Electrical Transport and Dynamics of Confined DNA through Highly Conductive 2D Graphene Nanochannels.

Confining DNA in nanochannels is an important approach to studying its structure and transportation dynamics. Graphene nanochannels are particularly attractive for studying DNA confinement due to their atomic flatness, precise height control, and excellent mechanical strength. Here, using femtosecond laser etching and wetting transfer, we fabricate graphene nanochannels down to less than 4.3 nm in height, with the length-to-height ratios up to 103. These channels exhibit high stability, low noise, and self-cleaning ability during the long-term ionic current recording. We report a clear linear relationship between DNA length and the residence time in the channel and further utilize this relationship to differentiate DNA fragments based on their lengths, ranging widely from 200 bps to 48.5 kbps. The graphene nanochannel presented here provides a potential platform for label-free analyses and reveals fundamental insights into the conformational dynamics of DNA and proteins in confined space.

High-Throughput Designed and Laser-Etched NiFeCrVTi High-Entropy Alloys with High Catalytic Activities and Corrosion Resistance for Hydrogen Evolution in Seawater.

Electrocatalytic hydrogen evolution from seawater through wind or solar energy is a cost-effective way to produce green hydrogen fuel. However, the lack of highly active and anti-corrosive electrocatalysts in seawater severely hinders the industrial application. Herein, a novel Ni1.1FeCr0.4V0.3Ti0.3 high-entropy alloy (HEA) is designed through high throughput computing and prepared via powder metallurgy with the surface treated by laser etching under different laser power. The laser-etched NiFeCrVTi high-entropy alloys exhibit a unique periodically ordered structure with multiple active centers and high porosity. The Ni-HEA-30 displays remarkable hydrogen evolution reaction (HER) performance with an overpotential of 55.9 mV and a Tafel slope of 47.3 mV dec-1 in seawater. Density functional theory (DFT) calculations are applied to identify the real active sites for HER on the HEA surface as the key factor for both proton and intermediate transformation, which also reveals that the Cr atom promotes the adsorption energy of water molecules, and the modulation of the electronic structure plays a crucial role in optimizing the hydrogen binding capabilities of the Ni atoms within the alloy. Additionally, the electrocatalyst displays high corrosion resistance in seawater, contributing to the good durability for hydrogen production. This work uncovers a new paradigm to develop novel electrocatalysts with superior reaction activity in seawater.

Biomimetic Zirconia with Cactus-Inspired Meso-Scale Spikes and Nano-Trabeculae for Enhanced Bone Integration.

Biomimetic design provides novel opportunities for enhancing and functionalizing biomaterials. Here we created a zirconia surface with cactus-inspired meso-scale spikes and bone-inspired nano-scale trabecular architecture and examined its biological activity in bone generation and integration. Crisscrossing laser etching successfully engraved 60 µm wide, cactus-inspired spikes on yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) with 200-300 nm trabecular bone-inspired interwoven structures on the entire surface. The height of the spikes was varied from 20 to 80 µm for optimization. Average roughness (Sa) increased from 0.10 µm (polished smooth surface) to 18.14 µm (80 µm-high spikes), while the surface area increased by up to 4.43 times. The measured dimensions of the spikes almost perfectly correlated with their estimated dimensions (R2 = 0.998). The dimensional error of forming the architecture was 1% as a coefficient of variation. Bone marrow-derived osteoblasts were cultured on a polished surface and on meso- and nano-scale hybrid textured surfaces with different spike heights. The osteoblastic differentiation was significantly promoted on the hybrid-textured surfaces compared with the polished surface, and among them the hybrid-textured surface with 40 µm-high spikes showed unparalleled performance. In vivo bone-implant integration also peaked when the hybrid-textured surface had 40 µm-high spikes. The relationships between the spike height and measures of osteoblast differentiation and the strength of bone and implant integration were non-linear. The controllable creation of meso- and nano-scale hybrid biomimetic surfaces established in this study may provide a novel technological platform and design strategy for future development of biomaterial surfaces to improve bone integration and regeneration.

Effect of Er:YAG laser etching on topography, microstructure, compressive strength, and bond strength of a universal adhesive to calcium silicate cements.

