Recent Advances in TiO2 -Based Nanostructured Surfaces with Controllable Wettability and Adhesion

Microstructure-Driven Self-Transport and Convection of Water on Membrane Surface for Ultra-Fast, Highly Sensitive, Low-Cost Lateral-Flow Assays

Lateral-flow assay (LFA) is one of the most commonly used detection technologies, in which the chromatographic membranes are currently used as the lateral-flow membrane (e.g., nitrocellulose membrane, NC Mem). However, several disadvantages of existing chromatographic membranes limit the performance of LFA, including relatively low flow velocity of sample solution and relatively more residuals of sample on membrane, which increase detection time and detection noise. Herein, a surface structure membrane (SS Mem) is proposed, which enables fast self-transport of water with a convection manner and realizes low residuals of sample on membrane surface after the flow. On SS Mem, the flow velocity of water is 7.1-fold higher, and the residuals of sample are decreased by 60-67%, comparing those in NC Mem. SS Mem is used as lateral-flow membrane to prepare lateral-flow strips of nanogold LFA and fluorescence LFA for rapid detection of SARS CoV-2 nucleocapsid protein. These LFAs require 210 s per detection, with limits of detection of 3.98 pg mL-1 and 53.3 fg mL-1, sensitivity of 96.5%, and specificity of 90%. The results suggest that SS Mem enables ultrafast, highly sensitive lateral-flow immunoassays and shows great potential as a new type of lateral-flow membrane to broaden the application of LFA.

Visible light-induced photocatalytic and antibacterial adhesion properties of superhydrophilic TiO2 nanoparticles

Bacterial infections triggered by patient or healthcare worker contact with surfaces are a major cause of medically acquired infections. By controlling the kinetics of tetrabutyl titanate hydrolysis and condensation during the sol-gel process, it is possible to regulate the content of Ti3+ and oxygen vacancies (OVs) in TiO2, and adjust the associated visible light-induced photocatalytic performance and anti-bacterial adhesion properties. The results have shown that the Ti3+ content in TiO2 was 9.87% at the calcination temperature of the reaction system was 300 °C and pH was 1.0, corresponding to optimal photocatalytic and hydrophilic properties. The formation of a hydrated layer on the superhydrophilic surface provided resistance to bacterial adhesion, preventing cross-contamination on high-touch surfaces. The excellent photocatalytic self-cleaning performance and anti-bacterial adhesion properties can be attributed to synergistic effects associated with the high specific surface area of TiO2 nanoparticles, the mesoporous structure, and the presence of Ti3+ and OVs. The formation of superhydrophilic self-cleaning surfaces under visible light can serve as the basis for the development of a new class of anti-bacterial adhesion materials.

Elucidating the effect of TiO2 nanoparticles on mung bean rhizobia via in vitro assay: Influence on growth, morphology, and plant growth promoting traits

Titanium dioxide nanoparticles (TiO2 NPs) are among the most commonly used nanomaterials and are most likely to end up in soil. Therefore, it is pertinent to study the interaction of TiO2 NPs with soil microorganisms. The present in vitro broth study evaluates the impacts of low-dose treatments (0, 1.0, 5.0, 10.0, 20.0, and 40.0 mg L-1 ) of TiO2 NPs on cell viability, morphology, and plant growth promoting (PGP) traits of rhizobia isolated from mung bean root nodule. Two types of TiO2 NPs, that is, mixture of anatase and rutile, and anatase alone were used in the study. These TiO2 NPs were supplemented in broth along with a multifunctional isolate (Bradyrhizobium sp.) and two reference cultures. The exposure of TiO2 (anatase+rutile) NPs at low concentrations (less than 20.0 mg L-1 ) enhanced the cell growth, and total soluble protein content, besides improving the phosphate solubilization, Indole-3-acetic acid (IAA) production, siderophore, and gibberellic acid production. The TiO2 (anatase) NPs enhanced exopolysaccharide (EPS) production by the test rhizobial cultures. The radical scavenging assay was performed to reveal the mode of action of the nano-TiO2 particles. The study revealed higher reactive oxygen species (ROS) generation by the TiO2 (anatase) NPs as compared with TiO2 (anatase+rutile) NPs. Exposure to TiO2 NPs also altered the morphology of rhizobial cells. The findings suggest that TiO2 NPs could act as promoters of PGP traits of PGP bacteria when applied at appropriate lower doses.

Ice Adhesion Properties on Micropillared Superhydrophobic Surfaces

In this work, we investigate the freezing behavior and ice adhesion properties of sessile drops on micropillared superhydrophobic surfaces (SHSs) with various sizes, which are of practical importance for anti/deicing. First of all, it is demonstrated that the recalescence is related only to the supercooling degree of drops but not to the geometrical parameters of micropillars. The freezing time of sessile drops first increases and then decreases with the area fraction of the SHSs, which demonstrates the nonmonotonic dependence of the icing time on the area fraction. Moreover, the influence of the geometrical parameters of the micropillars on the ice adhesion is discussed. With the decrease of the substrate temperature, the wetting state of the adhesive ice can be transformed from the Cassie ice to the Wenzel ice. For the Cassie ice, the adhesive force is proportional to the area fraction of the SHSs. Interestingly, experimental results show that there exist two interfacial debonding modes of the Wenzel ice: translational debonding and rotational debonding. Furthermore, it is found that the rotational debonding mode contributes to a much lower adhesive force between the ice and the micropillared surface compared to that of the translational debonding mode. By analyzing the critical interfacial energy release rate of the two modes, we deduce the threshold between the two modes, which is quantified as the geometrical parameters of the micropillars. In addition, quantitative relations between the geometrical parameters and the adhesion strengths of the two modes are also obtained. We envision that this work would shed new light on the design optimization of anti/deicing materials.

Construction and Tribological Performance of Ag Nanowire-Dotted 2D Ni-BDC Nanocomposites in Oil

The collaborative lubrication effect based on different lubricating nanostructures could not only overcome the respective drawbacks of different nanostructures as nanoadditives but also comprehensively improve friction performance. For this, we first developed a novel collaborative lubrication nanostructure based on Ag nanowires (NWs) and two-dimensional (2D) Ni-BDC nanosheets (Ag NWs/2D Ni-BDC) by the in situ chemical reduction strategy. The structural characterizations corroborated that Ag NWs with a width of approximately 20-30 nm grew on the surface of 2D Ni-BDC nanosheets, which presented the chemical interface between both. As the nanoadditive applied in oils, the tribological finding confirmed that the Ag NWs/2D Ni-BDC enabled the friction coefficient and wear scar diameter to reduce by 38 and 37% at 0.04 wt % additive content, respectively. The worn surface was characterized by a series of analytical techniques, which basically revealed the friction-reducing and antiwear mechanism based on the layered structure and self-repair effect. Consequently, the nanocomposite structure incorporating the nanowire and 2D nanosheets should be taken into account as a new potential lubricating material.

