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Sensors As Tools for Quantitation, Nanotoxicity and Nanomonitoring Assessment of Engineered Nanomaterials
Citation:
VARNER, K. E., S. Kikandi, AND O. Sadik. Sensors As Tools for Quantitation, Nanotoxicity and Nanomonitoring Assessment of Engineered Nanomaterials. H. Minhas (ed.), JOURNAL OF ENVIRONMENTAL MONITORING. Royal Society of Chemistry, Cambridge, Uk, 11:1782-1800, (2009).
Impact/Purpose:
Nanotechnology—the science of assembling or controlling matter atom-by-atom at the nanoscale level and its potential applications—presents both opportunities and challenges. Opportunity exists to create novel materials based on the enhanced catalytic, optical, magnetic and electrical properties of nanomaterials. Some engineered nanomaterials(ENMs) have already been incorporated into a range of commercial products, including pharmaceuticals, automobile additives, personal care, such as sunscreens and cosmetics, clothing, sporting equipment, tires, detergents, and stain-repellants1. ENMs are also being used as probes for ultrasensitive molecular sensing and diagnostic imaging, agents for photodynamic therapy (PDT) and actuators for drug delivery, triggers for photothermal treatment, and precursors for building solar cells, electronics and light emitting diodes2. Despite the increasing applications of engineered nanomaterials, a complete understanding of the size, shape, composition and aggregationdependant interactions of nanostructures with biological systems is limited. Also, there are a number of important, unresolved questions concerning the safety of ENMS. The potential exposure scenarios, and their interaction with the biological and environmental systems are largely unknown. Hence, subdisciplines of nanotechnology such as nanotoxicity, nanomonitoring and/or nanomeasurements are emerging. Nanotoxicology focuses on the characterization and categorization of the health effects caused by engineered nanomaterials in order to correlate the nanoparticles structure/function with toxicity3. Nanomonitoring or nano-measurement refers to the science of isolating, detecting, characterizing, and quantifying ENMs in complex environmental, biological or ecological samples.
Description:
The discovery of fullerenes in 1985 has ushered in an explosive growth in the applications of engineered nanomaterials and consumer products. Nanotechnology and engineered nanomaterials (ENMs) are being incorporated into a range of commercial products such as consumer electronics, cosmetics, imaging and sensors. Nanomaterials offer new possibilities for the development of novel sensing and monitoring technologies. Nanosensors can be classified under two main categories:(i) Nanotechnology-enabled sensors or sensors that are themselves nanoscale or have nanoscale materials or components, and (ii) Nanoproperty-quantifiable sensors or sensors that are used to measure nanoscale properties. The first category can eventually result in lower material cost, reduced weight and energy consumption. The second category can enhance our understanding of the potential toxic effects of emerging pollutants from nanomaterials including fullerenes, dendrimers, and carbon nanotubes. Despite the enormous literatures and reviews on Category I sensors, there are few sensors to measure nanoscale properties or sensors belonging to Category II. This class of nanosensors is an area of critical interest to nanotoxicology, detection and risk assessment, as well as for monitoring of environmental and/or biological exposure. The article discusses emerging fields of nanotoxicology and nanomonitoring including the challenges of characterizing engineered nanomaterials and the potentials of combining existing analytical techniques with conventional cytotoxicity methods. Two case studies are provided for development of Category II nanosensors for fullerene nanoparticles and quantum dots. One highlights the uniqueness of a portable, dissolved oxygen electrochemical sensor arrays capable of detecting the ENMs as well as provide rapid nanotoxicological information. This review has shown that addressing the complex and critical issues surrounding the environmental transformation and toxicity of ENMs must be accompanied by the creation of new approaches or further developments of existing instrumentation.