OBJECTIVE: To evaluate the effect of Er:YAG etching on topography, microstructure, compressive strength, and shear bond strength (SBS) of All-Bond Universal adhesive to mineral trioxide aggregate-Angelus (AMTA) and Biodentine (BD). METHODS AND MATERIALS: Sixty cylindrical specimens of each cement (AMTA and BD) in five groups were prepared and stored for 72 h. The control groups were non-etched, and four other groups were acid-etched and laser-etched with a pulse energy of 60, 80, or 100 mJ, followed by compressive strength testing. Surface micromorphology and topography were evaluated. Similar groups were bonded using All-Bond Universal with self-etch and etch-and-rinse (acid-etch) approaches, and laser-etch 60, 80, and 100 mJ, and SBS was tested. Data were analyzed using two-way and one-way ANOVA and the Bonferroni post hoc tests (α = 0.05). RESULTS: BD had a significantly higher compressive strength and SBS (except for laser-etch 100) compared to AMTA, regardless of the etching method (p < 0.001). Acid etching and laser etching 100 of both cements and laser etching 80 of BD alone produced a significantly lower compressive strength than that for the other groups. Contrary to BD, for AMTA, all the treatments significantly increased SBS compared to that of the self-etch group. CONCLUSIONS: Etching of AMTA was needed for stronger bonding; laser etching with 60 or 80 mJ without compromising compressive strength was recommended. Etching not only did not improve bonding ability of BD, but it also negatively affected the strength of BD. CLINICAL RELEVANCE: To achieve successful combined calcium silicate cement-resin material restoration, an adequate bond between the materials is mandatory. This might be provided with the ultramild adhesive through laser etching without compromising compressive strength, depending on cement composition and laser energy level used.

Energy-dispersive X-ray Spectroscopy Analysis of Erbium, Chromium:Yttrium-scandium-gallium-garnet-treated Enamel Surfaces: An In Vitro Study.

AIM AND OBJECTIVE: The present study evaluated the effects of erbium, chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser on the weight percentage of mineral content of enamel when etched at three different power settings. MATERIALS AND METHODS: Total 20 extracted molar teeth were taken as samples. Enamel slabs were prepared by sectioning the crown from the buccal and lingual aspect with a double-sided diamond disk at slow speed. The 40 specimens were divided into four groups, i.e., control, 1 W, 2 W, and 3 W of 10 specimens each and then irradiation by Er,Cr:YSGG was done. The elements evaluated were calcium (Ca), potassium (K), magnesium (Mg), sodium (Na), and phosphorus (P). The mean weights of these minerals and the Ca:P ratio in each slab were measured by energy-dispersive X-ray spectroscopy analysis (EDAX). One-way analysis of variance (ANOVA) followed by the Turkey's test was performed with the help of critical difference (CD) or least significant difference (LSD) at 5 and 1% level of significance. RESULTS: There was no significant differences among the four groups for the five minerals and for the calcium:phosphorous ratio (p > 0.05). Photomicrographs by scanning electron microscopy observations revealed that the surfaces exposed to a 3 watt irradiation showed more roughness than those of the 1 watt and 2 watt groups. CONCLUSION: The Er,Cr:YSGG irradiation of enamel at 1 W, 2 W, and 3 W had no significant effect on the mean percentage weights of Ca, K, Mg, Na, and P or the Ca/P ratio in any group. CLINICAL SIGNIFICANCE: Constriction with conviction is the new motto of restorative dentistry. Er,Cr:YSGG not only fulfills the aim but also is proving to alter the surface properties by recrystallization and change in composition making the prepared surface caries resistant.

Effect of Different Surface Treatments on Porcelain-Resin Bond Strength.

PURPOSE: The aim of this study was to evaluate the effects of various surface treatments on the surface structure and shear bond strength (SBS) of different ceramics. MATERIALS AND METHODS: A total of 192 disk-shaped cores were prepared using two all-ceramic systems, of which 168 were submitted to SBS tests, and 24 were investigated by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The ceramics used were IPS Empress e.max (EX) lithium glass-ceramic and Vita In-Ceram Zirconia glass-infiltrated zirconia (ICZ). The specimens were randomly divided into seven groups (n = 12) on the basis of the surface treatment used: control; SB-sandblasting with 50 µm Al2 O3 particles; CJ-chairside silica coating with 30 µm SiO2 particles and silanization (Clearfil Porcelain Bond Activator); HF-etching in 5% hydrofluoric acid and silanization; ER-etching with an Er:YAG laser (10 W); ND-Nd:YAG laser etching (0.8 W); and FS-etching with a femtosecond laser (860 mW). A luting cement (Clearfil Esthetic) was photopolymerized on each treated ceramic disk. After subjecting the specimens to thermocycling (1000 cycles, 5°C to 55°C), SBS tests were performed using a universal testing machine. The data were analyzed with two-way ANOVA and Tukey's tests using a significance limit of 5%. RESULTS: Among the EX ceramics, the CJ (29.10 MPa) and HF (26.07 MPa) specimens had statistically higher SBS values. For the ICZ ceramics, the highest value (28.08 MPa) was obtained for the CJ specimens. CONCLUSIONS: Silanization after coating with silica improves the bond strengths of both EX and ICZ specimens, while HF etching is favorable only for the EX specimens.