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.

Biocompatible Nanostructured Silver-Incorporated Implant Surfaces Show Effective Antibacterial, Osteogenic, and Anti-Inflammatory Effects in vitro and in Rat Model

Introduction

Titanium (Ti) and its alloys are widely utilized in endosseous implants. However, their clinical efficacy is marred by complications arising from bacterial infections owing to their inadequate antibacterial properties. Consequently, enhancing the antibacterial attributes of implant surfaces stands as a pivotal objective in the realm of implantable materials research.

Methods

In this study, we employed sequential anodization and plasma immersion ion implantation (PIII) technology to fabricate a silver-embedded sparsely titania nanotube array (SNT) on the near-β titanium alloy Ti-5Zr-3Sn-5Mo-15Nb (TLM) implants. The surface characteristics, antimicrobial properties, biocompatibility, and osteogenic activity of the silver-nanomodified SNT implant (SNT Ag) surface, alongside peri-implant inflammatory responses, were meticulously assessed through a combination of in vitro and in vivo analyses.

Results

Compared with polished TLM and SNT, the silver-embedded SNT (SNT Ag) surface retained the basic shape of nanotubes and stably released Ag+ at the ppm level for a long time, which demonstrated an effective inhibition and bactericidal activity against Staphylococcus aureus (SA) while maintaining ideal cytocompatibility. Additionally, the subtle modifications in nanotubular topography induced by silver implantation endowed SNT Ag with enhanced osteogenic activity and mitigated inflammatory capsulation in soft tissue peri-implants in a rat model.

Conclusion

Incorporating a silver-embedded SNT array onto the implant surface demonstrated robust antibacterial properties, impeccable cytocompatibility, exceptional osteogenic activity, and the potential to prevent inflammatory encapsulation around the implant site. The Silver-PIII modification strategy emerges as a highly promising approach for surface applications in endosseous implants and trans-gingival implant abutments.

Glycol 400 assisted preparation of high contact surface TiO2/GO nanocomposites for photocatalytic degradation rhodamine B

TiO2/graphene oxide (GO) nanocomposites with high contact interface were prepared with glycol 400 (PEG400) served as dispersant. This nanocomposite exhibits improved photocatalytic efficiency in contrast with the nanocomposite prepared without PEG400. In this work, the photocatalytic performance was investigated by observing the degradation rate of Rhodamine B (RhB). And it is found that the mass ratios of GO in nanocomposites plays an important role. When the mass ratio of GO reached 45%, the photocatalytic performance of the nanocomposites reached the highest, which is ∼72%. Moreover, the photocatalytic mechanism was studied through theoretical calculations, which can be summarized as follows: (1) the presence of GO decreases the band gap of TiO2nanoparticles. (2) GO inhibits the the recombination of photogenerated electron-hole pair. (3) GO improves the adsorption capacity of TiO2nanoparticles for RhB. This work promoted the application of TiO2/GO nanocomposites in wastewater treatment.

Impact of surface cooling on the water harvesting efficiency of nanostructured window glass

Humans face a severe shortage of fresh water due to economic growth, climate change, overpopulation, and overutilization. Atmospheric water harvesting (AWH) is a promising solution where clean water is collected from the air through various approaches, including dropwise condensation. However, designing surfaces that balance rapid condensation with efficient water removal is challenging. To address this issue, inspired by the efficient water collection mechanisms in the skin of cold-blooded tree frogs, we propose an eco-friendly approach to collect fresh water from cooled window glass. We fabricated various planar and TiO₂ nanostructured surfaces including surfaces mimicking a lotus leaf and a hybrid surface mimicking a desert beetle and a cactus, with different wettability levels such as superhydrophilic, hydrophilic, hydrophobic, superhydrophobic, and biphilic. Sub-cooling of glass substrates between 5 and 15 °C using a Peltier device significantly enhanced the condensation process for all surfaces, with modest dependency on surface properties. This cooling temperature regime could be achieved by geothermal cooling methods that consume little energy. To improve visibility for window applications, we developed hydrophobic polymer nanofilm-modified glass substrates using a simple spin-coating technique, and achieved comparable water harvesting efficiency to that of nanostructured substrates. Our study provides insight into the optimal surface structures and cooling temperature for window glass AWH systems that could be used with an underground cooling system.

A Microwave-Assisted, Solvent-Free Approach for the Versatile Functionalization of Carbon Nanotubes

While the functionalization of carbon nanotubes (CNTs) has attracted extensive interest for a wide range of applications, a facial and versatile strategy remains in demand. Here, we report a microwave-assisted, solvent-free approach to directly functionalize CNTs both in raw form and in arbitrary macroscopic assemblies. Rapid microwave irradiation was applied to generate active sites on the CNTs while not inducing excessive damage to the graphitic network, and a gas-phase deposition afforded controllable grafting for thorough or regioselective functionalization. Using methyl methacrylate (MMA) as a model functional group and a CNT sponge as a model assembly, homogeneous grafting was exhibited by the increased robust hydrophobicity (contact angle increase from 30 to 140°) and improved structural stability (compressive modulus increased by 135%). Therefore, when our MMA-functionalized CNTs served as a solar absorber for saline distillation, high operating stability with a superior water evaporation rate of ∼2.6 kg m^-2 h^-1 was observed. Finally, to highlight the efficacy and versatility of this functionalization approach, we fabricated asymmetrically hydrophobic CNT sponges by regioselective functionalization to serve as a moisture-driven generator, which demonstrated a stable open-circuit voltage of 0.6 mV. This versatile, solvent-free approach can complement conventional solution-based techniques in the design and fabrication of multifunctional nanocarbon-based materials.

