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In vitro bioactivity and biocompatibility of femtosecond laser-modified Ti6Al4V alloy
摘要： The present work investigates bioactivity and biocompatibility of femtosecond (fs) laser surface-modified Ti6Al4V alloy (Ti-alloy). Self-aligned conical surface features were generated on Ti-alloy when laser irradiated employing a Ti:sapphire pulsed fs laser of wavelength 800 nm. Modification of surface chemical composition resulting from fs-laser irradiation of Ti-alloy was examined using Grazing incidence X-ray diffraction (GIXRD) technique and micro-Raman spectroscopy. Sub-oxide phase of titanium was detected on Ti-alloy surface post-fs-laser irradiation leading to increased oxygen vacancies on sample surface. For in vitro bioactivity tests, untreated and fs-laser-treated samples were immersed in simulated body fluid for 2 weeks. Evidence of hydroxyapatite deposition on both untreated Ti-alloy, as well as, fs-laser-treated Ti-alloy surfaces after in vitro tests were provided by scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDX), GIXRD, Fourier transform infrared spectroscopy (FTIR), and micro-Raman spectroscopy. Superior growth of HAP was observed on fs-laser-modified Ti-alloy surface in comparison with untreated surface. Biocompatibility of the laser-treated Ti-alloy was investigated by studying anchoring and growth of human osteosarcoma cell line (U2OS) on it. Using MTT assay technique in vitro cell viability and growth potential in the presence of untreated and laser-treated Ti-alloy samples were assessed. MTT test results demonstrated that, neither cell viability, nor growth were affected in the presence of either the untreated or laser-treated sample surfaces. In addition, in comparison with the untreated Ti-alloy surface, the fs-laser-treated Ti-alloy surface showed more efficient cellular attachment when examined under confocal microscope.
关键词： Biocompatibility,Hydroxyapatite,Surface modification,Ti6Al4V alloy,Femtosecond laser,Bioactivity
更新于2025-11-21 11:08:12
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Coral-Like Perovskite Nanostructures for Enhanced Light-Harvesting and Accelerated Charge Extraction in Perovskite Solar Cells
摘要： A novel coral-like perovskite nanostructured layer was grown on a compact perovskite foundation layer by the facile surface modification with dimethylformamide/isopropanol (DMF/IPA) as co-solvent. Surface morphological characterizations with SEM and XRD analyses revealed a growing mechanism of the new morphology, which was composed of the perovskite decomposition and recrystallization, excessive-PbI2 extraction, and sequential formation of coral-like nanostructured perovskite layer. The coral-like perovskite nanostructures resulted in significant light scattering, enhancing the light harvesting efficiency, and thus augmenting the photocurrent density. Moreover, the geometric configuration of the perovksite solar cells was changed from planar to bulk heterojunction, which results in the acceleration of charge separation and extraction due to the high surface area at the interface between the obtained perovskite and hole-transport layers. The optimal perovskite solar cell exhibited an impressive power conversion efficiency (PCE) of 19.47%, as compared to that of the pristine cell (17.19%).
关键词： solar cells,Bulk heterojunction,light-harvesting,coral-like nanostructures,surface modification,perovskite
更新于2025-11-21 11:01:37
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Insights into the improved photocatalytic performance of fluorine surface modified mpg-C3N4 at room temperature under aqueous conditions
摘要： A novel fluorine surface modified mesoporous carbon nitride (mpg-C3N4) photocatalysts were synthesized by etching SiO2 with NH4HF2. The mechanism of formation and the factors that affect its photocatalytic activity were investigated. Interestingly, the introduction of F atoms improves the performance of surface state and widens the energy band gap of surface-modified mpg-C3N4 due to the higher separation and efficient mobility of the photoinduced carriers. Consequently, the fluorine-modified mpg-C3N4 exhibits higher carrier lifetime (8.64 ns) than mpg-C3N4 (7.14 ns), which improves the photocatalytic efficiency under ultraviolet light. The enhanced photocatalytic activity was evaluated by studying the degradation experiments of Rhodamine B. It is expected that the present fluorine modification at the surface of mpg-C3N4 may provide new insights in basic research and energy conversion.
