Characterization of eco-friendly fluorescent nanoparticle-doped tracers for environmental sensing
Particle tracers are extensively used in quantitative flow visualization and environmental sensing. In this paper, we provide a thorough characterization of the novel eco-friendly fluorescent particle tracers formulated in Tauro et al. (AIP Adv 3(3): 032108, 2013). The tracers are synthesized from natural beeswax and are functionalized by encapsulating nontoxic fluorophore nanoparticles in the beads’ matrix through an inexpensive thermal procedure. Visibility and durability studies are conducted through a wide array of techniques to investigate the tracers’ surface morphological microfeatures, crystal nature and size, chemical composition, fluorophore incorporation into the beeswax matrix, and fluorescence response under severe settings resembling exposure to natural environments. Our findings demonstrate that fluorescent nanoparticles ranging from 1.51 to 3.73 nm are homogeneously distributed in the superficial layer (12 nm) of the tracers. In addition, fluorescence emissions are observed up to 26 days of continuous exposure of the tracers to high energy radiation. To demonstrate the particles’ use in environmental flow sensing, a set of proof of concept outdoor tests are conducted, in which image analysis tools are utilized for detecting the fluorescent tracers. Experimental results suggest that fluorescent microparticles deployed in high flow-rate flows (2 m/s) and under direct sunlight can be sensed through commercially available cameras (frame rate set to 30 Hz).
KeywordsTracer Fluorescent nanoparticles Environmental sensing Microscopy
This research was partially supported by the Honors Center of Italian Universities, the MIUR project PRIN 2009 N. 2009CA4A4A, and the National Science Foundation under grant numbers CMMI-0745753 and CMMI-0926791. The authors also acknowledge the support of the Office of Naval Research through grant number N00014-10-1-0988 that has allowed the acquisition of equipment used in this study and the Department of Materials Science and Engineering at Rutgers University for access to microscopy characterization equipment. The authors are also grateful to Dr. Jin R. Kim for providing the opportunity of using PTI Quanta Master 40 spectrofluorometer.
- Bao X, Xiaochun G (1996) The minerageny of two groups of zircons from Plagioclase–Amphibolite of Mayuan group in Northern Fujian. Acta Petrologica et Mineralogica 15(1):73–79Google Scholar
- Berman ESF, Gupta M, Gabrielli C, Garland T, McDonnell JJ (2009) High-frequency field-deployable isotope analyzer for hydrological applications. Water Resour Res 45(10):W10201Google Scholar
- Gonzalez RC, Woods RE, Eddins SL (2004) Digital image processing using MATLAB. Pearson Prentice-Hall, Upper Saddle River, NJGoogle Scholar
- Raffel M, Willert CE, Wereley ST, Kompenhans J (2007) Particle image velocimetry: a practical guide. Springer, New YorkGoogle Scholar
- Tauro F, Grimaldi S, Petroselli A, Porfiri M (2012a) Fluorescent particle tracers in surface hydrology: a proof of concept in a natural stream. Water Resour Res 48(6):W06528Google Scholar
- US Food and Drug Administration (2006) http://www.accessdata.fda.gov
- Wen XF, Zhang SC, Sun XM, Yu GR, Lee X (2010) Water vapor and precipitation isotope ratios in Beijing, China. J Geophys Res 115(D1):D01103Google Scholar