Near-infrared light triggered antibacterial and antioxidant TiO2-CMO composite coating

Abstract

The invention provides a preparation method of an antibacterial and antioxidant TiO2-CMO composite coating triggered by near-infrared light. Firstly, a porous TiO2 substrate is formed on the surface of pure titanium through micro-arc oxidation, a spongy micro-nano layered structure is constructed through an alkali liquor hydrothermal method, and then the performance is optimized through annealing treatment. On the basis, CMO NPs nanoparticles are loaded by utilizing a polymerization reaction of chitosan oligosaccharide and ammonium molybdate, so that the layered porous TiO2-CMO composite coating is formed. The coating can kill more than 50% of adhesion bacteria at normal temperature, the antibacterial rate is increased to 98% when the coating is irradiated by near-infrared light, and meanwhile, the coating shows excellent oxidation resistance, biocompatibility and anti-inflammatory / angiogenesis promoting activity. By integrating micro-arc oxidation, hydrothermal reaction, annealing treatment and nano-particle loading technologies, multiple biological functions are successfully given to the surface of the titanium implant, and an innovative solution is provided for surface modification of orthopedic implant materials.

Description

Technical Field

[0001] The present invention relates to the technical field of variable testing, and specifically to a quality control system for a fully automatic coagulation tester. The present invention belongs to the technical field of biomedical materials, and specifically relates to a near-infrared light-triggered antibacterial and antioxidant TiO2-CMO composite coating. In particular, the constructed layered porous TiO2-CMO micro-nano composite coating loaded with adaptable molybdate oligosaccharide nanoparticles can endow the implant with antibacterial and antioxidant functions, thereby improving its bone integration ability, and belongs to the field of human hard tissue implant materials. Background Art

[0002] Titanium-based materials have excellent mechanical properties, good chemical stability and biocompatibility, and have been widely used in the preparation of orthopedic implants. However, there are still two problems when titanium-based implants are applied: First, its surface has biological inertness, and after being implanted into the body, it integrates poorly with the surrounding bone tissue, and even aseptic loosening occurs. Second, there is an infection risk after being implanted into the body, which is one of the most serious complications after orthopedic surgery. The main mechanism is that bacteria adhere to the surface of the titanium-based implant and form a biofilm and multiply, which hinders the adhesion of osteoblasts, and ultimately leads to infection of the tissue around the implant; and the biofilm is difficult to remove and has extremely strong drug resistance to antibiotics, increasing the treatment difficulty. However, how to regulate antibacterial and osteogenic components on the surface of titanium implants and balance the antibacterial performance and biocompatibility of the material is a huge challenge. Bacterial infection can lead to secondary hospitalization, surgical removal of the implant and multiple subsequent surgeries, as well as implant-specific complications, etc., bringing a double burden of physiology and psychology to the patient. Antibiotics are common drugs for the treatment of clinical diseases and are widely used to treat and control infectious diseases and prevent infections, etc. With the widespread application of antibiotics in clinical practice, the phenomenon of irrational drug use is common, which is likely to increase the drug resistance of pathogenic bacteria. Due to the increase in drug resistance, traditional antibacterial drugs are rapidly becoming ineffective, and the spread of multi-drug resistant bacteria complicates standard medical procedures such as surgery and transplantation.

[0003] Micro-arc oxidation is a technology for in-situ growth of ceramic oxide films directly on the surface of non-ferrous metals, also known as plasma electrolytic oxidation, anode spark phenomenon or spark discharge anodic oxidation. Its basic principle is to generate plasma discharge in the anode region under the action of high voltage and high current. Under the combined action of thermochemistry, plasma chemistry and electrochemistry, the oxides on the metal surface melt to form an oxide coating deposited on the surface of the metal matrix, forming a ceramic anodic oxidation film. The micro-arc oxidation technology can in-situ generate a micro-nano porous TiO2 coating on the surface of titanium-based metals. The constructed micro-nano porous structure can produce a "nano trap" effect on the surface, enabling light to be reflected multiple times therein, enhancing the absorption of near-infrared light, and endowing the implant with good near-infrared photothermal antibacterial properties. More notably, the porous micro-nano structure is conducive to the proliferation and adsorption of osteoblasts, meets the three-dimensional structure requirements for bone tissue growth, can effectively eliminate the stress shielding phenomenon, and avoid aseptic loosening of the implant.

