Real-time reconstruction of arbitrary slices for quantitative and in-situ three-dimensional characterization of nanoparticles

2021 ◽  
Author(s):  
Hans Vanrompay ◽  
Keyword(s):  
Gels ◽  
2018 ◽  
Vol 4 (4) ◽  
pp. 86 ◽  
Author(s):  
Brenda Molina ◽  
Eva Domínguez ◽  
Elaine Armelin ◽  
Carlos Alemán

In this work, we report the design and fabrication of a dual-function integrated system to monitor, in real time, the release of previously loaded 2-methyl-1,4-naphthoquinone (MeNQ), also named vitamin K3. The newly developed system consists of poly(3,4-ethylenedioxythiophene) (PEDOT) nanoparticles, which were embedded into a poly-γ-glutamic acid (γ-PGA) biohydrogel during the gelling reaction between the biopolymer chains and the cross-linker, cystamine. After this, agglomerates of PEDOT nanoparticles homogeneously dispersed inside the biohydrogel were used as polymerization nuclei for the in situ anodic synthesis of poly(hydroxymethyl-3,4-ethylenedioxythiophene) in aqueous solution. After characterization of the resulting flexible electrode composites, their ability to load and release MeNQ was proven and monitored. Specifically, loaded MeNQ molecules, which organized in shells around PEDOT nanoparticles agglomerates when the drug was simply added to the initial gelling solution, were progressively released to a physiological medium. The latter process was successfully monitored using an electrode composite through differential pulse voltammetry. The fabrication of electroactive flexible biohydrogels for real-time release monitoring opens new opportunities for theranostic therapeutic approaches.


2000 ◽  
Author(s):  
David R. Snelling ◽  
Gregory J. Smallwood ◽  
Robert A. Sawchuk ◽  
W. Stuart Neill ◽  
Daniel Gareau ◽  
...  

2011 ◽  
Vol 29 (3) ◽  
pp. E62-E66 ◽  
Author(s):  
Maria Riccarda Del Bene ◽  
Francesco Cappelli ◽  
Luigi Rega ◽  
Francesco Venditti ◽  
Giuseppe Barletta

2012 ◽  
Vol 49 (10) ◽  
pp. 1212-1220 ◽  
Author(s):  
Dinh Hong Doan ◽  
Pierre Delage ◽  
Jean François Nauroy ◽  
Anh Minh Tang ◽  
Souhail Youssef

The microstructure of oil sand samples extracted at a depth of 75 m from the estuarine Middle McMurray Formation (Alberta, Canada) has been investigated using high resolution three-dimensional (3D) X-ray microtomography (µCT) and cryo scanning electron microscopy (CryoSEM). µCT images evidenced some dense areas composed of highly angular grains surrounded by fluids, which are separated by larger pores full of gas. In dense areas, 3D image analysis provided porosity values comparable with in situ log data and macroscopic laboratory determinations, showing that they are representative of intact states. µCT hence provided some information on the morphology of the cracks and disturbance created by gas expansion. The CryoSEM technique, in which the sample is freeze fractured within the SEM chamber prior to observation, provided pictures in which the (frozen) bitumen clearly appears between the sand grains. No evidence of the existence of a thin connate water layer between grains and the bitumen, frequently mentioned in the literature, has been obtained. Bitumen appears to strongly adhere to the grains, with some grains being completely coated. The curved shape of some bitumen menisci suggests a bitumen wet behaviour.


2009 ◽  
Vol 75 (23) ◽  
pp. 7426-7435 ◽  
Author(s):  
Gabriela Hidalgo ◽  
Andrew Burns ◽  
Erik Herz ◽  
Anthony G. Hay ◽  
Paul L. Houston ◽  
...  

ABSTRACT Attached bacterial communities can generate three-dimensional (3D) physicochemical gradients that create microenvironments where local conditions are substantially different from those in the surrounding solution. Given their ubiquity in nature and their impacts on issues ranging from water quality to human health, better tools for understanding biofilms and the gradients they create are needed. Here we demonstrate the use of functional tomographic imaging via confocal fluorescence microscopy of ratiometric core-shell silica nanoparticle sensors (C dot sensors) to study the morphology and temporal evolution of pH microenvironments in axenic Escherichia coli PHL628 and mixed-culture wastewater biofilms. Testing of 70-, 30-, and 10-nm-diameter sensor particles reveals a critical size for homogeneous biofilm staining, with only the 10-nm-diameter particles capable of successfully generating high-resolution maps of biofilm pH and distinct local heterogeneities. Our measurements revealed pH values that ranged from 5 to >7, confirming the heterogeneity of the pH profiles within these biofilms. pH was also analyzed following glucose addition to both suspended and attached cultures. In both cases, the pH became more acidic, likely due to glucose metabolism causing the release of tricarboxylic acid cycle acids and CO2. These studies demonstrate that the combination of 3D functional fluorescence imaging with well-designed nanoparticle sensors provides a powerful tool for in situ characterization of chemical microenvironments in complex biofilms.


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