Titanium Surface Research Articles

Micro-arc oxidation for balancing antibacterial activity and bone formation on titanium surface

Ti surfaces must balance bone formation and antibacterial activity to achieve bone reconstruction and prevent infections. In this study, a Ti surface was electrochemically modified via micro-arc oxidation in an electrolyte containing calcium ions, phosphate ions, and either Ag, or Cu ions to form an antibacterial porous oxide layer on Ti surface. The resultant porous oxide layers consisted of both electrolyte and substrate elements. The Ag- and Cu-incorporated porous oxide layers exhibited antibacterial activity against methicillin-resistant Staphylococcus aureus. Furthermore, animal experiments were performed to reveal the bone-formation on the Ag- and Cu-incorporated porous oxide layers. Both porous oxide layers promoted bone formation more effectively than untreated Ti. Thus, the Ag- and Cu-incorporated porous oxide layers formed on the Ti surface by micro-arc oxidation balanced bone formation and antibacterial activity owing to their structural and compositional features. Our findings will be useful for the surface design of Ti-based medical devices and can provide a simple electrochemical treatment to form porous surfaces to balance antibacterial activity and bone formation on Ti surfaces.

Polydopamine-based surface coating fabrication on titanium implant by combining a photothermal agent and TiO2 nanosheets for efficient photothermal antibacterial therapy and promoted osteogenic activity

Developing titanium-based dental implants with both excellent antibacterial properties and good osseointegration is crucial for the success of the implant operation and the long-term durability of the implant. In this study, a polydopamine-based coating was created by attaching TiO2 nanosheets-cyanine composites onto the titanium surface, enabling the integration of effective photothermal antibacterial therapy with osseointegration. The exceptional dual-photothermal conversion abilities of polydopamine and cyanine in the coating resulted in outstanding photothermal antibacterial and antibiofilm therapy against four types of bacteria. Furthermore, TiO2 nanosheets promoted the adhesion, proliferation and early osteogenic differentiation of osteoblasts. In an infected dental implant model in rats, the developed coating exhibited potent antibacterial activity and remarkable osteogenic differentiation in the bone, leading to increased bone formation around the implants. This innovative approach, combining photothermal therapy with osteogenic two-dimensional nanomaterials, presents a novel method for surface functionalization of implants to achieve effective antibacterial and osseointegration capabilities.

Effect of Er,Cr:YSGG Laser Irradiation on the Surface Modification and Cell Adhesion on Titanium Discs: An In Vitro Study

This study evaluates the potential of erbium, chromium-doped:yttrium, scandium, gallium, and garnet (Er,Cr:YSGG) laser irradiation to modify the titanium surface for optimal seeding of fibroblasts and osteoblasts in the treatment of peri-implantitis. Titanium discs were treated using the Er,Cr:YSGG laser, an ultrasonic device with a stainless tip, or titanium scalers. Changes in surface properties were analyzed by profilometer and scanning electron microscopy (SEM). Murine fibroblast and osteoblast adhesion and proliferation were evaluated qualitatively and quantitatively at 24 and 72 h. Profilometric surface topography and SEM showed that titanium scalers and ultrasonic debridement techniques significantly changed the structure of the machined and rough titanium surfaces. The Er,Cr:YSGG laser irradiation, on the other hand, did not alter titanium microstructures. The Er,Cr:YSGG laser irradiation with the 40 Hz group showed a significantly higher attached fibroblast cell numbers than the titanium scaler group at 72 h after treatment (p = 0.023). Additionally, the number of the attached osteoblasts in the Er,Cr:YSGG laser irradiation with the 40 Hz group was significantly higher than that of the no-treatment groups 24 h after treatment (p = 0.045). The Er,Cr:YSGG laser effectively promoted adherence of fibroblasts and osteoblasts to the titanium surface without significantly altering the titanium surface, suggesting its superiority for treating peri-implantitis.

