Reactive magnetron co-sputtering of Ti-xCuO coatings: Multifunctional interfaces for blood-contacting devices

Multimodal Synergistic Antimicrobial Activity of the Copper-Doped and Oxygen-Defective In Situ Nanocoating on Medical Titanium

To combat escalating antibiotic resistance in titanium implant-associated infections, oxygen-vacancy-rich polydopamine/TiCu nanocoating (PDA/p-TiCu-300 °C) was developed on medical-grade titanium, uniquely enabling synergistic photothermal (PTT), photodynamic (PDT), and sonodynamic (SDT) antimicrobial strategies. Unlike previous dual-modal approaches, this trimodal strategy, activated by near-infrared light and ultrasound, achieved exceptional broad-spectrum bactericidal efficacy against both Escherichia coli (99.19% killing) and Staphylococcus aureus (95.03% killing) via enhanced reactive oxygen species (ROS) generation and membrane disruption. The engineered oxygen vacancies within the PDA/p-TiCu-300 °C nanocoating significantly boosted ROS production, outperforming conventional photocatalytic materials. Crucially, the nanocoatings demonstrated excellent in vitro cytocompatibility. This PTT-PDT-SDT platform exhibits synergistic multimodal bactericidal activity, overcoming the limitations of existing strategies and representing a paradigm shift in implant surface modification with significant translational potential against severe infections.

Transformative potential of plant-based nanoparticles in cancer diagnosis and treatment: bridging traditional medicine and modern therapy

Cancer is a primary global health concern, with an estimated 35.3 million cancer cases expected worldwide, representing a 76.6% increase in 2022, and 20 million by 2050, resulting from genetic mutation and environmental factors that cause uncontrolled cell growth. Other factors including smoking, unhealthy diets, physical inactivity, exposure to carcinogens, UV radiation, and aging increase DNA damage. Current cancer treatments like chemotherapy, radiation therapy, immunotherapy, and surgery are effective, but those have significant effects like lack of specificity, development of drug resistance, and significant side effects to healthy tissues. An advancement to conventional therapies is plant-based nanoparticles as transformative approaches in cancer diagnosis and treatment. These nanoparticles synthesized using plant bioactive compounds like flavonoids, alkaloids, polyphenols, and some metals-oxides like gold, silver, copper, zinc, etc. offer eco-friendly, cost-effective, and biocompatible alternatives. They enhance targeted drug delivery, allowing anticancer agents specifically to tumor cells, minimizing damage to health. Improves imaging techniques like MRI and fluorescence imaging, and helps early detection, cancer biomarkers, allowing for prompt intervention. Recent findings show that nanocarriers made from plant-based materials, such as polyphenols (curcumin, resveratrol) and plant-extracted metal nanoparticles (gold, silver), can improve drug stability and selectively target tumor cells. Plant-derived nanoparticles play a crucial role in cancer immunotherapy and nanovaccines. Biodegradable plant-based nanocarriers can deliver cancer vaccines, stimulating long-term immunity against tumors. Graphene oxide and gold nanoparticles synthesized from plant extracts can absorb near-infrared (NIR) light, generating heat to destroy cancer cells with minimal damage to surrounding tissues. This study discusses the types of plant-based nanoparticles like plant virus nanoparticles (TMV, PVX, CPMV), plant metallic nanoparticles (Au, Ag., Cu, Zn, Mg, Ca, and Mn), and flavonoid nanoparticles found in cancer treatment, their significant roles, chemotherapy-based nanomedicines available in the medical field, and a detailed vision of nanomaterial applications in cancer diagnosis, treatment, and targeted drug delivery.

