Jhunu Chatterjee

Polyethylene magnetic nanoparticle: a new magnetic material for biomedical applications

Polyethylene magnetic nanoparticles were synthesized by nonsolvent and temperature induced crystallization along with ultrasonication. Low molecular weight polyethylene wax and maghemite were used for forming the composite particles. These particles were further coated with avidin. The nanoparticles are characterized using STEM, AFM and SQUID. Nanomagnetic particles were found to have two distinct morphologies and have superparamagnetic properties.

Modification and characterization of polystyrene-based magnetic microspheres and comparison with albumin-based magnetic microspheres

Polystyrene- and albumin-based magnetic microspheres for red blood cell separation were modified and characterized by scanning electron and atomic force microscopy. Albumin microspheres show higher coupling efficiency with the protein, and protein-modified albumin microspheres bind the red blood cells more efficiently than the polystyrene-based microspheres.

Physically synthesized Ni-Cu nanoparticles for magnetic hyperthermia

BackgroundIn this paper, a physical method to prepare copper-nickel alloy particles in the sub-micron range for possible self controlled magnetic hyperthermia treatment of cancer is described. It is reported that an increase in tumor temperature decreases the tumor resistance to chemo- and radiation therapies. Self controlled heating at the tumor site to avoid spot heating is managed by controlling the Curie temperature of the magnetic particles. The process described in this paper to produce the nanomagnetic particles allows for a large scale production of these particles.MethodsThe process used here is mainly composed of melting of the Cu-Ni mixture and ball milling of the resulted bulk alloy. Both mechanical abrasion and continuous grinding were used to break down the bulk amount into the desired particle size.ResultsIt was found that the desired alloy is composed of 71% nickel and 29% copper by weight. It was observed that the coarse sand-grinded powder has a Curie temperature of 345 K and the fine ball-milled powder shows a temperature of 319 K – 320 K.ConclusionSelf regulating magnetic hyperthermia can be achieved by synthesizing nanomagnetic particles with desired Curie temperature. In this study the desired range of Curie temperatures was obtained by combination of melting and ball milling of nickel-copper alloy.

A biocompatible magnetic film: synthesis and characterization.

BackgroundBiotechnology applications of magnetic gels include biosensors, targeted drug delivery, artificial muscles and magnetic buckles. These gels are produced by incorporating magnetic materials in the polymer composites.MethodsA biocompatible magnetic gel film has been synthesized using polyvinyl alcohol. The magnetic gel was dried to generate a biocompatible magnetic film. Nanosized iron oxide particles (γ-Fe2O3, ~7 nm) have been used to produce the magnetic gel.ResultsThe surface morphology and magnetic properties of the gel films were studied. The iron oxide particles are superparamagnetic and the gel film also showed superparamagnetic behavior.ConclusionMagnetic gel made out of crosslinked magnetic nanoparticles in the polymer network was found to be stable and possess the magnetic properties of the nanoparticles.

Fabrication of functionalized carbon nanotube buckypaper electrodes for application in glucose biosensors.

A highly sensitive glucose detection method was developed using functionalized carbon nanotube buckypaper as a free standing electrode in an electrochemical biosensor. Glucose oxidase was immobilized onto various buckypaper samples in order to oxidize glucose resulting in a measureable current/voltage signal output of the biosensor. Cyclic voltammetry (CV) and amperometry were utilized to determine the sensitivity of these buckypaper electrodes. Sensors of three different types of buckypaper were prepared and compared. These modified buckypaper electrode-based sensors showed much higher sensitivity to glucose compared to other electrochemical glucose sensors.

Synthesis of Polyethylene Magnetic Nanoparticles

ABSTRACT Very low molecular weight polyethylene (average MW 700 g/mole) magnetic nanocomposite particles were synthesized by nonsolvent and temperature induced crystallization along with ultrasonication. The particles are further coated with poly dl-lactic acid to functionalize the polyethylene particles for biomedical applications. A solvent-nonsolvent emulsion was made with polyethylene and surface modified iron oxide and was raised to very high temperature followed by rapid cooling. Decalin and octamethylcyclotetrasiloxane (OMCTS) were used as solvent and tetraglyme as nonsolvent. The synthesized particles were found to have two different types of morphology. Particles sizes can be varied depending on the choice of solvent, polymer concentration and amplitude of ultrasonication. The composite particles were characterized by scanning transmission electron microscopy. Magnetic properties of the composite particles were also studied.

NANOMAGNETICS IN BIOTECHNOLOGY

Applications of nanomagnetic particles in cell separation and magnetic hyperthermia are presented here. In general, biological cells are weakly paramagnetic or diamagnetic. Therefore, to enhance the magnetic susceptibility of the biological cells to interact with an applied magnetic field, nanoto micron-sized magnetic particles are tagged to the biological cells. Nano-size magnetic particles are produced in-house for various biomagnetic applications.

Studies on Electrochemical Properties of Functionalized CarbonNanotube Bucky Paper Electrodes for Biosensor Applications

This paper investigates the effect of different conditions for conventional acid functionalization of carbon nanotubes in order to fabricate most uniform buckypaper with enhanced electrochemical properties for biosensor applications. This study compares the electrochemical properties of those electrodes in regard to detection of a biomolecule, dopamine. Carbon nanotubes (CNT) due to its inherent structures are difficult to be dispersed in any solvent. This hinders its application in many different areas in spite of its unique electrical, mechanical and chemical resistant properties. However functionalization of CNTs with different chemical groups helps to form a homogeneous dispersion which show enhanced properties when applied in dispersion or as film. In this work multi-walled carbon nanotubes are modified with mixture of strong acids under different conditions to impart functionality in nanotubes. Further thin sheets, commonly known as buckypapers are fabricated and have been used as electrodes in electrochemical biosensors. Their electrochemical properties are compared in electrochemical sensing system for a biomolecule, dopamine, a neurotransmitter and a biomarker for Parkinson’s disease. Thermal characterizations, structural characterizations and electrochemical activity of modified CNT buckypapers towards dopamine are presented in this article.

Development of Nano-Microtechnology and Biomedical Applications

Blood, air and water are not only most abundant but also the most important fluids on the earth. Each adult human carries almost a gallon of blood every moment. This paper concerns with the treatment of the blood and discusses in particular the blood cell separation (fluids engineering) and the safe elevation of the body temperature (thermal engineering). Unlike air and water the blood is a biological fluid. Therefore it comes with the complexity of blood composition and disorder of the blood affecting human life and health. This study presents applications of electro-magnetic field on nanomagnetic particles that attach to the blood cells in creating complex fluid dynamic cell separation from the whole blood and creating complex thermal heating, magnetic hyperthermia, for potential use in cancer treatment. In general, biological cells are weak paramagnetic or diamagnetic. Therefore nano-microtechnologies are developed to attach the nanoparticles to the selected cells and to enhance the magnetic susceptibility of the cells to interact with an applied magnetic field. The paper demonstrates that nano to micron size magnetic particles are tagged to the biological cells.Copyright