Surface treatment of 3D printed porous Ti6Al4V implants by ultraviolet photofunctionalization for improved osseointegration

Beyond microroughness: novel approaches to navigate osteoblast activity on implant surfaces

Considering the biological activity of osteoblasts is crucial when devising new approaches to enhance the osseointegration of implant surfaces, as their behavior profoundly influences clinical outcomes. An established inverse correlation exists between osteoblast proliferation and their functional differentiation, which constrains the rapid generation of a significant amount of bone. Examining the surface morphology of implants reveals that roughened titanium surfaces facilitate rapid but thin bone formation, whereas smooth, machined surfaces promote greater volumes of bone formation albeit at a slower pace. Consequently, osteoblasts differentiate faster on roughened surfaces but at the expense of proliferation speed. Moreover, the attachment and initial spreading behavior of osteoblasts are notably compromised on microrough surfaces. This review delves into our current understanding and recent advances in nanonodular texturing, meso-scale texturing, and UV photofunctionalization as potential strategies to address the "biological dilemma" of osteoblast kinetics, aiming to improve the quality and quantity of osseointegration. We discuss how these topographical and physicochemical strategies effectively mitigate and even overcome the dichotomy of osteoblast behavior and the biological challenges posed by microrough surfaces. Indeed, surfaces modified with these strategies exhibit enhanced recruitment, attachment, spread, and proliferation of osteoblasts compared to smooth surfaces, while maintaining or amplifying the inherent advantage of cell differentiation. These technology platforms suggest promising avenues for the development of future implants.

Nanofeatured surfaces in dental implants: contemporary insights and impending challenges

Dental implant therapy, established as standard-of-care nearly three decades ago with the advent of microrough titanium surfaces, revolutionized clinical outcomes through enhanced osseointegration. However, despite this pivotal advancement, challenges persist, including prolonged healing times, restricted clinical indications, plateauing success rates, and a notable incidence of peri-implantitis. This review explores the biological merits and constraints of microrough surfaces and evaluates the current landscape of nanofeatured dental implant surfaces, aiming to illuminate strategies for addressing existing impediments in implant therapy. Currently available nanofeatured dental implants incorporated nano-structures onto their predecessor microrough surfaces. While nanofeature integration into microrough surfaces demonstrates potential for enhancing early-stage osseointegration, it falls short of surpassing its predecessors in terms of osseointegration capacity. This discrepancy may be attributed, in part, to the inherent "dichotomy kinetics" of osteoblasts, wherein increased surface roughness by nanofeatures enhances osteoblast differentiation but concomitantly impedes cell attachment and proliferation. We also showcase a controllable, hybrid micro-nano titanium model surface and contrast it with commercially-available nanofeatured surfaces. Unlike the commercial nanofeatured surfaces, the controllable micro-nano hybrid surface exhibits superior potential for enhancing both cell differentiation and proliferation. Hence, present nanofeatured dental implants represent an evolutionary step from conventional microrough implants, yet they presently lack transformative capacity to surmount existing limitations. Further research and development endeavors are imperative to devise optimized surfaces rooted in fundamental science, thereby propelling technological progress in the field.

Future trends of additive manufacturing in medical applications: An overview

Additive Manufacturing (AM) has recently demonstrated significant medical progress. Due to advancements in materials and methodologies, various processes have been developed to cater to the medical sector's requirements, including bioprinting and 4D, 5D, and 6D printing. However, only a few studies have captured these emerging trends and their medical applications. Therefore, this overview presents an analysis of the advancements and achievements obtained in AM for the medical industry, focusing on the principal trends identified in the annual report of AM3DP.

Synergistic Effect of Nano Strontium Titanate Coating and Ultraviolet C Photofunctionalization on Osteogenic Performance and Soft Tissue Sealing of poly(ether-ether-ketone)