The promising application of pectin/ɛ-polylysine as coating material on anodized titanium surfaces for orthopedic implants: Preparation, characterization and biomedical properties

The increasing demands for implants due to aging and orthopedic necessitate advancements in coating technologies to enhance implant performance, especially when it comes to the infections and inflammation at the implantation site. The development of bioactive coatings with antibacterial properties, superior adhesion, and the controlled release of antibacterial agents is of significant importance. This study investigates the application of pectin/ɛ-polylysine (ɛ-PL) composite coatings on anodized titanium surfaces, with the aim of improving the bioactivity, biocompatibility, and antibacterial properties of the anodized surface. The multifunctional nature of these coatings addresses critical challenges associated with successful implantatins and offers promising solutions for biomedical applications. The anodization was first carried out at 40 V, followed by the dip coating of the pectin/ɛ-PL layer. Fourier-transform infrared (FTIR) analysis, field emission scanning electron microscope (FE-SEM), energy-dispersive X-ray spectroscopy (EDS) analysis, and laser profilometry were used to investigate the surface structure and the roughness of the applied layer. Corrosion tests, and MTT/anti-bacterial assays were utilized to investigate the electrochemical and biomedical properties of applied coating layers. Results indicated that pectin-1 % ɛ-PL exhibited excellent anti-bacterial properties, with cell viability above 50 %. Apatite crystals were also formed on coated specimens after 2-weeks of immersion in simulated body fluid (SBF), implying that applied coating layers are bioactive. Adhesion tests showed a remarkable improvement in mechanical properties of pectin top layer with the addition of ɛ-PL. Overall, the pectin-ɛ-PL composite coating exhibited some interesting properties, making it a promising easy-to-apply top coat on anodized surfaces in biomedical applications.

Biofilm morphology and antibiotic susceptibility of methicillin-resistant Staphylococcus aureus (MRSA) on poly-D,L-lactide-co-poly(ethylene glycol) (PDLLA-PEG) coated titanium

Biodegradable polymeric coatings are being explored as a preventive strategy for orthopaedic device-related infection. In this study, titanium surfaces (Ti) were coated with poly-D,L-lactide (PDLLA, (P)), polyethylene-glycol poly-D,L-lactide (PEGylated-PDLLA, (PP20)), or multi-layered PEGylated-PDLLA (M), with or without 1 % silver sulfadiazine. The aim was to evaluate their cytocompatibility, resistance to Staphylococcus aureus biofilm formation, and their potential to enhance the susceptibility of any biofilm formed to antibiotics. Using automated high-content screening confocal microscopy, biofilm formation of a clinical methicillin-resistant Staphylococcus aureus (MRSA) isolate expressing GFP was quantified, along with isogenic mutants that were unable to form polysaccharidic or proteinaceous biofilm matrices. The results showed that PEGylated-PDLLA coatings exhibited significant antibiofilm properties, with M showing the highest effect. This inhibitory effect was stronger in S. aureus biofilms with a matrix composed of proteins compared to those with an exopolysaccharide (PIA) biofilm matrix. Our data suggest that the antibiofilm effect may have been due to (i) inhibition of the initial attachment through microbial surface components recognising adhesive matrix molecules (MSCRAMMs), since PEG reduces protein surface adsorption via surface hydration layer and steric repulsion; and (ii) mechanical disaggregation and dispersal of microcolonies due to the bioresorbable/degradable nature of the polymers, which undergo hydration and hydrolysis over time. The disruption of biofilm morphology by the PDLLA-PEG co-polymers increased S. aureus susceptibility to antibiotics like rifampicin and fusidic acid. Adding 1 % AgSD provided additional early bactericidal effects on both biofilm and planktonic S. aureus. Additionally, the coatings were cytocompatible with immune cells, indicating their potential to enhance bacterial clearance and reduce bacterial colonisation of titanium-based orthopaedic biomaterials.

CO2-Laser Irradiation Affects Positively Surface Energy of Rough Titanium Surfaces.

