Systems and methods for delivering therapeutic agents

Abstract

A plasma system for depositing biomolecules, pharmaceuticals, and other therapeutic agents onto a surface is described. The system may include a plasma device having one or more electrodes, a gas supply inlet, a plasma outlet exposed to ambient pressure, and an ignition system operatively connected to the electrodes to provide a non-thermal equilibrium plasma within the plasma chamber. A particle delivery system may be used to introduce the active agent as a dry powder into or downstream of the plasma and deposit the plasma-treated active agent to create a coating on the surface. The coating may retain the activity of the active agent.

Description

(Case number 201780021294.8)

[0001] Cross-references to related applications

[0002] This application claims priority to U.S. Provisional Application No. 62 / 289,545, filed February 1, 2016, which is incorporated herein by reference in its entirety. Background Technology

[0003] Generally, there are two types of plasma: thermal equilibrium plasma and non-isothermal equilibrium plasma. Thermal equilibrium plasma is typically hot at around 10,000 K and is used in industry as plasma torches, jets, and arcs for welding. These thermal plasma systems are also used for thermal spraying, where they can be used to deposit metallic and ceramic coatings onto metal surfaces for a variety of applications, including generating biocompatible hydroxyapatite coatings on medical implants and depositing protective coatings on gas turbine components. Despite the wide range of applications for thermal plasma, their use is limited by the high thermal energy within the plasma device, which prevents these devices from depositing temperature-sensitive materials such as proteins, polysaccharides, and other chemical compounds and biological materials.

[0004] In contrast, non-isothermal plasmas are typically cold and can be used for manufacturing processes including surface cleaning (such as removing unwanted substances like contaminants), etching (e.g., removing bulk substrate material), activation (e.g., altering surface energy), and deposition of functional thin-film coatings onto surfaces. Historically, these coating apparatuses were limited to vacuum conditions and used only gas-phase precursors to produce coatings. Consequently, the chemical properties of the deposited materials were inherently oversimplified, and these apparatuses were incompatible with large, high-molecular-weight macromolecules.

[0005] However, plasma systems like these have been widely used to modify surfaces to allow for subsequent attachment of biomolecules via conventional wet chemical techniques. This biomolecule attachment technique relies on plasma activation as part of a multi-step process, where plasma is first used to clean and activate the substrate surface. Linker chemicals can then be deposited using either plasma deposition or standard wet chemical techniques. Finally, the target biomolecules are attached to the surface using a wet chemical method. Alternatively, plasma systems have been used to deposit coatings to which biomolecules can subsequently be attached in another wet chemical multi-step process. Regardless of the approach, complex linker and binder chemicals are required to prepare the surface before the target biomolecules can be introduced.

[0006] In recent years, plasma devices have been developed that operate at atmospheric pressure and can also produce functional coatings using gaseous monomers. However, the transition from vacuum systems to ambient pressure also allows for the use of precursors other than gaseous monomers in thin film production. US 4,929,319 discloses a method for introducing a liquid aerosol into an atmospheric corona discharge while simultaneously subjecting a flat plastic substrate to treatment via an open-air corona discharge.

[0007] US 7,455,892 discloses a method for producing a coating in which atomizes a polymeric material into a uniform atmospheric pressure plasma glow discharge to produce a polymeric coating on a substrate. The disclosed list of potential monomers includes materials known to polymerize upon exposure to free radicals or UV radiation to produce coatings. These precursors typically contain vinyl, cyclic, or other reactive groups.

[0008] WO 2007 / 106212 discloses a plasma system that incorporates an atmospheric pressure plasma device coupled to a vacuum deposition chamber for depositing biomolecules on a surface. The idea of ​​combining a vacuum chamber and an atmospheric pressure plasma jet into a single system presents complex engineering challenges. Furthermore, exposing biomolecules to a vacuum can lead to molecular damage, denaturation, and loss of functionality.

[0009] Argon plasma coagulation (APC) is a medical technique that uses high-energy argon plasma to alter tissues through a combination of protein coagulation and tissue dehydration. Under standard use, APC produces denatured and charred surfaces and is not used for depositing controlled surface chemistry. WO 02 / 28548 describes a method for introducing aerosols into atmospheric pressure glow discharge (APGD) plasma to form a coating on a substrate.

[0010] WO 2005 / 110626 describes the use of a nonthermal plasma apparatus to transfer a liquid aerosol containing an active agent and a reactive monomer into a dried coating, the dried coating comprising a polymer (generated by polymerizing the reactive monomer) and an active agent physically embedded in the polymer coating. Similarly, WO 2005 / 106477 describes an atmospheric pressure nonthermal plasma method involving the introduction of reactive monomers and an active agent into a plasma to produce a polymeric coating of reactive monomers that trap the active agent.

[0011] The requirement to induce polymer precursor reactions in vivo without impairing the surfactant limits the types of molecules that can undergo controlled polymerization in plasma without losing functionality. Typically, this requires reactive precursors containing vinyl or cyclic structures that preferentially react in plasma. If molecules do not possess such functional groups, they can polymerize via bond breaking and fragmentation in other regions of the molecule, which can lead to chemical alterations and loss of functionality. Some researchers have attempted to overcome this limitation by chemically modifying molecules, for example, by adding reactive chemical functionalities. However, before these modified materials are safe for human use, the resulting coatings may lose some of the surfactant's activity and / or produce unforeseen consequences in clinical settings requiring detailed safety studies. The requirement for chemically modified molecules also increases the complexity and cost of the entire process. Furthermore, these types of methods require the surfactant to be dissolved in a solvent, which may limit the applicability of these techniques. For example, the molecules may be partially or completely insoluble, or may require the use of organic solvents known to undergo plasma polymerization, thus potentially co-polymerizing with the molecules to produce coatings containing additional unwanted materials. These materials may generate negative biological reactions. For example, many biomolecules are biologically active due to their unique shape or conformation, where thermal energy can cause denaturation, thus inactivating them. Many pharmaceutical products suffer from similar limitations and cannot be directly exposed to plasma due to loss of activity caused by chemical and / or conformational changes.

[0012] Therefore, researchers often avoid intentionally exposing biomolecules to plasma sources because the heat, electricity, UV and other active substances in the plasma can induce irreversible chemical and / or conformational changes, which will destroy the bio / pharmaceutical activity of the molecules. Summary of the Invention

[0013] This disclosure includes a method for producing a coated substrate. For example, the method may include introducing a plurality of dried particles into a non-thermal plasma, each particle containing at least one active agent selected from biomolecules, pharmaceutical agents, or combinations thereof; and exposing a substrate to the plurality of dried particles and the plasma to deposit a coating containing at least one active agent onto the substrate. The active agent may have therapeutic biological activity and / or therapeutic pharmaceutical activity. In some instances, the plurality of dried particles may be introduced into the afterglow portion of the plasma.

[0014] According to some aspects of this disclosure, each particle consists of only at least one active agent, for example, wherein the dried particles do not contain reactive monomers or chemical components that induce the polymerization of the active agent. In some instances, the active agent may be cross-linked. Before being deposited onto a substrate to form a coating, the coating may retain at least some or all of the biological or pharmaceutical activity of at least one active agent. In at least one instance, the coating comprises at least one biomolecule and / or at least one antibiotic agent.

[0015] Exemplary substrates may include, for example, external tissue, internal tissue, diagnostic components, medical devices, or food. In at least one instance, the substrate comprises a porous plate, and at least one active agent comprises a biomolecule. In other instances, the substrate comprises an implantable medical device. In still other instances, the substrate comprises external and / or internal tissue, including, for example, injured, diseased, or damaged tissue.