Surface Bio-engineered Polymeric Nanoparticles

Surface bio-engineering of polymeric nanoparticles (PNPs) has emerged as a cornerstone in contemporary biomedical research, presenting a transformative avenue that can revolutionize diagnostics, therapies, and drug delivery systems. The approach involves integrating bioactive elements on the surfaces of PNPs, aiming to provide them with functionalities to enable precise, targeted, and favorable interactions with biological components within cellular environments. However, the full potential of surface bio-engineered PNPs in biomedicine is hampered by obstacles, including precise control over surface modifications, stability in biological environments, and lasting targeted interactions with cells or tissues. Concerns like scalability, reproducibility, and long-term safety also impede translation to clinical practice. In this review, these challenges in the context of recent breakthroughs in developing surface-biofunctionalized PNPs for various applications, from biosensing and bioimaging to targeted delivery of therapeutics are discussed. Particular attention is given to bonding mechanisms that underlie the attachment of bioactive moieties to PNP surfaces. The stability and efficacy of surface-bioengineered PNPs are critically reviewed in disease detection, diagnostics, and treatment, both in vitro and in vivo settings. Insights into existing challenges and limitations impeding progress are provided, and a forward-looking discussion on the field's future is presented. The paper concludes with recommendations to accelerate the clinical translation of surface bio-engineered PNPs.

Dealloyed nano-porous TiCu coatings with controlled copper release for cardiovascular devices

TiCu coatings with controlled copper release and nano-porous structures were fabricated as biocompatible, blood-contacting interfaces through a two-step process. Initially, coatings with 58 % Cu were created using HiPIMS/DC magnetron co-sputtering, followed by immersion in a dilute HF solution for varying durations to achieve dealloying. The presence of Ti elements in the as-deposited TiCu coatings facilitated their dissolution upon exposure to the dilute HF solution, resulting in the formation of nanopores and increased nano-roughness. Dealloying treatment time correlated with higher Cu/(Ti + Cu) values, nanopore size, and nano-roughness in the dealloyed samples. The dealloyed TiCu coatings with 87 % Cu exhibited a controlled release of copper ions and displayed nanopores (approximately 80 nm in length and 31.0 nm in width) and nano-roughness (Ra roughness: 82 nm). These coatings demonstrated inhibited platelet adhesion and suppressed smooth muscle cell behavior, while supporting favorable endothelial cell viability and proliferation, attributed to the controlled release of copper ions and the extent of nanostructures. In contrast, the as-deposited TiCu coatings with 85 % Cu showed high copper ion release, leading to decreased viability and proliferation of endothelial cells and smooth muscle cells, as well as suppressed platelet adhesion. The TiCu coatings met medical safety standards, exhibiting hemolysis rates of <5 %. The technology presented here paves the way for the simple, controllable, and cost-effective fabrication of TiCu coatings, opening new possibilities for surface modification of cardiovascular devices such as vascular stents and inferior vena cava filters.

Unravelling Surface Modification Strategies for Preventing Medical Device-Induced Thrombosis

The use of biomaterials in implanted medical devices remains hampered by platelet adhesion and blood coagulation. Thrombus formation is a prevalent cause of failure of these blood-contacting devices. Although systemic anticoagulant can be used to support materials and devices with poor blood compatibility, its negative effects such as an increased chance of bleeding, make materials with superior hemocompatibility extremely attractive, especially for long-term applications. This review examines blood-surface interactions, the pathogenesis of clotting on blood-contacting medical devices, popular surface modification techniques, mechanisms of action of anticoagulant coatings, and discusses future directions in biomaterial research for preventing thrombosis. In addition, this paper comprehensively reviews several novel methods that either entirely prevent interaction between material surfaces and blood components or regulate the reaction of the coagulation cascade, thrombocytes, and leukocytes.