The purpose of this study was to investigate the free surface energy before and after CO2 irradiation on rough titanium surfaces. Sandblasted, large grit, acidetched (SLA) implant surfaces were used for this study. Contact angle evaluations were performed for saline, albumin, and artificial blood using a contact angle goniometer in 25°C and 37°C (20 droplets in each group, 120 in total). The titanium disks were then irradiated with a CO2 laser (10,600 nm) using a non-contact, defocused, 2W continuous wave for 30 seconds. Contact angle measurements for saline, albumin and artificial blood were evaluated immediately after irradiation (new 120 in total contact angle measurements) and compared with the measurements before laser irradiation. Paired t-test using SPSS was performed for 5% statistical significance level. Lower numbers of contact angle measurements were found and changes after CO2-laser irradiation were statistically significant (p < 0.05) for all groups except for albumin at 25°C, as follows: 25℃: (saline) (Pre) 111.97° ±13.67°, (Post) 79.29° ±10.83° / p<0.0001; (albumin) (Pre) 89.04° ±12.02°, (Post) 83.29° ±20.71° / p&#61;0.297; (blood) (Pre) 97.79° ±14.44°, (Post) 86.29° ±10.82° / p&#61;0.019; 37℃: (saline) (Pre) 104.12° ±13.138°, (Post) 92.66° ±4.777° / p&#61;0.001; (albumin) (Pre) 89.04° ±12.02°, (Post) 83.29° ±20.71° / p&#61;0.297 (blood) (Pre) 80.42° ±19.00°, (Post) 58.62° ±24.34° / p&#61;0.012. The CO2 laser irradiation in general positively affected the wettability and hydrophilicity of rough titanium (SLA) surfaces.

In Vitro Comparison of Titanium Disc Surface Roughness and Bacterial Colonization After Ultrasonic Instrumentation With Three Different Tips.

During implant maintenance, preserving a smooth surface on the machined transmucosal abutment is critical to reduce biofilm attachment and colonization. The present study compared the surface roughness and bacterial colonization of machined titanium surfaces after instrumentation with various materials. Forty-four machined grade 23 titanium discs were instrumented with a round polyether ether ketone (PEEK) tip, a plastic curette tip, or a pure titanium curette tip with piezoelectric devices. Before and after instrumentation, the surface roughness (Ra and Rz) values were analyzed with a profilometer and scanning electron microscopy (SEM). Streptococcus sanguinis was cultured and incubated for 24 hours on the instrumented discs, and colony-forming units per milliliter were obtained for each group. Samples instrumented with the metal ultrasonic tip significantly increased surface roughness compared with the other groups. This resulted in greater colonization by S. sanguinis than surfaces instrumented with PEEK tips or the negative control. Samples instrumented with PEEK and plastic tips did not exhibit any statistically significant increase in surface roughness, and SEM analysis revealed a significantly rougher surface of discs instrumented with metal compared with discs instrumented with plastic or PEEK tips despite the possibility of debris from tip dissolution. Our results suggest that instrumentation with metal ultrasonic tips with piezoelectric devices significantly increased machined titanium's surface roughness and elicited higher biofilm formation in vitro. Meanwhile, instrumentation of machined titanium with PEEK or plastic ultrasonic tips did not affect the surface roughness or bacterial adhesion.

Electrodeposition of graphene oxide on titanium foil. Application field: Rechargeable batteries

The method of electrodepositing graphene oxide on titanium utilizes a thin grade 1 titanium foil with a thickness of 0.2 mm, a width of 10 mm, and a rectangular graphite plate with a parallelepiped shape with a thickness of 15 mm, a width of 40 mm, and a length of 100 mm. The titanium foil has a cut on one side, forming an isosceles triangle with a slightly inclined tip, creating an angle where the distance between the tip and the vertical symmetry axis of the foil is 3 mm. The titanium foil is positioned parallel to the graphite plate, with the tip as the only electrical contact. The two electrodes, titanium and graphite, assembled in this way, are immersed in an electrolytic solution composed of water and sulfuric acid. When a direct current voltage is applied between the two electrodes, a strong electric field is generated at the contact point, resulting in high temperature and the production of ultraviolet rays. Following a treatment described later in the so-called “preparation protocol,” reduced graphene oxide (rGO) is produced in suspension in the solution at the contact point between the tip of the titanium foil and the graphite plate, which, due to the electric field, tends to deposit on the titanium surface. A possible application found experimentally refers to rechargeable batteries.

Locally released dexamethasone and its effects on osteogenic activity at implant-tissue interface.