[0016] According to some aspects of this disclosure, the coating comprises at least one first layer containing a pharmaceutical agent and at least one second layer containing a biomolecule. The first layer may be adjacent to the second layer and / or the coating may include one or more first layers between one or more second layers. In some instances, the thickness of the first and / or second layers may range from 10 nm to 500 nm, such as 50 nm to 150 nm, 10 nm to 100 nm, 75 nm to 250 nm, or 300 nm to 500 nm. For example, the total thickness of the coating including the first and second layers may range from about 20 nm to 1 μm or more.

[0017] The coating may contain a single surfactant or two or more surfactants. In at least one instance, at least one surfactant comprises a first surfactant and a second surfactant, and introducing multiple dried particles into the plasma includes introducing different portions of the first surfactant and the second surfactant into the plasma, wherein the first surfactant is a biomolecule and the second surfactant is a pharmaceutical agent.

[0018] This disclosure also includes a method for producing a coated substrate, comprising: applying at least one surfactant to a substrate surface, said at least one surfactant being selected from biomolecules, pharmaceuticals, or combinations thereof; and exposing the substrate surface to the afterglow of a plasma to form a dried coating comprising at least one surfactant.

[0019] Applying at least one active agent may include forming a uniform layer of at least one active agent on a substrate surface. In some instances, the at least one active agent is applied as a dried solid. In some instances, a solution of at least one active agent with at least one solvent is applied to the substrate surface, and the substrate surface is dried before exposure to plasma. As described above and elsewhere herein, exemplary substrates include tissues (e.g., external and / or internal tissues, including injured, diseased, or damaged tissues), diagnostic components, medical devices, and food. The resulting dried coating may retain at least some or all of the biological or pharmaceutical activity of the at least one active agent.

[0020] This disclosure also includes a method for producing a coated substrate, comprising exposing the substrate to a pharmaceutical agent and plasma to deposit at least one first layer containing the pharmaceutical agent onto the substrate, wherein the at least one first layer retains the pharmaceutical activity of the pharmaceutical agent; and exposing the substrate to biomolecules and plasma to deposit at least one second layer containing the biomolecules onto the substrate, wherein the at least one second layer is adjacent to the at least one first layer; wherein the at least one first layer retains the pharmaceutical activity of the pharmaceutical agent, and the at least one second layer retains the bioactivity of the biomolecules. For example, at least one of the pharmaceutical agent or biomolecules may be introduced into the plasma (e.g., the afterglow or afterglow region of the plasma) in the form of dry particles.

[0021] According to some aspects of this disclosure, at least one first layer comprises a plurality of first layers with a total thickness ranging from 10 nm to 500 nm, such as 50 nm to 150 nm, 10 nm to 100 nm, 75 nm to 250 nm, or 300 nm to 500 nm. Additionally or alternatively, at least one second layer may comprise a plurality of second layers with a total thickness ranging from 10 nm to 500 nm, such as 50 nm to 150 nm, 10 nm to 100 nm, 75 nm to 250 nm, or 300 nm to 500 nm. In some instances, the total thickness of a coating comprising a plurality of first layers and a plurality of second layers ranges from 20 nm to 1 μm or greater, for example, a total coating thickness ranging from 50 nm to 800 nm, 100 nm to 500 nm, 250 nm to 750 nm, or 300 nm to 500 nm. For example, the total thickness of the coating can be about 50 nm, about 100 nm, about 150 nm, about 250 nm, about 300 nm, about 500 nm, about 750 nm, about 800 nm, about 900 nm, about 1 μm or greater than 1 μm.

[0022] As described above and elsewhere in this document, exemplary substrates include tissues (e.g., external and / or internal tissues, including injured, diseased, or damaged tissues), diagnostic components, medical devices, and food. In at least some instances, plasma can have greater power during substrate exposure to biomolecules and plasma compared to exposing the substrate to pharmaceuticals and plasma.

[0023] This document also discloses devices comprising coatings as described above and in the following detailed embodiments, such as coatings containing at least one active agent, such as a biomolecule, a pharmaceutical agent, or a combination thereof. For example, the devices may include diagnostic components or medical devices. Detailed Implementation

[0024] This disclosure includes systems, apparatus, and methods for delivering active therapeutic agents (e.g., biomolecules, pharmaceutical active agents, and / or combinations thereof) to surfaces (e.g., tissue surfaces or non-tissue substrates). The term "biomolecule" as used herein generally refers to molecules present in living organisms (including, for example, molecules involved in metabolic processes), including but not limited to large macromolecules such as proteins, carbohydrates, lipids, and nucleic acids, as well as small molecules such as primary metabolites, secondary metabolites, and natural products. The deposited coating may contain mixtures or combinations of different active agents, such as mixtures of different biomolecules and / or pharmaceutical agents. In some instances, one or more or all of the active agents in the coating are vinyl-free.

[0025] Plasma offers numerous advantages for coating deposition. The combination of reactive plasma and chemically active monomers can produce coatings that are uniform, pinhole-free, and / or well-bonded to the substrate. Furthermore, the curing of the coating material can occur almost instantaneously, providing processing advantages.

[0026] The methods described herein can be used to deposit one or more active agents onto external or internal tissues, or onto another substrate surface, such as medical devices or diagnostic components. Exemplary medical devices include, but are not limited to, scalpels, clamps, needles, and medical implants such as stents, catheters, ports, expandable balloons, prosthetic implants, orthopedic implants, dental implants, cochlear implants, ear tubes, implantable mesh, spinal cages, maxillofacial implants, scaffolds (e.g., for tissue regeneration or transplantation), pulse generators, valves, hormone delivery implants, skin grafts, bone grafts, artificial spectacle lenses, contact lenses, hearing aids, breast implants, trauma fixation devices, screws, plates, rods, pins, nails, needles, biosensors, sensory implants, neural implants, pacemakers, defibrillators, electrodes, subcutaneous implants including drug delivery implants, cosmetic implants, hip and knee replacement implants, hemodialysis devices, ventilators, and related tubing. Exemplary diagnostic components include, but are not limited to, multiwell plates, glass slides, pipettes and pipette tips, sample containers, glucose monitors, biosensors, enzyme biochips, affinity biochips, chemical sensors, pathogen sensors, contaminant sensors, diagnostic biochips, blood pressure monitors, ELISA detection components, and other diagnostic components.

[0027] In some aspects, this disclosure provides a plasma system or apparatus designed to generate non-thermal equilibrium or cold plasma. To achieve this, for example, the plasma can be powered at a frequency of at least 10 kHz, such as greater than 20 kHz, for example greater than 125 kHz. The maximum frequency can be less than 1 MHz, such as less than 900 kHz, for example less than 750 kHz.

[0028] In at least one aspect, the plasma is a pulsed plasma. The plasma can be pulsed at various duty cycles such that the delivered power is less than 100 W, such as less than 20 W, for example, less than 10 W. The pulse can cause the applied power to be switched off for at least 50% of the time, for example, the pulse is switched on and off multiple times per second. For example, the plasma can be pulsed on and off to provide an on-time ranging from about 1 nanosecond (ns) to about 500 milliseconds (ms). For example, the plasma can be pulsed with on-time ranging from 1 ms to 500 ms, such as 10 ms to 300 ms, 50 ms to 100 ms, for example, about 1 ms, about 10 ms, about 50 ms, about 75 ms, about 100 ms, about 200 ms, about 250 ms, about 300 ms, about 400 ms, or about 500 ms. In some aspects of this disclosure, the plasma can be an on-time pulse ranging from 1 ns to 500 ns, such as 10 ns to 300 ns, 50 ns to 100 ns, for example, on-times of about 1 ns, about 10 ns, about 50 ns, about 75 ns, about 100 ns, about 200 ns, about 250 ns, about 300 ns, about 400 ns, or about 500 ns. For example, for the treatment of tissues (such as cancerous tissue), the plasma can be a nanosecond or picosecond pulsed plasma. In these instances, the plasma can be turned on for only a fraction of a millisecond for each pulse, for example, less than 500 ns or less than 100 ns.