This study aimed to evaluate the bioactivity of poly(ether ether ketone) (PEEK) after surface modification by persistent photoconductive strontium titanate (SrTiO3) magnetron sputtering and ultraviolet (UV) C irradiation. According to the different modifications, the PEEK specimens were randomly divided into five groups (n = 38/group): PEEK, Sr100-PEEK, Sr200-PEEK, UV/PEEK, and UV/Sr200-PEEK. Then, the specimens of Sr100-PEEK and Sr200-PEEK groups were, respectively, coated with 100 and 200 nm thickness photocatalyst SrTiO3 on the PEEK surface by magnetron sputtering. Subsequently, UV-C light photofunctionalized the specimens of PEEK and Sr200-PEEK groups to form UV/PEEK and UV/Sr200-PEEK groups. The specimens were characterized by a step meter, scanning electron microscopy (SEM), atomic force microscopy (AFM), energy dispersive X-ray spectroscopy (EDX), and a water contact angle meter. The release test of the Sr ion was performed by inductively coupled plasma mass spectrometry (ICP-MS). In vitro study, osteogenic activity (MC3T3-E1 osteoblast-like cells) and epithelial and connective tissue attachment (gingival epithelial cells GE1 and fibroblasts NIH3T3) were analyzed in five groups. Surface morphology of the specimens was changed after coating, and the Sr content on the Sr-PEEK surface was increased with increasing coating thickness. In addition, the contact angle was increased significantly after magnetron sputtering. After UV-C photofunctionalization, the content of surface elements changed and the contact angle was decreased. The release of Sr ion was sustained, and the final cumulative release amount did not exceed the safety limit. In vitro experiments showed that SrTiO3 improved the cell activity of MC3T3-E1 and UV-C irradiation further enhanced the osteogenic performance of PEEK. Besides, UV-C irradiation also significantly promoted the cell viability, development, and expression of adhesion proteins of GE1 and NIH3T3 on PEEK. The present investigation demonstrated that nano SrTiO3 coating with UV-C photofunctionalization synergistically enhanced the osteogenic properties and soft tissue sealing function of PEEK in vitro.

Functionally Tailored Metal-Organic Framework Coatings for Mediating Ti Implant Osseointegration

Owing to their mechanical resilience and non-toxicity, titanium implants are widely applied as the major treatment modality for the clinical intervention against bone fractures. However, the intrinsic bioinertness of Ti and its alloys often impedes the effective osseointegration of the implants, leading to severe adverse complications including implant loosening, detachment, and secondary bone damage. Consequently, new Ti implant engineering strategies are urgently needed to improve their osseointegration after implantation. Remarkably, metalorganic frameworks (MOFs) are a class of novel synthetic material consisting of coordinated metal species and organic ligands, which have demonstrated a plethora of favorable properties for modulating the interfacial properties of Ti implants. This review comprehensively summarizes the recent progress in the development of MOF-coated Ti implants and highlights their potential utility for modulating the bio-implant interface to improve implant osseointegration, of which the discussions are outlined according to their physical traits, chemical composition, and drug delivery capacity. A perspective is also provided in this review regarding the current limitations and future opportunities of MOF-coated Ti implants for orthopedic applications. The insights in this review may facilitate the rational design of more advanced Ti implants with enhanced therapeutic performance and safety.

Multifunctional 3D-printed scaffolds eradiate orthotopic osteosarcoma and promote osteogenesis via microwave thermo-chemotherapy combined with immunotherapy

Tumor recurrence and a lack of bone-tissue integration are two critical concerns in the surgical treatment of osteosarcoma. Thus, an advanced multifunctional therapeutic platform capable of simultaneously eliminating residual tumor cells and promoting bone regeneration is urgently needed for efficient osteosarcoma treatment. Herein, to thoroughly eliminate tumors and simultaneously promote bone regeneration, an intelligent multifunctional therapeutic scaffold has been engineered by integrating microwave-responsive zeolitic imidazolate framework 8 (ZIF-8) nanomaterials loaded with a chemotherapeutic drug and an immune checkpoint inhibitor onto 3D-printed titanium scaffolds. The constructed scaffold features distinct microwave-thermal sensitization and tumor microenvironment-responsive characteristics, which can induce tumor immunogenic death by microwave hyperthermia and chemotherapy. Orthotopic implantation of the nanocomposite scaffold results in an enhanced immune response against osteosarcoma that may effectively inhibit tumor recurrence through synergistic immunotherapy. During long-term implantation, the zinc ions released from the degradation of ZIF-8 can induce the osteogenic differentiation of stem cells. The porous structure and mechanical properties of the 3D-printed titanium scaffolds provide a structural microenvironment for bone regeneration. This study provides a paradigm for the design of multifunctional microwave-responsive composite scaffolds for use as a therapy for osteosarcoma, which could lead to improved strategies for the treatment of the disease.