The osseointegration of titanium implants within the host tissue holds crucial importance. The introduction of functional coatings at tissue-implant interface enhances the bioactivity of titanium implants, improves their therapeutic outcomes, and enhances the effectiveness of treatments. In this study, we focused on enhancing the bioactivity of titanium-based implant materials by coating the titanium surfaces with chitosan microspheres, which are loaded with osseointegration-promoting agent dexamethasone (DEX). Initially, chitosan microspheres were successfully produced, followed by DEX loading through diffusion, resulting in a drug loading efficiency of around 50.2 (wt %). The subsequent drug release profile displayed a 24-hour duration, releasing approximately 32.6 (wt %) of the loaded DEX. In cell proliferation assays using human osteosarcoma (SAOS-2) cells, Ti surfaces coated with DEX-loaded chitosan microspheres initially exhibited lower cell numbers compared with DEX-free ones. This observation was attributed to transient osteogenic differentiation effects of DEX, since a notable increase in cell proliferation was observed on the 7th day. Von Kossa staining revealed mineralization beginning on the 14th day, particularly evident in DEX-loaded samples. Moreover, alkaline phosphatase (ALP) activity displayed a pattern of initial increase and subsequent decrease, with DEX release from chitosan microspheres showing a clear influence on the osteogenic differentiation, especially on the 7th day. These findings align with literature, highlighting DEX's potential to enhance osteogenic differentiation and cellular behavior on chitosan microsphere-coated titanium surfaces. This study emphasizes the promising implications for functionalizing surfaces of implant materials with DEX-loaded chitosan microspheres to improve their biocompatibility and bioactivity.

Preparation of zirconium hydrogen phosphate coatings on alkali thermal titanium via a one-step sol–gel method to improve the friction resistance, bioactivity, and osteogenic potential

Titanium implants are widely used in dental restorations for patients suffering from dentition defects. However, the biologically inert of Ti, poor osteoinduction properties and the release of Ti particles due to friction between the bone and the implants can inhibit osseointegration and adversely affect the success rate of implantation. In this study, a zirconium phosphate (ZrP) coating was constructed on the surface of alkali thermal titanium (AT-Ti) via a one-step sol–gel approach. Subsequently, the friction resistance, bioactivity, and osteogenesis properties of the prepared coating were studied. The surface characterization results confirmed that AT-Ti was successfully coated with amorphous ZrP, and ZrP modification was found to effectively reduce the friction rate. In addition, the surface morphology after friction test was smoother. In terms of the bioactivity, the presence of a phosphate group in the ZrP coating led to the effective enrichment of Ca2+ to promote the formation of hydroxyapatite (HAp). It was also discovered that ZrP exhibited an excellent performance in cell viability and mineralization experiments, in addition to up-regulating the expression of osteogenesis related genes. Overall, ZrP modification of AT-Ti leads to an excellent friction resistance, bioactivity, and osteoinductive properties, thereby indicating its broad application prospects in implant therapy.

Porous titanium/hydroxyapatite interpenetrating phase composites with optimal mechanical and biological properties for personalized bone repair

This study introduces the first fabrication of porous titanium/hydroxyapatite interpenetrating phase composites achieved through an innovative processing method. The approach combines additive manufacturing of a customized titanium skeleton with the infiltration of an injectable hydroxyapatite foam, followed by in situ foam hardening at physiological temperature. This biomimetic process circumvents ceramic sintering and metal casting, effectively avoiding the formation of secondary phases that can impair mechanical performance. Hydroxyapatite foams, prepared using two foaming agents (polysorbate 80 and gelatine), significantly reinforce the titanium skeleton while preserving the microstructural characteristics essential for osteoinductive properties. The strengthening mechanisms rely on the conformation of the foams to the titanium surface, thereby enabling a stable mechanical interlocking and effective interfacial stress transfer. This, combined with the mechanical constriction of phases, enhances damage tolerance and mechanically reliability of the interpenetrating phase composites. In addition, the interpenetrating phase composites feature a network of concave pores with an optimal size for bone repair, support human osteoblasts proliferation, and exhibit mechanical properties compatible with bone, offering a promising solution for the efficient and personalized reconstruction of large bone defects. The results demonstrate a significant advancement in composite fabrication, integrating the benefits of additive manufacturing for bone repair with the osteogenic capacity of calcium phosphate ceramics.

