determine a defined state of the surface.
  • the surface treatment for producing the hydrated implant surface may, for. B. be given by a cleaning treatment and subsequent storage in a treatment solution.
  • the implant surface can be stored in a neutral or slightly acidic aqueous solution, for example in a NaCl solution or WFI water (water for injection).
  • a neutral or slightly acidic aqueous solution for example in a NaCl solution or WFI water (water for injection).
  • the implant surface z. B. be subjected to a plasma treatment.
  • surfaces is an oxidation treatment with a
  • Surface charge reduction treatment such as. B. a plasma treatment.
  • the implant is preferably made of metal or a
  • Metal alloy in particular of a chromium-containing alloy, such as a cobalt chrome alloy or a platinum chromium alloy, or Nitinol. It can also stainless steel can be used. Such materials and their
  • the implant has a bare metal surface. There are thus no coating operations, as z. B. for medicines or the like is known, necessary. Also, the surface need not be aftertreated to produce a particular surface texture. Furthermore, a bare surface facilitates cleaning and thus enables highly pure
  • Implant surfaces Particularly preferably, a hydrophilic surface is provided.
  • the hydrophilicity can z. B. simultaneously with the
  • Medication coating be provided.
  • the metals or metal alloys used according to the invention for the vascular implants have metal surfaces which have an oxide layer in the outermost layer of their metal structure.
  • the oxide layer is 2 - 3 nm thick and has oxides corresponding to the metal used.
  • Cobalt chrome surface has e.g. a share of about 2 / 3Cr2O3 oxide.
  • the surface in the second state advantageously has an oxide layer which is opposite to the oxide layer in the first state, i. H. relative to the initial state, has altered amounts of oxides. It is also possible that the oxide layer in the second state has a changed thickness, preferably thicker, than in the first state.
  • the oxide layer of the surface in the second state relative to the first state may have an increased amount of chromium oxide and / or a reduced amount of cobalt oxide and nickel oxide.
  • a reduced amount of nickel oxide or an elimination of nickel oxide can be achieved.
  • composition of different oxides are produced in the oxide layer.
  • Implants are particularly suitable for chromium alloys.
  • chromium alloys containing at least 5% chromium are preferably used.
  • Empirical studies have shown that, due to the high affinity of chromium for oxygen, such chromium alloys have an increased proportion of chromium oxide on the surface compared to
  • an implant is preferably used, which consists of a
  • the surface has an oxide layer in which at least 30% of the oxide consists of chromium oxide, preferably of at least 50%.
  • the chromium oxide reacts with the
  • Implant surface is at least largely hydrated.
  • Proteins are complex copolymers whose 3-dimensional structure is composed of several levels.
  • the structure structure may include amino acid sequences, various helix and ⁇ -sheet structures, the shared structure of several polypeptides, and the like.
  • a natural conformation is understood to be a conformation of the proteins which the proteins occupy, when no external influences affect and influence the 3-dimensional structure of the proteins. As an at least almost natural, or nature-like
  • Conformation is said to be a conformation where there are small changes in protein structure, but these changes have no or negligible influence on the function and effect of the protein.
  • the proteins are different areas, eg. B. positively or negatively charged areas, hydrophilic and hydrophobic areas, which are exposed depending on the spatial organization of the proteins and can perform specific biological functions.
  • a protein has z.
  • a highly denatured conformation is present on a hydrophobic surface, while a less denatured conformation exists on a hydrophilic surface.
  • the hydrophilic components of the proteins in the natural conformation are usually located outside and the hydrophobic components are usually located inside and are accessible only by a strong conformational change for the hydrophobic surface.
  • information about protein conformation can be obtained.
  • z As fibrinogen on an implant surface according to the invention can be settled at least almost in its natural, or natural-like conformation, as confirmed by the above observations.
  • the effect of fibrinogen on an implant surface according to the invention can be improved, since fibrinogen mainly in a beneficial
  • Conformation is adsorbed.
