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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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Photo-Modification of Melanin by a Mid-Infrared Free-Electron Laser
摘要： Melanin is rigidly constructed by several nitrogen-containing aromatic rings, and its excess accumulation in skin tissue is closely associated with melanosis. Although visible lasers (wavelength: 600–1000 nm) are conventionally used for the photo-thermolysis of melanocyte, several pigmented nevi are difficult to be treated. Here, we propose an alternate method for targeting the molecular structure of melanin using an infrared free electron laser (FEL) tuned to 5.8 μm that corresponds to the stretching vibrational mode of carboxylate group. A drastic morphological change on the black-colored surface of melanin powder were observed after the pulse irradiation with a power of 500 mJ/cm2, and the minimum irradiation time for damage to the morphology was 1.4 seconds. Analyses by mass spectroscopy, infrared spectroscopy, and 13C-nuclear magnetic resonance implied that a pyrrole group was removed by the FEL irradiation. In addition, the FEL irradiation dispersed almost all of the melanoma cells from a culture solution without any influence on other ingredients in the medium, and one-cell analysis by infrared microscopy showed that the structure of melanoma could be substantially damaged by the irradiation. This study proposes the potency of intense mid-infrared laser as novel alternative way to reduce melanin.
关键词： Infrared free electron laser,Melanoma,Vibrational mode,Melanin,Photo-modification
更新于2025-11-21 11:03:13
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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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UV-ozone induced surface passivation to enhance the performance of Cu2ZnSnS4 solar cells
摘要： Interface property has been considered one of the most critical factors affecting the performance of semiconductor devices. In this work, we demonstrate an efficient surface passivation for the interface between Cu2ZnSnS4 (CZTS) and CdS buffer layer by using UV-ozone treatment at room temperature. The passivation led to a significant enhancement of short circuit current density (Jsc) of the device from 11.70 mA/cm2 to 18.34 mA/cm2 and thus efficiency of the CZTS solar cells from 3.18% to 5.55%. The study of surface chemistry has revealed that the UV-ozone exposure led to formation of a Sn–O rich surface on CZTS, which passivates the dangling bonds and forms an ultra-thin energy barrier layer at the interface of CZTS/CdS. The barrier is considered to be responsible for the reduction of non-radiative recombination loss in the solar cells as confirmed by photoluminescence (PL) measurement. The elongated lifetime of minority carriers in the CZTS solar cells by time-resolved PL has further verified the interface passivation effect induced by UV-ozone treatment. This work provides a fast, simple yet very effective approach for surface passivation of CZTS film to boost the performance of CZTS solar cells.
关键词： CZTS solar cell,UV-Ozone treatment,Interface modification,Surface passivation
更新于2025-11-21 11:01:37
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Spray pyrolysis synthesis of mesoporous TiO2 microspheres and their post modification for improved photocatalytic activity
摘要： Mesoporous TiO2 microspheres were prepared by spray pyrolysis for photocatalysis. Post modification of TiO2 by heat treatment was performed to optimize its photocatalytic performance. First, spherical TiO2 particles with mesoporous structure were synthesized at pyrolysis temperatures of 500, 600, and 700 oC. After characterization by XRD, SEM, and N2 adsorption, a sample prepared at 500 oC was found to possess desirable properties for photocatalytic performance through post-modification. In methylene blue degradation, mesoporous TiO2 microspheres synthesized at 500 oC outperformed other microspheres. Furthermore, samples obtained by spray pyrolysis at 500 oC were calcined at various temperatures as a post-modification process. The sample calcined at 350 oC showed improved photocatalytic activity due to optimal anatase crystallinity and surface area.
关键词： Spray Pyrolysis,MB Degradation,Post Modification,Mesoporous TiO2 Spheres
更新于2025-11-21 10:59:37
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Latent fingermark detection using functionalised silicon oxide nanoparticles: Method optimisation and evaluation
摘要： The application of nanoparticles for latent fingermark detection has been reported in the literature over the past two decades. One of the nanoparticles that shows promise to become a routine technique is functionalised silicon oxide nanoparticles (SiO2 NPs). In a recent optimisation of the technique, the use of carboxyl-functionalised SiO2 NPs doped with luminescent ruthenium complex was proposed as a breakthrough for latent fingermark detection. In this study, the aforementioned functionalised SiO2 NPs were extensively evaluated. Modification and optimisation of the original detection parameters were performed to enhance detection quality and improve applicability. Various detection parameters were evaluated and assessed. A lower concentration of the functionalised nanoparticles used in the colloidal dispersion was determined to offer improved detection effectiveness. A combination of increased bath temperature and reduced immersion time was found to produce good overall results. A set of modified detection parameters was suggested for the use of the functionalised SiO2 NPs to detect latent fingermarks. Performance of the modified detection parameters was compared against that of the published detection method. Comparison experiments were carried out on fingermark specimens deposited on aluminium foil, transparent polypropylene plastic and green polyethylene plastic. Three donors (weak, average and strong) and two age intervals (ten days and three months) were considered in the comparison study. Evaluation of the results suggested that the overall performance of the modified method for latent fingermark detection was superior to that obtained using the previously published detection parameters.
关键词： Bath temperature,Detection effectiveness,Method modification,Colloidal,Surface functionalisation,Luminescence technique
更新于2025-11-19 16:46:39
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Interface modified flexible printed conductive films via Ag <sub/>2</sub> O nanoparticle decorated Ag flake inks
摘要： A new approach to stable, low resistance inexpensive printed flexible conductive inks is proposed. Silver inks have been extensively studied and commercialized for applications in printed electronics due to the inherent high conductivity and stability of silver, even in particulate-based percolation networks processed at temperatures compatible with low cost polymer films such as polyethylene terephthalate (PET). Recent interest in flexible and even stretchable circuits, however, has presented new challenges for particle-based inks as mechanical strains can result in the opening of critical particle-to-particle contacts. Here we report a facile, low cost method for the single step synthesis of stable, printable nanoscale Ag2O-decorated Ag flake inks which can be converted to highly conductive Ag films at 150°C curing temperature without the use of limited shelf life organometallics or low metal loading nanoparticles to modify the interface between silver flakes. Analysis indicate that decoration of Ag flakes with Ag2O nanoparticles (NPs) during ink synthesis improves the conductivity and flexibility of printed silver films by forming bridging interconnections between Ag flakes after low temperature reduction of the Ag2O NPs. In this work, printed nano-decorated silver conductors with starting oxide to metal weight ratios of 5:95 exhibited lateral resistivities lower than 1.5×10-5 ? cm, which was 35% less than films derived from undecorated Ag flake inks of the same total Ag loading and binder system. This resistivity difference increased to 45% after cyclic bend testing showing increased resilience to repeated flexing for the nano-decorated inks. Through detailed compositional and morphological characterizations, we demonstrate that such improved conductivity and flexibility is due to a more effective bridging afforded by the in-situ synthesized Ag NPs on the surface of Ag flakes. These properties, combined with the simplified syntheses method of the nano-ink, make the material a viable, advantageous alternative to the limited number of stretchable conductors currently available.
关键词： Ag2O nanoparticle-decorated Ag flake inks,printed conductive films,interface modification,silver ink
更新于2025-11-14 17:04:02
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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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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