TY - JOUR

T1 - Detection of unlabeled particles in the low micrometer size range using light scattering and hydrodynamic 3D focusing in a microfluidic system

A1 - Zhuang,Guisheng

A1 - Jensen,Thomas G.

A1 - Kutter,Jörg P.

AU - Zhuang,Guisheng

AU - Jensen,Thomas G.

AU - Kutter,Jörg P.

PB - Wiley - V C H Verlag GmbH & Co. KGaA

PY - 2012

Y1 - 2012

N2 - In this paper, we describe a microfluidic device composed of integrated microoptical elements and a two‐layer microchannel structure for highly sensitive light scattering detection of micro/submicrometer‐sized particles. In the two‐layer microfluidic system, a sample flow stream is first constrained in the out‐of‐plane direction into a narrow sheet, and then focused in‐plane into a small core region, obtaining on‐chip three‐dimensional (3D) hydrodynamic focusing. All the microoptical elements, including waveguides, microlens, and fiber‐to‐waveguide couplers, and the in‐plane focusing channels are fabricated in one SU‐8 layer by standard photolithography. The channels for out‐of‐plane focusing are made in a polydimethylsiloxane (PDMS) layer by a single cast using a SU‐8 master. Numerical and experimental results indicate that the device can realize 3D hydrodynamic focusing reliably over a wide range of Reynolds numbers (0.5 <Re <20). Polystyrene particles of three sizes (2, 1, and 0.5 μm) were measured in the microfluidic device with integrated optics, demonstrating the feasibility of this approach to detect particles in the low micrometer size range by light scattering detection.

AB - In this paper, we describe a microfluidic device composed of integrated microoptical elements and a two‐layer microchannel structure for highly sensitive light scattering detection of micro/submicrometer‐sized particles. In the two‐layer microfluidic system, a sample flow stream is first constrained in the out‐of‐plane direction into a narrow sheet, and then focused in‐plane into a small core region, obtaining on‐chip three‐dimensional (3D) hydrodynamic focusing. All the microoptical elements, including waveguides, microlens, and fiber‐to‐waveguide couplers, and the in‐plane focusing channels are fabricated in one SU‐8 layer by standard photolithography. The channels for out‐of‐plane focusing are made in a polydimethylsiloxane (PDMS) layer by a single cast using a SU‐8 master. Numerical and experimental results indicate that the device can realize 3D hydrodynamic focusing reliably over a wide range of Reynolds numbers (0.5 <Re <20). Polystyrene particles of three sizes (2, 1, and 0.5 μm) were measured in the microfluidic device with integrated optics, demonstrating the feasibility of this approach to detect particles in the low micrometer size range by light scattering detection.

KW - Cytometry

KW - Hydrodynamic focusing

KW - Light scattering

KW - Microfluidics

KW - Particles

U2 - 10.1002/elps.201100674

DO - 10.1002/elps.201100674

JO - Electrophoresis

JF - Electrophoresis

SN - 0173-0835

IS - 12

VL - 33

SP - 1715

EP - 1722

ER -