  • fibrinogen is adsorbed on an implant surface in the initial state of a metal surface in a denatured state, thereby having a negative influence on the
  • the body's defense can detect the difference between natural and denatured protein, particularly fibrinogen, so that denatured protein is identified as a foreign body and a counter reaction is triggered. Fibrinogen and other proteins can be found in a natural conformation to a healthy body.
  • the Applicant therefore reserves the right to make a separate patent application on an implant for vascular implantation in a body having a surface intended to be in an implanted state for contact with the body or a body fluid, the surface comprising a layer of proteins, in particular of fibrinogen, in an at least almost natural, or
  • the location of proteins in an at least nature-like conformation is advantageously provided on a bare metal surface of the implant. Furthermore, the layer is advantageously provided on a hydrophilic surface of the implant.
  • Patent application will be fully within the scope of the present invention Patent application was added to the present to the present
  • the amount of adsorbed proteins can vary compared to the initial state of the implant surface in the defined second state of the surface. For example, the absolute amount of proteins adsorbed may be reduced and / or certain types of proteins may be increased and other types of proteins may be less adsorbed. Thus, the risk of unwanted
  • the nature of the adhered proteins can be regulated by generating a suitably defined second state with the hydration and, for example, different oxides in the oxide layer or different surface charge.
  • the adsorption of the proteins can be influenced.
  • the conformation of proteins on the surface can be regulated.
  • fibrinogen may correspond to its natural conformation on the
  • Implant surface are settled, as stated above. This preserves its natural activity and promotes the deposition of neutrophils.
  • FIG. 1 shows a schematic sequence of the ingrowth of a conventional bare metal stent (above) and of a bare metal stent according to the invention with an increased negative surface charge according to the invention (below),
  • Fig. 3a Diagram of the amount of adsorbed proteins on an implant metal sample with a cobalt chromium surface with a first Surface charge and a second surface charge from a measurement by ⁇ -BCA method
  • Fig. 3b Diagram of the amount of adsorbed proteins on an implant metal sample with a cobalt chrome surface with a first
  • 4a-4g are diagrams of the protein adsorption of a
  • Implant metal specimens having a cobalt chrome surface with a first one
  • Fig. 5 is a diagram of a number of neutrophils
  • Fig. 6 diagram of the relationship of a
  • Fig. 7 diagram of a number of neutrophils on
  • Implant surface without a hydration treatment favoring ingrowth of the implant without complications.
  • a stent was used with a bare metal surface, as z. B. made in the prior art and is used as a vascular prosthesis.
  • the outer surface of the stent is intended to rest against a vessel wall of a body.
  • the surfaces of the stent come into contact with the blood in the vessel.
  • metal samples were z. B. used in the form of discs for performing surface measurements.
  • the metal samples consist of a metal or a metal alloy, as it is also used for a vascular implant, or the stent.
  • the metal surfaces of the samples are equivalent to surfaces of stents intended for implantation. It is investigated cobalt chromium, platinum chromium and nitinol. Basically, other metals or metal alloys with
  • a cobalt chrome alloy MP35N (ASTM F562) consisting of about 34 wt% cobalt, about 35 wt% nickel, about 20 wt% chromium, about 10 wt% molybdenum, and less than 1 wt% of titanium and iron and one
  • Cobalt chromium alloy L605 (ASTM F90) consisting of about 51 wt% cobalt, about 20 wt% chromium, about 15 wt% tungsten, about 10 wt% nickel, less than 3 wt% iron, about 1 .5 wt% Manganese and less than 1 wt% silicon.
  • XPS measurement X-ray photoelectron spectroscopy
  • Kratos Axis Nova instrument a Kratos Axis Nova instrument on 12 different samples
  • zeta potential measurement with a Surpass Electrokintetik Analyzer with variable pH on 2
  • the investigated stents and the metal samples are initially in a first state with little or no hydration, the one
  • Initial state corresponds.
  • the initial state is z.
  • the stent is thus finished in the initial state and ready for implantation in the sense of the prior art.
