Experimental study of the separation behavior of nanoparticles in micro- and nanochannels

Abstract

In this article, we investigate the effects of pH, ionic strength, and channel height on the mobility and diffusivity of charged spherical particles within planar microfluidic channels. Specifically, we report results of a broad experimental study on the transport and separation behavior of 50 and 100 nm spherical carboxylated polystyrene nanoparticles, confined in 20 lm, 1 lm, and 250 nm deep fluidic channels. We find that pH, ionic strength, and channel height have coupled impacts on mobility changes. In particular, we show that, depending on pH, the dependence of particle mobility on channel size can have opposing behavior. In addition, we also show that at the nanoscale, at lower ionic strengths, there is a substantial increase in mobility, due to enhanced electric fields within the nanochannels. These effects are important to understand in order to avoid potential downfalls in terms of separation efficiency as well as design for better tuning of separation performance in micro-and nanochannels. Finally, we propose a method to estimate the effective zeta potential of spherical particles from measured electrophoretic mobility data. This could prove useful in characterizing a heterogeneous collection of particles having a distribution over a range of values of the zeta potential.

Electrokinetic characterization of individual nanoparticles in nanofluidic channels

“…14 and values shown in Tables 1 and 4 compared to both literature values (Napoli et al 2011) and measured bulk mobilities (Malvern Zetasizer Nano ZS). In general, our experimental nanochannel values are significantly lower than those in bulk or in larger channels.…”

“…Napoli et al (2011) reported the mobilities of 50-and 100-nm particles in channels ranging from 250 nm to 20 lm using electrophoretic injections in microchannels. Wood et al (2007) and Fraikin et al (2011) successfully characterized size and titre of micro and nano-scale polystryene beads using radio frequency refractometry methods integrated into a PDMS microfluidic system.…”

“…Furthermore, the resulting analysis from such tools are often ridden with inaccuracies due to the requirement of ensemble measurements (Fraikin et al 2011). Conversely, nanofluidics has the potential to perform such analysis non-invasively using minimal material while remaining cost and time efficient (Napoli et al 2011).…”

Nanomedicine Scale-up Technologies: Feasibilities and Challenges

“…This technology offers a number of advantages over the more traditional methods of preparation of liposomes such as extrusion and sonication. Microfluidic hydrodynamic focusing has been used to synthesize nanoparticles and vesicles of various lipids (12)(13)(14)(15).…”

Microfluidizer Technique for Improving Microfiber Properties Incorporated Into Edible and Biodegradable Films

“…Microfluidic process has become an attractive technology for numerous applications [Atalay et al, 2011;Cho et al, 2011;Napoli et al, 2011;Schirhagl et al, 2010;Thompson et al, 2010;Zhang et al, 2011] due to unique characteristics, such as: i) efficient and rapid mix leading to rapid chemical reaction; ii) homogeneous reaction environments; iii) continuously varied reaction conditions and iv) precise time intervals to add reagents during reaction [deMello, 2006;DeMello & DeMello, 2004]. Therefore, the application of the microfluidic devices improves the control of the synthesis parameters and thus the nanoparticle sizes and properties [Il Park et al, 2010] and optimizes the miniaturization of the microstructures.…”