Advances in Engineering Advances in Engineering features breaking research judged by Advances in Engineering advisory team to be of key importance in the Engineering field. Papers are selected from over 10,000 published each week from most peer reviewed journals.
Journal of Nanoparticle Research, 2014, 16:2253. Prasanna Bhomkar (1), Greg Goss (1,3,4), David S. Wishart (1,2,3).
- National Institute for Nanotechnology, 11421 Saskatchewan Drive, Edmonton, AB, T6G 2M9, Canada and
- Department of Biological Sciences, University of Alberta, Edmonton, AB, T6G 2E8, Canada and
- Office of Environmental Nanosafety, University of Alberta, Edmonton, AB, T6G 2E8, Canada and
- Department of Computing Science, University of Alberta, Edmonton, AB, T6G 2E8, Canada.
Abstract
Advances in nanoscience have led to a greater use of engineered nanoparticles (ENPs) in numerous applications. Due to their small size and unique surface properties, ENPs have many desirable features. However, they also interact with living cells in potentially undesirable manners highlighting the need to develop improved detection systems to manage risks associated with their accidental occupational exposure or environmental release. However, the routine detection of ENPs has not yet been demonstrated, especially for aquatic environments. Using standard protein engineering techniques, we generated a protein-based biosensor that can sensitively detect negatively charged ENPs in aquatic matrices. In particular, we genetically engineered a green fluorescent protein with a poly-lysine tag (His-GFP-LYS) to facilitate its electrostatic interaction with commercially available negatively charged NPs. These 5–6-nm-sized NPs have metallic cores comprising gold, iron oxide, cerium oxide, and zinc oxide and are stabilized via poly-acrylic acid (PAA) coating. The interaction between the recombinant positively charged GFP and the PAA coating of the negatively charged NPs resulted in visually observable turbidity changes that were quantified using a portable spectrophotometer (NANODROP). These interactions were confirmed using dynamic light scattering and visualized using agarose native gel electrophoresis. This simple and portable system could detect ENPs resuspended in pure aqueous buffer (0.08 mg/L) and those resuspended in environmental matrices, such as pond water (0.6 mg/L). This detection system also sensed ENPs in the presence of moderate concentrations of natural organic matter that is ubiquitously present in surface waters. These results suggest that this biosensor system could be used for the routine, portable, and affordable detection of negatively-charged ENPs under environmentally relevant aquatic conditions.
