Synthesis Of Gold Nanoparticles Via Laser Ablation In The Presence Of Phytoglycogen

Phytoglycogen is a naturally occurring glucose-based polymer that has promising applications in personal care, nutrition, and biomedicine. Gold nanoparticles were generated using two-step laser ablation in pure Milli-Q water (AuNP) and Milli-Q containing phytoglycogen (AuNP-Phg) and characterized for size, shape, and nanoparticle concentration. AuNP showed a unimodal distribution of diameters, peaked at 8.8 nm, but AuNP-Phg showed a bimodal distribution: smaller particles, peaked at 4.1 nm, had their growth limited by phytoglycogen; and larger particles, peaked at 7.9 nm, grew unhindered. AuNP, AuNP-Phg and AuNP mixed with phytoglycogen (AuNP+Phg) were used to catalyze the reduction of 4-nitrophenol using the Langmuir-Hinshelwood model. The dispersions had similar k, K_NP and K_BH4; however, the average surface-normalized apparent rate constant was smaller and the induction period was larger for AuNP+Phg compared to AuNP and AuNP-Phg. This suggests that phytoglycogen associates with the gold nanoparticles, preventing the reagent from reaching the catalytic site.

Nano-sized gold particles are generated by exploiting the laser ablation synthesis in solution technique (LASiS) from gold metal disc. We report on the kinetics of gold nanoparticle (AuNP) production during LASiS and the resulting size distributions. Studies were conducted as a function of laser irradiation in pure water samples, with anionic surfactants, sodium dodecylsulphate (SDS), and cationic surfactants, cetyltrimethylammonium bromide (CTAB) and cetyltrimethylammonium chloride (CTAC), in water. Our investigations provide a mechanistic insight into the laser-induced formation kinetics involved in AuNP production via 1064 nm laser irradiation in aqueous solution. This has been achieved by developing a kinetic model involving three different AuNP size regimes. Specifically, we have found that there is no apparent influence of the SDS concentration around the surfactant critical micelle concentration (CMC) on particle size during AuNP production. This is in contrast to results observed for size reduction via 532-nm irradiation where a clear CMC effect has previously been observed. [Yamada et al, J. Phys. Chem. B, 2006, 110, 11751-11756] In addition, we also explore the surface oxidation states of produced AuNPs in various surfactants using X-ray photoelectron spectroscopy (XPS). Our investigations shows the Au111 chemical oxidation state was present in produced AuNPs in high concentrations of CTAB and CTAC, but absent in those produced in pure water and SDS solution. Prior to XPS investigations on the LASiS prepared AuNPs, a study to observe the behavior of gold during irradiation of X-rays was performed. We report on the time evolution of the Au oxidation state in sodium tetrachloroaurate NaAuCl4 as a function of soft X-ray exposure time. Our investigations provide mechanistic insight into the photoreduction kinetics from Au111 to Au1 and then subsequently Au1 to Au0.We unambiguously show that XPS photoreduction occurs in stepwise fashion via the Au1 state.

In this book, the authors present current research in the study of the synthesis, optical properties and applications for cancer treatment of gold nanoparticles. Topics discussed include the use of gold nanoparticles in cancer treatment and biomedical applications to target tumors and provide detection, drug carriers, gene silencing and radiotherapy; gold nanoparticle fabrication by laser ablation technique and their optical and morphological study; gold nanoparticles for metabolite imaging; formation of gold nanoparticles inside the corona of amphiphilic triblock copolymer micelles; and the intracellular delivery of gold nanoparticles and their application in nanomedicine.

Gold nanoparticles provide a platform for the development of new and efficient diagnostic and therapeutic tools.This book offers a general guide to the synthesis and coating of gold nanoparticles. It describes the links between optical features and geometries of gold nanoparticles and provides a readily comprehensible connection in all the chapters between the geometry of gold nanoparticles and their final applications.

Gold Nanoparticles - Reaching New Heights contains recent research on the preparation, characterization, fabrication, and potential of optical and biological applications of gold nanoparticles (AuNPs). It is promising novel research that has received a lot of interest over the last few decades. It covers advanced topics on optical, physical, medicinal, and biological applications of AuNPs. Development of green nanotechnology is generating the interest of researchers towards the synthesis of eco-friendly, safe, non-toxic applications, which can be used for manufacture at a large scale. These are simple, cost-effective, stable, enduring, and reproducible aqueous room temperature synthesis applications to obtain the self-assembly of AuNPs. This potentially unique work offers various approaches to R

Gold Nanoparticles for Physics, Chemistry and Biology offers an overview of recent research into gold nanoparticles, covering their discovery, usage and contemporary practical applications.This Second Edition begins with a history of over 2000 years of the use of gold nanoparticles, with a review of the specific properties which make gold unique. Updated chapters include gold nanoparticle preparation methods, their plasmon resonance and thermo-optical properties, their catalytic properties and their future technological applications. New chapters have been included, and reveal the growing impact of plasmonics in research, with an introduction to quantum plasmonics, plasmon assisted catalysis and electro-photon conversion. The growing field of nanoparticles for health is also addressed with a study of gold nanoparticles as radiosensibiliser for radiotherapy, and of gold nanoparticle functionalisation. This new edition also considers the relevance of bimetallic nanoparticles for specific applications.World-class scientists provide the most up-to-date findings for an introduction to gold nanoparticles within the related areas of chemistry, biology, material science, optics and physics. It is perfectly suited to advanced level students and researchers looking to enhance their knowledge in the study of gold nanoparticles.

In the last decade, gold nanoparticles have provided a suitable platform for the development of novel and efficient diagnostic and therapeutic tools, which avoid the typical drawbacks of the old systems. They are biocompatible and they can be easily synthesised, encapsulated and functionalised with (bio)molecules. Nanoparticles produced by a wet chemistry synthesis have the geometry, which enables the complete control of their optical and physical properties. It is also possible to influence the targeting and stability/release behaviour by coating the nanoparticle surface. In this Update the reader can find in a single volume the methods used most often for the synthesis and coating of gold nanoparticles (spheres, cages, cubes, rods), the links between optical features and geometries of gold nanoparticles, and the novel applications in nanomedicine of gold nanoparticles determined by their geometry. One of the main objectives of this Update is to provide, a readily comprehensible connection in all the chapters between the geometry of gold nanoparticles and their final applications. Another target of this book is to provide information about efficient processes for the synthesis and the coating of gold nanoparticles, all of which have been directly tested by the author. This Update offers comprehensive information on the whole topic from the synthesis of the gold nanoparticles to their medical applications; this is accompanied by a complete and recent bibliography, in order to give to the readers the opportunity to research further the topics addressed in the book. In this way, students and researchers from academia and industry can have a complete picture of gold nanostructures, physicians and biologists can develop ideas and applications for the new nano-tools, and chemists can have a general guide to the synthesis of gold nanoparticles. This is a state-of-the-art guide for the synthesis and uses of gold nanoparticles.