[0029] The systems described herein may include a plasma device comprising one or more electrodes and an ignition system operatively connected to the electrodes for providing a non-thermal equilibrium plasma. The plasma device may also include a gas supply inlet and a plasma chamber exposed to ambient pressure, wherein the non-thermal equilibrium plasma may be generated within the plasma chamber.

[0030] In at least one embodiment, the plasma device is a plasma coagulation device, and plasma generated by the device is introduced into a chamber along with at least one biomolecule and / or at least one drug. One end of the chamber may be open to the atmosphere, and the substrate to be treated (e.g., the surface of a medical device or other object, or a soft tissue surface, such as a wound) is placed adjacent to the outlet. This may result in the plasma-treated material being deposited as a coating on the surface of the substrate. While plasma coagulation devices are considered destructive under normal operating conditions, when operated at low power in the configuration described herein, the delivered power and heat can be significantly reduced, and the active agents in the coating can retain their therapeutic efficacy (e.g., bioactivity and / or pharmaceutical activity). The gas used to generate the plasma may include, for example, helium or argon. For example, the device may include an argon plasma coagulator. In some embodiments, a helium plasma coagulator may be used, for example, instead of an argon coagulator.

[0031] In another aspect, a non-thermal plasma-treated biomolecule or non-thermal plasma-treated pharmaceutical active agent is provided for coating a substrate such as a soft tissue surface (e.g., a wound) or another surface, such as a hard surface (e.g., a medical device). The coating described herein can be applied to human and / or non-human animal tissues.

[0032] The methods disclosed herein can eliminate the need for the use of solvents in the process and / or the generation of coatings with biological and / or pharmaceutical activity.

[0033] In some embodiments, the active agent (e.g., a biomolecule and / or pharmaceutical active agent) may be introduced into the plasma in the form of dried particles (e.g., dried powder). Without being bound by theory, in the case of dried particles of the active agent, it is believed that the plasma can activate the outer surface or outermost layer of each particle, thereby promoting cross-linking of the particulate material to bind the particles to each other and to adjacent target surfaces, while the majority of the material contained within the dried particles (e.g., within the activated outer layer) is protected from the active substances present in the plasma. Moreover, without being bound by theory, it is believed that the thermal energy of the plasma is sufficient to at least partially melt the outermost layer of the particles, thereby promoting the solidification of adjacent particles into a continuous layer on a substrate surface (e.g., a medical device or other object, or a soft tissue surface). Thus, the bio / pharmaceutical activity of the powder can be preserved. According to some aspects of this disclosure, the coating may consist of or be substantially composed of the active agent. That is, no additional polymer-forming material other than the active agent is required, allowing the coating to be formed from greater than 99%, for example, 100%, pure active material. According to some aspects of this disclosure, the dried particles may be introduced into the plasma as a dried particulate material, where a solution or liquid may not be required to protect the active material from the plasma.

[0034] The methods disclosed herein involve delivering an active agent (e.g., an organic molecule, such as an active pharmaceutical agent and / or a biomolecule) in the form of dried particles to a substrate surface. Many biomolecules and other organics are typically soft and deformable, such that they can be activated and attached to the surface when at least some of these materials are inherently deformable and adhere to the target surface. Without being bound by theory, it is believed that the activation of such molecules can include ion charging, which can lead to the formation of electrostatic bonds or ionic bonding. For example, in some embodiments of this disclosure, exposing the substrate and / or the active agent to plasma can result in oxidation of the substrate surface and / or activation of the active agent particles. This oxidation can lead to the formation of polar functional groups on the surface of the substrate and / or the active agent, which can participate in bonding, such as the formation of polar covalent bonds. Furthermore, without being bound by theory, it is believed that the presence of free radicals in the plasma can lead to the formation of free radicals on the surface of the active agent particles and the substrate surface, which can generate covalent bonding.

[0035] The active agent suitable for introduction into plasma in the form of dry particles may have a melting point of less than about 100°C, for example, a melting point range of 60°C to 100°C, 75°C to 100°C, 85°C to 100°C, 75°C to 95°C, or 90°C to 100°C. Alternatively or additionally, the active agent suitable for introduction into plasma may have a Mohs hardness of less than about 3, for example, a Mohs hardness of 1 to 3. For example, the active agent may have a Mohs hardness of about 1, about 2, or about 3. In at least one embodiment, the active agent introduced into the plasma as dry particles has a melting point of less than 100°C and a hardness of less than 3 on the Mohs scale. In some embodiments, the active agent does not include harder inorganic materials or ceramic biomolecules, such as hydroxyapatite, calcium phosphate, or other biominerals with a Mohs hardness greater than 3, 4, or 5.

[0036] In at least one embodiment, plasma in the form of dry particles (powder) and an active agent interact within a plasma chamber having an open end or outlet, for example, such that the active agent can be activated by the plasma. The plasma chamber may contain an inert gas or a gas mixture. A substrate may be placed adjacent to the open end of the plasma chamber to allow the activating material to be deposited on the substrate surface adjacent to the outlet of the chamber. This allows activation to occur in areas primarily filled with an inert gas or gas mixture, such as nitrogen, helium, argon, or mixtures thereof. This method can be used, for example, to coat external wounds (e.g., damaged / damaged tissue of a patient) and / or for coating devices, such as medical devices and / or diagnostic components. Exemplary medical devices include, but are not limited to, scalpels, clamps, needles, and medical implants such as stents, catheters, ports, expandable balloons, prosthetic implants, orthopedic implants, dental implants, cochlear implants, ear tubes, implantable mesh, spinal cages, maxillofacial implants, scaffolds (e.g., for tissue regeneration or transplantation), pulse generators, valves, hormone delivery implants, skin grafts, bone grafts, artificial spectacle lenses, contact lenses, hearing aids, breast implants, trauma fixation devices, screws, plates, rods, pins, nails, needles, biosensors, sensory implants, neural implants, pacemakers, defibrillators, electrodes, subcutaneous implants including drug delivery implants, cosmetic implants, hip and knee replacement implants, hemodialysis devices, ventilators, and related tubing. Exemplary diagnostic components include, but are not limited to, multiwell plates, glass slides, pipettes and pipette tips, sample containers, glucose monitors, biosensors, enzyme biochips, affinity biochips, chemical sensors, pathogen sensors, contaminant sensors, diagnostic biochips, blood pressure monitors, ELISA detection components, and other diagnostic components.

[0037] The coating process disclosed herein is compatible with aseptic manufacturing techniques. For example, the active agent can be sterilized using appropriate filtration, heating, or other methods. Alternatively or additionally, plasma can neutralize bacterial species or other undesirable microbial species, for example, further reducing the bacterial count.

[0038] When treating internal tissues such as peptic ulcers or tumors in the pancreas or other organs, plasma and active agents can be introduced into the body via endoscopy, for example, allowing the plasma to activate active agents adjacent to the target tissue. The patient's internal space can provide a means of air removal, eliminating the need for a plasma chamber. The device for this internal treatment, along with the mechanisms or systems for deploying the active agent, can be similar to an endoscopic plasma coagulation device.

[0039] In some embodiments, one or more pharmaceutically active materials and / or biomolecules can be dissolved in a liquid to form a solution. The coating can then be formed by aerosolizing the active agent solution into a low-energy, non-thermal equilibrium atmospheric pressure plasma and exposing the surface to be coated to the plasma and aerosol. This may result in the atomized active agent undergoing activation in the plasma and forming a dry coating of the active agent on the substrate surface. For example, the coating may contain solidified active agent. This method can allow pharmaceuticals and / or biomolecules to be deposited on a substrate surface without the use of adhesives, binders, polymers, or other materials.

[0040] In some instances, the method can simultaneously produce a coating chemically bonded to the surface. The surfactant can be chemically bonded to the substrate surface with or without surfactant crosslinking. In some instances, the surfactant does not polymerize in the coating. For example, one or more, or all, surfactants in the coating are free of vinyl groups or other chemical functionalities expected to undergo free radical polymerization.

