Noppakun Sanpo

Biocompatibility of transition metal-substituted cobalt ferrite nanoparticles

Transition metals of copper, zinc, manganese, and nickel were substituted into cobalt ferrite nanoparticles via a sol–gel route using citric acid as a chelating agent. The microstructure and elemental compositions of the nanoparticles were characterized using scanning electron microscopy combined with energy dispersive X-ray spectroscopy. The particle size of the nanoparticles was investigated using particle size analyzer, and the zeta potentials were measured using zeta potential analyzer. The phase components of the synthesized transition metal-substituted cobalt ferrite nanoparticles were studied using Raman spectroscopy. The biocompatibility of the nanoparticles was assessed using osteoblast-like cells. Results indicated that the substitution of transition metals strongly influences the physical, chemical properties, and biocompatibility of the cobalt ferrite nanoparticles.

Transition metal-substituted cobalt ferrite nanoparticles for biomedical applications

Transition metals of copper, zinc, chromium and nickel were substituted into cobalt ferrite nanoparticles via a sol-gel route using citric acid as a chelating agent. The microstructure and elemental composition were characterized using scanning electron microscopy combined with energy-dispersive X-ray spectroscopy. Phase analysis of transition metal-substituted cobalt ferrite nanoparticles was performed via X-ray diffraction. Surface wettability was measured using the water contact angle technique. The surface roughness of all nanoparticles was measured using profilometry. Moreover, thermogravimetric analysis and differential scanning calorimetry were performed to determine the temperature at which the decomposition and oxidation of the chelating agents took place. Results indicated that the substitution of transition metals influences strongly the microstructure, crystal structure and antibacterial property of the cobalt ferrite nanoparticles.

Microstructural and antibacterial properties of zinc-substituted cobalt ferrite nanopowders synthesized by sol-gel methods

Zinc-substituted cobalt ferrite nanopowders were prepared via a sol-gel route using citric acid as a chelating agent. The influence of zinc concentration on the microstructure, crystal structure, surface wettability, surface roughness, and antibacterial property of zinc-substituted cobalt ferrite nanopowders was investigated systematically. The substitution of zinc influences slightly the microstructure, surface wettability, surface roughness, and crystal structure but strongly affects the antibacterial property of the cobalt ferrite nanopowders.

Thermal Spray Maps: Material Genomics of Processing Technologies

There is currently no method whereby material properties of thermal spray coatings may be predicted from fundamental processing inputs such as temperature-velocity correlations. The first step in such an important understanding would involve establishing a foundation that consolidates the thermal spray literature so that known relationships could be documented and any trends identified. This paper presents a method to classify and reorder thermal spray data so that relationships and correlations between competing processes and materials can be identified. Extensive data mining of published experimental work was performed to create thermal spray property-performance maps, known as “TS maps” in this work. Six TS maps will be presented. The maps are based on coating characteristics of major importance; i.e., porosity, microhardness, adhesion strength, and the elastic modulus of thermal spray coatings.

Sol-Gel Synthesized Copper-Substituted Cobalt Ferrite Nanoparticles for Biomedical Applications

Copper-substituted cobalt ferrite nanoparticles were prepared via a sol-gel route using citric acid as a chelating agent. The influence of copper concentration on the microstructure, crystal structure and antibacterial property of copper-substituted cobalt ferrite nanoparticles against E. coli and S. aureus has been systematically investigated. The results indicate that the substitution of copper influences strongly the microstructure, crystal structure, particle diameter and antibacterial property of cobalt ferrite nanoparticles.

Effect of Zinc Substitution on Microstructure and Antibacterial Properties of Cobalt Ferrite Nanopowders Synthesized by Sol-Gel Methods

Zinc substituted cobalt ferrite nanopowders with the general formula Co(1-x)ZnxFe2O4(with x = 0, 0.3, 0.5, 0.7, and 1) were prepared via the sol-gel route using citric acid as a chelating agent. The influence of zinc concentration on the microstructure, crystal structure and antibacterial property of zinc substituted cobalt ferrite nanopowders has been systematically investigated. The microstructure and elemental composition were characterized using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX), respectively. Phase analysis of cobalt ferrite nanopowders was performed using X-ray diffractometry (XRD). The antibacterial properties of zinc substituted cobalt ferrite nanopowders were investigated. The results indicate that the substitution of zinc influences strongly the microstructure, crystal structure and antibacterial property of the cobalt ferrite nanopowders.

Solution Precursor Plasma Spray System

Suspension and solution thermal spraying technology, an attractive technique in coating technology, has been used for depositing nano-structured coatings. It is technically difficult to feed powders of particle size less than 5-10 μm due to the effect of surface forces on powder flow. In the newly-developed suspension plasma spray (SPS) process, nano-sized particles are suspended in a liquid before being injected into the plasma plume; thus circumventing the normal feeding methods. Similarly, the solution precursor plasma spray (SPPS) process deposits melted feedstock onto a substrate as splats. The difference between SPPS and SPS processes is the nature of the feedstock material. The SPPS and SPS methods combine the simplicity and high through-put of the plasma spray process with versatility and economics of the spray pyrolysis process to produce the desired nanostructured materials [14].

New approaches to the study of spinel ferrite nanoparticles for biomedical applications

This chapter is prepared into six different sections. The first part will provide a brief introduction of spinel ferrite nanoparticles synthesis, the use of chelating agents in the sol-gel method, and applications of spinel ferrite nanoparticles in biomedical fields. The second part will cover an overview of the structure and magnetism of spinel ferrites. The third part will present a summary of different types of chelating agents. The fourth part will provide information of the sol-gel synthesis for ceramic nanoparticles. The fifth part will focus on the preparation of cobalt ferrite nanoparticles by sol-gel methods using polyvinyl alcohol (PVA) and citric acid (CA) as chelating agents. The influence of chelating agents on the physical properties and antibacterial property of cobalt ferrite nanoparticles will be highlighted in the last part. A discussion on chelating agent-metal ion formation and the antibacterial mechanisms of spinel ferrite nanoparticles will be presented.

Development of Thermal Spray Map for Liquid Feeding Thermal Spray System

This research work exhibits a procedure to classify and reorder thermal spray data point so that relationships and correlations between competing processes and materials can be identified. The broad range data mining of published experimental work was performed to create thermal spray map (TS map). A single TS map displayed the correlation between standoff distance (SOD) and feeding particle size is mainly focused. The discussion and evaluation of TS map was taken place. These data mining could be useful to use and/or adapt as reference points for the thermal spray experiment set up in the future.

Antimicrobial Property of Cold-Sprayed Transition Metals-Substituted Hydroxyapatite/PEEK Coating

The antibacterial property of several types of transition metals such as silver, nickel, zinc, and copper substituted hydroxyapatite (HA) composite coatings was investigated against staphylococcus aureus (S. aureus). Microstructural characterization and phase analysis of feedstock powders and as-deposited coatings were carried out using scanning electron microscope (SEM) and energy-dispersive X-ray spectroscopy (EDX). Transition metals-substituted hydroxyapatite/PEEK coatings were successfully deposited using cold spraying parameters of 10-14 bars at preheated air temperature between 150 and 160 °C. The results indicated that copper substituted hydroxyapatite showed the best antimicrobial property against S. aureus.