Osteoblastic Cell Behavior and Gene Expression Related to Bone Metabolism on Different Titanium Surfaces

The surface topography of titanium dental implants has a great influence on osseointegration. In this work, we try to determine the osteoblastic behavior and gene expression of cells with different titanium surfaces and relate them to the physicochemical properties of the surface. For this purpose, we have used commercial titanium discs of grade 3: as-received corresponds to machined titanium without any surface treatment (MA), chemically acid etched (AE), treated via sand blasting with Al₂O₃ particles (SB) and a sand-blasting treatment with acid etching (SB+AE). The surfaces have been observed using scanning electron microscopy (SEM) and the roughness, wettability and surface energy with dispersive and polar components have been characterized. Osteoblastic cultures were performed with SaOS-2 osteoblastic cells determining cell viability as well as alkaline phosphatase levels for 3 and 21 days, and osteoblastic gene expression was determined. The roughness values of the MA discs was 0.02 μm, which increases to 0.3 μm with acid attack and becomes the maximum for the sand-blasted samples, reaching values of 1.2 μm for SB and SB+AE. The hydrophilic behavior of the MA and AE samples with contact angles of 63° and 65° is superior to that of the rougher samples, being 75° for SB and 82° for SB+AE. In all cases, they show good hydrophilicity. GB and GB+AE surfaces present a higher polar component in the surface energy values, 11.96 and 13.18 mJ/m², respectively, than AE and MA, 6.64 and 9.79 mJ/m², respectively. The osteoblastic cell viability values at three days do not show statistically significant differences between the four surfaces. However, the viability of the SB and SB+AE surfaces at 21 days is much higher than that of the AE and MA samples. From the alkaline phosphatase studies, higher values were observed for those treated with sand blasting with and without acid etching compared to the other two surfaces, indicating a greater activity in osteoblastic differentiation. In all cases except in the Osterix (Ostx) -osteoblast-specific transcription factor-a decrease in gene expression is observed in relation to the MA samples (control). The most important increase was observed for the SB+AE condition. A decrease in the gene expression of Osteoprotegerine (OPG), Runt-related transcription factor 2 (Runx2), Receptor Activator of NF-κB Ligand (RANKL) and Alkaline Phosphatase (Alp) genes was observed in the AE surface.

Mesoporous BiVO4/TiO2 heterojunction: enhanced photoabsorption and photocatalytic ability through promoted charge transfer

BiVO₄ has been constructed into heterojunctions with TiO₂ to boost the photocatalytic ability under visible illumination. Here, mesoporous BiVO₄/TiO₂ nanocomposites have been fabricated by a facile sol-gel approach utilizing nonionic surfactant and addressed for morphological, optical, structural, and degradation of ciprofloxacin (CIP) in water under visible illumination as an antibiotic pollutant model. The TEM images demonstrated that the TiO₂ NPs are homogenous in terms of shape and size (15 ± 5 nm). The introduction of BiVO₄ into mesoporous TiO₂ could effectively enhance the rapid separation efficiency of the photoinduced carriers and optical absorption. The 3%BiVO₄/TiO₂ photocatalyst possessed the best degradation efficiency (100%) within 60 min which was promoted 20-folds larger than TiO₂ NPs (5%). 3%BiVO₄/TiO₂ nanocomposite exhibited the fastest degradation rate (2.15 × 10^-2 min^-1), which was 40 times faster than bare TiO₂ photocatalyst (0.05 × 10^-2 min^-1). The enhanced photocatalytic ability originated from superior charge separation characteristics and high solar energy absorption in mesopore structures. The recombination rate and mobility of charge carriers were characterized utilizing photoluminescence (PL) and photoelectrochemical measurements. This work highlights the advantages of mesoporous heterojunction BiVO₄/TiO₂ nanocomposites for photocatalytic performances and provides a multilateral route to design an effective wide-spectrum response photocatalyst for the development of comparable materials. The photocatalytic mechanism for degradation CIP over BiVO₄/TiO₂ was discussed in detail..

Elastic Textile Threads for Fog Harvesting

The potential applications of textile materials in fog harvesting have long been demonstrated. This work designed novel fog harvesters according to the distinct features of elastic textile threads (ETTs) to enhance droplet capture, large-droplet growth, and droplet pouring and improve fog harvesting efficiency. We prepared m@ETTs (modified ETTs) using three novel chemical and physical methods. First, we prepared spandex elastic threads with a non-uniform rough surface containing silica nanoparticles and titanium particles through the sol-gel triethoxymethylsilane method. Second, we prepared a rubber/polyester thread with a rough surface by breaking the thread shell with toluene solution, creating knots on the surface of the rubber core. Third, we prepared a polyurethane thread with a bumpy superhydrophobic surface by spraying a tetrafluoroethylene adhesive and silica nanoparticles on the thread. Furthermore, we connected ETTs to an automatic stretching-recovery system to obtain auto-ETTs as another group of harvesters. We obtained auto-i@ETTs by introducing elastic bumps/knots onto the auto-ETT surface. The fog harvesting efficiencies of m@ETTs were approximately 60-120% greater than those of the ETTs. The water harvesting rate of the auto-i@ETT was 2.5 times that of the ETT, with the highest water harvesting rate of auto-i@ETT reaching 3.35 g/h/cm². Moreover, several novel principles of droplet behavior and thread elasticity were revealed. The elastic elongation level of the ETTs was proportional to their water harvesting efficiency. The stretching-recovery state of the elastic thread did not influence the water contact angle but affected the droplet state on the thread surface. The temporary slack/stick state of adjacent elastic threads on auto-ETTs contributed to droplet convergence and pouring. Overall, this novel approach demonstrates the significant potential of elastic threads in fog harvesting applications.

The Interrelation of Synthesis Conditions and Wettability Properties of the Porous Anodic Alumina Membranes

The results of studies on the wettability properties and preparation of porous anodic alumina (PAA) membranes with a 3.3 ± 0.2 μm thickness and a variety of pore sizes are presented in this article. The wettability feature results, as well as the fabrication processing characteristics and morphology, are presented. The microstructure effect of these surfaces on wettability properties is analyzed in comparison to outer PAA surfaces. The interfacial contact angle was measured for amorphous PAA membranes as-fabricated and after a modification technique (pore widening), with pore sizes ranging from 20 to 130 nm. Different surface morphologies of such alumina can be obtained by adjusting synthesis conditions, which allows the surface properties to change from hydrophilic (contact angle is approximately 13°) to hydrophobic (contact angle is 100°). This research could propose a new method for designing functional surfaces with tunable wettability. The potential applications of ordinary alumina as multifunctional films are demonstrated.