[0041] In at least some aspects of this disclosure, for example, the coating may comprise at least one crosslinking material. The crosslinking material may be an active agent and / or other materials, such as polymers. Crosslinking can increase the strength and / or density of the coating, which can result in controlled elution of the active agent from the coating. Depending on the material of the coating and the degree of crosslinking, the release of the active agent from the coating (e.g., into adjacent tissue) can range from hours to days. In some instances, the active agent can be eluted from coatings with a thickness of less than 200 nm or less than 300 nm within hours, for example, from 1 hour to 8 hours, or from 3 hours to 5 hours. For example, a relatively thin material coating on a substrate (e.g., with a thickness ranging from about 10 nm to 50 nm) can be eluted within hours (e.g., from 1 hour to 5 hours). By increasing the coating thickness to 500 nm or more (e.g., 500 nm to 1 μm, such as 600 nm, 700 nm, 750 nm, 800 nm, 900 nm, 1 μm, or a thickness greater than 1 μm), the surfactant can be eluted within a few days, such as 1 to 14 days, 2 to 10 days, or 5 to 7 days. The release rate of the surfactant from the coating can depend on the solubility of the surfactant and / or the degree of cross-linking of the coating. For example, if the cross-linking density is increased, a coating of the same thickness can remain on the substrate surface for more than 1 day, such as up to 10 days, such as 7 to 10 days, before the coating is degraded by enzymes.

[0042] The operating parameters of the plasma can be adjusted to control the crosslinking of the material during deposition onto the substrate. For example, increasing the applied voltage generally increases the amount of active material in the plasma, which can enhance crosslinking. For instance, an activator coating can be deposited using an applied voltage of about 6 kV (peak-to-peak) at a frequency ranging from 10 kHz to 600 kHz with a 20% duty cycle. Increasing the voltage to 7 kV to 10 kV can increase the degree of crosslinking, for example, forming a more durable coating. Furthermore, increasing the duty cycle in a pulsed plasma system can enhance crosslinking, for example. The duty cycle can be increased by increasing the on-time or decreasing the off-time, for example, increasing the duty cycle from about 20% to about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, or even continuous wave operation.

[0043] Unbound by theory, it is believed that, in at least some cases and depending on the surfactant, the deposition process does not involve polymerization of the material, but rather some cross-linking of the surfactant (in particulate or aerosol form) and additionally the formation of bonds with the activated substrate surface. This activation can begin when the material first comes into contact with the plasma and can continue as long as the material remains in contact with the plasma and / or substances emitted from the plasma. Alternatively or alternatively, the substrate can also be activated by plasma and be able to react with the surfactant to produce a well-adhered coating. The degree of activation and bonding can be proportional to the energy of the plasma and / or the time spent in contact with the surfactant and / or the substrate.

[0044] In some embodiments, the time spent by the active agent in the plasma chamber can be less than 1 second, such as less than 0.5 seconds, for example, 0.1 to 1 second or 0.1 to 0.5 seconds. Upon reaching the surface of the substrate, the material can be exposed to further plasma energy, for example, from long-lived particles or substances exiting the plasma chamber. In practice, plasma can be used to initiate the coagulation and / or cross-linking of active chemical / biochemical agents to form coatings or chemical bonds of molecules (including, for example, chemical bonds of particles). Surprisingly, this method has been found not to deactivate biomolecules or cause the degradation of agents, thus maintaining high activity in the resulting coatings.

[0045] The deposited material can be firmly bonded to the substrate or may only form a loose attachment, depending on the properties of the substrate and material, the operating parameters of the plasma (e.g., the level of plasma power used), and how the material is exposed to the plasma. For example, in some embodiments, increasing the plasma power can increase the crosslinking strength between surfactants and / or enhance the bonding strength with the surface, which can lead to the formation of covalent bonds between adjacent particles or surfactant aerosols and / or covalent bonds between the surfactant and the substrate. Decreasing the plasma power can result in relatively weaker types of bonding, such as hydrogen bonds, which are generally understood to be less strong than covalent bonds. Further reducing the plasma power can then limit interactions with other types of bonding, such as electrostatic or van der Waals attraction.

[0046] In some embodiments, the coating can be formed without the addition of a film-forming material. For example, the coating may consist of one or more surfactants or substantially one or more surfactants. It may not be necessary to add materials that undergo standard plasma-induced radical or ionic polymerization via reactive groups such as unsaturated bonds (e.g., double or triple bonds), cyclic ring structures, aromatic rings, peroxides, silanes, epoxides, or other reactive groups. Instead, the only material introduced into the plasma for deposition onto the substrate may be a biomaterial and / or a pharmaceutical active agent (e.g., as a precursor material).

[0047] As described above, in some aspects of this disclosure, a one-step approach involves directly introducing biomolecules and / or active pharmaceutical materials as dry, atomized powders into a low-energy atmospheric pressure or vacuum plasma to create a stable, dry, adhesive coating that retains the biological or pharmaceutical activity of the starting material. Without being bound by theory, it is conceivable that plasma can activate the surface of active agent particles to generate reactive chemical sites that can react with the surfaces of other particles. For example, plasma may contain free radicals that extract atoms from the particle surface, thereby generating particles with radical portions on their surface that can be used to bind with adjacent particles and / or substrate surfaces. Similarly, plasma devices, including those operating at atmospheric pressure, can be able to oxidize the surface of materials and generate polar functional groups such as carboxyl, carbonyl, and hydroxyl groups, which can participate in hydrogen bonding. Moreover, plasma is typically rich in charged ions and free electrons, and these substances can generate reactive chemical sites on particle surfaces that can participate in ionic bonding. Additionally or alternatively, collisions with ions or free electrons can generate positive or negative charges on the particles, which can lead to electrostatic bonding with other surfaces.

[0048] The active agent can be atomized using any suitable sprayer or atomizer, including, for example, ultrasonic, piezoelectric, pneumatic, mechanical, electrical, vibrating screen, or jet atomizers. In at least one embodiment, the active agent (e.g., a pharmaceutical agent and / or biomolecule) is trapped in or on the surface of a foam, mesh, or fabric in a solid state (e.g., powder), and a gas is blown across the surface of the foam, mesh, or fabric to deliver the active agent to the target substrate surface. The average diameter of the powder particles can be less than 1000 μm, such as less than 100 μm, for example, less than 10 μm. For example, the average diameter of the dried particles can range from about 1 μm to about 10 μm, about 5 μm to about 50 μm, about 25 μm to about 75 μm, about 50 μm to about 100 μm, about 100 μm to about 200 μm, about 250 μm to about 500 μm, and about 500 μm to about 750 μm. The foam, mesh, or fabric can be made of any suitable non-reactive material or combination of materials, such as polymers or metals. This material is permeable enough to allow gas to pass through and extract powder particles for transport to the surface.

[0049] The coating can be applied directly to the tissue. For example, one or more active agents can be deposited on the tissue to form a drug delivery patch. The tissue can be external or internal. For example, a suitable endoscopic plasma device, as described above, can be used to apply the coating to internal tissue. In other instances, the coating can be applied to the patient's external skin (e.g., injured tissue) and allow the active agent to diffuse into the tissue, thus serving as a transdermal drug delivery system.

