Ferromagnetic carbon/graphite: from CBRN Defense to sensors applied to oncology as a promising way to detect and fight cancer and tumors/ neoplasms

Abstract

The emerging field of multifunctional sensors for different application sectors requires high sensitivity, accuracy, reproducibility, mechanical flexibility, and low cost for a wide range of applications, from medicine to security and defense. While many national defense institutions and services have developed sensors to detect chemical, biological, radiological and nuclear threats (i.e., for CBRN Defense), better sensors are needed as well as the ability to feed the right data quickly into command centers for analysis and action on threats. All these new devices depend on new material like the so-called nanocarbons, with novel properties and morphologies. For example, nanocarbons, such as graphene, are beginning to be obtained from the use of pulsed laser deposition (PLD) to manufacture sensors for the detection of substances that can be used as chemical warfare agents. On the other side of novel applications, nanostructured materials are beginning to be used in nanomedicine. This is the case of nanostructured carbon used as a drug carrier. This is the main subject of the present article. Despite all the incredible and recent advances in all technological areas, including those applied to medicine, depending on the stage of detection, cancer is still a difficult-to-treat disease associated with a negative prognosis. Each year, the American Cancer Society estimates the number of new cancer cases and deaths in the United States and compiles the most recent data on population-based cancer occurrence and outcomes. As expected, it shows that cancer is one of the leading causes of death, accounting for millions of deaths worldwide each year. All over the last decade, new techniques and methods for the prevention, diagnosis, and treatment of diseases based on new materials and new morphologies have emerged. Many of the basic technologies of medical physics are well-established, using well-understood physics principles. Clinical applications of those technologies have improved spectacularly, in many cases because of improvements in physics and engineering. In this context, new materials have been playing an important role. Carbon is starting to be one of those materials with promising applications in medicine, especially ferromagnetic carbon/graphite. The occurrence of magnetism in carbon-based materials has been the subject of many investigations and some controversy over the past four decades, given the enormous interest in the possibility of producing carbon-based magnetic materials free from metallic elements like Fe, Co, and Ni. Exactly two decades ago, in 2004, we presented to the scientific community a very low-cost chemical route to reach one of the most sought-after materials in the history of science: pure organic carbon-based magnetic material stable at room temperature. The prospect of carbon-based magnetic materials like that, has been of immense fundamental and practical importance. Information on atomic-scale features was required for a better understanding of the mechanisms leading to carbon magnetism. That came out only in 2015, when we published an article at Nature Scientific Reports, reporting strong and incontrovertible results proving that magnetism in this material was genuine and independent of the presence of any magnetic impurity. We presented experimental confirmation that its magnetism originates from defects in the atomic structure. Those results were obtained from direct measurement of the local magnetic field using ¹³C nuclear magnetic resonance associated with the numerical results obtained from DFT (Density-Functional Theory) calculations. In this review, exclusively about our own work, we describe the obtention and main properties of carbon-based nanostructured magnetic material and how it is starting to be one of those materials with promising applications in medicine.

Here, we give a comprehensive and complete view of our search looking for the obtention of this material, which is stable at room temperature and is free from metallic ferromagnetic elements. Besides its chemical obtention and properties, here we show its use from magnetic bio-hybrid matrices until the so-called MAGUS® (MAgnetic Graphite Universal System), a sensor with promising applications in oncology aiming to detect and fight cancer and tumors/neoplasms.

The paper is organized as follows: (a) in section 1 we give the scope and purpose of the article; (b) in section 2 we describe the discovery, the intrinsic nature, the nanofluid behavior, and the potential for both a drug delivery system and the use for diagnosis or imaging of carbon-based nanostructured magnetic material; (c) in section 3 we show the detailed methodology and explanation of why the methods were chosen following the same order of those topics of section 2; (d) in section 4 we show and discuss the obtained results and we answer all research open questions; and (e) in section 5 we give the conclusions. At the end, we give a list of references, most of which are our own.