Biosensors - A Global Market Overview

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Traditionally, magnetism is a physical property that has been linked to metals such as iron, nickel and cobalt. Despite this, over the recent past, researchers have been perplexed with weak signs of magnetism as displayed by graphite, an organic mineral that comprises stacks of individual carbon sheets. The quest for enlightenment of this strange property of graphite has had its fair share of controversies, with each research group putting forward its own theories. The latest evocation has been proposed in the EPL (Europhysics Letters) journal by a research group from the University of Manchester that includes a Nobel prize-winning scientist.

This group has established that magnetism in several commercially available graphite crystals boils down to micron-sized clusters principally comprising iron, which would be extremely intricate in detection but for using appropriate instruments in a specific method. Determining a technique to enhance graphite’s magnetic properties would be of immense help in using it as a biocompatible magnet in the medical and biological fields as an efficient biosensor.

To achieve this, the researchers have initially cut up a piece of commercially-available graphite into four sections, measuring the magnetization of each piece. Much to their amazement, the researchers observed sizeable deviations in the magnetism of each sample, enabling them to reason out that external factors, such as small impurities of another material, were the cause of this magnetic response.

Confirmation of this theory was carried out by deeply examining the structure of the samples with a scanning electron microscope (SEM), an extremely powerful microscope capable of imaging samples by scanning them with a beam of electrons, with the result showing the presence of unusually heavy particles positioned deep under the surface. Using a technique called X-ray microanalysis, a major chunk of these particles was validated as iron and titanium. The presence of oxygen, too, meant that the particles were either magnetite or titanomagnetite, both of which are magnetic.

Further research has revealed as to how many magnetic particles would be required and how far apart would they be needed to be spaced so as to create the originally observed magnetism. Experimental observations have clarified the group’s estimations, implying that the visualized magnetic particles could justify the sample’s entire magnetic signal. If creating and controlling magnetism in an organic carbon-based material, such as graphene, could be ascertained, this would constiitute a major step forward in the fields of sensors and spintronics.