[0004] Antibacterial photothermal therapy (APTT) based on near-infrared light (NIR) irradiation can convert light energy into local high temperature, which can damage the integrity of the bacterial membrane, cause protein / enzyme denaturation, cell cavitation and evaporation of cell fluid. It has the advantages of remote controllability, non-invasiveness, site specificity, deep tissue penetration, good tissue compatibility, etc., and has become a safe and effective broad-spectrum antibacterial strategy. Therefore, by constructing a coating with excellent near-infrared light response activity on the surface of titanium implants, the implant can be endowed with excellent antibacterial infection function.

[0005] Molybdenum is one of the essential trace elements in organisms. This element plays an important role in biomedical materials. Research shows that molybdenum is crucial for most organisms because it is a component of more than 50 enzymes involved in oxygen transfer and redox reactions. Molybdenum cofactor deficiency can lead to severe metabolic disorders and early childhood death. Enzymes containing the element molybdenum, such as sulfite oxidase and mitochondrial aminooxime reductase component, are directly involved in regulating mitochondrial function. Molybdenum is also involved in the aerobic respiration process of macrophage mitochondria. Selective therapeutic nanorods based on molybdenum disulfide can effectively stimulate cell proliferation and promote wound healing in vitro, and have good photothermal antibacterial effects and anti-inflammatory capabilities. The degradation product of chitosan, chitosan oligosaccharide (COS), is a physiologically active substance with immunomodulatory, anti-inflammatory and anti-tumor properties. Previous studies have shown that COS can induce macrophages to polarize towards the M2 phenotype and promote the secretion of anti-inflammatory cytokines such as interleukin IL-10 and cluster of differentiation CD206, indicating its immunomodulatory and anti-inflammatory properties.

[0006] Molybdate-oligosaccharide (CMO NPs) nanoparticles are an immunomodulatory and angiogenesis-promoting material, with good pH sensitivity, good biocompatibility, and excellent anti-inflammatory and angiogenesis activities derived from COS and Mo, among which Mo is released in a pH-responsive manner 2+and COS. In addition, Mo 2+ The incorporation endows COS with bioenergetic effects, thereby enhancing mitochondrial function and shaping the transformation of macrophages from M1 to M2. CMO NPs also stimulate angiogenesis promotion through the PI3K / HIF-1α / VEGF pathway. CMO NPs can regulate the inflammatory microenvironment by reducing inflammation and promoting angiogenesis to accelerate wound healing granulation tissue synthesis, extracellular matrix deposition, and tissue remodeling. CMO provides a potential comprehensive approach to address the challenges of wound healing by promoting a smooth transition from the inflammatory phase to the proliferative phase. This pH-responsive nanosystem with immunomodulatory properties and angiogenic and mitochondrial promoting capabilities offers promising potential for wound repair.

[0007] A porous titanium dioxide coating with excellent near-infrared photothermal response activity was constructed on the surface of pure titanium by micro-arc oxidation technology, and its surface structure was regulated by hydrothermal and annealing technologies. At the same time, multifunctional molybdate-oligosaccharide nanoparticles were synthesized, and the molybdate-oligosaccharide nanoparticles were loaded on the surface of the porous titanium dioxide coating. Finally, a layered porous TiO2-CMO composite coating with environmental response and photothermal response, antibacterial, and antioxidant properties was obtained, endowing the titanium implant with excellent broad-spectrum antibacterial ability, good anti-inflammatory and antioxidant ability, and biocompatibility. At normal temperature and normal state, it can kill more than 50% of the adhered bacteria. Under near-infrared light irradiation, the antibacterial performance can be further enhanced, and more than 95% of the adhered bacteria can be removed, ultimately achieving the effect of avoiding implant failure caused by bacterial infection around the implant, and greatly improving its application potential in bone implantation and other aspects in the medical field. There are few reports in the technical field related to biomaterials. In view of this, the present invention provides a near-infrared light-triggered antibacterial and antioxidant TiO2-CMO composite coating. Summary of the Invention

[0008] The object of the present invention is to address the urgent needs of biomedical implant materials and propose a layered porous TiO2-CMO composite coating with photothermal response antibacterial and antioxidant properties on the surface of micro-arc oxidized titanium. The implantation of this coating can effectively antibacterial and avoid the failure of the material implant caused by bacterial infection. At the same time, it has good anti-inflammatory and antioxidant functions and biological safety.