Single-crystal diamond refractive lens for focusing X-rays in two dimensions. Erratum.

A correction is made to a citation in the article by Antipov et al. (2016) [J. Synchrotron Rad. 23, 163-168].

Single-crystal diamond refractive lens for focusing X-rays in two dimensions.

The fabrication and performance evaluation of single-crystal diamond refractive X-ray lenses of which the surfaces are paraboloids of revolution for focusing X-rays in two dimensions simultaneously are reported. The lenses were manufactured using a femtosecond laser micromachining process and tested using X-ray synchrotron radiation. Such lenses were stacked together to form a standard compound refractive lens (CRL). Owing to the superior physical properties of the material, diamond CRLs could become indispensable wavefront-preserving primary focusing optics for X-ray free-electron lasers and the next-generation synchrotron storage rings. They can be used for highly efficient refocusing of the extremely bright X-ray sources for secondary optical schemes with limited aperture such as nanofocusing Fresnel zone plates and multilayer Laue lenses.

Light-Sharing Interface for dMiCE Detectors Using Sub-Surface Laser Engraving.

We have previously reported on dMiCE, a method of resolving depth or interaction (DOI) in a pair of discrete crystals by encoding light sharing properties as a function of depth in the interface of a crystal-element pair. A challenge for this method is the cost and repeatability of interface treatment for each crystal pair. In this work, we report our preliminary results on using sub-surface laser engraving (SSLE) as a means of forming this depth-dependent interface in a dMiCE detector. A surplus first-generation SSLE system was used to create a partially reflective layer 100-microns thick at the boundary between two halves of a 1.4-by-2.9-by-20 mm3 LYSO crystal. The boundary of these paired crystal elements was positioned between two 3-mm wide Silicon photomultiplier arrays. The responses of these two photodetectors were acquired for an ensemble of 511-keV photons collimated to interact at a fixed depth in just one crystal element. Interaction position was then varied to measure detector response as a function of depth, which was then used to maximum-likelihood positions. Despite use of sub-optimal SSLE processing we found an average DOI resolution of 3.4 mm for front-sided readout and 3.9 mm for back-sided readout while obtaining energy resolutions on the order of 10%. We expect DOI resolution can be improved significantly by optimizing the SSLE process and pattern.

Comparative evaluation of surface topography of tooth prepared using erbium, chromium: Yttrium, scandium, gallium, garnet laser and bur and its clinical implications.

BACKGROUND: Erbium, chromium: Yttrium, scandium, gallium, garnet (Er, Cr: YSGG) laser has been successfully used in the ablation of dental hard and soft tissues. It has been reported that this system is also useful for preparing tooth surfaces and etching, but no consensus exist in the literature regarding the advantage of lasers over conventional tooth preparation technique. MATERIALS AND METHODS: Labial surfaces of 25 extracted human maxillary central incisors were divided into two halves. Right half was prepared with diamond bur and left half with Er, Cr; YSGG laser and a reduction of 0.3-0.5 mm was carried out. Topography of prepared surfaces of five teeth were examined under scanning electron microscope (SEM). The remaining samples were divided into 4 groups of 10 specimens each based on the surface treatment received: One group was acid etched and other was nonetched. Composite resin cylinders were bonded on prepared surfaces and shear bond strength was assessed using a universal testing machine. RESULTS: The SEM observation revealed that the laser prepared surfaces were clean, highly irregular and devoid of a smear layer. Bur prepared surfaces were relatively smooth but covered with smear layer. Highest bond strength was shown by laser prepared acid etched group, followed by bur prepared the acid etched group. The bur prepared nonacid etched group showed least bond strength. CONCLUSIONS: Er, Cr: YSGG laser can be used for preparing tooth and bond strength value achieved by laser preparation alone without surface treatment procedure lies in the range of clinical acceptability.

