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Novel strategy for fabrication of sensing layer on thiol-functionalized fiber-optic tapers and their application as SERS probes
摘要： This work presents a new strategy to fabricate optical fiber surface-enhanced Raman scattering (SERS) probes with high-performance remote sensing prepared by thiol functionalization of silica fiber taper, and further in situ nucleation and growth of silver nanoparticles (AgNPs). The prepared fiber probes can effectively identify the analyte 4-aminothiophenol (4-ATP) with a limit of detection (LOD) as low as 2.15×10-11 M using a portable commercial Raman spectrometer. Simultaneously, such fiber probes have shown a good reproducibility with the relative standard deviation (RSD) value of 7.6%, and possessed high signal stability at room temperature over one month. Furthermore, this approach provides new insight into the fabrication of fiber SERS probe integrated the advantages in terms of sensitivity, reproducibility and stability, which shows great potential for practical SERS applications.
关键词： Thiol functionalization,SERS performance,Probe,Silver nanoparticles,Optical fiber
更新于2025-09-23 15:21:01
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Growth mechanisms of F4-TCNQ on inorganic substrates and nanostructures
摘要： The organic semiconductor tetrafluorotetracyanoquinodimethane (F4-TCNQ) is a promising candidate for the doping of organic semiconductors, two-dimensional materials and inorganic compounds, such as ZnO, and also to enhance the charge carrier injection at contacts in organic electronics. In order to evaluate its applicability as a functionalization material or as an electrically active part in devices, we present a systematic study on the growth mode of F4-TCNQ beyond the first few monolayers on different inorganic substrates that cover a broad variety regarding their physical, chemical and morphological surface properties. The materials used are silicon, silicon carbide, graphene on silicon, sapphire, nanocrystalline diamond, as well as gallium nitride (GaN) layers and nanowire arrays. While the surface termination influences the shape and morphology of the islands of F4-TCNQ which form on all substrates investigated, no significant dependence of the growth mode on the substrate doping type and concentration is observed. GaN nanowires are found to act as nucleation sites for F4-TCNQ islands and to be covered by few monolayers of F4-TCNQ forming a closed coaxial shell. In conclusion, F4-TCNQ is identified to nucleate via Stranski-Krastanov growth consisting of monolayers and islands of different size and shape. The findings in this work provide basic growth information for the implementation of F4-TCNQ as functionalization material for nanowire-based applications.
关键词： GaN nanowires,surface functionalization,growth mode,organic semiconductors,organic electronics,surface doping,F4-TCNQ
更新于2025-09-23 15:21:01
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Alkyne Functionalization of a Photoactivated Ruthenium Polypyridyl Complex for Click-Enabled Serum Albumin Interaction Studies
摘要： Studying metal-protein interactions is key for understanding the fate of metallodrugs in biological systems. When a metal complex is not emissive and too weakly bound for mass spectrometry analysis, however, it may become challenging to study such interactions. In this work a synthetic procedure was developed for the alkyne functionalization of a photolabile ruthenium polypyridyl complex, [Ru(tpy)(bpy)(Hmte)](PF6)2, where tpy = 2,2′:6′,2′′-terpyridine, bpy = 2,2′-bipyridine, and Hmte = 2-(methylthio)ethanol. In the functionalized complex [Ru(HCC-tpy)(bpy)(Hmte)](PF6)2, where HCC-tpy = 4′-ethynyl-2,2′:6′,2′′-terpyridine, the alkyne group can be used for bioorthogonal ligation to an azide-labeled fluorophore using copper-catalyzed “click” chemistry. We developed a gel-based click chemistry method to study the interaction between this ruthenium complex and bovine serum albumin (BSA). Our results demonstrate that visualization of the interaction between the metal complex and the protein is possible, even when this interaction is too weak to be studied by conventional means such as UV?vis spectroscopy or ESI mass spectrometry. In addition, the weak metal complex-protein interaction is controlled by visible light irradiation, i.e., the complex and the protein do not interact in the dark, but they do interact via weak van der Waals interactions after light activation of the complex, which triggers photosubstitution of the Hmte ligand.