Gradient Annealing as a New Strategy to Fabricate Gradient Nanoparticle Array on Microwires

Creating gradients of nanostructure on the surface has found broad applications such as enhanced optical spectroscopy, optical storage of information, and broadband solar energy harvesting. Here, a facile strategy is presented for fabricating gradient nanoparticle arrays with tunable size. It takes a ZnO:Ga microwire as the starting material, and the Ga³⁺ doping gradient along the microwire is induced by the high voltage applied. Such a doping gradient facilitates the formation of a temperature gradient in a Joule heating process. And this temperature gradient produced by this technique can be as high as 800 °C/mm, which could be later used for gradient annealing of thin metal films. After annealing, the thin metal films turn to gradient nanoparticle arrays. The obtained gradient nanoparticle arrays are confirmed effective in multi-wavelength surface enhanced Raman scattering enhancement.

Smart Titanium Wire Used for the Evaluation of Hydrophobic/Hydrophilic Interaction by In-Tube Solid Phase Microextraction

Evaluation of the hydrophobic/hydrophilic interaction individually between the sorbent and target compounds in sample pretreatment is a big challenge. Herein, a smart titanium substrate with switchable surface wettability was fabricated and selected as the sorbent for the solution. The titanium wires and meshes were fabricated by simple hydrothermal etching and chemical modification so as to construct the superhydrophilic and superhydrophobic surfaces. The micro/nano hierarchical structures of the formed TiO₂ nanoparticles in situ on the surface of Ti substrates exhibited the switchable surface wettability. After UV irradiation for about 15.5 h, the superhydrophobic substrates became superhydrophilic. The morphologies and element composition of the wires were observed by SEM, EDS, and XRD, and their surface wettabilities were measured using the Ti mesh by contact angle goniometer. The pristine hydrophilic wire, the resulting superhydrophilic wire, superhydrophobic wire, and the UV-irradiated superhydrophilic wire were filled into a stainless tube as the sorbent instead of the sample loop of a six-port valve for on-line in-tube solid-phase microextraction. When employed in conjunction with HPLC, four kinds of wires were comparatively applied to extract six estrogens in water samples. The optimal conditions for the preconcentration and separation of target compounds were obtained with a sample volume of 60 mL, an injection rate of 2 mL/min, a desorption time of 2 min, and a mobile phase of acetonile/water (47/53, v/v). The results showed that both the superhydrophilic wire and UV-irradiated wire had the highest extraction efficiency for the polar compounds of estrogens with the enrichment factors in the range of 20-177, while the superhydrophobic wire exhibited the highest extraction efficiency for the non-polar compounds of five polycyclic aromatic hydrocarbons (PAHs). They demonstrated that extraction efficiency was mainly dependent on the surface wettability of the sorbent and the polarity of the target compounds, which was in accordance with the molecular theory of like dissolves like.

Eco-friendly bacteria-killing by nanorods through mechano-puncture with top selectivity

Nanorods can induce mechano-puncture of Staphylococcus aureus (S. aureus) that often impairs osseointegration of orthopedic implants, while the critical nanorod top sharpness able to puncture S. aureus and the predominant contributor between top sharpness and length to mechano-puncture activity remains elusive. Herein, we fabricated three kinds of Al₂O₃-wrapped nanorods patterned arrays with different lengths and top sharpness. The top-sharp nanorods have lengths of 469 and 884 nm and the shorter show a length identical to the top-flat nanorods. Driven by the equivalent adhesive force of S. aureus, the top-flat nanorods deform cell envelops, showing a bacteriostatic rate of 29% owing to proliferation-inhibited manner. The top-sharp nanorods puncture S. aureus, showing a bactericidal rate of 96% for the longer, and 98% for the shorter that simultaneously exhibits fair osseointegration in bacteria-infected rat tibias, identifying top sharpness as a predominate contributor to mechano-puncture activity. Based on finite-element simulation, such top-flat nanorod derives the maximum stress (S_max) of 5.65 MPa on cell wall, lower than its ultimate-tensile-strength (13 MPa); while such top-sharp and shorter nanorod derives S_max of 20.15 MPa to puncture cell envelop. Moreover, a critical top conical angle of 138° is identified for nanorods able to puncture S. aureus.

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Top sharpness depended mechano-puncture of nanorods against S. aureus is clarified.

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Top-flat nanorods deform bacterial cell envelop to inhibit their proliferation.

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Top-sharp nanorods (conical angle of 50°) puncture bacteria to intensely kill them.

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138° is confirmed as critical top conical angle for nanorods to puncture S. aureus.

Light-Excited Ag-Doped TiO2-CoFe2O4 Heterojunction Applied to Toluene Gas Detection

(1) Background: Toluene gas is widely used in indoor decoration and industrial production, and it not only pollutes the environment but also poses serious health risks. (2) Methods: In this work, TiO₂−CoFe₂O₄−Ag quaternary composite gas-sensing material was prepared using a hydrothermal method to detect toluene. (3) Results: The recombination of electron–hole pairs was suppressed, and the light absorption range was expanded after constructing a heterojunction and doping with Ag, according to ultraviolet–visible (UV–vis) diffuse reflectance spectra and photoluminescence spectroscopy. Moreover, in the detection range of toluene gas (3 ppm–50 ppm), the response value of TiO₂−CoFe₂O₄−Ag increased from 2 to 15, which was much higher than that of TiO₂−Ag (1.7) and CoFe₂O₄−Ag (1.7). In addition, the working temperature was reduced from 360 °C to 263 °C. Furthermore, its response/recovery time was 40 s/51 s, its limit of detection was as low as 10 ppb, and its response value to toluene gas was 3–7 times greater than that of other interfering gases under the same test conditions. In addition, the response value to 5 ppm toluene was increased from 3 to 5.5 with the UV wavelength of 395 nm–405 nm. (4) Conclusions: This is primarily due to charge flow caused by heterojunction construction, as well as metal sensitization and chemical sensitization of novel metal doping. This work is a good starting point for improving gas-sensing capabilities for the detection of toluene gas.