The effect of different surgical drilling procedures on full laser-etched microgrooves surface-treated implants: an experimental study in sheep.

OBJECTIVES: To evaluate the influence of instrumentation technique on the early osseointegration histomorphometrics and biomechanical fixation of fully laser-etched microgrooves implant surfaces in a sheep model. MATERIAL AND METHODS: Six sheep were subjected to bilateral hip surgeries 3 and 6 weeks before euthanasia. A total of 48 implants (∅4.5 mm, 8 mm in length) were distributed among four sites (8 per animal) and placed in bone sites drilled to 4.6 mm (reamer), 4.1 mm (loose), 3.7 mm (medium) and 3.2 mm (tight) in diameter. After healing, the animals were euthanized and half of the implants were biomechanically tested, while the remainder was subjected to non-decalcified histologic processing. The histomorphometric parameters assessed were bone-to-implant contact (BIC) and bone area fraction occupancy (BAFO). Statistical analysis was performed using a mixed-model analysis of variance with significance level set at P < 0.05. RESULTS: A general increasing trend is present from 3 to 6 weeks for most of the variables. The groups prepared to be press fit seemed to present higher values, which were maintained throughout the observation period. The reamer group presented the lowest BIC probably due to the drilling technique; however qualitatively, more new bone seemed to be in contact to the implant surface, at 3 weeks, whereas the implants placed in press-fit situations were mainly supported by cortical bone. CONCLUSION: The laser-etched microgrooved implant presented osteoconductive and biocompatible properties for all surgical procedures tested. However, procedures providing increasingly higher press-fit scenarios presented the strongest histomorphometric and biomechanical responses at 3 and 6 weeks.

Rapid Fabrication of Antilunar Dust Aluminum Surface by Nanosecond Laser Etching.

Although a dust-repellent surface is desirable for lunar exploration missions, its fabrication process is complicated and time-consuming. Herein, we report a simple and fast method to fabricate a lunar dust-repellent surface by texturing on an Al substrate via nanosecond laser etching. The laser-induced photothermal effect can rapidly create hierarchical papillary structures on 25 × 25 mm Al substrates (within 30 s). Both atomic force microscopy (AFM) and in situ scanning electron microscopy (SEM) reveal that such structures enable a reduced contact area between the Al substrate and lunar dust and thus reduced adhesion. The reduced dust adhesion force of Al substrates facilitates improving their antidust performance. By optimizing processing parameters, the Al substrate etched with a laser scanning spacing of 80 µm exhibits a lower dust adhesion force (9.58 nN) due to the smallest contact area with dust. Accordingly, its static antilunar dust performance (dust coverage of 1.95%) is significantly improved compared to the pristine Al substrate (dust coverage of 12.98%). Besides, the accumulated dust on the laser-etched Al substrates with low surface adhesion force is easily cleaned up by flipping and gravity (the dust residual rates are less than 17%). The Al substrate with excellent antidust ability presents good potential for lunar exploration missions.

Study on the effect of crystal changes on acid resistance of erbium laser etched enamel surface.

To investigate the mechanism underlying high acid resistance of enamel after erbium laser etching. Forty-five premolars were collected and assigned to three groups. A 4×4×1 mm enamel sample was prepared, the left side was the control side, the right side was the treated side, which was treated with different surface treatments, including 35% phosphoric acid etching, Er:YAG laser etching, and Er,Cr:YSGG laser etching. The hydroxyapatite crystal size on the enamel surface of the samples was observed. The contents of Ca, P, O, F, Cl, C, Mg were detected. The crystallinity of the hydroxyapatite crystal was analyzed. After erbium laser etching, the enamel surface had high hydroxyapatite crystal size, beneficial content of chemical elements and crystallinity. The morphological and composition changes of crystals in the enamel surface after erbium laser etching may be one of the crucial mechanisms underlying the enhancement of acid resistance of enamel after erbium laser etching.

Effect of Various Etching Techniques on Shear Strength of Newer Generation Composites.

