Application of Silver-Coated Magnetic Microspheres to a SERS-Based Optofluidic Sensor

Han, Byunghee; Choi, Nak Sam; Kim, Ki Hyung; Lim, Dong Woo; Choo, Jaebum

doi:10.1021/jp112265e

Cited by 81 publications

(72 citation statements)

References 39 publications

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“…3 The detection of DNA and proteins has been performed using this phenomenon. The aggregation of metal NPs has also been applied to surface-enhanced Raman scattering (SERS) [8][9][10] and light-scattering detection. 7,11 The manipulation and separation of particles play key roles in the successful implementation of particle-based bioanalyses.…”

Section: Introductionmentioning

confidence: 99%

Acoustic Sensing Based on Density Shift of Microspheres by Surface Binding of Gold Nanoparticles

et al. 2017

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Herein, we propose a concept for sensing based on density changes of microparticles (MPs) caused by a biochemical reaction. The MPs are levitated by a combined acoustic-gravitational force at a position determined by the density and compressibility. Importantly, the levitation is independent of the MPs sizes. When gold nanoparticles (AuNPs) are bound on the surface of polymer MPs through a reaction, the density of the MPs dramatically increases, and their levitation position in the acoustic-gravitational field is lowered. Because the shift of the levitation position is proportional to the number of AuNPs bound on one MP, we can determine the number of molecules involved in the reaction. The avidinbiotin reaction is used to demonstrate the effectiveness of this concept. The number of molecules involved in the reaction is very small because the reaction space is small for an MP; thus, the method has potential for highly sensitive detection.

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Section: Introductionmentioning

confidence: 99%

Acoustic Sensing Based on Density Shift of Microspheres by Surface Binding of Gold Nanoparticles

et al. 2017

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“…[16][17][18] In another form of optofluidic SERS, active concentration of the nanoparticle-analyte conjugates into the SERS detection volume has been demonstrated using a number of methods, including a spinning microfluidic compact disk platform, 19 electro-kinetic forces across a microfluidic channel, [20][21][22] and magnetic concentration of nanostructured silver-coated microbeads in a microfluidic channel. 23 A simpler optofluidic SERS approach is to employ a fluidic design that passively concentrates analyte-nanoparticle conjugates into the detection volume. Nanoparticles and adsorbed/ bound analyte in the sample are concentrated as they flow into the channel; there is no need for additional active components in the device to concentrate the sample.…”

Section: Introductionmentioning

confidence: 99%

A nanoporous optofluidic microsystem for highly sensitive and repeatable surface enhanced Raman spectroscopy detection

Yazdi

White

2012

Biomicrofluidics

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We report the demonstration of an optofluidic surface enhanced Raman spectroscopy (SERS) device that leverages a nanoporous microfluidic matrix to improve the SERS detection performance by more than two orders of magnitude as compared to a typical open microfluidic channel. Although it is a growing trend to integrate optical biosensors into microfluidic channels, this basic combination has been detrimental to the sensing performance when applied to SERS. Recently, however, synergistic combinations between microfluidic functions and photonics (i.e., optofluidics) have been implemented that improve the detection performance of SERS. Conceptually, the simplest optofluidic SERS techniques reported to date utilize a single nanofluidic channel to trap nanoparticle-analyte conjugates as a method of preconcentration before detection. In this work, we leverage this paradigm while improving upon the simplicity by forming a 3D nanofluidic network with packed nanoporous silica microspheres in a microfluidic channel; this creates a concentration matrix that traps silver nanoclusters and adsorbed analytes into the SERS detection volume. With this approach, we are able to achieve a detection limit of 400 attomoles of Rhodamine 6G after only 2 min of sample loading with high chip-to-chip repeatability. Due to the high number of fluidic paths in the nanoporous channel, this approach is less prone to clogging than single nanofluidic inlets, and the loading time is decreased compared to previous reports. In addition, fabrication of this microsystem is quite simple, as nanoscale fabrication is not necessary. Finally, integrated multimode fiber optic cables eliminate the need for optical alignment, and thus the device is relevant for portable and automated applications in the field, including point-of-sample and point-of-care detection. To illustrate a relevant field-based application, we demonstrate the detection of 12 ppb of the organophosphate malathion in water using the nanofluidic SERS microsystem.

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“…The third compartment acts to trap and detect magnetic immunocomplexes. To achieve effective trapping of the magnetic beads in the stream, two yoke-type mini-solenoids (Afshar et al, 2011;Han et al, 2011;Liu et al, 2007) were arranged at the end of each channel. After trapping the immunocomplexes, PGA free serum was introduced from the inlet, located in the middle part of the device, to wash out unbound PGA antigens and AuNPs.…”

Section: Fabrication Of the Solenoid-embedded Dual Channel Microfluidmentioning

confidence: 99%

Fast and sensitive detection of an anthrax biomarker using SERS-based solenoid microfluidic sensor

Gao

Cha

et al. 2015

Biosensors and Bioelectronics

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Application of Silver-Coated Magnetic Microspheres to a SERS-Based Optofluidic Sensor

Cited by 81 publications

References 39 publications

Acoustic Sensing Based on Density Shift of Microspheres by Surface Binding of Gold Nanoparticles

Acoustic Sensing Based on Density Shift of Microspheres by Surface Binding of Gold Nanoparticles

A nanoporous optofluidic microsystem for highly sensitive and repeatable surface enhanced Raman spectroscopy detection

Fast and sensitive detection of an anthrax biomarker using SERS-based solenoid microfluidic sensor

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