On-Chip Hydrodynamic Chromatography Separation and Detection of Nanoparticles and Biomolecules

Abstract

For the first time, on-chip planar hydrodynamic chromatography is combined with UV absorption detection. This technique is suitable for size characterization of synthetic polymers, biopolymers, and particles. Possible advantages of an on-chip hydrodynamic chromatography system over conventional techniques, such as size exclusion chromatography, and field-flow fractionation are fast analysis, high efficiency, reduced solvent consumption, and easy temperature control. The hydrodynamic separations are performed in a planar configuration realized in fused silica using a mixture of fluorescent and nonfluorescent polystyrene particles with sizes ranging from 26 to 155 nm. The planar chip configuration consists of a 1-microm-high, 0.5-mm-wide, and 69-mm-long channel, an integrated 150-pL injection structure, and a 30-microm-deep and 30-microm-wide detection cell, suitable for UV absorption detection. By combination of the separation data obtained in the new fused-silica chip with those obtained using a previously presented planar hydrodynamic chromatography chip, which was realized using silicon and glass microtechnology, a description of the retention and dispersion behavior of planar hydrodynamic chromatography is obtained. Especially the influence of the sidewalls on the dispersion is investigated. Furthermore a hydrodynamic separation within 70 s of several biopolymers is shown in the glass-silicon chip.

Separation enhancement in pinched flow fractionation

“…The separation in the two types of devices were compared and an amplification in the separation of up to 70% was achieved. Numerical [3][4][5][6][7][8][9][10][11][12][13][14] Pinched flow fractionation ͑PFF͒ is a microchip based size separation technique for nanometer to micrometer sized particles relying on a laminar flow sheet. The method was first demonstrated by Yamada et al, 15 where 15 and 30 m polystyrene microspheres were separated.…”

Solute Distribution Coupled with Laminar Flow in Wide-Bore Capillaries: What Can Be Separated without Chemical or Physical Fields?

“…Although the applicability of this method was very restricted, recent developments of chip technology have brought about a remarkable progress. 23,24 If a capillary of radius a is used for HDC, the time for the elution of a particle of radius rp is given bywhere t0 is the time required for solute to pass through the capillary at the average flow rate, and λ = rp/a. Solute diffusion coupled with an orthogonal laminar flow has been systematically studied with wide-bore capillaries to establish its limitations and reveal its potentials as separation methodology requiring neither chemical nor physical interactions.…”

“…Hydrodynamic chromatography (HDC) is such a case, which allows separation of particles or macromolecules according to their hydrodynamic sizes just by passing them through a narrow channel. [20][21][22][23][24] Particles with larger diameter for example cannot approach the channel wall, and thus flow through the channel faster than the smaller particles, when the laminar flow profile is maintained therein. Although the applicability of this method was very restricted, recent developments of chip technology have brought about a remarkable progress.…”

Unconventional detection methods for microfluidic devices

“…The attractiveness of this approach is that it provides a modular detector that potentially could be integrated with any microanalytical system. Blom et al [46] performed planar hydrodynamic chromatography in microchip format with UV absorption detection for the first time. They analyzed polystyrene latex nanoparticles in a chip fabricated from fused silica.…”