  • the stent and metal samples are surface treated.
  • Such a surface treatment for generating the hydration may, for. B. be a bath in a previously mentioned solution.
  • a surface treatment to change the surface charge can be done, for. Example, by an oxidation treatment in the form of a plasma treatment and / or a bath in a previously mentioned aqueous solution.
  • the plasma treatment results in oxidation and removal of hydrocarbon.
  • an oxygen plasma is used.
  • the bath may have a predetermined pH, which is tailored to the material of the metal samples.
  • an alkaline solution is used.
  • an argon plasma that is non-oxidizing may be used in combination with a bath in an aqueous NaCl solution that acts as an oxidizer.
  • the treated surface has uniform surface properties with a second, lower surface charge and hydration in the sense of the invention.
  • Implant surface are maintained.
  • the stent may be subjected to a surface treatment even if it is already inserted in or on an insertion system for introducing the stent into the body or a body lumen, or after
  • Treatment can be used in such a system. It is important to ensure that the surface charge of the second state is maintained.
  • FIGS. 1a to 1c show the process of ingrowth of a conventional bare-surface metal stent V in a first state (above) and a bare-surface metal stent 1 according to the invention in a second state with an increased negative surface charge (below).
  • FIG. 1d shows for the stents 1 and V the ingrowth of the stents in a coronary artery of a pig after 30 days.
  • the stent is placed at the site of implantation and the
  • neutrophil inhibitors 2 a 2 -macroglobulin, apolipoprotein A.
  • the stent 1 with increased negative surface charge are the neutrophil inhibitors 2 (a 2 -macroglobulin, apolipoprotein A).
  • Neutrophil inhibitors are strongly reduced and at the same time deposit both proteins that prevent the adhesion of platelets (Kininogen high molecular weight - HMWK), as well as proteins that promote the adhesion of neutrophils on the stent surface (eg plasminogen, fibrinogen in natural or Accordingly, the stent V in the first state (FIG. 1 b, top) on the neutrophil inhibitors 2 is then mainly colonized by platelets 4, which are generally undesirable.
  • the stent 1 with increased negative surface charge FIG. 1 b, bottom
  • neutrophils 5 from the patient's blood are placed on the neutrophil promoters 3 and activated, while platelets are rejected.
  • stent V in the first state cathelicidin was found only to a small extent. The studies have shown that the stent 1 in the second state accumulates two to three times more cathelicidin than the conventional stent.
  • FIG. 1 d shows for the stents 1 and 1 'the ingrowth of the stents in a coronary artery of a pig after 30 days.
  • the stent 1 with a hydrated surface shows a uniform ingrowth behavior with a widely open inner lumen (see Fig. 1 d, bottom).
  • the stent V in the initial state shows ingrowth with a re-narrowing of the passageway (see Fig. 1d, top).
  • the surface of the stent 1 with a surface that is hydrated at least largely in relation to conventional stents supports and promotes those bioactive processes that lead to a healthy and desirable ingrowth of the stent 1.
  • FIG. 2 shows the states during hydration of an implant surface with chromium oxide in the outer oxide layer. On the left, the chromium oxide is shown in a state without hydration. The chromium atoms, bound by their high affinity for oxygen, oxygen atoms.
  • the chromium oxide is converted into chromium hydroxide by chemisorption of water molecules, in which the hydroxy groups are bound by a strong bond to the surface (Figure 2, center).
  • Figure 2, center By water physisorption, another state ( Figure 2, right) is obtained with a physisorbed water layer in which the water may be partially dissociated.
  • the water molecules are through a
  • the implant surface has a water monolayer, as is preferably provided for the hydration according to the invention.
  • this water Monolage can, for. B. by a water bath, other water molecules
  • water molecules are weaker bound, such as van der Waals or dipole-dipole forces.
  • the physisorption of water molecules can be achieved by a suitable pretreatment, for. As a cleaning and in particular by reducing the surface charge, be supported, so that an at least largely hydrated implant surface can be reliably prepared.