[0050] The coating described herein may contain at least one biomolecule. For example, the coating may contain one or more proteins, such as collagen, fibronectin, and fibronectin; and / or biopolymers, such as hyaluronic acid, chitosan, alginate, and cellulose. Alternatively or additionally, the coating may contain one or more other biomolecules, such as phosphocholine, polypeptides, polysaccharides, hormones, lipids, interferon, cartilage, cells, and synthetically derived therapeutic biological agents, autologous, homologous, and allogeneic and physiological biological agents, autologous or homologous, recombinant, and synthetically derived blood cells, and products containing antimicrobial / antibiotic agents, bacteriostatic agents, stem cells, mesenchymal stem cells, amniotic membrane materials, fluorescein-labeled collagen, bovine serum albumin, fibroblast-derived human skin collagen, matrix proteins, fibrin, coagulation factors, growth factors, or cytokines. The coating may contain mixtures of chemical and / or biological materials. In some instances, the biomolecules do not contain vinyl or other chemical functionalities intended to polymerize.

[0051] The coating may contain type I, II, III, IV, V, VI, or VII collagen, or mixtures thereof. The coating can be used to reduce scar formation, such as when plasma-treated collagen is applied directly to cuts, incisions, or other wounds. In at least one embodiment, the coating contains type VII collagen and is used to treat patients with epidermolysis bullosa.

[0052] In at least one embodiment, the coating may comprise an autologous material applied to the surface of the implant or transplanted organ, for example, to improve biocompatibility and reduce rejection of the implant or transplanted organ. The autologous material may be blood, platelet-rich plasma, extracellular fluid, tissue (e.g., for tissue transplantation), and / or other autologous materials.

[0053] In at least one embodiment, the coating can be deposited by dissolving the pharmaceutical agent in a solvent, atomizing the solvent into a non-thermal atmospheric plasma, and depositing the resulting material as a dry coating onto an adjacent substrate surface. In some aspects of this disclosure, the active pharmaceutical ingredient does not contain any isolated vinyl or alkynyl groups. However, the pharmaceutically active substance may contain resonantly stable aromatic unsaturations or conjugated vinyl groups. For example, it has been found that resonantly stabilizing groups remain unreacted during deposition and are not destroyed by the plasma. The pharmaceutical active agent can be deposited as a pure compound without polymers, binders, linkers, pretreatments, biomolecules, excipients, or other materials. Therefore, the coating can be formed solely from the pharmaceutical agent without other materials.

[0054] If prolonged elution is required, or if the drug or biomolecule is particularly sensitive to active substances in the plasma, the active agent can be encapsulated within microspheres. Microspheres can be prepared from biocompatible drug delivery materials, including but not limited to proteins, polysaccharides, or liposomes. Microspheres can simultaneously protect the active agent from more aggressive plasma substances and / or limit the diffusion of the active agent from the surrounding material to provide prolonged elution.

[0055] The average diameter of the microspheres can be from about 0.1 μm to about 500 μm, such as about 0.1 μm to about 100 μm, about 0.5 μm to about 100 μm, about 1 μm to about 50 μm, about 5 μm to about 10 μm, or about 50 μm to about 250 μm. In at least one example, the average diameter of the microspheres suitable for drug delivery applications can range from 0.1 μm to 100 μm. Microspheres can be manufactured in a variety of ways, including, for example, emulsion polymerization, phase separation or precipitation and / or emulsion / solvent evaporation methods. Furthermore, mechanical methods for producing microspheres include air suspension, disc coating, spray drying, spray condensation, microporous systems, and rotating fluidized bed granulation methods.

[0056] In at least one embodiment, the coating contains only one or more pharmaceutically active agents, such as anticancer drugs (chemotherapeutic agents), anti-inflammatory drugs, immunosuppressants, antibiotics, analgesics, blood pressure medications, antithrombotic agents, anticoagulants, antiplatelet agents, thrombolytic agents, antiproliferative agents, antimitotic agents, antimicrobial agents, restenosis inhibitors, smooth muscle cell inhibitors, fibrinolytic agents, immunosuppressants and antiantigens, vaccines, and combinations thereof. The coating may contain one or more antibodies, including endothelial progenitor cell antibodies or monoclonal antibodies. Monoclonal antibodies can be delivered directly to the target tissue using a suitable plasma deposition apparatus. This can then be used to deliver targeted chemotherapy, radiotherapy, or immunotherapy. For example, the presence of antibodies can stimulate the immune system to respond, thereby delivering immunotherapy. For internal organs or targets, the coating can be deposited using an endoscopic or arthroscopic plasma device.

[0057] The elution of the active pharmaceutical ingredient can be adjusted by increasing the degree of crosslinking or by selecting a hydrophobic material with low solubility in aqueous solution. Crosslinking can be enhanced by increasing plasma power or increasing the contact time between the plasma and the coating. If desired, additional crosslinking can be provided by adding one or more chemical crosslinking agents. For example, hydrogen peroxide can be added. When exposed to plasma, hydrogen peroxide can generate additional free radicals in the mixture and produce additional reactivity within the plasma, thereby resulting in enhanced crosslinking of the active ingredient. To prevent over-oxidation, the peroxide content should be kept below 3% by weight relative to the total weight of the active ingredient. For example, the amount of hydrogen peroxide can range from about 0.1% to about 3.0% by weight, about 0.5% to about 2% by weight, or about 0.1% to about 1% by weight relative to the total weight of the active ingredient. Peroxides and other molecules besides hydrogen peroxide can be used to enhance crosslinking. However, such other peroxides may leave residues in the coating that may alter biocompatibility.

[0058] According to some aspects of this disclosure, the coating may comprise multiple layers. For example, a first layer of agent (e.g., an antibiotic) may be applied to the surface using a plasma apparatus as disclosed herein. The thickness of the first layer may range from about 50 nm to about 150 nm, such as about 50 nm to about 75 nm, about 75 nm to about 100 nm, or about 100 nm to about 150 nm. Additional agent layers may be deposited, for example, by completing additional coating passes, each coating pass producing an additional coating thickness ranging from 50 nm to 150 nm. Thus, for example, this method may be used to produce coating thicknesses up to about 600 nm (e.g., 2, 3, or 4 or more first layers). One or more second layers (e.g., 2, 3, or 4 or more second layers) comprising one or more biomolecules may then be applied on top of the first layers. Each second layer may have a thickness similar to that of each first layer, for example, ranging from 50 nm to 150 nm, providing a coating thickness of up to 1.2 μm. In some aspects of this disclosure, the coating may include at least one first layer (comprising an agent) between two second layers (comprising biomolecules). In some aspects of this disclosure, the coating may include at least one first layer (including biomolecules) between two second layers (containing pharmaceuticals).

[0059] In such examples comprising one or more first-layer pharmaceutical agents and one or more second-layer biomolecular agents, the second layer may reduce the elution rate of the first-layer pharmaceutical agent from the coating. For example, a monolayer of protein may be applied to create a second layer as a topcoat on top of the first-layer pharmaceutical agent, with a protein thickness ranging from about 50 nm to about 150 nm. Additional protein layers (or other biomolecules) may be added to increase the thickness of the topcoat until the desired thickness is reached. For example, a 500 nm topcoat may be sufficient to slow the elution of the pharmaceutical material in the first layer, thereby prolonging release from the coating over several days. For highly soluble pharmaceutical agents (and therefore more likely to be released from the coating more quickly), a thicker layer may be required. Thus, for example, the topcoat may range from about 500 nm to about 900 nm, or from about 600 nm to about 800 nm. The combined thickness of the topcoat of the first and second (one or more) layers of pharmaceutical and biomolecular agents may range from about 200 nm to about 1500 nm. For example, the total coating thickness can be as thin as 200 nm, or the combined thickness can range from 500 nm to 900 nm, or even up to 1500 nm. Some coatings thicker than 1500 nm tend to be brittle and may crack or delaminate.