Influence of Surface Contaminants and Hydrocarbon Pellicle on the Results of Wettability Measurements of Titanium

Hydrophilicity/hydrophobicity-or wettability-is a key surface characterization metric for titanium used in dental and orthopedic implants. However, the effects of hydrophilicity/hydrophobicity on biological capability remain uncertain, and the relationships between surface wettability and other surface parameters, such as topography and chemistry, are poorly understood. The objective of this study was to identify determinants of surface wettability of titanium and establish the reliability and validity of the assessment. Wettability was evaluated as the contact angle of ddH2O. The age of titanium specimens significantly affected the contact angle, with acid-etched, microrough titanium surfaces becoming superhydrophilic immediately after surface processing, hydrophobic after 7 days, and hydrorepellent after 90 days. Similar age-related loss of hydrophilicity was also confirmed on sandblasted supra-micron rough surfaces so, regardless of surface topography, titanium surfaces eventually become hydrophobic or hydrorepellent with time. On age-standardized titanium, surface roughness increased the contact angle and hydrophobicity. UV treatment of titanium regenerated the superhydrophilicity regardless of age or surface roughness, with rougher surfaces becoming more superhydrophilic than machined surfaces after UV treatment. Conditioning titanium surfaces by autoclaving increased the hydrophobicity of already-hydrophobic surfaces, whereas conditioning with 70% alcohol and hydrating with water or saline attenuated pre-existing hydrophobicity. Conversely, when titanium surfaces were superhydrophilic like UV-treated ones, autoclaving and alcohol cleaning turned the surfaces hydrorepellent and hydrophobic, respectively. UV treatment recovered hydrophilicity without exception. In conclusion, surface roughness accentuates existing wettability and can either increase or decrease the contact angle. Titanium must be age-standardized when evaluating surface wettability. Surface conditioning techniques significantly but unpredictably affect existing wettability. These implied that titanium wettability is significantly influenced by the hydrocarbon pellicle and other contaminants inevitably accumulated. UV treatment may be an effective strategy to standardize wettability by making all titanium surfaces superhydrophilic, thereby allowing the characterization of individual surface topography and chemistry parameters in future studies.

An Optimized Method for Microcomputed Tomography Analysis of Trabecular Parameters of Metal Scaffolds for Bone Ingrowth

Owing to its superior mechanical and biological properties, titanium metal is widely used in dental implants, orthopedic devices, and bone regenerative materials. Advances in 3D printing technology have led to more and more metal-based scaffolds being used in orthopedic applications. Microcomputed tomography (μCT) is commonly applied to evaluate the newly formed bone tissues and scaffold integration in animal studies. However, the presence of metal artifacts dramatically hinders the accuracy of μCT analysis of new bone formation. To acquire reliable and accurate μCT results that reflect new bone formation in vivo, it is crucial to lessen the impact of metal artifacts. Herein, an optimized procedure for calibrating μCT parameters using histological data was developed. In this study, the porous titanium scaffolds were fabricated by powder bed fusion based on computer-aided design. These scaffolds were implanted in femur defects created in New Zealand rabbits. After 8 weeks, tissue samples were collected to assess new bone formation using μCT analysis. Resin-embedded tissue sections were then used for further histological analysis. A series of deartifact two-dimensional (2D) μCT images were obtained by setting the erosion radius and the dilation radius in the μCT analysis software (CTan) separately. To get the μCT results closer to the real value, the 2D μCT images and corresponding parameters were subsequently selected by matching the histological images in the particular region. After applying the optimized parameters, more accurate 3D images and more realistic statistical data were obtained. The results demonstrate that the newly established method of adjusting μCT parameters can effectively reduce the influence of metal artifacts on data analysis to some extent. For further validation, other metal materials should be analyzed using the process established in this study.

Osseointegration in additive-manufactured titanium implants: A systematic review of animal studies on the need for surface treatment

The objective of the systematic review is to find an answer to a question: "Do surface treatments on titanium implants produced by additive manufacturing improve osseointegration, compared to untreated surfaces?". This review followed the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA 2020) and was registered in the International Prospective Register of Systematic Reviews (PROSPERO) (CRD42022321351). Searches were performed in PubMed, Scopus, Science Direct, Embase, and Google Scholar databases on March 22nd, 2022. Articles were chosen in 2 steps by 2 blinded reviewers based on previously selected inclusion criteria: articles in animals that addressed the influence of surface treatments on osseointegration in implants produced by additive manufacturing. Articles were excluded that (1) did not use titanium surface, 2) that did not evaluate surface treatments, 3) that did not described osseointegration, 4) Studies with only in vitro analyses, clinical studies, systematic reviews, book chapters, short communications, conference abstracts, case reports and personal opinions.). 1003 articles were found and, after applying the eligibility criteria, 17 were used for the construction of this review. All included studies found positive osseointegration results from performing surface treatments on titanium. The risk of bias was analyzed using the SYRCLE assessment tool. Surface treatments are proposed to promote changes in the microstructure and composition of the implant surface to favor the adhesion of bone cells responsible for osseointegration. It is observed that despite the benefits generated by the additive manufacturing process in the microstructure of the implant surface, surface treatments are still indispensable, as they can promote more suitable characteristics for bone-implant integration. It can be concluded that the surface treatments evaluated in this systematic review, performed on implants produced by additive manufacturing, optimize osseointegration, as it allows the creation of a micro-nano-textured structure that makes the surface more hydrophilic and allows better contact bone-implant.