Zinc and melatonin mediated antimicrobial, anti-inflammatory, and antioxidant coatings accelerate bone defect repair

Inflammation and bacterial infection are important causes of implant failure, and the development of multifunctional titanium surfaces to address these issues is an effective means of treating infected bone defects. In this study, polyphenols (EGCG) and Zn2+ were first loaded onto the titanium surface to construct an EGCG/Zn2+ polyphenol metal network coating. Then melatonin (MT) was loaded into the EGCG/Zn2+ network structure to prepare the EGCG/Zn2+/MT composite coating. The results proved that the EGCG/Zn2+/MT coating had good mechanical properties, hydrophilicity, corrosion resistance and bioactivity. In vitro, the inhibition rates of EGCG/Zn2+/MT against E. coli and S. aureus were about 97 % and 81 %, respectively. In vitro experiments revealed that EGCG/Zn2+/MT could regulate the polarization of macrophages (RAW264.7) to M2 type, could induce vascularization of human umbilical vein endothelial cells (HUVEC), and could promote the differentiation of pro-osteoblasts (MC3T3-E1) to osteogenesis. Meanwhile, EGCG/Zn2+/MT achieved effective ROS scavenging within HUVEC and MC3T3-E1. In vivo experiments demonstrated that the EGCG/Zn2+/MT coatings possessed favorable biosafety, anti-inflammatory, antimicrobial, and bone repair capabilities. This study provides a simple and versatile strategy for designing multifunctional surfaces with both antimicrobial, anti-inflammatory, antioxidant, angiogenic and osteogenic properties.

Titanium surface functionalization via directed energy deposition of CuNiTi ternary alloy

Pure titanium is a soft material that tends to degrade quickly during service due to wear and microbiologically influenced corrosion. Therefore, current research aims at the deposition, microstructural characterization, and surface functionalization of the TiCuNi coatings on pure titanium substrate to improve its surface properties. Cu–Ni premixed elemental powders are deposited on the pure Ti by laser-directed energy deposition (LDED) using a novel method of extracting Ti from the substrate through melt pool convection. The single-track deposit geometry and integrity characterization using dilution percentage, heat-affected zone width (HAZ), and microhardness values show the sound metallurgical bonding with the substrate. The X-ray diffraction (XRD) pattern and microstructure image reveal the presence of NiTi binary (B2) and Ti2CuNi ternary (B19) hard phases and equiaxed dendritic morphology, respectively, demonstrating ternary alloy coating formation. The microhardness value of the coatings is thrice that of the substrate due to the presence of hard NiTi (B2) binary and Ti2CuNi (B19) ternary phases. The coating’s wear resistance is significantly (80%) higher than the substrate, owing to hard phases and Cu as a solid lubricant. The wear track consists of small grooves, adhered debris, and a smooth profile, mainly due to a significant reduction in adhesion and abrasion compared to the substrate. Moreover, the polarisation corrosion potential and current density are increased and decreased by 53% and 97%, respectively, displaying symbolic improvement in the corrosion resistance. Hence, this work has presented the LDED ability to enhance the pure Ti anti-wear and corrosion resistance properties by depositing CuNiTi ternary alloy coating for potential aerospace, marine, and biomedical applications.

Deposition of cellulose acetate coatings on titanium substrates by electrospraying for biomedical applications

Functional coatings have gained interest in the field of metal implants, as they reduce the complications associated with mechanical parameters and promote its integration. Among the other coating production methods electrospraying remains very little researched for this application despite its advantages. This study investigates the feasibility of the electrospraying method for the production of coatings with extended mechanical properties. Six biocompatible cellulose acetate coatings from solutions of (6–16) wt% were fabricated on titanium substrates using electrospraying. The layer thickness varied between the samples from 1.8 to 16.4 μm, while the roughness varied between the samples from 1 to 2 μm. Bending tests showed that the maximum elongation of the coatings between the samples gradually decreased from 40.00 % to 13.33 %. Stretching of detached films revealed decrease in tensile strength and elastic modulus from 58 to 30 MPa and from 2082 MPa to 978 MPa, respectively. Pull-off tests showed coatings adhesion strength of 0.8–1.4 MPa after sandblasting. Investigation of chemical composition and structure of the coatings using X-ray photoelectron spectroscopy, Fourier-transformed infrared and Raman spectroscopy showed results typical of cellulose acetate materials and confirmed that no structural changes took place during electrospraying. X-ray diffraction analysis revealed that the coatings obtained are amorphous. The coatings produced by the fast and cost-effective electrospraying process have competitive overall properties, while the coatings prepared from 10 and 12 wt% solutions are most suitable for use on titanium surfaces due to their mechanical properties and uniformity.