The construction of bio-inspired hierarchically porous graphene aerogel for efficiently organic pollutants absorption

Three-dimensional graphene aerogel shows a wide application in many frontier domains, which have attracted extensive research interest owing to its large specific surface area and high porosity. However, it is still a great challenge to construct the ideal hierarchical pore structure while guaranteeing excellent absorption and mechanical performance. In this paper, inspired by the bio-based porous material, a hierarchical graphene aerogel with inter-connected micro-/nano-scale pore structure was constructed. The micro and nano-scale pores are generated by the bubble and nanoparticles (NPs) template, respectively. The resulting graphene aerogel (GA) presents low density, increased interfacial areas, high mechanical performance, and excellent absorption performance towards a mass of organic solvents. In combination with its high compressibility, a diverse organic solvent can be absorbed efficiently and recycled by extrusion conveniently. Besides, owing to the scattered hydrophilic sites of functional groups and NPs on the surface of GA-b/NP, it shows high adhesion properties for water droplets, thus presents great potential in high-efficiency fog collecting materials. In a word, the proposed approach presents a novel strategy for the construction of the hierarchical aerogel with light-weight and elasticity, as well as the achievement of efficient functionalization, which has great potential for the preparation of diverse functional composites.

Renewable Superhydrophobic Surfaces Prepared by Nanoimprinting Using Anodic Porous Alumina Molds

Renewable superhydrophobic surfaces based on laminated polymer films with nanopillar array structures were prepared. Polymer nanopillar arrays exhibiting superhydrophobic properties were prepared by nanoimprinting using anodic porous alumina as a mold. The hydrophobic properties of the obtained polymer nanopillar arrays could be controlled and optimized by changing the geometrical structures of anodic porous alumina molds used for nanoimprinting. The polymer films were laminated using a photocurable monomer. The ordered polymer nanopillar array structures could be maintained even after delamination of the films. Renewed polymer nanopillar arrays exposed by peeling off the upper films exhibited a water contact angle higher than 150°. Using this process, superhydrophobic surfaces could be obtained repeatedly by delamination of a film even when superhydrophobicity deteriorated with the collapse of surface patterns. The obtained renewable superhydrophobic surfaces can be used for various applications requiring high durability.

Hygro-responsive, Photo-decomposed Superoleophobic/Superhydrophilic Coating for On-Demand Oil-Water Separation

The superoleophobic/superhydrophilic material has attracted considerable interest due to the incomparable property of it for the oil-water separation. However, it is a challenge to make the prepared surface superoleophobic and superhydrophilic at the same time since the oleophobic surface tends to repel water. Herein, a hygro-responsive superoleophobic/superhydrophilic coating was fabricated by liquid-phase deposition of TiO₂ with perfluorooctanoic acid. The wettability of the coating could complete the transformation from superoleophobicity/superhydrophilicity to superhydrophobicity/superoleophilicity, both of which exhibit excellent selective superwettability under the air, underwater, salt, alkali, and acid conditions. The hygro-responsive coating can separate different types of oil-water mixtures, and the separation efficiency could be over 99% using different capillary forces acting on the oil and water phases before and after wettability transformation. Last but not least, long-chain perfluoroalkyl substances on the coating could be decomposed by UV irradiation, which could reduce the harm to the environment and human beings. It is anticipated that the developed superoleophobic/superhydrophilic coating provides a feasible solution for the application of oil-water separation.

Understanding and optimizing the antibacterial functions of anodized nano-engineered titanium implants

Nanoscale surface modification of titanium-based orthopaedic and dental implants is routinely applied to augment bioactivity, however, as is the case with other cells, bacterial adhesion is increased on nano-rough surfaces. Electrochemically anodized Ti implants with titania nanotubes (TNTs) have been proposed as an ideal implant surface with desirable bioactivity and local drug release functions to target various conditions. However, a comprehensive state of the art overview of why and how such TNTs-Ti implants acquire antibacterial functions, and an in-depth knowledge of how topography, chemistry and local elution of potent antibiotic agents influence such functions has not been reported. This review discusses and details the application of nano-engineered Ti implants modified with TNTs for maximum local antibacterial functions, deciphering the interdependence of various characteristics and the fine-tuning of different parameters to minimize cytotoxicity. An ideal implant surface should cater simultaneously to ossoeintegration (and soft-tissue integration for dental implants), immunomodulation and antibacterial functions. We also evaluate the effectiveness and challenges associated with such synergistic functions from modified TNTs-implants. Particular focus is placed on the metallic and semi-metallic modification of TNTs towards enabling bactericidal properties, which is often dose dependent. Additionally, there are concerns over the cytotoxicity of these therapies. In that light, research challenges in this domain and expectations from the next generation of customizable antibacterial TNTs implants towards clinical translation are critically evaluated. STATEMENT OF SIGNIFICANCE: One of the major causes of titanium orthopaedic/dental implant failure is bacterial colonization and infection, which results in complete implant failure and the need for revision surgery and re-implantation. Using advanced nanotechnology, controlled nanotopographies have been fabricated on Ti implants, for instance anodized nanotubes, which can accommodate and locally elute potent antibiotic agents. In this pioneering review, we shine light on the topographical, chemical and therapeutic aspects of antibacterial nanotubes towards achieving desirable tailored antibacterial efficacy without cytotoxicity concerns. This interdisciplinary review will appeal to researchers from the wider scientific community interested in biomaterials science, structure and function, and will provide an improved understanding of controlling bacterial infection around nano-engineered implants, aimed at bridging the gap between research and clinics.

Superamphiphilic TiO2 Composite Surface for Protein Antifouling

Unwanted protein adsorption deteriorates fouling processes and reduces analytical device performance. Wettability plays an important role in protein adsorption by affecting interactions between proteins and surfaces. However, the principles of protein adsorption are not completely understood, and surface coatings that exhibit resistance to protein adsorption and long-term stability still need to be developed. Here, a nanostructured superamphiphilic TiO₂ composite (TiO₂ /SiO₂ ) coating that can effectively prevent nonspecific protein adsorption on water/solid interfaces is reported. The confined water on the superamphiphilic surface enables a low adhesion force and the formation of an energy barrier that plays a key role in preventing protein adsorption. This adaptive design protects the capillary wall from fouling in a harsh environment during the bioanalysis of capillary electrophoresis and is further extended to applications in multifunctional microfluidics for liquid transportation. This facile approach is not only perfectly applied in channels with complicated configurations but may also offer significant insights into the design of advanced superwetting materials to control biomolecule adhesion in biomedical devices, microfluidics, and biological assays.