Bioceramic scaffolds with triply periodic minimal surface architectures guide early-stage bone regeneration

The pore architecture of porous scaffolds is a critical factor in osteogenesis, but it is a challenge to precisely configure strut-based scaffolds because of the inevitable filament corner and pore geometry deformation. This study provides a pore architecture tailoring strategy in which a series of Mg-doped wollastonite scaffolds with fully interconnected pore networks and curved pore architectures called triply periodic minimal surfaces (TPMS), which are similar to cancellous bone, are fabricated by a digital light processing technique. The sheet-TPMS pore geometries (s-Diamond, s-Gyroid) contribute to a 3‒4-fold higher initial compressive strength and 20%-40% faster Mg-ion-release rate compared to the other-TPMS scaffolds, including Diamond, Gyroid, and the Schoen's I-graph-Wrapped Package (IWP) in vitro. However, we found that Gyroid and Diamond pore scaffolds can significantly induce osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs). Analyses of rabbit experiments in vivo show that the regeneration of bone tissue in the sheet-TPMS pore geometry is delayed; on the other hand, Diamond and Gyroid pore scaffolds show notable neo-bone tissue in the center pore regions during the early stages (3-5 weeks) and the bone tissue uniformly fills the whole porous network after 7 weeks. Collectively, the design methods in this study provide an important perspective for optimizing the pore architecture design of bioceramic scaffolds to accelerate the rate of osteogenesis and promote the clinical translation of bioceramic scaffolds in the repair of bone defects.

Decomposing Organic Molecules on Titanium with Vacuum Ultraviolet Light for Effective and Rapid Photofunctionalization

Ultraviolet (UV) photofunctionalization counteracts the biological aging of titanium to increase the bioactivity and osseointegration of titanium implants. However, UV photofunctionalization currently requires long treatment times of between 12 min and 48 h, precluding routine clinical use. Here, we tested the ability of a novel, xenon excimer lamp emitting 172 nm vacuum UV (VUV) to decompose organic molecules coated on titanium as a surrogate of photofunctionalization. Methylene blue as a model organic molecule was coated on grade 4 commercially pure titanium and treated with four UV light sources: (i) ultraviolet C (UVC), (ii) high-energy UVC (HUVC), (iii) proprietary UV (PUV), and (iv) VUV. After one minute of treatment, VUV decomposed 57% of methylene blue compared with 2%, 36%, and 42% for UVC, HUVC, and PUV, respectively. UV dose-dependency testing revealed maximal methylene blue decomposition with VUV within one minute. Equivalent decomposition was observed on grade 5 titanium alloy specimens, and placing titanium specimens in quartz ampoules did not compromise efficacy. Methylene blue was decomposed even on polymethyl methacrylate acrylic specimens at 20-25% lower efficiency than on titanium specimens, indicating a relatively small contribution of titanium dioxide-mediated photocatalytic decomposition to the total decomposition. Load-testing revealed that VUV maintained high efficacy of methylene blue decomposition regardless of the coating density, whereas other UV light sources showed low efficacy with thin coatings and plateauing efficacy with thicker coatings. This study provides foundational data on rapid and efficient VUV-mediated organic decomposition on titanium. In synergy with quartz ampoules used as containers, VUV has the potential to overcome current technical challenges hampering the clinical application of UV photofunctionalization.

Clinical Applications of Photofunctionalization on Dental Implant Surfaces: A Narrative Review

Dental implant therapy is a common clinical procedure for the restoration of missing teeth. Many methods have been used to promote osseointegration for successful implant therapy, including photofunctionalization (PhF), which is defined as the modification of titanium surfaces after ultraviolet treatment. It includes the alteration of the physicochemical properties and the enhancement of biological capabilities, which can alter the surface wettability and eliminate hydrocarbons from the implant surface by a biological aging process. PhF can also enhance cellular migration, attachment, and proliferation, thereby promoting osseointegration and coronal soft tissue seal. However, PhF did not overcome the dental implant challenge of oral cancer cases. It is necessary to have more clinical trials focused on complex implant cases and non-dental fields in the future.

