Analyte transport to micro- and nano-plasmonic structures

Lynn, N. Scott; Špringer, Tomáš; Slabý, Jiří; Špačková, Barbora; Grafová, Michaela; Ermini, Maria Laura; Homola, Jiřı́

doi:10.1039/c9lc00699k

Cited by 7 publications

(5 citation statements)

References 32 publications

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“…Several of these advantages, such as reduced LOD, depend on the analyte-receptor moiety interaction. To be able to utilize these devices effectively, developing new designs to facilitate specific analytereceptor moiety interactions can be critical in the fabrication of efficient diagnostic devices [10,11].…”

Section: Introductionmentioning

confidence: 99%

Curved passive mixing structures: a robust design to obtain efficient mixing and mass transfer in microfluidic channels

Oevreeide

Zoellner

Mielnik

et al. 2020

J. Micromech. Microeng.

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Analyte mixing and delivery to a functionalized sensor surface are important to realize several advantages associated with biosensors integrated with microfluidic channels. Here, we present a comparison between a herringbone structure (HBS) and a curved passive mixing structure of their efficiency at facilitating mixing and surface saturation using fluorescein included in one of the inlets of a Y-channel microfluidic device. We performed a large parametric study to assess the effects of varying the height of the microfluidic channel as well as the height, width, and spacing of the passive mixing structures. Scanning confocal microscopy combined with a custom-designed image-analysis procedure were utilized to visualize and quantify the observed changes in efficiency in inducing solute mixing by the different designs. The flow patterns within the channels were found to vary significantly with changes in the geometry of the passive mixing structures, which in turn affected the efficiency of the channel at mixing the fluid and saturating the surface opposite the mixing structures. The solute mixing as a function of the channel length was also determined; an initial slow mixing rate does not always coincide with a low mixing index (MI). We found that the range of MIs for the curved mixing structure 1 cm downstream from the inlet was 0.85–0.99 whilst for our HBS it was 0.74–0.98, depending on the design parameters of the passive mixing structures. Overall, this study shows that the curved passive mixing structure family is more robust in inducing efficient mixing than the HBSs.

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Section: Introductionmentioning

confidence: 99%

Curved passive mixing structures: a robust design to obtain efficient mixing and mass transfer in microfluidic channels

Oevreeide

Zoellner

Mielnik

et al. 2020

J. Micromech. Microeng.

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“…Passive mixing structures in microfluidic channels have been used in conjunction with surface biosensors to enhance analyte concentration at the sensor [ 50 ], thus decreasing the LOD and readout time. Lynn et al implemented an SHM in the ceiling of a microfluidic channel, which, combined with a surface plasmon resonance (SPR) sensor, showed an increase in sensitivity, where different parameters varied the efficiency of the sensor [ 51 , 52 , 53 , 54 , 55 ].…”

Section: Introductionmentioning

confidence: 99%

Characterization of Mixing Performance Induced by Double Curved Passive Mixing Structures in Microfluidic Channels

Oevreeide

Zoellner²,

Stokke

2021

Micromachines

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Functionalized sensor surfaces combined with microfluidic channels are becoming increasingly important in realizing efficient biosensing devices applicable to small sample volumes. Relaxing the limitations imposed by laminar flow of the microfluidic channels by passive mixing structures to enhance analyte mass transfer to the sensing area will further improve the performance of these devices. In this paper, we characterize the flow performance in a group of microfluidic flow channels with novel double curved passive mixing structures (DCMS) fabricated in the ceiling. The experimental strategy includes confocal imaging to monitor the stationary flow patterns downstream from the inlet where a fluorophore is included in one of the inlets in a Y-channel microfluidic device. Analyses of the fluorescence pattern projected both along the channel and transverse to the flow direction monitored details in the developing homogenization. The mixing index (MI) as a function of the channel length was found to be well accounted for by a double-exponential equilibration process, where the different parameters of the DCMS were found to affect the extent and length of the initial mixing component. The range of MI for a 1 cm channel length for the DCMS was 0.75–0.98, which is a range of MI comparable to micromixers with herringbone structures. Overall, this indicates that the DCMS is a high performing passive micromixer, but the sensitivity to geometric parameter values calls for the selection of certain values for the most efficient mixing.

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“…Optimizing such a many-particle sensor consists of two main components: the optical characteristics of sensing elements and the transport of analyte from the bulk volume to the sensor surface. Here, we focus on the refractive index sensitivity, as the overall biosensing performance was found to be a product of two factors, optical performance and the rate of analyte transport. , …”

Section: Introductionmentioning

confidence: 99%

“…Here, we focus on the refractive index sensitivity, as the overall biosensing performance was found to be a product of two factors, optical performance and the rate of analyte transport. 25,26 In this paper, we present a comprehensive computational study on the optimization of the size of gold nanorods for single-molecule plasmonic sensing in terms of optical refractive index sensitivity. We define contrast-to-noise ratio (CNR) as a universal measure of sensitivity, hence a universal figure of merit for plasmonic biosensing, which describes how effectively can a single molecular binding be resolved.…”

Section: Introductionmentioning

confidence: 99%

Computational Optimization of the Size of Gold Nanorods for Single-Molecule Plasmonic Biosensors Operating in Scattering and Absorption Modes

2021

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We present a comprehensive computational study on the optimization of the size of gold nanorods for single-molecule plasmonic sensing in terms of optical refractive index sensitivity. We construct an experimentally relevant model of single-molecule–single-nanoparticle sensor based on spherically capped gold nanorods, tip-specific functionalization and passivation layers, and biotin-streptavidin affinity system. We introduce a universal figure of merit for the sensitivity, termed contrast-to-noise ratio (CNR), which relates the change of measurable signal caused by the discrete molecule binding events to the inherent measurement noise. We investigate three distinct sensing modalities relying on direct spectral measurements, monitoring of scattering intensity at fixed wavelength and photothermal effect. By considering a shot-noise-limited performance of an experimental setup, we demonstrate the existence of an optimum nanorod size providing the highest sensitivity for each sensing technique. The optimization at constant illumination intensity (i.e., low-power applications) yields similar values of approximately 20 × 80 nm2 for each considered sensing technique. Second, we investigate the impact of geometrical and material parameters of the molecule and the functionalization layer on the sensitivity. Finally, we discuss the variable illumination intensity for each nanorod size with the steady-state temperature increase as its limiting factor (i.e., high-power applications).

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Analyte transport to micro- and nano-plasmonic structures

Abstract: We examine analyte transport to numerous plasmonic micro- and nano-structures having variable fill fraction, and via sensorgram analysis (ssDNA detection), we show that measured rates of transport match well to a simple theoretical model.

Cited by 7 publications

References 32 publications

Curved passive mixing structures: a robust design to obtain efficient mixing and mass transfer in microfluidic channels

Curved passive mixing structures: a robust design to obtain efficient mixing and mass transfer in microfluidic channels

Characterization of Mixing Performance Induced by Double Curved Passive Mixing Structures in Microfluidic Channels

Computational Optimization of the Size of Gold Nanorods for Single-Molecule Plasmonic Biosensors Operating in Scattering and Absorption Modes

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