[0009] The present invention is specifically realized through the following technical solutions:

[0010] A near-infrared light-triggered antibacterial and antioxidant TiO2-CMO composite coating, characterized in that the multifunctional coating is composed of a porous titanium dioxide micro-nano structure grown on the surface of titanium or titanium alloy by micro-arc oxidation regulated by hydrothermal method and annealing technology, and anti-inflammatory and antioxidant molybdate-oligosaccharide nanoparticles loaded thereon. The preparation method of the layered porous TiO2-CMO micro-nano composite coating includes the following steps:

[0011] (1) Preparation of porous titanium dioxide coating: pure titanium or titanium alloy of a certain size is cut as a substrate, ultrasonically cleaned with acetone, anhydrous ethanol and deionized water respectively, and then dried and surface treated with a micro-arc oxidation device to grow a porous titanium dioxide coating in situ on the surface, and then taken out, dried and set aside;

[0012] (2) Prepare a sodium hydroxide solution and stir it thoroughly to make it dissolve evenly. After marking the back of the sample, place the sample face up in a reactor, pour in the prepared sodium hydroxide solution, assemble the reactor and place it in an oven, set the time and temperature, wait for the reaction to be completed, cool it in the oven, take out the sample, wash it, and dry it;

[0013] (3) Place the sample to be annealed with the front side facing up in a ceramic boat, wrap the ceramic boat with tin foil, and place it in a reactor. Adjust the temperature and time according to the reactor heating rate of 3°C / min. After annealing is completed, cool the sample in the furnace and take it out.

[0014] (4) COS was completely dissolved in deionized water, and the sample prepared in (3) was placed therein and the temperature was adjusted to 50° C. Then, the ammonium molybdate solution was added to the COS solution, and the solution was placed under continuous stirring. The titanium sheet was taken out, washed with deionized water, and dried to finally obtain a near-infrared light-triggered antibacterial and antioxidant TiO2-CMO composite coating.

[0015] Furthermore, the electrolyte system of step (1) is a mixed solution of 15-25 g / L Na2CO3 and 1-2 g / L NaOH, and the process parameters are: the working voltage adjustment range is 200-1000 V for the forward voltage and 0-300 V for the negative voltage, the pulse frequency adjustment range is 50 Hz-1000 Hz for the positive pulse and 50 Hz-1000 Hz for the negative pulse, the duty cycle is 4%-50% for the positive direction and 4%-50% for the negative direction, and the reaction time is 0.5-10 min;

[0016] Furthermore, in the step (2), the concentration of sodium hydroxide in the hydrothermal reaction is 0.05 to 0.4 g / ml, the temperature is 70 to 100° C., and the reaction time is 4 to 24 h;

[0017] Furthermore, the annealing temperature in step (3) is 400-800° C., and the annealing time is 2-6 hours;

[0018] Furthermore, in step (4), the concentration of chitosan oligosaccharide is 100-800 mg / ml, the concentration of ammonium molybdate solution is 100-600 mg / ml, and the stirring time is 24-48 hours.

[0019] Beneficial Effects

[0020] The beneficial effects of the present invention are:

[0021] (1) This coating has good antibacterial effects against Staphylococcus aureus, can endow the surface of biomedical implants with antibacterial properties, reduce the risk of postoperative infection of biomedical implants, and can endow the surface of micro-arc oxidation titanium implants with excellent antibacterial performance, reducing the probability of implant failure caused by bacterial infection after titanium implants are implanted into the human body;

[0022] (2) This coating has a simple structure and is easy to prepare, and has good antibacterial, biocompatible and anti-inflammatory and antioxidant activities.

[0023] (3) This coating does not require complex preparation processes, is inexpensive and easy to prepare, and has general applicability. Description of the Drawings

[0024] To make the objectives, technical solutions and beneficial effects of the present invention clearer, the following drawings are provided for the description of the present invention:

[0025] Figure 1 It is a schematic flow diagram in an embodiment of the present invention.

[0026] Figure 2 It is an XRD spectrum of the near-infrared light-triggered antibacterial and antioxidant TiO2-CMO composite coating HT COS NPs in Example 1.

[0027] Figure 3 It is the antibacterial effect of Staphylococcus aureus under near-infrared light irradiation (λ = 808 nm, 0.6 W / cm 2 ) in Ti and HT COS NPs in Example 1.

[0028] Figure 4 It is a scanning electron microscope photograph of the near-infrared light-triggered antibacterial and antioxidant TiO2-CMO composite coating HT COS NPs obtained in Example 2.

[0029] Figure 5 It is the total antioxidant capacity of the near-infrared light-triggered antibacterial and antioxidant TiO2-CMO composite coating obtained in Example 2.