Aim: To evaluate the effect of lasers on the shear bond strength of Giomer and G-aenial flo composite using three different etching techniques. Materials and Methods: 60 Samples (extracted human premolar teeth) are cut horizontally using a diamond disk to expose a flat occlusal surface involving enamel and dentin. On exposed occlusal surfaces, etching is done by various methods. These were divided into six groups of ten samples each as follows: group I (acid etched for Giomer), group II (acid etched for G-aenial flo composite), group III (laser etched for Giomer), group IV (Laser etched for G-aenial flo composite), group V (air abrasion etched for Giomer), group VI (Air abrasion etched for G-aenial flo composite). Then, restorative material is placed and cured with light for 20 seconds. The samples were thermocycled to simulate the oral environment. The samples were subjected to a universal testing machine for bond strength testing at a cross-head speed of 3 mm/min until the restoration will fracture. Results: The intergroup comparison between both the materials using Student's t-test gives insignificant results. The intergroup comparison between different etching techniques using two-way ANOVA tests gives insignificant results. Conclusion: Within the limitation of this study, it can be concluded that Giomer and G-aenial flo composite achieved the same shear bond strength in all the etching techniques.

Suppression of Secondary Electron Emission by Vertical Graphene Coating on Ni Microcavity Substrate.

Suppression of secondary electron emission (SEE) from metal surfaces is crucial for enhancing the performance of particle accelerators, spacecraft, and vacuum electronic devices. Earlier research has demonstrated that either etching the metal surface to create undulating structures or coating it with materials having low secondary electron yield (SEY) can markedly decrease SEE. However, the effectiveness of growing vertical graphene (VG) on laser-etched metal surfaces in suppressing SEE remains uncertain. This study examined the collective impact of these methods by applying nanoscale arrays of VG coating using plasma-enhanced chemical vapor deposition on Ni substrates, along with the formation of micrometer-sized microcavity array through laser etching. Comparative tests conducted revealed that the SEY of the samples subjected to VG coating on a microcavity array was lower compared to samples with either only a microcavity array or VG coating alone. Additionally, the crystallinity of VG grown on substrates of varying shapes exhibited variations. This study presents a new method for investigating the suppression of SEE on metal surfaces, contributing to the existing body of knowledge in this field.

Prediction of Femtosecond Laser Etching Parameters Based on a Backpropagation Neural Network with Grey Wolf Optimization Algorithm.

Investigating the optimal laser processing parameters for industrial purposes can be time-consuming. Moreover, an exact analytic model for this purpose has not yet been developed due to the complex mechanisms of laser processing. The main goal of this study was the development of a backpropagation neural network (BPNN) with a grey wolf optimization (GWO) algorithm for the quick and accurate prediction of multi-input laser etching parameters (energy, scanning velocity, and number of exposures) and multioutput surface characteristics (depth and width), as well as to assist engineers by reducing the time and energy require for the optimization process. The Keras application programming interface (API) Python library was used to develop a GWO-BPNN model for predictions of laser etching parameters. The experimental data were obtained by adopting a 30 W laser source. The GWO-BPNN model was trained and validated on experimental data including the laser processing parameters and the etching characterization results. The R2 score, mean absolute error (MAE), and mean squared error (MSE) were examined to evaluate the prediction precision of the model. The results showed that the GWO-BPNN model exhibited excellent accuracy in predicting all properties, with an R2 value higher than 0.90.

The Effects of Etchant on via Hole Taper Angle and Selectivity in Selective Laser Etching.

This research focuses on the manufacturing of a glass interposer that has gone through glass via (TGV) connection holes. Glass has unique properties that make it suitable for 3D integrated circuit (IC) interposers, which include low permittivity, high transparency, and adjustable thermal expansion coefficient. To date, various studies have suggested numerous techniques to generate holes in glass. In this study, we adopt the selective laser etching (SLE) technique. SLE consists of two processes: local modification via an ultrashort pulsed laser and chemical etching. In our previous study, we found that the process speed can be enhanced by changing the local modification method. For further enhancement in the process speed, in this study, we focus on the chemical etching process. In particular, we try to find a proper etchant for TGV formation. Here, four different etchants (HF, KOH, NaOH, and NH4F) are compared in order to improve the etching speed. For a quantitative comparison, we adopt the concept of selectivity. The results show that NH4F has the highest selectivity; therefore, we can tentatively claim that it is a promising candidate etchant for generating TGV. In addition, we also observe a taper angle variation according to the etchant used. The results show that the taper angle of the hole is dependent on the concentration of the etchant as well as the etchant itself. These results may be applicable to various industrial fields that aim to adjust the taper angle of holes.

Surveying the Directional Transport of Water Droplets upon Impact on Metallic Topographic Gradients.