Titanium Dioxide Derived Materials with Superwettability

Titanium dioxide (TiO2) is widely used in various fields both in daily life and industry owing to its excellent photoelectric properties and its induced superwettability. Over the past several decades, various methods have been reported to improve the wettability of TiO2 and plenty of practical applications have been developed. The TiO2-derived materials with different morphologies display a variety of functions including photocatalysis, self-cleaning, oil-water separation, etc. Herein, various functions and applications of TiO2 with superwettability are summarized and described in different sections. First, a brief introduction about the discovery of photoelectrodes made of TiO2 is revealed. The ultra-fast spreading behaviors on TiO2 are shown in the part of ultra-fast spreading with superwettability. The part of controllable wettability introduces the controllable wettability of TiO2-derived materials and their related applications. Recent developments of interfacial photocatalysis and photoelectrochemical reactions with TiO2 are presented in the part of interfacial photocatalysis and photoelectrochemical reactions. The part of nanochannels for ion rectification describes ion transportation in nanochannels based on TiO2-derived materials. In the final section, a brief conclusion and a future outlook based on the superwettability of TiO2 are shown.

All-graphene-based open fluidics for pumpless, small-scale fluid transport via laser-controlled wettability patterning

Open microfluidics have emerged as a low-cost, pumpless alternative strategy to conventional microfluidics for delivery of fluid for a wide variety of applications including rapid biochemical analysis and medical diagnosis. However, creating open microfluidics by tuning the wettability of surfaces typically requires sophisticated cleanroom processes that are unamenable to scalable manufacturing. Herein, we present a simple approach to develop open microfluidic platforms by manipulating the surface wettability of spin-coated graphene ink films on flexible polyethylene terephthalate via laser-controlled patterning. Wedge-shaped hydrophilic tracks surrounded by superhydrophobic walls are created within the graphene films by scribing micron-sized grooves into the graphene with a CO2 laser. This scribing process is used to make superhydrophobic walls (water contact angle ∼160°) that delineate hydrophilic tracks (created through an oxygen plasma pretreatment) on the graphene for fluid transport. These all-graphene open microfluidic tracks are capable of transporting liquid droplets with a velocity of 20 mm s-1 on a level surface and uphill at elevation angles of 7° as well as transporting fluid in bifurcating cross and tree branches. The all-graphene open microfluidic manufacturing technique is rapid and amenable to scalable manufacturing, and consequently offers an alternative pumpless strategy to conventional microfluidics and creates possibilities for diverse applications in fluid transport.

Stable Superhydrophobic Aluminum Surfaces Based on Laser-Fabricated Hierarchical Textures

Laser-microtextured surfaces have gained an increasing interest due to their enormous spectrum of applications and industrial scalability. Direct laser interference patterning (DLIP) and the well-established direct laser writing (DLW) methods are suitable as a powerful combination for the fabrication of single (DLW or DLIP) and multi-scale (DLW+DLIP) textures. In this work, four-beam DLIP and DLW were used independently and combined to produce functional textures on aluminum. The influence of the laser processing parameters, such as the applied laser fluence and the number of pulses, on the resulting topography was analyzed by confocal microscopy and scanning electron microscopy. The static long-term and dynamic wettability characteristics of the laser-textured surfaces were determined through water contact angle and hysteresis measurements, revealing superhydrophobic properties with static contact angles up to 163° and hysteresis as low as 9°. The classical Cassie–Baxter and Wenzel models were applied, permitting a deeper understanding of the observed wetting behaviors. Finally, mechanical stability tests revealed that the DLW elements in the multi-scale structure protects the smaller DLIP features under tribological conditions.

Continuous Movement Mechanism of Oil Droplets Adhered on Surfaces with Different Wettability in the Flow Field

In this aticle, the continuous movement patterns and characteristic parameters of oil droplets on surfaces with different wettability immersed in a laminar flow field were observed, and the change rules of the geometric parameters of oil droplets under different experimental conditions were obtained. Then, the factors influencing the continuous moving behaviors of the oil droplets were analyzed, and the continuous movement velocity of the oil droplets under different experimental conditions was demonstrated. On this basis, the change law of the continuous movement velocity of oil droplets with the flow velocity was discussed. In addition, the coupling effect of the oil drops' height, surface properties, and water flow velocity on the continuous movement of oil droplets was studied, and the critical conditions for the continuous movement were obtained. According to the critical conditions, the mathematical model which described the law of continuous motion of the oil droplets adhered on surfaces with different wettability in the laminar flow field was established. The quantitative relationships among the average continuous moving velocity of oil droplets, physical properties, geometric parameters, water flow velocity, and surface wettability were obtained, which defined the necessary conditions for the uniform and accelerated movement of oil droplets, providing an important basis for choices of suitable surface wettability and flow field conditions in practical engineering applications.

Self-cleaning structural colors by TiO2/Ti nanostructures

Structural colors are fascinating due to their stability in comparison with dyes and pigments; nevertheless, environmental pollutants contaminate surfaces and redefine structural colors. To overcome this problem, cleaning of the surface is necessary at regular intervals, which is cumbersome and costly. We have circumvented this issue in this article and fabricated scalable self-cleaning structural colors. The structural colors are generated by TiO₂ nanorods and thin films on Ti sputtered glass and flexible polyethylene terephthalate substrates employing a glancing angle deposition (GLAD) technique. Theoretical calculations based on thin film interference validate the experimental results and suggest Al, Ni, Co, and Cu as an alternative of Ti for generating structural colors. Structural colors are transformed to a superhydrophilic state, i.e., a self-cleaning state, via UV exposure and annealing at elevated temperatures. In addition to a self-cleaning state, annealing could control the opaqueness and color tunability of the structural colors. A permanent wettability state in between the superhydrophobic and superhydrophilic states of the structural colors is controlled by the GLAD technique. Moreover, the structural colors are demonstrated for information encryption and optical ethanol sensing applications.

Large area Al2O3-Au raspberry-like nanoclusters from iterative block-copolymer self-assembly

In the field of functional nanomaterials, core–satellite nanoclusters have recently elicited great interest due to their unique optoelectronic properties. However, core–satellite synthetic routes to date are hampered by delicate and multistep reaction conditions and no practical method has been reported for the ordering of these structures onto a surface monolayer. Herein we show a reproducible and simplified thin film process to fabricate bimetallic raspberry nanoclusters using block copolymer (BCP) lithography. The fabricated inorganic raspberry nanoclusters consisted of a ∼36 nm alumina core decorated with ∼15 nm Au satellites after infusing multilayer BCP nanopatterns. A series of cylindrical BCPs with different molecular weights allowed us to dial in specific nanodot periodicities (from 30 to 80 nm). Highly ordered BCP nanopatterns were then selectively infiltrated with alumina and Au species to develop multi-level bimetallic raspberry features. Microscopy and X-ray reflectivity analysis were used at each fabrication step to gain further mechanistic insights and understand the infiltration process. Furthermore, grazing-incidence small-angle X-ray scattering studies of infiltrated films confirmed the excellent order and vertical orientation over wafer scale areas of Al₂O₃/Au raspberry nanoclusters. We believe our work demonstrates a robust strategy towards designing hybrid nanoclusters since BCP blocks can be infiltrated with various low cost salt-based precursors. The highly controlled nanocluster strategy disclosed here could have wide ranging uses, in particular for metasurface and optical based sensor applications.