Porous construction and surface modification of titanium-based materials for osteogenesis: A review

Titanium and titanium alloy implants are essential for bone tissue regeneration engineering. The current trend is toward the manufacture of implants from materials that mimic the structure, composition and elasticity of bones. Titanium and titanium alloy implants, the most common materials for implants, can be used as a bone conduction material but cannot promote osteogenesis. In clinical practice, there is a high demand for implant surfaces that stimulate bone formation and accelerate bone binding, thus shortening the implantation-to-loading time and enhancing implantation success. To avoid stress shielding, the elastic modulus of porous titanium and titanium alloy implants must match that of bone. Micro-arc oxidation technology has been utilized to increase the surface activity and build a somewhat hard coating on porous titanium and titanium alloy implants. More recently, a growing number of researchers have combined micro-arc oxidation with hydrothermal, ultrasonic, and laser treatments, coatings that inhibit bacterial growth, and acid etching with sand blasting methods to improve bonding to bone. This paper summarizes the reaction at the interface between bone and implant material, the porous design principle of scaffold material, MAO technology and the combination of MAO with other technologies in the field of porous titanium and titanium alloys to encourage their application in the development of medical implants.

Three-dimensional-printed titanium prostheses with bone trabeculae enable mechanical-biological reconstruction after resection of bone tumours

Reconstruction after resection has always been an urgent problem in the treatment of bone tumours. There are many methods that can be used to reconstruct bone defects; however, there are also many complications, and it is difficult to develop a safe and effective reconstruction plan for the treatment of bone tumours. With the rapid development of digital orthopaedics, three-dimensional printing technology can solve this problem. The three-dimensional printing of personalised prostheses has many advantages. It can be used to print complex structures that are difficult to fabricate using traditional processes and overcome the problems of stress shielding and low biological activity of conventional prostheses. In this study, 12 patients with bone tumours were selected as research subjects, and based on individualised reverse-engineering design technology, a three-dimensional model of each prosthesis was designed and installed using medical image data. Ti6Al4V was used as the raw material to prepare the prostheses, which were used to repair bone defects after surgical resection. The operation time was 266.43 ± 21.08 minutes (range 180-390 minutes), and intraoperative blood loss was 857.26 ± 84.28 mL (range 800-2500 mL). One patient had delayed wound healing after surgery, but all patients survived without local tumour recurrence, and no tumour metastasis was found. No aseptic loosening or structural fracture of the prosthesis, and no non-mechanical prosthesis failure caused by infection, tumour recurrence, or progression was observed. The Musculo-Skeletal Tumour Society (MSTS) score of limb function was 22.53 ± 2.09 (range 16-26), and ten of the 12 patients scored ≥ 20 and were able to function normally. The results showed that three-dimensional printed prostheses with an individualised design can achieve satisfactory short-term clinical efficacy in the reconstruction of large bone defects after bone tumour resection.

Carboxymethyl carrageenan immobilized on 3D-printed polycaprolactone scaffold for the adsorption of calcium phosphate/strontium phosphate adapted to bone regeneration

Three dimensional (3D) substrates based on natural and synthetic polymers enhance the osteogenic and mechanical properties of the bone tissue engineering scaffolds. Here, a novel bioactive composite scaffolds from polycaprolactone /kappa-carrageenan were developed for bone regeneration applications. 3D PCL scaffolds were fabricated by 3D printing method followed by coating with carboxymethyl kappa-carrageenan. This organic film was used to create calcium and strontium phosphate layers via a modified alternate soaking process in CaCl ₂ /SrCl ₂ and Na₂HPO₄ solutions in which calcium ions were replaced by strontium, with different amounts of strontium in the solutions. Various characterization techniques were executed to analyze the effects of strontium ion on the scaffold properties. The morphological results demonstrated the highly porous with interconnected pores and uniform pore sizes scaffolds. It was indicated that the highest crystallinity and compressive strength were obtained when 100% CaCl₂ was replaced by SrCl₂ in the solution (P-C-Sr). Incorporation of Sr onto the structure increased the degradation rate of the scaffolds. Mesenchymal stem cells (MSCs) culture on the scaffolds showed that Sr effectively improved attachment and viability of the MSCs and accelerated osteogenic differentiation as revealed by Alkaline phosphatase activity, calcium content and Real Time-Reverse transcription polymerase chain reaction assays.