关键词： fluorine surface modification,mpg-C3N4,room temperature,photocatalyst
更新于2025-11-14 15:28:36
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Zinc ions modified InP quantum dots for enhanced photocatalytic hydrogen evolution from hydrogen sulfide
摘要： Through direct addition of inorganic zinc ions into the solution of indium phosphide quantum dots (InP QDs) at ambient environment, we here present a facile but effective method to modify InP QDs for photocatalytic hydrogen evolution from hydrogen sulfide (H2S). X-ray diffraction patterns and transmission electron microscopic images demonstrate that zinc ions have no significant influence on the crystal structure and morphology of InP QDs, while X-ray photoemission spectra and UV–Vis diffuse and reflectance spectra indicate that zinc ions mainly adsorbed on the surface of InP QDs. Photocatalytic results show the average hydrogen evolution rate has been enhanced to 2.9 times after modification and H2S has indeed involves in the hydrogen evolution process. Steady-state and transient photoluminescence spectra prove that zinc ions could effectively eliminate the surface traps on InP QDs, which is crucial to suppress the recombination of charge carriers. In addition, the electrostatic interaction between zinc ions and the surface sulfide from InP QDs could mitigate the repulsion between QDs and sulfide/hydrosulfide, which may promote the surface oxidative reaction during photocatalysis. This work avoids the traditional harsh and complicated operations required for surface passivation of QDs, which offers a convenient way for optimization of QDs in photocatalysis.
关键词： Hydrogen sulfide,Photocatalytic hydrogen evolution,InP quantum dots,Surface modification
更新于2025-10-22 19:38:57
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Cu and Zr surface sites in photocatalytic activity of TiO2 nanoparticles: The effect of Zr distribution
摘要： The present work is focused on the role of ZrO2 modification in the performance of CuO modified TiO2. Zirconia loading leads to formation of more resistant photocatalytic layers compared to samples modified with only copper containing species. Surface modification of mixed phase TiO2 with CuO/ZrO2 improves the degradation of Reactive blue 19 dye under simulated solar irradiation. An in-depth investigation of the catalysts showed that in case of CuO/ZrO2 modification, the covering of the TiO2 surface with zirconium containing species prevents morphological and harmful energetic changes induced by copper species formed on the rutile TiO2 phase at a higher copper loading.
关键词： Hammett indicators,titanium dioxide,surface modification,XAS analysis,surface acidity
更新于2025-09-23 15:23:52
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Modification of nanocrystalline TiO <sub/>2</sub> coatings with molecularly imprinted TiO <sub/>2</sub> for uric acid recognition
摘要： Combining the surface modification and molecular imprinting technique, a novel piezoelectric sensing platform with excellent molecular recognition capability was established for the detection of uric acid (UA) based on the immobilization of TiO2 nanoparticles onto quartz crystal microbalance (QCM) electrode and modification of molecularly imprinted TiO2 (MIT) layer on TiO2 nanoparticles. The performance of the fabricated biosensor was evaluated, and the results indicated that the biosensor exhibited high sensitivity in UA detection, with a linear range from 0.04 to 45 μM and a limit of detection of 0.01 μM. Moreover, the biosensor presented high selectivity towards UA in comparison with other interferents. The analytical application of the UA biosensor confirmed the feasibility of UA detection in urine sample.
关键词： highly selective detection,uric acid biosensor,piezoelectric sensing,surface modification,molecularly imprinted TiO2
更新于2025-09-23 15:23:52
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Surface-Immobilized Conjugated Polymers Incorporating Rhenium Bipyridine Motifs for Electrocatalytic and Photocatalytic CO <sub/>2</sub> Reduction
摘要： The solar-driven conversion of CO2 to value-added products provides a promising route for solar energy storage and atmospheric CO2 remediation. In this report, a variety of supporting electrode materials were successfully modified with a [2,2′-bipyridine]-5,5′-bis(diazonium) rhenium complex through a surface-localized electropolymerization method. Physical characterization of the resulting multilayer films confirms that the coordination environments of the rhenium bipyridine tricarbonyl sites are preserved upon immobilization and that the polymerized catalyst moieties exhibit long-range structural order with uniform film growth. UV?vis studies reveal additional absorption bands in the visible region for the polymeric films that are not present in the analogous rhenium bipyridine complexes. Electrochemical studies with modified graphite rod electrodes show that the electrocatalytic activity of these films increases with catalyst loading up to an optimal value, beyond which electron and mass transport through the material become rate-limiting. Electrocatalytic studies performed at ?2.25 V vs Fc/Fc+ for 2 h reveal CO production with faradaic efficiencies and turnover numbers up to 99% and 3606, respectively. Photocatalytic studies of the modified TiO2 devices demonstrate enhanced activity at low catalyst loadings, with turnover numbers up to 70 during 5 h of irradiation.