Immunomodulatory effect of Ti-Cu alloy by surface nanostructure synergistic with Cu2+ release

The inflammatory response induced by implant/macrophage interaction has been considered to be one of the vital factors in determining the success of implantation. In this study, TiCuNxOy coating with an immunomodulatory strategy was proposed for the first time, using nanostructured TiCuNxOy coating synthesized on Ti-Cu alloy by oxygen and nitrogen plasma-based surface modification. It was found that TiCuNxOy coating inhibited macrophage proliferation but stimulated macrophage preferential activation and presented an elongated morphology due to the surface nanostructure. The most encouraging discovery was that TiCuNxOy coating promoted the initial pro-inflammatory response of macrophages and then accelerated the M1-to-M2 transition of macrophages via a synergistic effect of fast-to-slow Cu2+ release and surface nanostructure, which was considered to contribute to initial infection elimination and tissue healing. As expected, TiCuNxOy coating released desirable Cu2+ and generated a favorable immune response that facilitated HUVEC recruitment to the coating, and accelerated proliferation, VEGF secretion and NO production of HUVECs. On the other hand, it is satisfying that TiCuNxOy coating maintained perfect long-term antibacterial activity (≥99.9%), mainly relying on Cu2O/CuO contact sterilization. These results indicated that TiCuNxOy coating might offer novel insights into the creation of a surface with immunomodulatory effects and long-term bactericidal potential for cardiovascular applications.

Antibacterial Ti-Cu implants: A critical review on mechanisms of action

Titanium (Ti) has been widely used for manufacturing of bone implants because of its mechanical properties, biological compatibility, and favorable corrosion resistance in biological environments. However, Ti implants are prone to infection (peri-implantitis) by bacteria which in extreme cases necessitate painful and costly revision surgeries. An emerging, viable solution for this problem is to use copper (Cu) as an antibacterial agent in the alloying system of Ti. The addition of copper provides excellent antibacterial activities, but the underpinning mechanisms are still obscure. This review sheds light on such mechanisms and reviews how incorporation of Cu can render Ti-Cu implants with antibacterial activity. The review first discusses the fundamentals of interactions between bacteria and implanted surfaces followed by an overview of the most common engineering strategies utilized to endow an implant with antibacterial activity. The underlying mechanisms for antibacterial activity of Ti-Cu implants are then discussed in detail. Special attention is paid to contact killing mechanisms because the misinterpretation of this mechanism is the root of discrepancies in the literature.

Adhesive and Self-Healing Polyurethanes with Tunable Multifunctionality

Many polyurethanes (PUs) are blood-contacting materials due to their good mechanical properties, fatigue resistance, cytocompatibility, biosafety, and relatively good hemocompatibility. Further functionalization of the PUs using chemical synthetic methods is especially attractive for expanding their applications. Herein, a series of catechol functionalized PU (C-PU-PTMEG) elastomers containing variable molecular weight of polytetramethylene ether glycol (PTMEG) soft segment are reported by stepwise polymerization and further introduction of catechol. Tailoring the molecular weight of PTMEG fragment enables a regulable catechol content, mobility of the chain segment, hydrogen bond and microphase separation of the C-PU-PTMEG elastomers, thus offering tunability of mechanical strength (such as breaking strength from 1.3 MPa to 5.7 MPa), adhesion, self-healing efficiency (from 14.9% to 96.7% within 2 hours), anticoagulant, antioxidation, anti-inflammatory properties and cellular growth behavior. As cardiovascular stent coatings, the C-PU-PTMEGs demonstrate enough flexibility to withstand deformation during the balloon dilation procedure. Of special importance is that the C-PU-PTMEG-coated surfaces show the ability to rapidly scavenge free radicals to maintain normal growth of endothelial cells, inhibit smooth muscle cell proliferation, mediate inflammatory response, and reduce thrombus formation. With the universality of surface adhesion and tunable multifunctionality, these novel C-PU-PTMEG elastomers should find potential usage in artificial heart valves and surface engineering of stents.