[0030] Figure 6 It is the time-temperature curve of the untreated titanium material (Ti), micro-arc oxidation titanium material (mao), hydrothermal group (H), annealing group (HT) and the layered porous TiO2-CMO micro-nano composite coating HT COS NPs under near-infrared light irradiation (λ = 808 nm, 0.6 W / cm 2 ) in Example 2. Detailed Embodiments

[0031] Example 1

[0032] (1) Preparation of porous titanium dioxide coating: Cut pure titanium or titanium alloy with a size of 10×10×2 mm as the substrate, ultrasonically clean it with acetone, absolute ethanol and deionized water for 5 min respectively, dry it, and then use a micro-arc oxidation device to perform surface treatment in a constant voltage mode to in-situ grow a porous titanium dioxide coating on its surface. Then take it out, dry it and set it aside; the process parameters are: frequency 800 Hz, duty cycle 12%, applied positive voltage 300 V, and treatment time 1 min.

[0033] (2) Prepare a 200 mg / ml sodium hydroxide solution. After marking the back of the sample, place the sample face up in the reaction kettle, pour in the pre-prepared sodium hydroxide solution, assemble the reaction kettle and put it into the oven, set the time to 2 h and the temperature to 120 h. After the reaction is completed, take out the sample after cooling with the furnace and wash and dry it.

[0034] (3) Place the sample to be annealed face up in a ceramic boat, wrap the ceramic boat with tin foil, put it into the reaction furnace, adjust the temperature to 650 °C according to the heating rate of the reaction furnace of 3 °C / min, adjust the time to 2 h. After annealing is completed, take out the sample after cooling with the furnace.

[0035] (4) Completely dissolve 600 mg COS in 100 ml deionized water, put the sample prepared in (3) into it and adjust the temperature to 50 °C. Then add a 5 mg / ml ammonium molybdate solution to the above COS solution, place it for 48 h under continuous stirring, take out the titanium sheet, wash it with deionized water and dry it. Finally, a near-infrared light-triggered antibacterial and antioxidant TiO2-CMO composite coating is obtained, named HT COS NPs.

[0036] Figure 2 XRD pattern of the near-infrared light-triggered antibacterial and antioxidant TiO2-CMO composite coating HT COS NPs in Example 1.

[0037] Figure 3 Antibacterial effect of Ti and HT COS NPS in Example 1 against Staphylococcus aureus under near-infrared light irradiation (λ = 808 nm, 0.6 W / cm 2 ). Ti has no antibacterial effect, and the antibacterial rate of HT COS NPs reaches 99%.

[0038] Example 2

[0039] (1) Preparation of porous titanium dioxide coating: Cut pure titanium or titanium alloy with dimensions of 10×10×2 mm as the substrate, ultrasonically clean it with acetone, absolute ethanol, and deionized water for 5 min respectively. After drying, use a micro-arc oxidation device to perform surface treatment in a constant voltage mode, in-situ grow a porous titanium dioxide coating on its surface, then take it out, dry it, and set it aside; the process parameters are: frequency 800 Hz, duty cycle 12%, applied positive voltage 300 V, and treatment time 1 min.

[0040] (2) Prepare a 200 mg / ml sodium hydroxide solution. After marking the back of the sample, place the sample face up in the reaction kettle, pour in the pre-prepared sodium hydroxide solution, assemble the reaction kettle and put it into the oven, set the time to 2 h and the temperature to 120 °C. After the reaction is completed, take out the sample and clean and dry it after cooling with the furnace.

[0041] (3) Place the sample to be annealed face up in a ceramic boat, wrap the ceramic boat with tin foil, put it into the reaction furnace, adjust the temperature to 650 °C according to the heating rate of the reaction furnace of 3 °C / min, and adjust the time to 2 h. After the annealing is completed, take out the sample after cooling with the furnace.

[0042] (4) Completely dissolve 600 mg COS in 120 ml of deionized water, put the sample prepared in (3) into it and adjust the temperature to 50 °C. Then add a 5 mg / ml ammonium molybdate solution to the above COS solution, place it for 24 h under continuous stirring, take out the titanium sheet, wash it with deionized water, and dry it. Finally, obtain a near-infrared light-triggered antibacterial and antioxidant TiO2-CMO composite coating, named HT COS NPs.

[0043] Figure 4 SEM photograph of the near-infrared light-triggered antibacterial and antioxidant TiO2-CMO composite coating HT COS NPs obtained in Example 2.

[0044] Figure 5 Total antioxidant capacity of the near-infrared light-triggered antibacterial and antioxidant TiO2-CMO composite coating obtained in Example 2.