Drop impact phenomena on raw, polished, and topography-altered gradient surfaces are investigated and presented. The main aim of this study is to demonstrate that in using a one-step industrial patterning process, it is possible to obtain metal topographical wetting gradients that can produce various desired outcomes after droplet impact. The findings could be applied to improving wind or steam turbine blades. The ranges of Weber (We) and Reynolds (Re) numbers in the study are 3-300 and 650-6500, respectively. It is demonstrated that for a fixed We, the droplet transport outcomes change from bouncing-off to side-flipping to deposition depending on the impact location and the gradient strength. The effect of We in combination with the gradient strength was also considered to demonstrate droplet behavior similar to that observed on a uniform water repellent surface and on biphilic systems. In addition, full bouncing-off and directional control have been demonstrated. For the condition We = 95 ± 3, it was possible to achieve a maximum droplet recoil height of ∼6 mm and a side motion of almost 8 mm. A combination of different outcomes (e.g., splashing on one side of a droplet and passive horizontal translation on another) was observed on the studied gradients at We > 200 due to different wetting regimes across the droplet's three-phase line.

Microcavity well-plate for automated parallel bioelectronic analysis of 3D cell cultures.

Three-dimensional (3D) in vitro cell culture models serve as valuable tools for accurately replicating cellular microenvironments found in vivo. While cell culture technologies are rapidly advancing, the availability of non-invasive, real-time, and label-free analysis methods for 3D cultures remains limited. To meet the demand for higher-throughput drug screening, there is a demanding need for analytical methods that can operate in parallel. Microelectrode systems in combination with microcavity arrays (MCAs), offer the capability of spatially resolved electrochemical impedance analysis and field potential monitoring of 3D cultures. However, the fabrication and handling of small-scale MCAs have been labour-intensive, limiting their broader application. To overcome this challenge, we have established a process for creating MCAs in a standard 96-well plate format using high-precision selective laser etching. In addition, to automate and ensure the accurate placement of 3D cultures on the MCA, we have designed and characterized a plug-in tool using SLA-3D-printing. To characterize our new 96-well plate MCA-based platform, we conducted parallel analyses of human melanoma 3D cultures and monitored the effect of cisplatin in real-time by impedance spectroscopy. In the following we demonstrate the capabilities of the MCA approach by analysing contraction rates of human pluripotent stem cell-derived cardiomyocyte aggregates in response to cardioactive compounds. In summary, our MCA system significantly expands the possibilities for label-free analysis of 3D cell and tissue cultures, offering an order of magnitude higher parallelization capacity than previous devices. This advancement greatly enhances its applicability in real-world settings, such as drug development or clinical diagnostics.

Impact of nano-scale trabecula size on osteoblastic behavior and function in a meso-nano hybrid rough biomimetic zirconia model.

PURPOSE: A novel implant model consisting of meso-scale cactus-inspired spikes and nano-scale bone-inspired trabeculae was recently developed to optimize meso-scale roughness on zirconia. In this model, the meso-spike dimension had a significant impact on osteoblast function. To explore how different nano-textures impact this model, here we examined the effect of different nano-trabecula sizes on osteoblast function while maintaining the same meso-spike conformation. METHODS: Zirconia disks with meso-nano hybrid surfaces were created by laser etching. The meso-spikes were fixed to 40 µm high, whereas the nano-texture was etched as large and small trabeculae of average Feret diameter 237.0 and 134.1 nm, respectively. A polished surface was also prepared. Rat bone marrow-derived and human mesenchymal stromal cell-induced osteoblasts were cultured on these disks. RESULTS: Hybrid rough surfaces, regardless of nano-trabecula dimension, robustly promoted the osteoblastic differentiation of both rat and human osteoblasts compared to those on polished surfaces. Hybrid surfaces with small nano-trabeculae further enhanced osteoblastic differentiation compared with large nano-trabeculae. However, the difference in osteoblastic differentiation between small and large nano-trabeculae was much smaller than the difference between the polished and hybrid rough surfaces. The nano-trabecula size did not influence osteoblast attachment and proliferation, or protein adsorption. Both hybrid surfaces were hydro-repellent. The atomic percentage of surface carbon was lower on the hybrid surface with small nano-trabeculae. CONCLUSIONS: Small nano-trabeculae promoted osteoblastic differentiation more than large nano-trabeculae when combined with meso-scale spikes. However, the biological impact of different nano-trabeculae was relatively small compared with that of different dimensions of meso-spikes.