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Size-exclusive Nanosensor for Quantitative Analysis of Fullerene C60: A Concept Paper
Citation:
Kikandi, S. N., V. A. Okello, Q. Wang, O. A. Sakik, K. E. VARNER, AND S. A. Burns. Size-exclusive Nanosensor for Quantitative Analysis of Fullerene C60: A Concept Paper. ENVIRONMENTAL SCIENCE AND TECHNOLOGY. John Wiley & Sons, Ltd., Indianapolis, IN, 45:5294-5300, (2012).
Impact/Purpose:
The discovery of fullerenes in 1985 has ushered in an explosive growth in the applications of engineered nanomaterials (ENMs) and products (1-5). The rapid development of nanotechnology and the increasing production of nanomaterials-based products and processes present great opportunities and challenges. To date, the potential impacts of nanomaterials on human health and the environment have been limited due to insufficient understanding of the risks associated with its development, manipulation and wide-ranging applications. The first step in assessing the risks posed by ENMs is to develop a broad array of analytical tools and methods that are applicable to a wide range of manufactured nanomaterials. Conventional methods of assessing the properties and characteristics of raw nanomaterials focus on the size distribution and effects. They are, however, unsuitable for detection and quantification of complex environmental samples or for differentiating between the total or dissolved metal fractions or metal oxidation states. The toxicity, detection and characterization of nanomaterials are dependent on factors such as functionalization, geometry, and the type of nanomaterials. For example, the cytotoxicity of fullerenes can be decreased following its hydroxylation with 24 hydroxyl groups(3), while the cytotoxicity of carbon nanomaterials may be enhanced if it was functionalized with carboxylic acid moieties(4). The potential toxicity of fullerenes and its derivatives is still a subject of intense discussion (5). Some reports depict fullerenes as non-toxic while others demonstrate their ability to both quench and generate reactive oxygen species(ROS) (6), which may lead to DNA damage(7). Additionally, positive cytotoxicity and genotoxicity have been reported for the water-soluble C60 aggregates (nC60) despite its low hydrophobicity(8).
Description:
This paper presents the first development of a mass-sensitive nanosensor for the isolation and quantitative analyses of engineered fullerene (C60) nanoparticles, while excluding mixtures of structurally similar fullerenes. Amino-modified beta cyclodextrin (β-CD-NH2) was synthesized and confirmed by 1HNMR as the host molecule to isolate the desired fullerene C60. This was subsequently assembled onto the surfaces of gold-coated quartz crystal microbalance (QCM) electrodes using N-Dicyclohexylcarbodiimide/N-hydroxysuccinimide (DCC/NHS) surface immobilization chemistry to create a selective molecular configuration described as (Au)-S–(CH2)2-CONH-beta–CD sensor. The mass change on the sensor configuration on the QCM was monitored for selective quantitative analysis of fullerene C60 from a C60/C70 mixture and soil samples. About ~1014-1016 C60 particles/cm2 were successfully quantified by QCM measurements. Continuous spike of 200 μl of 0.14 mg C60