  • the oxide layer in the initial state the oxide layer has a thickness of 2-3 nm.
  • the oxide layer consists essentially of about 66% Cr 2 Os (Cr (III)) oxide, about 10% Co-oxide, about 10% Mo oxide, about 9% Ni Oxide, about 5% Ti oxide.
  • Cr (III) Cr 2 Os
  • a second MP35N sample was subjected to an oxidation treatment followed by storage in a neutral solution and thus is in a second state according to the
  • the MP35N oxide layer also has a thickness of 2 - 3 nm and is made of 75% Cr 2 O (Cr (III)) oxide, about 7% Co oxide, about 8% Mo oxide, ca 7% Ni oxide and about 4% Ti oxide.
  • Cr (III) Cr 2 O
  • the MP35N oxide layer also has a thickness of 2 - 3 nm and is made of 75% Cr 2 O (Cr (III)) oxide, about 7% Co oxide, about 8% Mo oxide, ca 7% Ni oxide and about 4% Ti oxide.
  • the amount of chromium oxide is higher and the amount of cobalt oxide and nickel oxide is lower than in the first state.
  • a hydration forms on the surface, the water molecules z. B. to the
  • Chromium ions bind, as previously explained.
  • the surface charge can be changed to a more negative value and on the other hand, the composition of the oxide layer can be influenced and thus regulated.
  • the zeta potential and the surface charge were determined.
  • the zeta potential was measured at pH 7.4 in dilute KCl solution as it corresponds to the pH conditions in blood.
  • the MP35N sample In the second state after the surface treatment, the MP35N sample has a zeta potential of about -95 mV.
  • a zeta potential of -80mV is measured. This corresponds to a more negative surface charge for both samples after surface treatment. Both treated samples have an isoelectric point below 5.0.
  • the zeta potential was determined by means of an electrokinetic analysis.
  • FIGS. 3a and 3b show results from the determination of the total amount of proteins adsorbed on the surfaces.
  • FIG. 3 a shows the result of a ⁇ -BCA measurement in which the effect of protein-copper chelate formation and the reduction of the copper with bicinchoninic acid (BCA) to a colored solution product for a fluorescence measurement is utilized.
  • FIG. 3b shows the result of a qubit measurement in which the proteins adhering to the surface are desorbed and labeled with a marker
  • Fluorescence analysis be provided. Both methods show a significant reduction in protein adsorption.
  • Figure 3a shows the total adsorption of proteins for a metal sample with no or low hydration (first state, left bar) and for the metal sample with a hydrated surface (second state, right bar).
  • first state between 1 .2 and 1 .7 ⁇ g / cm 2 Proteins adsorbed on the metal surface.
  • second state right bar
  • first state between 1 .2 and 1 .7 ⁇ g / cm 2 Proteins adsorbed on the metal surface.
  • 0.7 and 0.9 ⁇ g / cm 2 proteins are adsorbed in the second state.
  • first state left bar
  • second state right bar
  • first state between 36 and 40 arbitrary units of proteins are measured on the surface.
  • second state between 30 to 34 arbitrary units of proteins are measured.
  • FIGS. 4a to 4g are graphs of measurements of the protein adsorption of an implant having a cobalt chrome surface with little or no hydration (first state) and an at least predominantly hydrated (second state) surface for the proteins plasminogen (FIG. 4a), kininogen (FIG. 4b) , Apolipoprotein E ( Figure 4c), apolipoprotein A (Figure 4d), a2-macroglobulin ( Figure 4e), fibrinogen ( Figure 4f), and albumin ( Figure 4g).
  • the metal samples correspond to the material of an implant according to the invention and have a bare cobalt chrome surface. In the first state, the surface is measured without further treatment steps, ie in the initial state.
  • the surface has been subjected to a hydration treatment as previously described and thus has an at least for the most part hydrated surface according to the invention.
  • the zeta potential in the first state is approximately -55 mV and in the second state approximately -95 mV.