Biomimetic concentric microgrooved titanium surfaces influence bone marrow-derived mesenchymal stem cell osteogenic differentiation via H3K4 trimethylation epigenetic regulation.

Material surface micromorphology can modulate cellular behavior and promote osteogenic differentiation through cytoskeletal rearrangement. Bone reconstruction requires precise regulation of gene expression in cells, a process governed by epigenetic mechanisms such as histone modifications, DNA methylation, and chromatin remodeling. We constructed osteon-mimetic concentric microgrooved titanium surfaces with different groove sizes and cultured bone marrow-derived mesenchymal stem cells (BMSCs) on the material surfaces to study how they regulate cell biological behavior and osteogenic differentiation through epigenetics. We found that the cells arranged in concentric circles along the concentric structure in the experimental group, and the concentric microgrooved surface did not inhibit cell proliferation. The results of a series of osteogenic differentiation experiments showed that the concentric microgrooves facilitated calcium deposition and promoted osteogenic differentiation of the BMSCs. Concentric microgrooved titanium surfaces that were 30 μm wide and 10 μm deep promoted osteogenic differentiation of BMSC by increasing WDR5 expression via H3K4 trimethylation upregulation.

A self-assembled layer on titanium surface via silane coupling of chlorogenic acid and strontium chelate improves the osteogenic potential in a high-glucose environment

Bioactive coatings on titanium surfaces represent a crucial strategy to enhance the success rate of titanium implants in diabetic patients. In this study, a chelate comprising chlorogenic acid (CGA) and strontium (Sr) was synthesized and subsequently immobilized onto titanium surface through aminoethyl-aminopropyltrimethoxysilane (AEAPTMS) coupling, wherein AEAPTMS was selected from four silanes based on quantum chemistry analysis. This novel coating was characterized by XPS, SEM, contact angle measurements, and friction experiments, and its effects on cell adhesion, proliferation, osteogenic differentiation, and mitochondrial function in a high-glucose environment were evaluated by comparison with the surface treatments of none, alkali thermal treatment, and physically immersed CGA&Sr solution. It was proven that CGA&Sr could be grafted onto the titanium surface by AEAPTMS coupling, via Si-O bonds and -NH-C = O- bonds at the two ends of AEAPTMS. Furthermore, it provided satisfactory friction resistance and hydrophilicity, as well as improvement in proliferation, adhesion, and osteogenic mineralization of MC3T3-E1 cells in a high-glucose environment. The AEAPTMS-CGA&Sr coating significantly enhanced the osteogenic potential of cells by upregulating the expression levels of key osteogenesis-related genes such as—OCN, OSX, ALP, Runx2, and COL-1 and promoted the secretion of osteogenesis-related proteins. Mitochondrial dynamics analysis showed that CGA&Sr effectively restored hyperglycemia-induced alterations in mitochondrial dynamics and function by modulating the downregulation of mitochondrial fission genes Fis1 and Drp1, upregulating fusion genes Mfn1 and Mfn2, promoting recovery of mitochondrial membrane potential, and eliminating reactive oxygen species. The study results suggested that the AEAPTMS-CGA&Sr coating might be a promising strategy for modifying titanium implants for tolerance to a high-glucose environment.

Preparation Method of a Metal Carrier for a Catalyst for the Recovery of Exhaust Gases from Nitrogen Oxides

The article shows the process of preparing an oxide layer on the surface of titanium for use in industrial catalysis. Data from physical and chemical studies are presented, namely microhardness, porosity, thickness, specific surface area, adhesion and thermal stability of the active layer.To determine the physicochemical characteristics of the resulting oxide layer, the following analysis methods were used: X-ray diffraction analysis (XRD), X-ray diffraction phase analysis (XPA), X-ray absorption analysis (XRA), and X-ray fluorescence analysis. The thickness of the oxide layer depending on the duration of anodization was estimated by optical microscopy.

