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DNA Engineered Noble Metal Nanoparticles (Fundamentals and State-of-the-art-of Nanobiotechnology) || Photochemical and Photophysical Events
摘要： DNA Engineered Noble Metal Nanoparticles: Fundamentals and State-of-the-art of Nanobiotechnology. This chapter covers photochemical and photophysical events involving noble metal nanoparticles, DNA nucleobases, DNA/PNA interactions, DNA-dye conjugates, DNA-AuNP-dye conjugates, DNA-gold nanoparticle conjugates, DNA-AgNPs, and hot gold nanoparticles, discussing their applications in bioanalysis, spectroscopy, photothermal therapy, imaging, and sensing.
关键词： biosensing,nanobiotechnology,localized surface plasmon resonance,noble metal nanoparticles,photophysical events,DNA,photochemical events,photothermal therapy,fluorescence
更新于2025-09-23 15:23:52
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Optical Control of Biomimetic Nanoparticle Catalysts Based Upon the Metal Component
摘要： Nanoparticle catalysts provide an intriguing route to achieving sustainable reactivity. Recent evidence has suggested that both the underlying metallic core and the passivating ligand layer can be exploited to control reactivity. The intimate interactions between the core metal and structure of the ligand layer can change based upon the metal used to generate the catalytic particle. Through judicious selection of both components, nanoparticle catalytic systems can be designed to be stimuli responsive for controlled reactivity. Herein we demonstrate the effects of the underlying metal on the optically modulated catalytic activity of peptide-capped noble metal nanoparticles. For this, a photoswitch was incorporated into the peptide that enables reversible reconfiguration of the bioligand overlayer structure between two conformations based upon the isomerization state of the photoswitch. These changes in activity are dependent upon the inorganic metal of the particle core, and we exploit this dependence to demonstrate changes in the activity. The materials were fully characterized via spectroscopic methods and microscopy to correlate the observed reactivity to the material composition. The results provide new pathways to achieve remotely responsive catalysts that could be important for controlled multistep reactions or be exploited for other applications including biosensing and plasmonic devices.
关键词： optically modulated catalytic activity,peptide-capped noble metal nanoparticles,biosensing,Nanoparticle catalysts,photoswitch,plasmonic devices
更新于2025-09-23 15:21:21
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Laser-Induced Optoacoustic Spectroscopy Studies of Inorganic Functionalized Metallic Nanorods
摘要： Plasmonic nanoparticles can be used in photothermal therapy thanks to their ability to generate local heat. The light-to-heat conversion efficiency is crucial for therapeutic and diagnostic applications. The photothermal properties of gold nanorods functionalized with silica layers of controllable thickness were characterized using both theoretical and experimental approaches. The time-resolved laser-induced optoacoustic spectroscopy (LIOAS) was used to determine the amount of absorbed energy changed promptly into heat. The heat generation efficiencies were simulated by the means of finite integration technique. The obtained parameters were correlated with silica thickness. Experimental results are consistent with theoretical predictions, thus LIOAS is a unique reliable method for studying photothermal effect in gold nanoparticles.
关键词： noble metal nanoparticles,finite integration technique,laser-induced optoacoustic spectroscopy,surface plasmon resonance,photothermal effect
更新于2025-09-19 17:13:59
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Copper nanoparticles obtained by laser ablation in liquids as bactericidal agent for dental applications
摘要： The dramatic increase of antibiotic-resistant bacteria is considered one of the greatest threats to human health at global scale. The antibacterial activity of noble metal nanoparticles, could be the solution against bacterial infectious diseases which currently do not respond to conventional treatments. In this work, copper nanoparticles were produced by laser ablation using two different lasers. A nanosecond laser operating at 532nm and a picosecond laser at 1064nm were used to ablate a copper target submerged in water and methyl alcohol. The obtained colloidal solutions consisted of copper oxide nanoparticles in suspension with diameters ranging from few nanometers to 45 nm. The nanoparticles formation process is highly influenced by laser parameters, but the solvent plays a crucial role on their characteristics. Cu oxide nanoparticles obtained in water present chain-like nanostructure, while those obtained in methyl alcohol are spherical with lower presence of oxide. All the obtained nanoparticles are crystalline and noticeably stable. Microbiology confirm their strong activity against Aggregatibacter actinomycetemcomitans. Cytocompatibility with human periodontal ligament stem cells is also confirmed. The biological assays evidence that ions release is not the main parameter responsible for the bactericidal activity of copper nanoparticles. Other factors such as oxidation state, size and crystallographic structure, have a greater influence on the process.
关键词： noble metal nanoparticles,laser ablation,copper nanoparticles,antibacterial effect
更新于2025-09-12 10:27:22
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Comparison and convergence of optical absorption spectra of noble metal nanoparticles computed using linear-response and real-time time-dependent density functional theories
摘要： The real-time time-dependent density functional theory (RT-TDDFT) is rapidly gaining prominence as an alternative approach to capture optical properties of molecular systems, which warrants the necessity to benchmark the traditional linear response (LR) method and the RT approach. We calculate the absorption spectra of noble metal nanoparticles with a variety of sizes and shapes to demonstrate the consistency of the two methods over a broad range of energy. The RT spectrum obtained using a grid-based basis set with pseudopotentials achieves results in good agreement with the LR spectrum obtained with large QZ4P atom-centered basis sets. Factors that lead to convergence of the spectra are considered. In addition, the real-time variation of the electron density is visualized to show the collective oscillation of electron density for the plasmon modes of noble metal nanoparticles. The RT approach is most useful when calculating wide absorption spectra of larger gold or silver nanoparticles.
关键词： optical absorption spectra,noble metal nanoparticles,RT-TDDFT,LR-TDDFT,plasmon modes
更新于2025-09-10 09:29:36
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Synthesis of Fluorescent Core-Shell Metal Nanohybrids: A Versatile Approach
摘要： A ?exible way of fabricating core-shell noble metal-organic nanohybrids with tailored chemical and spectroscopic properties is proposed here. The synthetic protocol consists of a multi-step procedure able to guarantee acceptable reproducibility of core size and shape as well as control of the organic outer layer. The proposed method highlights limitations in obtaining highly controllable products, although the heterogeneity degree of the nanostructures is in line with that expected from bottom-up approaches in solution. Selective functionalization of the nanohybrids with properly-substituted ?uorescent dyes under variable experimental conditions allowed the preparation of composite systems of tunable spectroscopic properties to be employed as nanoprobes in sensing or photonic applications. To this end, preliminary investigation on embedding the nanohybrids in compatible polymeric matrices is also reported.
关键词： polymeric matrix,spectroscopic properties,core-shell architecture,noble metal nanoparticles,self-assembly
更新于2025-09-04 15:30:14
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Preparation and Use of Chemically Modified Noble Metal Nanoparticles
摘要： Papers dealing with chemical modi? cation of the surface of noble metal nanoparticles and their use in analytical and bioanalytical chemistry, pharmacology, etc., are analyzed. Grafting of a layer of preset chemical composition on the nanoparticle surface allows preparation of functional materials combining the properties of the metal core (surface plasmon resonance, enhancement of ? uorescence and nonelastic scattering) and shell (selective interaction with components of the surrounding medium). Combination of these properties opens wide prospects for using the modi? ed nanoparticles in various branches of science and engineering, primary in chemical and biochemical analysis, and also in pharmacology.
关键词： functional materials,biochemical analysis,noble metal nanoparticles,chemical analysis,chemical modi? cation of the surface
更新于2025-09-04 15:30:14