Foreword:

JEM Spotlight: Applications of advanced nanomaterials for environmental monitoring

Omowunmi A. Sadik

Omowunmi Sadik is a professor of Chemistry at State University of New York at Binghamton and the director of the Center for Advanced Sensors & Environmental Systems. She received her PhD in Chemistry from the University of Wollongong in Australia, and did her postdoctoral research at the US Environmental Protection Agency. Dr Sadik has held previous appointments at Harvard University, Cornell University and Naval Research Laboratories, Washington, DC. Sadik has over 290 scientific publications and presentations in the areas of biosensors, environmental and materials chemistry.

---

Nanomaterials—emerging subdisciplines that combine chemistry and material science—have enabled the development of new classes of biosensors, biochips, nanosensors, and remediation approaches. This is due to their high surface-to-volume ratios, as well as favorable electronic, optical and magnetic properties. The use of nanoscale materials for sensing purposes has seen an explosive growth in the past 5 years, since they were first reported for low-potential detection of nicotine adenine dinucleotide using carbon nanotubes-modified electrodes by J. Wang and co-workers. Since then, hundreds of research articles elucidating the use of nanomaterials for electrochemical bioassays have been published. During the same period, several review articles were published in JEM and other leading journals with a focus on the environmental applications and implications of nanotechnology.

Nanomaterials offer new possibilities for the development of novel sensing and monitoring technologies. According to the US-EPA whitepaper on nanotechnology, nanosensors can be classified under two main categories. These include: (1) sensors that are used to measure nanoscale properties; and (2) sensors that are themselves nanoscale or have nanoscale materials or components. The first category can enhance our understanding of the potential toxic effects of industrial pollutants. This is an area of critical interest to detection and risk assessment, as well as for monitoring of environmental exposure. The second category can eventually result in lower material cost, reduced weight and power consumption. Novel nanomaterials have been designed to detect very low concentrations of environmental contaminants. These materials, which possess high surface area, are capable of collecting and pre-concentrating a large number of molecules per unit volume mostly via surface adsorption. Specific control and design of materials at the molecular level may impart increased affinity, capacity, and selectivity for pollutants, thereby reducing the release of such hazardous materials to the air and water, thus enabling the protection of human health and the environment.

As the following article by Silvana Andreescu et al. shows, nanoscale materials have been used to achieve direct wiring of enzymes to electrode surfaces, to promote electrochemical reactions, to impose barcodes for biomaterials, and to amplify the signal of biorecognition events. Carbon nanotubes, metal nanoparticles, nanowires, nanorods, quantum dots and dendrimers have also been applied for gas sensing, nanoporous sorbents, inactivation of pathogenic bacteria and viruses, as well as for the adsorption and/or degradation of contaminants.

The concept of manipulating nanomaterials at the atomic and molecular level has the potential to substantially enhance environmental quality and sustainability through pollution prevention, treatment, and remediation. Nanotechnology has the potential to improve the environmental performance of existing monitoring technologies, reduce consumption of resources and energy, and allow the achievement of environmentally benign economic expansion. The applications of nanotechnology for remediation and treatment are already available and many more are likely to appear in the coming years. Nanomaterial-based remediation has enabled the design of a nanoreactor for environmental remediation of chromium (VI) to chromium (III) at 99.8% efficiency. The integration of biological-building-blocks to synthetic nanomaterials may permit the unprecedented ability to detect and manipulate a single pathogen in water.

Interest in the application of nanotechnology for environmental monitoring appears to be driven by several factors including, but not limited to, reduced costs, improved ability to selectively remove contaminants, durability, and size. JEM is leading the way in the publication of outstanding reviews, and contributing to the advancement of nanotechnology in a broad spectrum of environmental areas, including filters, catalysts, magnetic nanoparticles, and sensors. While the current application of nanomaterials for hazardous wastes may be rather limited, many researchers believe that future generations of waste treatments, bioremediation, and phytoremediation will capitalize on the new properties of nanoscale materials. Since major chemical companies and a host of other spin-off companies have started developing nanomaterials/nanomaterial-based consumer products (e.g. solar & hydrogen cell technologies, computer technologies, fuel additive technology, and photovoltaic cells etc.), nanotechnology could create needed and unintended consequences. Future research should therefore focus on both the positive and negative environmental implications of nanotechnology.

---