Influence of Surface Roughness on Phosphonation and Wettability of Nanosecond Laser‐Treated Titanium Surfaces

The duplex treatments of metal surfaces combining laser‐assisted functionalization and chemical modification attract a growing interest in view of better control of functional properties such as wettability. Patterned titanium oxides layers of different nature and roughness are produced in ambient atmosphere on a titanium surface using a nanosecond 532 nm Nd:YAG laser. Standalone lines and hatched surfaces obtained with different laser parameters are characterized by scanning electronic microscopy coupled with EDS analysis, micro‐Raman, XRD and X‐ray photoelectron spectroscopy (XPS). A set of surfaces having featureless and saw‐tooth morphologies of different roughnesses is modified with octylphosphonic acid (OPA). The effect of surface roughness on the efficiency of OPA grafting is investigated using XPS. It is found that the organic load on the chemically modified surfaces increases with surface roughness. The apparent thickness of the OPA layers is estimated using a standard uniform overlap model and considering the correction due to the corrugated appearance of the laser‐treated surfaces. The wetting properties of the surfaces before and after chemical modification are compared. The laser‐treated surfaces show superhydrophilic behavior consistent with Wenzel model. On the other hand, the chemically modified surfaces demonstrate a strong increase in hydrophobicity along with the roughness increase, in agreement with the Cassie–Baxter model.

Influence of Pd, Pt and Au nanoparticles in the photocatalytic performance of N-TiO2 support under visible light.

In this article, we report the modification and photocatalytic evaluation of commercial TiO2-P25 under visible light for methyl orange (MO) dye degradation under visible light. The activity of materials doped with N, Pd, Pt and Au on to the TiO2-P25 was evaluated, with optimal photocatalytic performance achieved using Au nanoparticles doped on an N-functionalized titania surface. X-ray diffraction (XRD), physical nitrogen adsorption/desorption isotherm curves, transmission electron microscopy (TEM), diffuse reflectance spectroscopy, scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) were used to study the structural and textural properties of the samples. The chemical species present in the bulk and surface of the catalysts were identified using X-ray photoelectron spectroscopy (XPS) and microwave plasma-atomic emission spectroscopy. The results show that Au/N-TiO2 photocatalyst presents a remarkable enhanced activity for MO dye degradation, under visible light illumination, reaching 100% after 4 h. The enhanced photocatalytic activity using this composite is attributable to the well-dispersed and small size of Au nanoparticles, large surface area, reduction of band-gap energy and the interaction between nitrogen and Au which promoted a synergistic effect. This article is part of the discussion meeting issue 'Green carbon for the chemical industry of the future'.

Titanium implant modification by ZIF-8 and epigallocatechin gallate-improved bioactivity and antibacterial activity

This study explores the modification of titanium implant surfaces using ZIF-8 and epigallocatechin gallate (EGCG). The modified material was comprehensively characterized using SEM/EDS analysis and FT-IR mapping. The bioactivity of the synthesized layer was assessed through hydroxyapatite (HAp) growth tests and protein adsorption assays. The results demonstrated that the synthesized layer was evenly distributed across the titanium surface, exhibited consistent protein adsorption, and promoted HAp growth, thereby confirming its bioactive properties. These enhancements were significantly superior to those of unmodified titanium. The antimicrobial properties of the material were also investigated, showing significant inhibition of microbial growth, particularly against Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Bacillus cereus, and Candida albicans. Notably, substantial antimicrobial activity was observed only in the systems incorporating EGCG. Specifically, titanium modified using ZIF-8 and EGCG inhibited microbial growth by 41–65 %, with C. albicans being the most susceptible, followed by E. coli and the Gram-positive species S. aureus and B. cereus. Among the tested microorganisms, P. aeruginosa demonstrated the highest resistance. The study conclusively attributes the observed antimicrobial properties to the presence of EGCG. The described modification holds significant potential for enhancing implant properties and protecting surfaces against biofilm formation.