Gold nanoparticle-based optical microfluidic sensors for analysis of environmental pollutants

Abstract

Conventional methods of environmental analysis can be significantly improved by the development of portable microscale technologies for direct in-field sensing at remote locations. This report demonstrates the vast potential of gold nanoparticle-based microfluidic sensors for the rapid, in-field, detection of two important classes of environmental contaminants - heavy metals and pesticides. Using gold nanoparticle-based microfluidic sensors linked to a simple digital camera as the detector, detection limits as low as 0.6 μg L(-1) and 16 μg L(-1) could be obtained for the heavy metal mercury and the dithiocarbamate pesticide ziram, respectively. These results demonstrate that the attractive optical properties of gold nanoparticle probes combine synergistically with the inherent qualities of microfluidic platforms to offer simple, portable and sensitive sensors for environmental contaminants.

Modification of microfluidic paper-based devices with silica nanoparticles

“…31 These modifications result in the formation of carbonyl, aldehyde, or amino groups than can be used to permanently immobilize enzymes using covalent bonds and well-known conditions. μPADs can also be modified using ceria nanoparticles, 22 gold nanoparticles, 32 silver nanoparticles, 33, 34 and carbon nanotubes 35, 36 to aid with the detection step. Although each of these strategies presents their own advantages, they are not widely applicable and require the implementation of specific processes.…”

Microfluidic Optical Devices

“…Lafleur et al [13] improved conventional methods of environmental analysis by demonstrating the vast potential of gold nanoparticle-based microfluidic sensors for the rapid detection of two important categories of environmental contaminants -heavy metals and pesticides. Using gold nanoparticle-based microfluidic sensors integrated with a simple fluorescence detector allows the detection range of concentrations as low as 0.6 mg/L up to at least 200 mg; a simple fluorescence detector allows the detection range of concentrations as low as 0.6 mg/L up to at least 200 mg/L.…”

“…Presenting a comprehensive review of all the research in the field of microfluidic and optics integration is out the scope of this entry, but several numbers of representative examples of this integration are provided. Moreover, this integration results in handing:• Electric field induction by light exposure [1] • Integrated detection systems for microfluidic application (which increases the portability of the entire system) [3-5] • Sensitivity increase for the existing detection system [7,8] • Cell manipulation [9,11,12] • Small cell population sorting with high accuracy by tunable optical fibers [12] • Rapid detection of environmental contaminants [13] • A platform to study mammalian individual axonal injury [14] • Variable-focus liquid lens [15] …”

Dielectrophoresis for Biomedical Sciences Applications: A Review

“…In Phol’s paper, he defined DEP as a phenomenon seen in the relative motion of suspensions and media resulting from polarization forces produced by an inhomogeneous electric field. Since then, DEP research has expanded into various fields in the industry, including microfluidics [22,23], biosensors [24,25], environmental studies [26,27] and medical diagnostics [28,29]. …”