[0060] Alternatively or concurrently, the elution of the surfactant can be controlled by the degree of cross-linking of the materials within the coating. For example, one or more layers containing the agent may be coated with one or more layers of cross-linked biomolecules. In at least one embodiment, the top layer may contain collagen and / or chitosan deposited using plasma deposition as described above. The degree of cross-linking in the protein deposition layer can be controlled, for example, by adjusting the plasma power level, regulating the plasma exposure time, and / or adding one or more chemical cross-linking agents. For example, the protein coating can be cross-linked using materials such as glutaraldehyde, formaldehyde, glyoxal, or diisocyanates. Similar effects can be found by incorporating relatively low levels (e.g., less than 3%, less than 2%, or less than 1 wt%) of hydrogen peroxide into the surfactant to induce additional reactive free radical reactions in the plasma. These materials can synergize with the plasma to maximize cross-linking without exposing the protein to high levels of plasma energy. Alternatively, relatively low levels (e.g., less than 3%, less than 2%, or less than 1 wt%) of enzymatic cross-linking agents (such as transglutaminase) can be premixed with the protein solution to produce a cross-linked thin film deposition. Increasing the thickness of the coating can result in slower coating decomposition in vivo and reduce the elution of any underlying material by limiting diffusion through the coating.

[0061] Exemplary anticancer agents (drugs) that can be deposited using these plasma methods include acivicin, aclarubicin, acodazole, acronycine, adozelesin, alanosine, interleukin, allopurinol sodium, hexamethylmelamine, aminoglutethimide, amonafide, ampligen, amsacrine, androgens, anguidine, aphidicolin glycinate, asaley, asparaginase, 5-azacitidine, azathioprine, BCG, Behringer's antifolate (soluble), β-2'-deoxyguanosine, bismuth subcitrate, bleomycin sulfate, busulfan, sulfonamide butylthionine, and BWA. 773U82, BW502U83.HCl, BW 7U85 mesylate, ceramide, carbeteem, carboplatin, carmustine, chlorambucil, chloroquine-sulfonamide, chloruremycin, chromomycin A3, cisplatin, cladribine, corticosteroids, short anaerobic corynebacterium, CPT-11, cristatol, cyclocytidine, cyclophosphamide, cytarabine, septopalpine, dabis maleate, dacarbazine, actinomycin, daunorubicin hydrochloride, dexamethasone, dextromethorphan. Imine, dehydrociprofloxacin, dibromodulcitol, membranacein, diethyl dithiocarbamate, diethylene glycol aldehyde, dihydro-5-azacytidine, doxorubicin, echinomycin, edatrexate, edelfosine, efornithine, elamitrucin solution, elsamitrucin, epirubicin, esorubicin, estamustine phosphate phosphate), estrogen, etanidazole, ethiofos, etoposide, fadrazole, fazarabine, fenretinide, filgrastim, finasteride, flavonoid acetate, fluorouridine, fludarabine phosphate, 5-fluorouracil, fluolusol, flutamide, gallium nitrate, gemcitabine, goserelin acetateAcetate), hepsulfam, hexamethylenediacetamide, homoharringtonine, hydrazine sulfate, 4-hydroxyandrostenedione, hydroxyurea, idarubicin hydrochloride HCl), ifosfamide, interferon α, interferon β, interferon γ, interleukin-1 α and β, interleukin-3, interleukin-4, interleukin-6, 4-sweet potato picrol, isopropylplatin, isotretinoin, calcium leucovorin, leuprolideacetate, levamisole, liposomal daunorubicin, liposomal encapsulated doxorubicin, lomustine, lonidamine, maytansine, nitrogen mustard hydrochloride, melphalan, menogaril, mebarone, 6-mercaptopurine, mesna, methanol extract residue of BCG, methotrexate, N-methylformamide, mifepristone, mitoguazone, mitomycin C, mitoxantrone hydrochloride hydrochloride, monocyte / macrophage colony-stimulating factor, nabilone, nafoxidine, neomycin, octreotide acetate, oxaliplatin, paclitaxel, pala, pentostatin, piperazine dione, piperazine, pirarubicin, pirritrexim, piroxantrone hydrochloride, PIXY-321, plicamycin, porfimer sodium Sodium, prednimustine, procarbazine, progestins, pyrazofurin, razoxane, sargramostim, semustine, spiromustine, streptonigrin, streptozocin, sulfofenureur, suramin sodiumsodium, tamoxifen, taxotere, tegafur, teniposide, terephthalamidine, teroxirone, thioguanine, thiotepa, thymidine injection, tiazofurin, topotecan, toremifene, trifluoperazine hydrochloride, trifluridine, trimetrexate, tumor necrosis factor, uracil mustard, vinca sulfate, vinca sulfate aldehyde, vindesine, vinorelbine, vinzolidine, Yoshi864, zorubicin, and mixtures thereof.

[0062] In at least one embodiment, the pharmaceutical agent (pharmaceutical active agent) is an anti-inflammatory drug selected from nonsteroidal anti-inflammatory drugs (NSAIDs), COX-2 inhibitors, glucocorticoids, and mixtures thereof. Exemplary NSAIDs include aspirin, diclofenac, indomethacin, sulindac, ketoprofen, flurbiprofen, ibuprofen, naproxen, piroxicam, tenoxicam, tolmetin, ketorolac, oxaprosin, mefenamic acid, fenoprofen, naproxen, acetaminophen, and mixtures thereof. Exemplary COX-2 inhibitors include nimesulide, NS-398, flossulide, L-745337, celecoxib, rofecoxib, SC-57666, DuP-697, parecoxib sodium, JTE-522, valdecoxib, SC-58125, etoricoxib, RS-57067, L-748780, L-761066, APHS, etodolac, meloxicam, S-2474, and mixtures thereof. Exemplary glucocorticoids include hydrocortisone, cortisone, prednisone, prednisolone, methylprednisolone, meprednisone, triamcinolone, paramethasone, fluprednisolone, betamethasone, dexamethasone, fludrocortisone, deoxycorticosterone, and mixtures thereof.

[0063] Other exemplary agents applicable to this disclosure include conventional cell cycle inhibitors, apoptosis inducers, antiproliferators / antimitotic agents, including natural products such as vinca alkaloids (e.g., vincristine, vinorelbine, and vinorelbine), paclitaxel, colchicine, epipodophyllotoxins (e.g., etoposide, teniposide), enzymes (e.g., L-asparaginase, which systemically metabolizes L-asparagine and deprives cells incapable of synthesizing their own asparagine); and antiplatelet agents such as G(GP) II. b / III aInhibitors, GP-IIa inhibitors, and porphyrin receptor antagonists; antiproliferative / antimitotic alkylating agents such as nitrogen mustard (diethyldichloroethylene, cyclophosphamide and analogs, melphalan, chlorambucil), aziridine and methylmelamine (hexamethylmelamine and thiotepa), alkyl sulfonates-busulfan, nitrosoureas (carmustine (BCNU) and analogs, streptozotocin), triazine-dacarbazine (DTIC); antiproliferative / antimitotic antimetabolites such as folic acid analogs (methotrexate), pyrimidine analogs (fluorouracil, fluorouracil, and cytarabine), purine analogs and related inhibitors (mercaptopurine, thioguanine, pentostatin, and 2-chlorodeoxyadenosine (cladribine)); platinum coordination complexes. Cisplatin, carboplatin, procarbazine, hydroxyurea, mitotane, aminoglutethimide; hormones (such as estrogen); anticoagulants (heparin, synthetic heparin salts and other thrombin inhibitors); fibrinolytic agents (such as tissue plasminogen activator, streptokinase and urokinase), aspirin, dipyridamole, ticlopidine, clopidogrel, abciximab; antimyolytics; antisecretory agents (breveldin); anti-inflammatory drugs: such as corticosteroids (cortisol, cortisone, flucortisone, prednisone, prednisolone). Prednisolone, 6α-methylprednisolone, triamcinolone, betamethasone, and dexamethasone; nonsteroidal anti-inflammatory drugs (salicylic acid derivatives, such as aspirin; p-aminophenol derivatives, such as acetaminophen); indole and indeneacetic acids (indomethacin, sulindac, and etodalac); heteroarylaceous acids (tolmetin, diclofenac, and ketorolac); arylpropionic acids (ibuprofen and its derivatives); and anthranilic acids (mefenamic acid and meclofenamic acid). Enolic acids (piroxicam, tenoxicam, phenylbutazone, oxyphenthatrazone), nabumetone, gold compounds (auranofin, aurothioglucose, sodium gold thiomalate); immunosuppressants (cyclosporine, tacrolimus (FK-506), sirolimus (rapamycin), azathioprine, mycophenolate mofetil); antigens: vascular endothelial growth factor (VEGF), fibroblast growth factor (FGF);Angiotensin receptor blockers; nitric oxide donors; antisense oligonucleotides and combinations thereof; cell cycle inhibitors, mTOR inhibitors, and growth factor receptor signal transduction kinase inhibitors; retinoids; cyclin / CDK inhibitors; HMG-coenzyme reductase inhibitors (statins); and protease inhibitors (matrix protease inhibitors).