关键词： metallopolymers,surface modification,photocatalysis,rhenium bipyridine,solar energy conversion,electrocatalysis
更新于2025-09-23 15:23:52
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Cross-linked lignin coatings produced by UV light and SF6 plasma treatments
摘要： Lignin is one of the most abundant macromolecules in vascular plants and has been studied for many years due to its high availability and low cost, regarding that lignin is the main by-product of the paper pulping process, and also typically burned as fuel. Despite that, lignin has only a few industrial applications. In this study, we found a simple method for preparing well-defined lignin surfaces. Lignin was extracted from sugar cane bagasse by Soda pulping and its coatings were prepared using solutions with different solvents on various substrates (silicon wafers, paper, steel and glass) by spin-coating. Two methods were tested in order to promote cross-linking on the surface of lignin coatings: SF6 plasma treatment and ultra-violet radiation. Both treatments reduced the amount of hydroxyl groups on the surface leading to more stable, cross-linked coatings as observed by FTIR and thermal analysis. Ultra-violet light radiation turned lignin coatings hydrophilic while stable super-hydrophobic lignin coatings were obtained using SF6 plasma.
关键词： Cross-linking,Surface modification,Coatings,Plasma,Superhydrophobicity,Lignin
更新于2025-09-23 15:23:52
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Surfactant templated oriented 1-D nanoscale platinum and palladium systems on a modified silicon surface
摘要： A templating method has been improved to form oriented one-dimensional metal nanostructures on a silicon surface. To achieve this, the silicon surface is modified with 3-aminopropyl trimethoxysilane. The cationic surfactant cetyltrimethylammonium bromide is used as a micellar template. The average width of the obtained Pt strips is 35 nm, the average width of the obtained Pd strips is 60 nm.
关键词： Platinum group,Atomic force microscopy,Surface modification,Nanostructured materials,Micelle templates
更新于2025-09-23 15:23:52
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Synergistic effect of carboxylated-MWCNTs on the performance of acrylic acid UV-grafted polyamide nanofiltration membranes
摘要： Surface modification of a commercial polyamide nanofiltration membrane was achieved by UV induced graft polymerization of acrylic acid and incorporation of carboxylated-MWCNTs (COOH-MWCNTs). The grafting process was done under different monomer concentrations and UV exposure times. The modified membranes were characterized through scanning electron microscopy (SEM), atomic force microscopy (AFM), contact angle and zeta-potential analysis, and cross-flow filtration experiments. Changes in the surface hydrophilicity, negative charge and roughness of the modified membranes improved their permeability and fouling resistance significantly. The membrane grafted with 50 g/L acrylic acid under 5 min UV exposure showed the best filtration performance including pure water flux of 38.8 L/m2 h, salt rejections of 97.43% (Na2SO4) and 93.4% (NaCl), and flux recovery ratio (FRR) of 80.2% during bovine serum albumin (BSA) filtration. After optimizing grafting condition, different amounts of COOH-MWCNTs were dispersed in the monomer solution for embedding in the grafting layer. By adding 0.2 wt% COOH-MWCNTs to the grafting layer, a water flux improvement of around 30% was observed. But, excess loading of the COOH-MWCNTs led to compaction of the grafting layer and made it inflexible and subsequently, reduced the hydrophilicity and permeability of the membrane. Fouling tests with BSA aqueous solution showed that antifouling ability of the modified membranes was remarkably improved at all concentrations of the COOH-MWCNTs. Furthermore, salt rejection results displayed that simultaneous surface modification through grafting and COOH-MWCNTs embedding could effectively improve the nanofiltration performance of the membranes in the term of permeability, desalination and fouling resistance.
关键词： Acrylic acid,Nanofiltration,Antifouling,Surface modification,Multiwalled carbon nanotube,Grafting
更新于2025-09-23 15:23:52