Sizing of Metallic Nanoparticles Confined to a Microfluidic Film Applying Dark-Field Particle Tracking

Haiden, Christoph; Wopelka, Thomas; Jech, Martin; Keplinger, Franz; Vellekoop, Michael J.

doi:10.1021/la5016675

Cited by 23 publications

(28 citation statements)

References 66 publications

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“…In comparison to other methods for directly confining nanoparticles at similar length scales, our ability to pattern complex structures enables arbitrary functions, 47 and our resolution and range are record. 48 In contrast to other methods of confining nanoparticles for tracking analysis, our analytical separation does not require diffusion analysis 14, 18 or surface functionalization, 17 relying on steric interactions which are more direct and general, respectively. Further, our quantitative measurements of nanoparticle size and emission intensity have revealed a surprising relationship between these essential characteristics of common fluorescent probes, invalidating the expectation of volumetric scaling.…”

Section: Resultsmentioning

confidence: 99%

“…In this way, we establish a subnanometer limit of the fluidic manipulation of particulate matter, and enable critical-dimension particle tracking with subnanometer accuracy. In comparison to other fluidic methods of manipulating and measuring nanoparticles, 14–18 which generally involve tracking particle motion or sensing device occlusion, our method is more direct and capable of resolving smaller nanoparticles. Moreover, our method is optimal for quantitative measurement of the optical properties of nanoparticles, which are among their most important properties and depend on their dimensions.…”

Section: Introductionmentioning

confidence: 99%

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Subnanometer structure and function from ion beams through complex fluidics to fluorescent particles

et al. 2018

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The vertical dimensions of complex nanostructures determine the functions of diverse nanotechnologies. In this paper, we investigate the unknown limits of such structure-function relationships at subnanometer scales. We begin with a quantitative evaluation of measurement uncertainty from atomic force microscopy, which propagates through our investigation from ion beam fabrication to fluorescent particle characterization. We use a focused beam of gallium ions to subtractively pattern silicon surfaces, and silicon nitride and silicon dioxide films. Our study of material responses quantifies the atomic limits of forming complex topographies with subnanometer resolution of vertical features over a wide range of vertical and lateral dimensions. Our results demonstrate the underutilized capability of this standard system for rapid prototyping of subnanometer structures in hard materials. We directly apply this unprecedented dimensional control to fabricate nanofluidic devices for the analytical separation of colloidal nanoparticles by size exclusion. Optical microscopy of single nanoparticles within such reference materials establishes a subnanometer limit of the fluidic manipulation of particulate matter and enables critical-dimension particle tracking with subnanometer accuracy. After calibrating for optical interference within our multifunctional devices, which also enables device metrology and integrated spectroscopy, we reveal an unexpected relationship between nanoparticle size and emission intensity for common fluorescent probes. Emission intensity increases supervolumetrically with nanoparticle diameter and then decreases as nanoparticles with different diameters photobleach to similar values of terminal intensity. We propose a simple model to empirically interpret these surprising results. Our investigation enables new control and study of structure-function relationships at subnanometer scales.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Subnanometer structure and function from ion beams through complex fluidics to fluorescent particles

et al. 2018

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“…A MATLAB script (2011b, MathWorks, Natick, MU, USA) utilizing 2D particle tracking (Crocker–Grier algorithm [ 28 ]) is used to link the exact position (centroids) of objects appearing over subsequent frames [ 29 , 30 ]. Based on this approach, a single frame i ( i = 1, …, N ) is processed to detect multiple bright spots (representing particles) over a dark background (here the variability in pixel intensity is used to ‘find’ a particle) (see Figure 3 b).…”

Section: Design and Methodsmentioning

confidence: 99%

Biosensing System for Concentration Quantification of Magnetically Labeled E. coli in Water Samples

Malec

Haiden

Giouroudi

2018

Sensors

Self Cite

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Bacterial contamination of water sources (e.g., lakes, rivers and springs) from waterborne bacteria is a crucial water safety issue and its prevention is of the utmost significance since it threatens the health and well-being of wildlife, livestock, and human populations and can lead to serious illness and even death. Rapid and multiplexed measurement of such waterborne pathogens is vital and the challenge is to instantly detect in these liquid samples different types of pathogens with high sensitivity and specificity. In this work, we propose a biosensing system in which the bacteria are labelled with streptavidin coated magnetic markers (MPs—magnetic particles) forming compounds (MLBs—magnetically labelled bacteria). Video microscopy in combination with a particle tracking software are used for their detection and quantification. When the liquid containing the MLBs is introduced into the developed, microfluidic platform, the MLBs are accelerated towards the outlet by means of a magnetic field gradient generated by integrated microconductors, which are sequentially switched ON and OFF by a microcontroller. The velocities of the MLBs and that of reference MPs, suspended in the same liquid in a parallel reference microfluidic channel, are calculated and compared in real time by a digital camera mounted on a conventional optical microscope in combination with a particle trajectory tracking software. The MLBs will be slower than the reference MPs due to the enhanced Stokes’ drag force exerted on them, resulting from their greater volume and altered hydrodynamic shape. The results of the investigation showed that the parameters obtained from this method emerged as reliable predictors for E. coli concentrations.

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“…158 This prolongs the tracking by darkfield microscopy of the diffusion in two dimensions of gold nanoparticles, which otherwise diffuse far out of focus. This increased temporal range confers improved statistics in the analysis of diffusion, and a more precise estimate of nanoparticle size from the Stokes-Einstein relation.…”

Section: Applicationsmentioning

confidence: 96%

Optical tracking of nanoscale particles in microscale environments

Mathai

Liddle

Stavis

2016

Applied Physics Reviews

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The trajectories of nanoscale particles through microscale environments record useful information about both the particles and the environments. Optical microscopes provide efficient access to this information through measurements of light in the far field from nanoparticles. Such measurements necessarily involve trade-offs in tracking capabilities. This article presents a measurement framework, based on information theory, that facilitates a more systematic understanding of such trade-offs to rationally design tracking systems for diverse applications. This framework includes the degrees of freedom of optical microscopes, which determine the limitations of tracking measurements in theory. In the laboratory, tracking systems are assemblies of sources and sensors, optics and stages, and nanoparticle emitters. The combined characteristics of such systems determine the limitations of tracking measurements in practice. This article reviews this tracking hardware with a focus on the essential functions of nanoparticles as optical emitters and microenvironmental probes. Within these theoretical and practical limitations, experimentalists have implemented a variety of tracking systems with different capabilities. This article reviews a selection of apparatuses and techniques for tracking multiple and single particles by tuning illumination and detection, and by using feedback and confinement to improve the measurements. Prior information is also useful in many tracking systems and measurements, which apply across a broad spectrum of science and technology. In the context of the framework and review of apparatuses and techniques, this article reviews a selection of applications, with particle diffusion serving as a prelude to tracking measurements in biological, fluid, and material systems, fabrication and assembly processes, and engineered devices. In so doing, this review identifies trends and gaps in particle tracking that might influence future research.

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Sizing of Metallic Nanoparticles Confined to a Microfluidic Film Applying Dark-Field Particle Tracking

Cited by 23 publications

References 66 publications

Subnanometer structure and function from ion beams through complex fluidics to fluorescent particles

Subnanometer structure and function from ion beams through complex fluidics to fluorescent particles

Biosensing System for Concentration Quantification of Magnetically Labeled E. coli in Water Samples

Optical tracking of nanoscale particles in microscale environments

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