关键词： ruthenium polypyridyl complex,click chemistry,bovine serum albumin,photoactivation,alkyne functionalization,metal-protein interactions
更新于2025-09-23 15:21:01
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Surface functionalization by laser-induced periodic surface structures
摘要： In recent years, the improved understanding of the formation of laser-induced periodic surface structures (LIPSS) has led to an emerging variety of applications that modify the optical, mechanical, and chemical properties of many materials. Such structures strongly depend on the laser beam polarization and are formed usually after irradiation with ultrashort linearly polarized laser pulses. The most accepted explanation for the origin of the structures is based on the interference of the incident laser radiation with electromagnetic surface waves that propagate or scatter at the surface of the irradiated materials. This leads to an intensity modulation that is finally responsible for the selective ablation in the form of parallel structures with periods ranging from hundreds of nanometers up to some micrometers. The versatility when forming such structures is based on the high reproducibility with different wavelengths, pulse durations and repetition rate laser sources, customized micro- and nanometric spatial resolutions, and compatibility with industrially relevant processing speeds when combined with fast scanning devices. In this contribution, we review the latest applications in the rapidly emerging field of surface functionalization through LIPSS, including biomimetic functionalities on fluid transport, control of the wetting properties, specific optical responses in technical materials, improvement of tribological performance on metallic surfaces, and bacterial and cell growth for medical devices, among many others.
关键词： applications,laser processing,surface functionalization,laser-induced periodic surface structures (LIPSS)
更新于2025-09-23 15:21:01
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Graphene Quantum Dot Oxidation Governs Noncovalent Biopolymer Adsorption
摘要： Graphene quantum dots (GQDs) are an allotrope of carbon with a planar surface amenable to functionalization and nanoscale dimensions that confer photoluminescence. Collectively, these properties render GQDs an advantageous platform for nanobiotechnology applications, including optical biosensing and delivery. Towards this end, noncovalent functionalization offers a route to reversibly modify and preserve the pristine GQD substrate, however, a clear paradigm has yet to be realized. Herein, we demonstrate the feasibility of noncovalent polymer adsorption to GQD surfaces, with a specific focus on single-stranded DNA (ssDNA). We study how GQD oxidation level affects the propensity for polymer adsorption by synthesizing and characterizing four types of GQD substrates ranging ~60-fold in oxidation level, then investigating noncovalent polymer association to these substrates. Adsorption of ssDNA quenches intrinsic GQD fluorescence by 31.5% for low-oxidation GQDs and enables aqueous dispersion of otherwise insoluble no-oxidation GQDs. ssDNA-GQD complexation is confirmed by atomic force microscopy, by inducing ssDNA desorption, and with molecular dynamics simulations. ssDNA is determined to adsorb strongly to no-oxidation GQDs, weakly to low-oxidation GQDs, and not at all for heavily oxidized GQDs. Finally, we reveal the generality of the adsorption platform and assess how the GQD system is tunable by modifying polymer sequence and type.
关键词： molecular dynamics simulations,Graphene quantum dots,oxidation level,ssDNA,adsorption,noncovalent functionalization,fluorescence quenching
更新于2025-09-23 15:21:01
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Solution-Based Property Tuning of Black Phosphorus
摘要： The air instability of black phosphorus (BP) severely hinders the development of its electronic and optoelectronic applications. Although a lot of effort has been made to passivate it against degradation in ambient conditions, approaches to further manipulate the properties of passivated BP are still very limited. Herein, we report a simple and low-cost chemical method that can achieve BP passivation and property tailoring simultaneously. The method is conducted by immersing a BP sample in the solution containing both 2,2,6,6-tetramethylpiperidinyl-N-oxyl (TEMPO) and triphenylcarbenium tetrafluorobor in a mixture of water and acetone (v/v = 1:1). After the treatment, the BP sample is functionalized with TEMPO, which not only efficiently passivates BP but also p-dopes BP to a degenerated density level of 1013 cm?2. The performance of the BP field effect transistor is improved after functionalization with a high Ion/Ioff ratio of 106 and carrier mobility of 881.5 cm2/(V·s). The functionalization-induced doping also significantly reduces the contact resistance between BP and the Cr/Au electrode to 0.97 kΩ·μm. Additionally, we observe a great reduction of BP electrical and optical anisotropies after functionalization. This chemical functionalization method provides a viable route to simultaneously passivate and tune the properties of BP.
关键词： p-type doping,anisotropy,functionalization,black phosphorus,contact resistance
更新于2025-09-23 15:21:01
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Spatially resolved covalent functionalization patterns on graphene
摘要： Spatially resolved functionalization of 2–D materials is highly demanded but very challenging to achieve. The chemical patterning is typically tackled by preventing contact between the reagent and material, with various accompanying challenges. Photochemical transformation on the other hand inherently provides remote high spatiotemporal resolution using the cleanest reagent – a photon. Here, we combine two competing reactions on a graphene substrate to create functionalization patterns on a micrometre scale via the Mitsunobu reaction. The mild reaction conditions allow introduction of covalently dynamic linkages, which can serve as reversible labels for surface- or graphene-enhanced Raman spectroscopy characterization of the patterns prepared. The proposed methodology thus provides a pathway for local introduction of arbitrary functional groups on graphene.