[0045] Figure 6 Time-temperature curves of the untreated titanium material (Ti), micro-arc oxidation titanium material (mao), hydrothermal group (H), annealing group (HT), and layered porous TiO2-CMO micro-nano composite coating HT COS NPs prepared in Example 2 under near-infrared light irradiation (λ = 808 nm, 0.6 W / cm 2 )

[0046] Obviously, the above examples of the present invention are merely illustrations for clearly explaining the present invention, rather than limitations on the implementation manners of the present invention. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to enumerate all implementation manners here, and these obvious changes or modifications derived from the spirit of the present invention still fall within the protection scope of the present invention.

Claims

1. A near-infrared light-triggered antibacterial and antioxidant TiO2-CMO composite coating, characterized in that, The described layered porous TiO2-CMO composite coating with antibacterial and antioxidant properties is composed of layered porous titanium dioxide in-situ grown on the surface of titanium or titanium alloy and the loaded adaptable molybdate-oligosaccharide nanoparticles; the micro-nano porous TiO2 coating is combined with the metal matrix surface, in-situ generated by micro-arc oxidation of the titanium matrix surface in a specific electrolyte system, and the micro-nano structure of the coating is regulated by the hydrothermal method; the near-infrared light triggering function is realized by the excellent near-infrared light-to-heat response activity of the layered porous TiO2 micro-nano coating structure; the wavelength range of the near-infrared light is 650-1200 nm, and the excitation power of the near-infrared light is 0.3-1.5 W / cm 2 ; the good anti-inflammatory and angiogenesis activities of the layered porous TiO2-CMO composite coating are realized by a nano-system (CMONPs) with good pH sensitivity, good biocompatibility, and excellent anti-inflammatory and angiogenesis activities; under normal temperature and normal conditions, the layered porous TiO2-CMO composite coating can kill more than 50% of the adhered bacteria, and under near-infrared light irradiation, the antibacterial performance can be further enhanced, and more than 95% of the adhered bacteria can be removed; The method for preparing the near-infrared light-triggered antibacterial and antioxidant TiO2-CMO composite coating comprises the following steps: (1) Construction of micro-nano arrays on the surface of titanium-based implants: The purchased titanium plates (thickness 2 mm; purity 99.5%) were cut into 10 mm × 10 mm × 2 mm sizes using a CNC wire cutting machine. The surfaces of the titanium plates were then polished step by step using sandpaper of different mesh sizes (600#, 800#, 1000#) to make the surfaces smooth. The dirt and impurities on the surfaces were then ultrasonically cleaned with anhydrous ethanol and deionized water in turn. (2) Using a titanium sheet as an anode and stainless steel as a cathode in a specific electrolyte, a bipolar pulse micro-arc oxidation device is used to micro-arc oxidize the titanium sheet to construct a layered porous TiO2 micro-nanostructure coating on the surface of the titanium substrate, which is then taken out, dried, and set aside; (3) Prepare a sodium hydroxide solution and stir it thoroughly to make it dissolve evenly. Place the sample face up in a reactor to carry out a hydrothermal reaction. After the reaction is completed, cool it in the furnace, take out the sample, wash it, and dry it; (4) Place the sample obtained in (3) face up in a ceramic boat, wrap the ceramic boat with tin foil, and place it in a reaction furnace. Adjust the temperature and time according to the heating rate of the reaction furnace at 3°C / min. After annealing is completed, cool it in the furnace and take out the sample; (5) COS is completely dissolved in deionized water, the sample prepared in (4) is placed therein and the temperature is adjusted, then ammonium molybdate solution is added to the COS solution, and the mixture is placed under continuous stirring. The obtained sample is taken out, washed with deionized water, and dried to finally obtain a near-infrared light-triggered antibacterial and antioxidant TiO2-CMO composite coating.

2. The preparation method of the near-infrared light-triggered antibacterial and antioxidant TiO2-CMO composite coating according to claim 1, characterized in that In the step (3), the hydrothermal reaction temperature is 70 to 200° C., and the reaction time is 2 to 24 hours.

3. The preparation method of the near-infrared light-triggered antibacterial and antioxidant TiO2-CMO composite coating according to claim 1, characterized in that, In the step (4), the sample annealing temperature is between 400 and 800° C., and the annealing time is between 2 and 6 hours.

4. The preparation method of the near-infrared light-triggered antibacterial and antioxidant TiO2-CMO composite coating according to claim 1, characterized in that The concentration of the chitosan oligosaccharide solution is between 2 and 10 mg / ml, and the concentration of the ammonium molybdate solution is between 2 and 10 mg / ml, and stirring is continued for 24 to 48 hours.

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