The contribution of pore size and porosity of 3D printed porous titanium scaffolds to osteogenesis

Porous titanium implants were popularly fabricated to promote bone formation. A desirable porous scaffold was recommended to be with porosity of >60% or/and pore size of >300 μm for better osteointegration. However, whether the pore size and porosity could be randomly selected within the recommended values? And what is the correlation between pore size and porosity for accelerating osteointegration? In this study, porous titanium with cubic cell structure was produced by selective laser melting. The designed porosities of scaffolds with 700-μm pore size were 40%, 70% and 90%; and the pore sizes of scaffolds with 70% porosity were 400, 700 and 900 μm. The in vitro osteogenic potential and in vivo bone formation were investigated. Results showed that porosity and pore size could be tuned by altering strut size, which was further directly responsible for mechanical properties. Besides, pore size and porosity synergistically contributed to osteogenic activity in vitro and new bone formation in vivo. In regard to pore sizes herein, the optimized one for better osteogenic response and bone forming ability was ~600-700 μm (p70). Too smaller or too larger pore size might more or less hinder cellular behaviors and bone regeneration, even if both pore size (300-900 μm) and porosity (70%) were within the recommended value range. At a constant pore size (~600-700 μm), p70 and p90 with higher porosity was more conductive to biological effects, compared with p40. As a result, pore-size variation revealed more significant influence on osteogenesis, compared with variation of porosity within recommended values. However, the applicable porosity within recommended values should be designed with the consideration of specific load-bearing conditions. This study helps to provide guidance for designing porous scaffolds with appropriate mechanical strengths and effective bone-forming ability, so as to develop better custom-made bone substitutes.

Advancing of 3D-Printed Titanium Implants with Combined Antibacterial Protection Using Ultrasharp Nanostructured Surface and Gallium-Releasing Agents

This paper presents the development of advanced Ti implants with enhanced antibacterial activity. The implants were engineered using additive manufacturing three-dimensional (3D) printing technology followed by surface modification with electrochemical anodization and hydrothermal etching, to create unique hierarchical micro/nanosurface topographies of microspheres covered with sharp nanopillars that can mechanically kill bacteria in contact with the surface. To achieve enhanced antibacterial performance, fabricated Ti implant models were loaded with gallium nitrate as an antibacterial agent. The antibacterial efficacy of the fabricated substrates with the combined action of sharp nanopillars and locally releasing gallium ions (Ga³⁺) was evaluated toward Staphylococcus aureus and Pseudomonas aeruginosa. Results confirm the significant antibacterial performance of Ga³⁺-loaded substrates with a 100% eradication of bacteria. The nanopillars significantly reduced bacterial attachment and prevented biofilm formation while also killing any bacteria remaining on the surface. Furthermore, 3D-printed surfaces with microspheres of diameter 5-30 μm and interspaces of 12-35 μm favored the attachment of osteoblast-like MG-63 cells, as confirmed via the assessment of their attachment, proliferation, and viability. This study provides important progress toward engineering of next-generation 3D-printed implants, that combine surface chemistry and structure to achieve a highly efficacious antibacterial surface with dual cytocompatibility to overcome the limitations of conventional Ti implants.

Surface Characterisation of Human Serum Albumin Layers on Activated Ti6Al4V

Adpsortion of protein layers on biomaterials plays an important role in the interactions between implants and the bio-environment. In this context, human serum albumin (HSA) layers have been deposited on modified Ti6Al4V surfaces at different ultraviolet (UV-C) irradiation times to observe possible changes in the adsorbed protein layer. Protein adsorption was done from solutions at concentraions lower than the serum protein concentration, to follow the surface modifications at the beginning of the albumin adhesion process. For this purpose, the surface of the protein-coated samples has been characterized by time of flight secondary ion mass spectrometry (ToF-SIMS), contact angle and zeta potential measurements. The results obtained show a reduction in the total surface tension and zeta potential of samples treated with UV-C light when coated with a protein layer. Furthermore, the UV-C light treatment applied to titanium alloy surfaces is able to modify the conformation, orientation and packing of the proteins arranged in the adsorbed layer. Low irradiation time generates an unstable surface with the lowest protein adsorption and the highest hydrophobic/hydrophilic protein ratio, indicating a possible denaturalization of the protein on these surfaces. However, surface changes are stabilized after 15 h or UV-C irradiation, favoring the protein adsorption through electrical interactions.