[0064] In at least one embodiment, the active agent may include one or more antibiotics selected from the following: tobramycin, vancomycin, gentamicin, ampicillin, amoxicillin, carbapenems, penicillin, chloramphenicol, cephalosporin C, cephalexin, cefaclor, cefamandole, ciprofloxacin, dactinomycin, and actinomycin D. D) daunorubicin, doxorubicin, idarubicin, penicillins, piperacillin, streptomycin, cephalosporins, quinolones, anthracyclines, mitoxantrone, tetracyclines, ticarcillin, bleomycins, plicamycin (photomycin), mitomycin, polymyxin, ciprofloxacin, glycopeptides, and aminoglycan antibiotics, and mixtures thereof.

[0065] In some embodiments, the active agent may include one or more immunosuppressants, such as cyclosporine, rapamycin, and tacrolimus (FK-506), ZoMaxx, everolimus, sirolimus, zotarolimus, paclitaxel, etoposide, mitoxantrone, azathioprine, basiliximab, daclizumab, leflunomide, lymphocyte immunoglobulin, methotrexate, muromonab-CD3, mycophenolate, and thalidomide.

[0066] In some instances, the agent does not contain vinyl or other chemical functionalities that are expected to polymerize.

[0067] In some implementations, the active agent (e.g., coating precursor, pharmaceutical compound, or biomolecule) is not chemically modified to include foreign reactive chemical functionalities.

[0068] The coatings disclosed herein can be applied to medical devices, for example, to modify the surface of a medical device. For example, the coating can modify an implantable medical device. In some embodiments, the coating can increase the biocompatibility of the medical device surface by incorporating biomolecules or other active agents that do not promote an inflammatory response. Additionally or alternatively, the coating may contain pharmaceutically active agents that inhibit inflammation, cell growth, cell attachment, and / or other biological processes; and / or inhibit the growth of bacteria and / or fungi. This can be achieved, for example, by depositing agents including antibiotics and antifungals, or by depositing biomolecules such as antimicrobial peptides or combinations thereof. The medical device can be made of metals, ceramics, plastics, carbon, or combinations thereof, including composite materials. Non-limiting examples of metals and metal alloys include steel, titanium, titanium alloys including nickel-titanium alloys, cobalt-chromium alloys, gold, silver, and platinum. Non-limiting examples of ceramics and glasses include alumina, zirconium oxide, calcium phosphate, hydroxyapatite, and bioactive glasses such as 45S5. Non-limiting examples of polymers include polytetrafluoroethylene (PTFE), polyetheretherketone (PEEK), poly(methyl methacrylate), (PMMA), polyethylene (PE), siloxanes, hydrogels, and polyurethanes. Non-limiting examples of composite materials include PMMA-glass fillers, such as fillings used in dental restorations.

[0069] Examples of medical devices applicable to this disclosure include, but are not limited to, scalpels, clamps, needles, and medical implants such as stents, catheters, ports, expandable balloons, prosthetic implants, orthopedic implants, dental implants, cochlear implants, ear tubes, implantable mesh, spinal cages, maxillofacial implants, scaffolds (e.g., for tissue regeneration or transplantation), pulse generators, valves, hormone delivery implants, skin grafts, bone grafts, artificial spectacle lenses, contact lenses, hearing aids, breast implants, trauma fixation devices, screws, plates, rods, pins, nails, needles, biosensors, sensory implants, neural implants, pacemakers, defibrillators, electrodes, subcutaneous implants including drug delivery implants, cosmetic implants, hip and knee replacement implants, hemodialysis equipment, ventilators and related tubing, valves, and other air-exposed components.

[0070] The coatings disclosed herein can be applied directly to soft tissue surfaces, such as wounds. The deposited materials may include those that inhibit bacterial infection, stop bleeding, and / or promote healing. In one exemplary method, a plasma system or device is first used to induce hemostasis, reduce bacterial load, and treat the wound. In cases of significant bleeding (such as that encountered during liver surgery), the hemostatic properties of plasma can be enhanced by co-depositing materials that induce blood clotting and minimize bleeding. Such hemostatic materials include clotting factors, fibrin, kaolin, hyaluronic acid, collagen, gelatin, adrenaline, thrombin, and chitosan. Plasma can also be used, alternatively, to ablate and / or cut unwanted tissue, reduce bacterial load, or treat tumors. Following this treatment of the wound, a plasma system or device can be used to deposit a coating that aids in the repair or healing of patient tissue. The coating may contain pharmaceutically active substances, DNA or RNA, proteins or polysaccharides, or mixtures thereof. For example, a coating containing an anticancer drug can be deposited directly onto residual tumor cells or nearby tissue to provide a locally available antitumor effect. This can be achieved, for example, by local deposition or by endoscopic delivery. Nanosecond or picosecond pulsed plasma can be used to treat tumors or cancer.

[0071] In another example, injured tissue can be treated with a combination of plasma and deposited materials to enhance tissue regeneration. In this case, the coating may include materials such as collagen, hyaluronic acid, deacetylated chitosan, and / or growth factors or other regenerative materials, optionally along with agents designed to inhibit bacterial growth or suppress pain. In at least one embodiment, the deposit contains epidermal growth factor. In some embodiments, the tissue sample may be treated with plasma and coated with one or more active agents before, during, or after use in a tissue graft. Such tissue may include autologous grafts (e.g., tissue samples from the same patient being treated), allogeneic grafts (e.g., tissue samples from a person other than the patient), or xenografts (e.g., tissue samples from animals).

[0072] In some embodiments, damaged tissue can be repaired by inserting an implant having at least one surface modified with a plasma-deposited coating. For example, the implant may be a scaffold, and the coating may be formed solely of an antiproliferative drug, such as sirolimus, paclitaxel, everolimus, zotarolimus, or biolimus. Because the implant surface contains no polymers, binders, adhesives, or other excipients, the risk of late restenosis due to the breakdown of exogenous materials is minimized, thus benefiting patient recovery. Optionally, in addition to or in place of the pharmaceutically active substance, the coating may contain materials such as heparin, phosphocholine, or endothelial progenitor cell capture antibodies.

[0073] In some implementations, the methods disclosed herein can be used for agricultural purposes, such as applying a coating to plants, seeds, fruits, vegetables and / or other foods, the substance of which alters shelf life, size, appearance and / or nutritional value.

[0074] In at least one embodiment, an active agent is introduced downstream of the plasma. For example, the active agent may be in indirect contact with a higher-energy region of the plasma, which exists within the plasma chamber, rather than in direct contact. By introducing the active agent downstream of or within the afterglow region, the degradation effect of the plasma can be minimized. In this region, outside the plasma chamber and far from the electrodes, glow plasma is typically no longer present, and only long-lived plasma material remains. In some embodiments, two or more active agents may be introduced substantially simultaneously into different regions of the plasma or near them. Because the amount of active material present is significantly less, and the highly active material has been quenched, the introduced material undergoes fewer reactions and participates only in lower-energy reactions, thus preserving the functionality of the active agent.