  • the metal samples were incubated to measure protein adsorption in blood. For this purpose, the samples were placed in dishes with fresh blood and incubated for two hours at 37 ° C and static conditions. Subsequently, the samples were measured by the aforementioned method.
  • Adsorption on the untreated surface is normalized to 100. Thus, the deviation therefrom present in a treated surface becomes clear.
  • 4c shows the amount of apolipoprotein E on the stent surface in the first state (left bar) and in the second state (right bar).
  • the adsorption in the first state is normalized to 100 +/- 3.
  • a value of 150 +/- 30 is reached.
  • Kininogen and Apolipoprotein E are known to aggregate
  • the amount of platelets on an implanted stent surface can be regulated by increasing the proteins kininogen and apolipoprotein E on the surface.
  • the amount of apolipoprotein A is shown on the stent surface in the first state (left bar) and in the second state (right bar).
  • the adsorption in the first state is normalized to 100 +/- 10.
  • the amount of ⁇ 2-macroglobulin on the stent surface is shown in the first state (left bar) and in the second state (right bar).
  • the adsorption in the first state is normalized to 100 +/- 2.
  • the second state however, only a value of 80 +/- 3 is reached. In the second state, therefore, there is in each case a significantly smaller amount of apolipoprotein A and a2-macroglobulin.
  • Apolipoprotein A and a2-macroglobulin reduce the adsorption of neutrophils and inhibit the function of neutrophils.
  • Apolipoprotein A also inhibits cathelicidin (LL-37), which promotes positive implant ingrowth.
  • FIG. 4f shows the amount of fibrinogen on the stent surface in the first state (left bar) and in the second state (right bar).
  • the adsorption in the first state is normalized to 100 +/- 10.
  • the second state only a value of 70 +/- 5 is reached.
  • Fibrinogen can promote the adsorption of platelets and inhibit neutrophils. It is therefore advantageous to reduce the amount of fibrinogen on the implant surface.
  • Platelet inhibitors such as kininogen, and neutrophil promoters, such as
  • neutrophils can rapidly attach to an implanted surface and promote successful ingrowth of the stent.
  • a defined second surface charge and / or a defined predetermined composition of the oxide layer is formed on the implant surface by a surface charge reduction treatment and / or by an oxidation treatment, as above
  • a stent with a hydrated surface according to the invention can reduce the amount of the implant
  • the middle pair of bars in Figure 5 shows a measurement in which a metal sample was exposed to neutrophil fluid but does not contain proteins, as would normally be the case with a blood fluid.
  • the right bar pair shows a measurement in which a metal sample is first placed in
  • Blood plasma was incubated. That is, it was first a deposition of proteins from blood and then an adsorption of neutrophils. In the hydrated state (right bar) approximately 20 times more neutrophils are deposited than in the state with no or low hydration (left bar). The measurements confirm that with a hydrated metal surface, compared to an untreated metal surface in the initial state, neutrophils are significantly more adsorbed if proteins are available that can react with the surface.
  • the example of the protein fibrinogen shows the influence of the presence of this protein on a metal surface state with and without
  • the measurements carried out prove the positive effect of an implant surface with a hydrated surface on the ingrowth of an implant after the implantation, as is shown in FIGS. vivo experiments is shown.
  • Targeted adjustment of surface properties on the implant surface can be used to regulate the adsorption of proteins on the surface.
  • An implant with at least a largely hydrated surface compared to conventionally used implants thus reduces the risk of restenosis or otherwise
  • Figures 7 and 8 show the adsorption of neutrophils (Figure 7) and platelets (Figure 8) on several different metal surfaces. Measurements were made on the surface of an MP35N metal sample as described above and on pure metal surfaces.
  • Pure metal surfaces include chromium, cobalt, nickel, titanium and molybdenum. These samples were prepared by placing glass slides with each
  • PVD Physical Vapor Deposition
  • the bar pair for the pure cobalt metal sample shows that on a hydrated surface significantly more neutrophils are settled than on a hydrated chromium metal surface or MP35N surface.
