Simultaneous Determination of the Size and Surface Charge of Individual Nanoparticles Using a Carbon Nanotube-Based Coulter Counter

Abstract

A resistive-pulse Coulter counter based on a membrane containing a single multiwall carbon nanotube (MWNT) channel was used to simultaneously determine the size and surface charge of carboxy-terminated polystyrene nanoparticles. The membrane was prepared from an epoxy section containing a MWNT channel mounted on a poly(dimethylsiloxane) (PDMS) support structure. The PDMS support reduced the background noise level by a factor of > 20 compared to the Si/Si3N4 support structure used in our previous study. The lower noise level makes it possible to accurately measure the height and width of resistive-pulse signals resulting from transport of individual particles through the MWNT channel. Particle sizes, calculated from current pulse heights, were comparable to those determined by transmission electron microscope (TEM). The width of the current pulses is a measure of the nanoparticle transport time, and it permits calculation of the electrokinetic surface charge. Different types of polystyrene nanoparticles having nearly the same size, but different electrokinetic surface charge, could be resolved on the basis of the difference in their transport time.

Resistive pulse sensing of magnetic beads and supraparticle structures using tunable pores

“…3,34,35 Similar approaches have been extensively applied in other resistive pulse studies. [15][16][17][23][24][25]28,[70][71][72] For investigation of particle clusters, we extend the model to accommodate multiple on-axis particles, thereby improving on the established approach for sizing spheres using the proportionality of pulse magnitude and particle volume. 3,34 The pore geometry used was a truncated cone of larger opening radius b, with a symmetric constriction of radius a located a distance c from the trans-membrane surface ( Fig.…”

“…16 Within this range, many particle types present opportunities for improved characterization or quality control-drug delivery capsules, viruses, functionalized particles for diagnostic assays, blood platelets, emulsions, and magnetic beads are a few important examples. The sophistication of resistive pulse sensing has also increased, making use of channels made from carbon nanotubes, 17,18 glass, [19][20][21][22][23] silicon, 5,8,15,24 polymers, [25][26][27][28] and elastomers. [29][30][31][32][33][34][35][36][37][38] Resistive pulses can now be used for study and measurement of particle size, 2,3,17,18,20,21,34 concentration, 33 and charge.…”

“…[29][30][31][32][33][34][35][36][37][38] Resistive pulses can now be used for study and measurement of particle size, 2,3,17,18,20,21,34 concentration, 33 and charge. 17,38 There is clear potential to extend applications towards sensing of complicated dynamic interactions 24 and specific particle shapes. a) Author to whom correspondence should be addressed.…”

PMMA Polymer Membrane-Based Single Cylindrical Submicron Pores: Electrical Characterization and Investigation of Their Applicability in Resistive-Pulse Biomolecule Detection

“…Transient changes in I open (temporary I open blockade events) will occur when a particle slightly smaller than the pore traverses (translocates). This resistive-pulse can be analyzed to derive information regarding the particle size and even its morphology, concentration in the electrolyte, and affinity for the pore [6,7]: pulse amplitudes in the ionic current through the pore are proportional to the volume of the passing particles, the frequency of pulses is related to the concentration of particles in a sample flowing through the pore, and the residence time of a particle in the pore is related to its structure, affinity towards the pore, as well as its velocity.…”

Electron Hopping through Redox Moieties Anchored to Well‐Defined Nanostructures

“…[2,3] My interest in nanostructured materials was initiated while I was a postdoc with Prof. Richard Crooks at Texas A&M University (2001)(2002)(2003)(2004). During this time, I studied resistivepulse detection with a carbon nanotube pore for characterization of individual nanoparticles [6][7][8] and electrokinetic enrichment of DNA with a track-etched nanoporous membrane incorporated into a microfluidic device. [9] These experiments took full advantage of the nanoscale size, cylindrical shape and surface properties of the pores in developing unique analytical devices.…”