[0075] When co-depositing a mixture of materials (biomolecules or pharmaceuticals), it may be found that one material is relatively more reactive than the other, or more easily denatured by plasma. In this case, the more robust or stable material can be introduced upstream of the less stable material. For example, the more robust or stable material can be introduced directly into the plasma, and the less unstable material can be introduced downstream of the plasma. This ensures that the more robust material receives sufficient energy to initiate a crosslinking reaction, while the less unstable material is introduced downstream and isolated from most of the more reactive plasma material. Thus, the two materials can react without one of them being denatured or otherwise deactivated. In an exemplary embodiment, the more robust material can be introduced into the plasma in which it is activated. This plasma-activated material is then allowed to leave the plasma and react with a second, less stable material without any further meaningful contribution from the plasma material. For example, if a coating comprising a stable protein and a highly reactive pharmaceutical agent is to be deposited, the protein can be injected into the plasma, and the pharmaceutical agent can be introduced downstream of the plasma. This can be achieved by injecting the protein directly into the plasma chamber and introducing the pharmaceutical agent into the afterglow just outside the chamber. This allows both materials to be sufficiently activated to crosslink on the target surface to produce a coating. Similarly, coatings containing relatively stable pharmaceuticals and less stable biomolecules can be formed by injecting pharmaceuticals into plasma and injecting biomolecules downstream of plasma.

[0076] In one exemplary embodiment, a biomaterial and / or pharmaceutical agent, acting as an active agent, can be placed on a target substrate surface and then exposed to plasma. The material may include, for example, biomolecules and / or pharmaceutical active agents. The active agent may be deposited as a layer less than 1 mm thick, such as less than 500 μm, for example less than 200 μm or less than 1 μm thick. The layer may be homogeneous on a portion or the entire substrate surface. The material may be a liquid or gel solution, for example, already mixed with or dissolved in water or other solvents, or may be present as a dry powder. By exposing the material to plasma, the material can be activated and crosslinked, thereby transforming it into a coating. Plasma activation can also bind the material to the surface. In some embodiments, this method does not produce a highly adhesive coating, for example, if the plasma does not directly activate the substrate surface due to the presence of a deposited layer that can act as a barrier. To address this issue, in some embodiments, the substrate surface may be activated first using plasma, and then the material may be applied in a thin layer. The bio or pharmaceutical activity of the active material can be retained by using low-energy, non-thermal plasma. In some embodiments, the plasma is pulsed. As described above, the target substrate surface may include a surface that forms part of a diagnostic component (e.g., a porous plate and other components), a medical device (e.g., a medical implant and other devices), or a wound (e.g., a cut, lesion, tumor, burn, and other wound). In some embodiments, the precursor may be selected from the group consisting of proteins, peptides, antibodies, and polysaccharides.

[0077] The following examples are intended to illustrate this disclosure, but are not restrictive in nature. It should be understood that this disclosure covers additional embodiments consistent with the foregoing description and the following examples.

[0078] Example

[0079] Example 1 Antibiotic coating on steel specimens

[0080] Metal samples (10 mm in diameter and 1 mm thick) made of 304 stainless steel were rinsed again in deionized water, acetone, and water. After drying, multiple samples were coated with gentamicin sulfate (a broad-spectrum antibiotic) as described below.

[0081] Gentamicin sulfate solution was prepared by dissolving salt in water to produce a concentration of 50 mg / ml. This solution was then injected via a pneumatic nebulizer (T2100 nebulizer, Burger Research Inc., Ontario, Canada) at a rate of 25 μL / min. This produced a consistent and stable fine particulate spray.

[0082] The atomizer is then inserted to spray the plasma into a cylindrical plasma chamber (20 mm in diameter and 45 mm in length). Additionally, helium gas (99% purity) is flowed through this chamber at a rate of 6 L / min. Metal electrodes are inserted into the chamber, and RF power is supplied using a Redline G2000 power supply. The outlet voltage is set to 135 V with a duty cycle of 45%. This voltage is fed to an external transformer directly connected to the electrodes. Upon power-up, the helium gas within the plasma chamber is ignited, forming a cold plasma.

[0083] Plasma was scanned onto a sample holder holding a clean stainless steel specimen. The plasma moved along a grating pattern at a speed of 15 mm / s with a step size of 3 mm. Each specimen was coated three times on each surface, resulting in a total of six coatings. The coatings were clearly visible on the surface of the steel specimens after coating.

[0084] Example 2 The antimicrobial properties of coated steel.

[0085] The antimicrobial properties of the metal sample from Example 1 coated with gentamicin against common bacteria, Escherichia coli, were then analyzed: ATCC 8739 determined whether the antibiotic remained active.

[0086] Six gentamicin-coated samples were placed in 10 ml of buffered sodium chloride peptone solution (BSCPS) and then inoculated with 1 ml of E. coli stock solution. Six uncoated samples were similarly placed in BSCPS and 1 ml of E. coli inoculum as controls. Finally, 10 ml of BSCPS was inoculated with 1 ml of bacterial stock solution, then immediately diluted and plated to determine the initial bacterial CFU / ml. The samples were incubated at 30–35 °C for 24 hours, and then removed from the incubation period. Bacterial levels in each container were measured by serial dilution and duplicated plating. The results are shown in Table 1.

[0087] Table 1

[0088] sample Average CFU Log cfu initial inoculum <![CDATA[1.1x10 6 ]]> 6.04 Uncoated samples after 24 hours <![CDATA[7.2x10 7 ]]> 7.85 Samples coated with gentamicin 24 hours later <![CDATA[1.2x10 5 ]]> 4.71

[0089] The results showed that for steel samples coated with gentamicin, the average E. coli count decreased by 1.33 log, while the uncoated samples showed an average increase of 1.81 log. This confirms that the antibiotic remains active after deposition.

[0090] Other embodiments of this disclosure will be apparent to those skilled in the art upon consideration of this specification and by implementing the embodiments disclosed herein. The specification and examples are intended to be illustrative only, and the true scope and spirit of this disclosure are indicated by the appended claims.

Claims

1. A method of producing a coated substrate, comprising: introducing a plurality of dry particles into a non-thermal plasma, each particle comprising at least one active agent selected from a biomolecule, a pharmaceutical agent, or a combination thereof; and exposing a substrate to the plurality of dry particles and the plasma to deposit a coating comprising the at least one active agent onto the substrate.

2. The method of claim 1, wherein each particle consists only of the at least one active agent.

3. The method of claim 1 or 2, wherein the coating retains a biological or pharmaceutical activity of the at least one active agent.

4. The method of any one of claims 1-3, wherein the substrate is selected from a tissue, a diagnostic component, a medical device, or a food.

5. The method of any one of claims 1-4, wherein the substrate comprises a multi-well plate and the at least one active agent comprises a biomolecule.

6. The method of any one of claims 1-5, wherein the coating comprises at least one first layer comprising a pharmaceutical agent and at least one second layer comprising a biomolecule, and the at least one first layer is adjacent to the at least one second layer.

7. The method of claim 6, wherein the biomolecule of the at least one second layer is cross-linked.

8. The method of any one of claims 1-7, wherein the at least one active agent comprises a first active agent and a second active agent, and introducing the plurality of dry particles into the plasma comprises introducing the first active agent and the second active agent into different portions of the plasma, wherein the first active agent is a biomolecule and the second active agent is a pharmaceutical agent.

9. The method of any one of claims 1-8, wherein the plurality of dry particles are introduced into a afterglow region of the plasma.

10. A method of producing a coated substrate, comprising: applying at least one active agent to a surface of a substrate, the at least one active agent selected from a biomolecule, a pharmaceutical agent, or a combination thereof; and exposing the surface of the substrate to an afterglow of a plasma to form a dry coating comprising the at least one active agent.