  • the nickel, titanium and molybdenum samples show only a slight adsorption of neutrons. At the nickel metal sample are not at the
  • neutrophil adsorption is not
  • hydrated sample almost negligible.
  • molybdenum metal sample about 100% more neutrophils are deposited in the non-hydrated samples than in the hydrated sample, but significantly less than in one at least for the most part hydrated surface of a chrome or
  • Cobalt metal sample The measurements show that the hydration of an MP35N alloy, a chromium metal sample and a cobalt metal sample can significantly increase the adsorption of neutrophils and thus support a desired ingrowth behavior of the implant.
  • Cobalt metal sample is generally adsorbed to only a few platelets. In the non-hydrated cobalt metal sample (left) only about 100% more
  • Platelets as absorbed on the hydrated cobalt metal sample In the samples of nickel, titanium and molybdenum, the hydrated samples show a negligible number of platelets, while in the non-hydrated samples the deposition of platelets is clearly detectable and in the

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  • Health & Medical Sciences (AREA)
  • Public Health (AREA)
  • Heart & Thoracic Surgery (AREA)
  • Veterinary Medicine (AREA)
  • Vascular Medicine (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Animal Behavior & Ethology (AREA)
  • General Health & Medical Sciences (AREA)
  • Epidemiology (AREA)
  • Surgery (AREA)
  • Engineering & Computer Science (AREA)
  • Biomedical Technology (AREA)
  • Chemical & Material Sciences (AREA)
  • Inorganic Chemistry (AREA)
  • Cardiology (AREA)
  • Oral & Maxillofacial Surgery (AREA)
  • Transplantation (AREA)
  • Materials For Medical Uses (AREA)

Abstract

L'invention concerne un implant, destiné à être implanté dans un vaisseau d'un corps, qui possède une surface appelée à être en contact, dans l'état implanté, avec le corps ou avec un fluide corporel et qui est hydratée au moins en majeure partie. De manière avantageuse, la surface est réalisée sous la forme d'une surface métallique nue constituée d'un alliage contenant du chrome. L'implant vasculaire est utilisé pour réguler une adsorption de protéines sur la surface de l'implant en termes de nature, de quantité et/ou de conformation de certaines protéines par une surface définie hydratée au moins en majeure partie.
EP14796766.5A 2013-11-14 2014-11-12 Implant doté de propriétés de surface améliorées Withdrawn EP3068451A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CH01904/13A CH708834A1 (de) 2013-11-14 2013-11-14 Implantat mit verbesserten Oberflächeneigenschaften.
PCT/EP2014/074394 WO2015071324A1 (fr) 2013-11-14 2014-11-12 Implant doté de propriétés de surface améliorées

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EP3415651A1 (fr) * 2017-06-14 2018-12-19 Heraeus Deutschland GmbH & Co. KG Procédé de fabrication d'un produit passivé
US11697869B2 (en) 2020-01-22 2023-07-11 Heraeus Deutschland GmbH & Co. KG Method for manufacturing a biocompatible wire

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EP1150620B1 (fr) * 1999-01-29 2003-11-05 Institut Straumann AG Implants osteophiles
US8097269B2 (en) * 2004-02-18 2012-01-17 Celonova Biosciences, Inc. Bioactive material delivery systems comprising sol-gel compositions
EP2292178A1 (fr) * 2006-02-28 2011-03-09 Straumann Holding AG Implant de deux pièces
JP2012235797A (ja) * 2009-09-18 2012-12-06 Terumo Corp ステント

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
RAVAL A ET AL: "Development and assessment of 316LVM cardiovascular stents", MATERIALS SCIENCE AND ENGINEERING: A, ELSEVIER, AMSTERDAM, NL, vol. 386, no. 1-2, 25 November 2004 (2004-11-25), pages 331 - 343, XP004604674, ISSN: 0921-5093, DOI: 10.1016/J.MSEA.2004.07.051 *
See also references of WO2015071324A1 *

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