A high-hydrophilic Cu2O-TiO2/Ti2O3/TiO coating on Ti-5Cu alloy: Perfect antibacterial property and rapid endothelialization potential

In order to make novel antibacterial Ti-Cu alloy more suitable for cardiovascular implant application, a Cu-containing oxide coating was manufactured on Ti-Cu alloy by plasma-enhanced oxidation deposition in plasma enhanced chemical vapor deposition (PECVD) equipment to further improve the antibacterial ability and the surface bioactivity. The results of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and water contact angle indicated that a sustainably high-hydrophilic Cu₂O-TiO₂/Ti₂O₃/TiO coating with nano-morphology on Ti-5Cu was successfully constructed. The corrosion performance results showed that the coating enhanced the corrosion resistance while releasing more Cu²⁺, compared with Ti-5Cu. Antibacterial tests confirmed the perfect antibacterial property of the coating (R ≥ 99.9 %), superior to Ti-Cu alloy (R > 90 %). More delightfully, it was observed by phalloidin-FITC and DAPI staining that the coating improved the early adhesion of HUVEC cells mainly due to strong hydrophilicity and nano-morphology. It was demonstrated that the extract of the coated sample significantly promoted proliferation (RGR = 112 %-138 % after cultivation for 1 to 3 days) and migration of HUVEC cells due to the appropriate Cu²⁺ release concentration. Hemolysis assay and platelet adhesion results showed that the coating had excellent blood compatibility. All results suggested that the coating on Ti-Cu alloy might be a promising surface with the perfect antibacterial ability, blood compatibility and evident promoting endothelialization ability for the cardiovascular application.

Polylactic acid/polyvinyl alcohol-quaternary ammonium chitosan double-layer films doped with novel antimicrobial agent CuO@ZIF-8 NPs for fruit preservation

ZIF-8, a subclass of metal organic frameworks (MOFs), was employed as the CuO carriers because of its high surface areas and good dispersibility. A novel antibacterial agent CuO@ZIF-8 was synthesized by environmentally-friendly direct calcination strategy, and introduced into the composite double-layer films for packing materials. The double-layer films were prepared via solution casting method with polylactic acid (PLA) and polyvinyl alcohol (PVA)-quaternary ammonium chitosan as the matrix of outer layer and inner layer, respectively; and CuO@ZIF-8 nanoparticles were introduced into the PVA-quaternary ammonium chitosan layer. The double-layer films exhibited superior antibacterial activity resulted from the uniform dispersion of CuO by ZIF-8 carriers. The elongation at break was enhanced and up to 17.13%, about 2.4-fold that of PLA films. Meanwhile, the films provided low water vapor permeability and strong UV-barrier ability which were attributed to the lay-by-layer casting, CuO@ZIF-8 doping and TiO₂ addition. Cherry tomato preservation experiment revealed that the composite films retarded the growth of harmful microorganisms on the fruit surface. MTT assay confirmed the cytocompatibility of the films. The easily fabricated double-layer films presented potential possibility in the field of biodegradable food packaging.

Development of a low elastic modulus and antibacterial Ti-13Nb-13Zr-5Cu titanium alloy by microstructure controlling

In order to prepare a titanium with a low elastic modulus and good antibacterial property to meet the requirements as a biomedical material, Ti-13Nb-13Zr-5Cu (TNZ-5Cu) alloy was prepared by high vacuum consume electric arc melting furnace and then subjected to a solution treatment at 950 °C followed by a short-term aging treatment at 600 °C, for 15 min, 30 min, 1 h and 2 h, respectively. The microstructure, mechanical property, antibacterial property and biocompatibility of TNZ-5Cu were investigated in detail. The research results have shown that the solid solution treated alloy was mainly composed of β-phase and α″-phase, while the aged alloys of β-phase, α″-phase, α-phase and Ti₂Cu. Compared with Ti-13Nb-13Zr alloy (65 GPa) and Ti-6Al-4 V alloy (111 GPa), the elastic modulus of TNZ-5Cu alloy after solution treatment was about 72 GPa and increased with the aging treatment up to 85 GPa, and the hardness was maintained at a higher level than that of Ti-13Nb-13Zr alloys (288 HV). The bacteria plate count results showed that the antibacterial ability of TNZ-5Cu alloy increased with the extension of the aging duration from <60% at 15-30 min to >90% at 1-2 h. Cell experiments showed that all TNZ-5Cu alloy had good cell compatibility. The low modulus and the antibacterial property could provide potential to avoid stress shield and device-related inflection in the clinical application.