Large area Al₂O₃–Au raspberry-like nanoclusters and other complex structures have been created by iterative block-copolymer self-assembly, paving the way to a new generation of on-demand metallic architectures.

Programming Multiphase Media Superwetting States in the Oil-Water-Air System: Evolutions in Hydrophobic-Hydrophilic Surface Heterogeneous Chemistry

Studies toward tailoring macroscopic extreme wetting behaviors on a certain well-defined surface in multiphase media are significant but still at an infant stage. Herein, superantiwetting evolutions in the oil-water-air system can be programmed from single to quadruple superrepellence by controlling the surface hydrophobic-hydrophilic heterogeneous chemistry. Ammonia vapor exposure makes the realization of challenging superhydrophilicity-superoleophobicity possible in air medium, causing the transition from quadruple to triple superantiwetting states in the oil-water-air system. Upon UV illumination, only single superrepellence-underwater superoleophobicity is maintained on titanium dioxide (TiO₂, P25)-based coatings. A reversible transition between underoil superhydrophilicity and superhydrophobicity via an alternating UV irradiation and heating process leads to a switching between "water-absorbing" and "size-sieving" effects in water-in-oil emulsion separation. A comparative study for investigating two such effects in emulsion separation is further investigated. The current conceptual insights not only extend superwetting states to multiphase media, but can also deepen the understanding of the relationship between macroscopic extreme wetting behaviors and surface chemistry.

Droplet Impact on the Cold Elastic Superhydrophobic Membrane with Low Ice Adhesion

The elastic membranes with different surface stiffness were fabricated via spin-coating followed by the laser ablation. The as-fabricated elastic membrane exhibited superhydrophobicity with a rough microstructure. The droplet impacting experiment on the cold elastic superhydrophobic membrane was conducted, and the influence of surface stiffness and impacting speed on the droplet impacting process were investigated. It was found that the elastic superhydrophobic membrane exhibits a robust anti-icing performance compared with the elastic hydrophobic membrane. A lower surface stiffness corresponds to a larger deformation degree of the elastic membrane and to a smaller maximum droplet spreading diameter. Moreover, the contact time decreases with the increase of impacting speed as for the same stiffness of the cold elastic superhydrophobic membrane. The underlying mechanism of the cold elastic membrane with low ice adhesion may be due to the face that the deformation of the superhydrophobic membrane provides an elastic force for the droplet to detach from the surface and thus reduce the heat transfer between the droplet and the surface.

Nanointeraction: The profound influence of nanostructured and nano-drug delivery biomedical implant surfaces on cell behavior

Nanostructured surfaces feature promising biological properties on biomaterials attracting large interest at basic research, implant industry development, and bioengineering applications. Thou, nanoscale interactions at a molecular and cellular level are not yet completely understood and its biological and clinical implications need to be further elucidated. As follows, the aim of this comprehensive review was to evaluate nanostructured surfaces at biomedical implants focusing on surface development, nanostructuration, and nanoengineered drug delivery systems that can induce specific cell interactions in all relevant aspects of biological, reparative, anti-bacterial, anti-inflammatory and clinical processes. The methods and the physio-chemical properties involved in nanotopography performance, the main cellular characteristics involved at surface/cell interaction, and a summary of results and outlooks reported in studies applying nanostructured surfaces and nano-drug delivery systems is presented. The future prospects and commercial translation of this developing field, particularly concerning multifunctional nanostructured surfaces and its clinical implications are further discussed. At a cellular level, nanostructured biomedical implant surfaces can enhance osteogenesis by targeting osteoblasts, osteocytes, and mesenchymal cells, stimulate fibroblast/epithelial cells proliferation and adherence, inhibit bacterial cell proliferation and biofilm accumulation, and act as immune-modulating surfaces targeting macrophages and reducing pro-inflammatory cytokine expression. Moreover, several methodological options to create drug-delivery systems on metallic implant surfaces are available, however, the clinical translation is yet incomplete. The efficiency of which nanostructured/nano-delivery surfaces may target specific cell interactions and favor clinical outcomes needs to be further elucidated in pre-clinical and clinical studies, along with engineering solutions for commercial translation and approval of controlling agencies.

Light-Responsive Inorganic Biomaterials for Biomedical Applications

Light-responsive inorganic biomaterials are an emerging class of materials used for developing noninvasive, noncontact, precise, and controllable medical devices in a wide range of biomedical applications, including photothermal therapy, photodynamic therapy, drug delivery, and regenerative medicine. Herein, a range of biomaterials is discussed, including carbon-based nanomaterials, gold nanoparticles, graphite carbon nitride, transition metal dichalcogenides, and up-conversion nanoparticles that are used in the design of light-responsive medical devices. The importance of these light-responsive biomaterials is explored to design light-guided nanovehicle, modulate cellular behavior, as well as regulate extracellular microenvironments. Additionally, future perspectives on the clinical use of light-responsive biomaterials are highlighted.

Extension of hydrophilicity stability by reactive plasma treatment and wet storage on TiO2 nanotube surfaces for biomedical implant applications

Micro and nanoscale changes allow the optimization of physico-chemical properties of titanium implant surfaces. Recently UV and plasma treatments have allowed surface hydrophilicity to take increased prominence; however, this beneficial effect is short-lived. The aim of this study is to investigate methodologies post-anodizing treatment to generate and maintain high surface hydrophilicity along with high biocompatibility. Anodized surfaces were characterized regarding physical-chemical properties. Then, surface wettability with nanomorphology was evaluated at different times and with distinct post-treatments: as deposited, with a reactive plasma and UV-light post-treatment, stored in air or deionized (DI) water. Adhesion, alkaline phosphatase (ALP) activity and bone cell viability tests were executed after the incremental treatments. The anodizing process generated a surface with TiO2 nanotubes morphology and micro-roughness. Plasma-treated surfaces resulted in the most hydrophilic samples and this property was maintained for a longer period when those were stored in DI water (angle variation of 7° to 12° in 21 days). Furthermore, plasma post-treatment changed the titanium surface crystalline phase from amorphous to anatase. Anodized surfaces modified by reactive plasma and stored in DI water suggest better hydrophilicity stability, biocompatibility, ALP activity and achievement of crystalline phase alteration, indicating future potential use on biomedical implants.

