Challenges and approaches for particle size analysis on micrographs of nanoparticles loaded onto textile surfaces

Underwood, Samuel J.; Gorham, Justin M.

doi:10.6028/nist.sp.1200-22

Cited by 10 publications

(11 citation statements)

References 4 publications

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“…Other tools in ImageJ can be used to aid in segmenting particles, such as morphological operators and filtering to clean images, or manual input to segment or throw out particles. 42,65 Machine learning segmentation methods relying on hand-labeled training data have also been implemented in ImageJ. 61 Other published algorithms that segment closely spaced nanoparticles require the high resolution and contrast of TEM micrographs 48,78 and do not function for SEM micrographs.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Quantitative Analysis of Nanorod Aggregation and Morphology from Scanning Electron Micrographs Using SEMseg

et al. 2020

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General methods to achieve better physical insight about nanoparticle aggregation and assembly are needed because of the potential role of aggregation in a wide range of materials, environmental, and biological outcomes. Scanning electron microscopy (SEM) is fast and affordable compared to transmission electron microscopy, but SEM micrographs lack contrast and resolution due to lower beam energy, topographic contrast, edge effects, and charging. We present a new segmentation algorithm called SEMseg that is robust to the challenges inherent in SEM micrograph analysis and demonstrate its utility for analyzing gold (Au) nanorod aggregates. SEMseg not only supports nanoparticle size analysis for dispersed nanoparticles, but also discriminates between nanoparticles within an aggregate. We compare our algorithm to those incorporated into the commonly used software ImageJ and demonstrate improved segmentation of aggregate structures. New physical insight about aggregation is demonstrated by the introduction of an order parameter describing side-by-side structure in nanoparticle aggregates. We also present the segmentation and fitting algorithms included in SEMseg within a user-friendly graphical user interface. The resulting code is provided with an open-source interface to provide quantitative image processing tools for researchers to characterize both dispersed nanoparticles and nanoparticle assemblies in SEM micrographs with high throughput.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Quantitative Analysis of Nanorod Aggregation and Morphology from Scanning Electron Micrographs Using SEMseg

et al. 2020

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“…The images were taken from one arbitrary section of the silicon wafer, moving from the center to its edge. Approximately 3–6 images per sample, depending on the size of the coffee ring at ×5000 or ×10,000 magnification, were collected and then analyzed with ImageJ using a previously published guide 37 . All images were calibrated to scale and cropped to remove artifacts that might affect particle analysis.…”

Section: Methodsmentioning

confidence: 99%

“…Approximately 3-6 images per sample, depending on the size of the coffee ring at ×5000 or ×10,000 magnification, were collected and then analyzed with ImageJ using a previously published guide. 37 All images were calibrated to scale and cropped to remove artifacts that might affect particle analysis. All particles were analyzed using the manual thresholding feature.…”

Section: Particle Analysis Protocolmentioning

confidence: 99%

Fabrication and characterization of chitosan nanoparticles using the coffee‐ring effect for photodynamic therapy

et al. 2022

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Background and Objectives: Biocompatible nanoparticles have been increasingly used in a variety of medical applications, including photodynamic therapy. Although the impact of synthesis parameters and purification methods is reported in previous studies, it is still challenging to produce a reliable protocol for the fabrication, purification, and characterization of nanoparticles in the 200-300 nm range that are highly monodisperse for biomedical applications. Study Design/Materials and Methods: We investigated the synthesis of chitosan nanoparticles in the 200-300 nm range by evaluating the chitosan to sodium tripolyphosphate (TPP) mass ratio and acetic acid concentration of the chitosan solution. Chitosan nanoparticles were also crosslinked to rose bengal and incubated with human breast cancer cells (MCF-7) to test photodynamic activity using a green laser (λ = 532 nm, power = 90 mW). Results: We established a simple protocol to fabricate and purify biocompatible nanoparticles with the most frequent size occurring between 200 and 300 nm. This was achieved using a chitosan to TPP mass ratio of 5:1 in 1% v/v acetic acid at a pH of 5.5. The protocol involved the formation of nanoparticle coffee rings that showed the particle shape to be spherical in the first approximation. Photodynamic treatment with rose bengal-nanoparticles killed ~98% of cancer cells. Conclusion: A simple protocol was established to prepare and purify spherical and biocompatible chitosan nanoparticles with a peak size of ~200 nm. These have remarkable antitumor activity when coupled with photodynamic treatment.

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“…The ZOI was determined by measuring the cleared area using ImageJ based on previous reports and further described in the SI. [33] Statistical analysis was performed using Orgin2018b (OriginLab Corp., Northhampton, MA, USA). A test for normality was performed before ANOVA and posthoc testing using Tukey HSD.…”

Section: Materials and Methods1mentioning

confidence: 99%

Chemical and physical transformations of silver nanomaterial containing textiles after modeled human exposure

et al. 2019

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The antimicrobial properties of silver nanomaterials (AgNM) have been exploited in various consumer applications, including textiles such as wound dressings. Understanding how these materials chemically transform throughout their use is necessary to predict their efficacy during use and their behavior after disposal. The aim of this work was to evaluate chemical and physical transformations to a commercial AgNM-containing wound dressing during modeled human exposure to synthetic sweat (SW) or simulated wound fluid (WF). Scanning electron microscopy with energy dispersive X-ray spectroscopy (EDS) revealed the formation of micrometer-sized structures at the wound dressing surface after SW exposure while WF resulted in a largely featureless surface. Measurements by X-ray photoelectron spectroscopy (XPS) revealed a AgCl surface (consistent with EDS) while X-ray diffraction (XRD) found a mixture of zero valent silver and AgCl suggesting the AgNM wound dressings surface formed a passivating AgCl surface layer after SW and WF exposure. For WF, XPS based findings revealed the addition of an adsorbed protein layer based on the nitrogen marker which adsorbed released silver at prolonged exposures. Silver release was evaluated by inductively coupled plasma mass spectrometry which revealed a significant released silver fraction in WF and minimal released silver in SW. Analysis suggests that the protein in WF sequestered a fraction of the released silver which continued with exposure time, suggesting additional processing at the wound dressing surface even after the initial transformation to AgCl. To evaluate the impact on antimicrobial efficacy, zone of inhibition (ZOI) testing was conducted which found no significant change after modeled human exposure compared to the pristine wound dressing. The results presented here suggest AgNM-containing wound dressings transform chemically in simulated human fluids resulting in a material with comparable antimicrobial properties with pristine wound dressings. Ultimately, knowing the resulting chemical properties of the AgNM wound dressings will allow better predictive models to be developed regarding their fate.

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Challenges and approaches for particle size analysis on micrographs of nanoparticles loaded onto textile surfaces

Cited by 10 publications

References 4 publications

Quantitative Analysis of Nanorod Aggregation and Morphology from Scanning Electron Micrographs Using SEMseg

Quantitative Analysis of Nanorod Aggregation and Morphology from Scanning Electron Micrographs Using SEMseg

Fabrication and characterization of chitosan nanoparticles using the coffee‐ring effect for photodynamic therapy

Chemical and physical transformations of silver nanomaterial containing textiles after modeled human exposure

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