关键词： patterned functionalization,Mitsunobu reaction,photochemistry,graphene,Raman spectroscopy
更新于2025-09-23 15:21:01
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[Springer Series on Polymer and Composite Materials] Polymer/POSS Nanocomposites and Hybrid Materials (Preparation, Properties, Applications) || Synthesis Routes of POSS
摘要： The study of the chemistry of materials containing Si–O bonds was in the past mainly applied to both inorganic silica and minerals or to organic silicones ?eld in which the R2SiO unit dominates. However, in the last decade, the ?eld of silsesquioxane chemistry with general composition RSiO3/2 has grown dramatically and many structures have been proposed in the literature. The idea of this chapter is to make an overview of the main synthetic approaches used to prepare completely and partially polyhedral oligomeric silsesquioxanes (POSS), highlighting the advantages and the weakness of each procedure. A brief description of the characterization techniques used to analyze the physicochemical properties of POSS was also carried out.
关键词： Hydrosilylation,Functionalization,Close-cage POSS,POSS synthesis,Open-cage POSS,Polyhedral oligomeric silsesquioxanes,Corner capping,Cleavage
更新于2025-09-23 15:21:01
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[NanoScience and Technology] Silicene (Prediction, Synthesis, Application) || Surface Functionalization of Silicene
摘要： For two-dimensional (2D) materials, an attractive feature is that all the atoms of the materials are exposed on the surface. Thus tuning the structure and properties by surface treatments becomes straightforward. Similar as graphene, the nearly zero-gap character of silicene hinders its applications in electronic and optoelectronic devices. In the case of graphene, functionalization through hydrogenation, halogenation, oxidation, have been widely explored in order to modify the electronic structure of graphene. However, the stable aromatic π-bond network of graphene makes it very inert and difficult to bond with foreign atoms. For example, hydrogen atoms on graphene usually form clusters instead of an ordered structure. In contrast, silicene possesses hybrid sp2-sp3 bonding, which is more readily to be modified or functionalized. Since the early stage of silicene research, theoretical investigations on the hydrogenation, halogenation, and oxidation of silicene have been widely reported in literature. Recently, increasing experimental successes have been achieved on functionalization of silicene. It is now imperative to review the progresses in the fast-growing field. In this chapter, we will discuss hydrogenation, halogenation oxidization individually. In each section, we first describe those theoretical predictions and then illustrate recent experimental successes. Finally, we will give some overview and outlook of this field.
关键词： electronic structure,silicene,functionalization,halogenation,2D materials,hydrogenation,oxidation
更新于2025-09-23 15:21:01
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Synthesis, characterization, and cytotoxicity assessment of N-acetyl-L-cysteine capped ZnO nanoparticles as camptothecin delivery system
摘要： The chemical stability, good biocompatibility and high drug loading capacity of zinc oxide nanoparticles (ZnO NPs) and their biomedical potentials make them a promising candidate for drug delivery. The aim of this study was to develop and assess a simple procedure for surface functionalization of ZnO NPs by N-acetyl-L-cysteine (NAC) for anticancer camptothecin (CPT) delivery. NAC capped ZnO NPs were successfully made using ZnCl2 and NaOH in the presence of NAC. CPT was covalently conjugated to the surface of as-synthesized ZnO-NAC NPs. To characterize the synthesized conjugate product (ZnO-NAC-CPT NPs), X-ray diffraction, Fourier Transform Infrared spectroscopy, transmission electron microscopy, scanning electron microscopy, and dynamic light scattering method were used. Our results indicated that the ZnO-NAC-CPT NPs exhibit near-spherical morphology and uniform dispersion with an average diameter of ~70 nm. The hemolysis assay showed that ZnO-NAC-CPT NPs has almost no hemolytic activity. In addition, MTT cytotoxicity assessment on A549 lung cancer cells revealed a drop of IC50 values from 1.17 μg/mL (free CPT) to 0.66 μg/mL (ZnO-NAC-CPT NPs). This result showed an augmented cancer-inhibitory effect of nanoconjugate complex. In conclusion, the novel ZnO-NAC-CPT NPs could be considered for new therapeutic endeavors.
关键词： surface functionalization,N-acetyl-L-cysteine,camptothecin,ZnO nanoparticles,cytotoxicity
更新于2025-09-23 15:21:01