Reversible Structure Engineering of Bioinspired Anisotropic Surface for Droplet Recognition and Transportation

Surfaces with tunable liquid adhesion have aroused great attention in past years. However, it remains challenging to endow a surface with the capability of droplet recognition and transportation. Here, a bioinspired surface, termed as TMAS, is presented that is inspired by isotropic lotus leaves and anisotropic butterfly wings. The surface is prepared by simply growing a triangular micropillar array on the pre-stretched thin poly(dimethylsiloxane) (PDMS) film. The regulation of mechanical stress in the PDMS film allows the fine tuning of structural parameters of the micropillar array reversibly, which results in the instantaneous, in situ switching between isotropic and various degrees of anisotropic droplet adhesions, and between strong adhesion and directional sliding of water droplets. TMAS can thus be used for robust droplet transportation and recognition of acids, bases, and their pH strengths. The results here could inspire the design of robust sensor techniques.

Laser Fabrication of Bioinspired Graphene Surfaces With Superwettability

The past decades have seen growing research interest in developing efficient fabrication techniques for preparing bioinspired graphene surfaces with superwettability. Among the various fabrication methods, laser fabrication stands out as a prominent one to achieve this end and has demonstrated unique merits in the development of graphene surfaces with superwettability. In this paper, we reviewed the recent advances in this field. The unique advantages of laser fabricated graphene surfaces have been summarized. Typical graphene surfaces with superwettability achieved by laser fabrication, including superhydrophobic graphene surfaces, oil/ water separation, fog collection, antibacterial surfaces, surface enhanced Raman scattering (SERS), and desalination, have been introduced. In addition, current challenges and future perspectives in this field have been discussed. With the rapid progress of novel laser physical/ chemical fabrication schemes, graphene surfaces with superwettability prepared by laser fabrication may undergo sustained development and thus contribute greatly to the scientific research and our daily life.

Wetting Properties of Transparent Anatase/Rutile Mixed Phase Glancing Angle Magnetron Sputtered Nano-TiO2 Films

Transparent polycrystalline TiO2 thin films have been deposited on unheated glass substrates using RF reactive magnetron sputtering. Depositions were carried out at different glancing angles and with different total gas mixture pressures. The variation of these parameters affected the crystal phase composition and the surface morphology. Depending on the glancing angle and the pressure, rutile, mixed anatase/ rutile and pure anatase were deposited at low substrate temperature. Both hydrophilic and hydrophobic TiO2 were obtained, exhibiting fast photoconversion to superhydrophilic upon UV irradiation. The effect of the materials physicochemical properties on the wettability and rate of the UV induced superhydrophilicity is evaluated.

Nanoasperity Adhesion of the Silicon Surface in Humid Air: The Roles of Surface Chemistry and Oxidized Layer Structures

The interfacial adhesion between silicon oxide surfaces is normally believed to be governed by the surface chemistry of the topmost surface affecting the water contact angle and hydrogen bonding interactions. In the case of a silicon wafer, the physical structure of the native oxide at the surface can vary drastically depending on the aging process; thus, not only the surface chemistry but also the history of surface treatment can also have a profound impact on nanoasperity adhesion. This study reports the effect of aging conditions (ambient air, liquid water, and liquid ethanol) on the nanoasperity adhesion behaviors of a silicon surface. When the silicon surface is kept in liquid alcohol, the surface remains hydrophobic, and adhesion in ambient air can be explained with the capillary effect of the liquid meniscus condensed around the annulus of the nanoasperity contact. When the silicon surface is oxidized in ambient air, the surface gradually becomes hydrophilic, and the strongly hydrogen-bonded water network of adsorbed water plays a dominant role in the nanoasperity interfacial adhesion force. When the silicon surface is aged in liquid water, the interfacial adhesion force measured in ambient air is significantly larger than the value predicted from the theoretical model based on the water contact angle and the hydrogen bonding interaction at the topmost surface. This is because the surface layer oxidized in liquid water is gel-like and thus can swell upon uptake of water from the humid air. To fully encompass all these behaviors, a solid-adsorbate-solid model predicting the adhesion force is developed by introducing a fitting parameter β, which can be adjusted depending on the adsorbed water structure and the swelling capacity of the oxidized surface layer.

Er,Cr:YSGG laser surface treatment of gamma titanium aluminide: Scanning electron microscopy-energy-dispersive X-ray spectrometer analysis, wettability and Eikenella corrodens and Aggregatibacter actinomycetemcomitans bacteria count-in vitro study

Dental implants play an important role in oral health. Titanium dental implants must endure the complex microflora environment of the oral cavity. Moreover, bacterial infections have been considered as one of the most important factors of implant failure. The issue of dental improvement through modification of chemical composition and surface treatment has received considerable critical attention. γ-TiAl as a novo biocompatible material revealed a slower corrosion rate in biological media rather Ti-6Al-4V. The objective of this study is to investigate the effect of Er,Cr:YSGG laser on γ-TiAl in comparison with sandblasted and acid-etched samples as the control groups and machined samples.Wettability, surface roughness, surface topography, scanning electron microscopy-energy dispersive X-ray spectrometer analysis of surface and subsurface of samples were investigated and bacteria counts of two periodontal bacterial strains (Aggregatibacter actinomycetemcomitans and Eikenella corrodens) were evaluated on the Er,Cr:YSGG laser surface-treated sandblasted and acid-etched and machined samples.The results of this investigation show that Er,Cr:YSGG laser surface treatment affects surface roughness, surface topography, wettability, chemical composition of the surface and bacteria count. Scanning electron microscopy-energy dispersive X-ray spectrometer analysis of the sample revealed the increment of titanium and oxygen content and reduction of aluminum content in the surface and subsurface layer. A. actinomycetemcomitans and E. corrodens count were found from the lowest level to highest in the sandblasted and acid-etched samples, laser samples and machined samples, respectively.Using controlled parameters of Er,Cr:YSGG laser ensured no significant adverse alteration. The findings to emerge from this study revealed the significant correlation between microbial count and wettability. Furthermore, the contact angle strongly correlated with surface roughness.