scholarly journals Correlative cathodoluminescence electron microscopy bioimaging: towards single protein labelling with ultrastructural context

Nanoscale ◽  
2020 ◽  
Vol 12 (29) ◽  
pp. 15588-15603
Author(s):  
Kerda Keevend ◽  
Toon Coenen ◽  
Inge K. Herrmann

We discuss the opportunities and challenges of correlative cathodoluminescence electron microscopy for biomedical applications.

2021 ◽  
Vol 22 (11) ◽  
pp. 5730
Author(s):  
Jomarien García-Couce ◽  
Marioly Vernhes ◽  
Nancy Bada ◽  
Lissette Agüero ◽  
Oscar Valdés ◽  
...  

Hydrogels obtained from combining different polymers are an interesting strategy for developing controlled release system platforms and tissue engineering scaffolds. In this study, the applicability of sodium alginate-g-(QCL-co-HEMA) hydrogels for these biomedical applications was evaluated. Hydrogels were synthesized by free-radical polymerization using a different concentration of the components. The hydrogels were characterized by Fourier transform-infrared spectroscopy, scanning electron microscopy, and a swelling degree. Betamethasone release as well as the in vitro cytocompatibility with chondrocytes and fibroblast cells were also evaluated. Scanning electron microscopy confirmed the porous surface morphology of the hydrogels in all cases. The swelling percent was determined at a different pH and was observed to be pH-sensitive. The controlled release behavior of betamethasone from the matrices was investigated in PBS media (pH = 7.4) and the drug was released in a controlled manner for up to 8 h. Human chondrocytes and fibroblasts were cultured on the hydrogels. The MTS assay showed that almost all hydrogels are cytocompatibles and an increase of proliferation in both cell types after one week of incubation was observed by the Live/Dead® assay. These results demonstrate that these hydrogels are attractive materials for pharmaceutical and biomedical applications due to their characteristics, their release kinetics, and biocompatibility.


Nanomaterials ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 78 ◽  
Author(s):  
Priscila Siqueira ◽  
Éder Siqueira ◽  
Ana Elza De Lima ◽  
Gilberto Siqueira ◽  
Ana Delia Pinzón-Garcia ◽  
...  

Hydrogels have been studied as promising materials in different biomedical applications such as cell culture in tissue engineering or in wound healing. In this work, we synthesized different nanocellulose-alginate hydrogels containing cellulose nanocrystals, TEMPO-oxidized cellulose nanocrystals (CNCTs), cellulose nanofibers or TEMPO-oxidized cellulose nanofibers (CNFTs). The hydrogels were freeze-dried and named as gels. The nanocelluloses and the gels were characterized by different techniques such as Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and dynamic mechanical thermal analysis (DMTA), while the biological features were characterized by cytotoxicity and cell growth assays. The addition of CNCTs or CNFTs in alginate gels contributed to the formation of porous structure (diameter of pores in the range between 40 and 150 μm). TEMPO-oxidized cellulose nanofibers have proven to play a crucial role in improving the dimensional stability of the samples when compared to the pure alginate gels, mainly after a thermal post-treatment of these gels containing 50 wt % of CNFT, which significantly increased the Ca2+ crosslinking density in the gel structure. The morphological characteristics, the mechanical properties, and the non-cytotoxic behavior of the CNFT-alginate gels improved bioadhesion, growth, and proliferation of the cells onto the gels. Thus, the alginate-nanocellulose gels might find applications in tissue engineering field, as for instance, in tissue repair or wound healing applications.


2012 ◽  
Vol 507 ◽  
pp. 127-133 ◽  
Author(s):  
Sigrid Seuss ◽  
Tayyab Subhani ◽  
Min Yi Kang ◽  
Kenji Okudaira ◽  
Isaac E. Aguilar Ventura ◽  
...  

Electrophoretic deposition (EPD) has been successfully used to deposit composite coatings composed of polyetheretherketone (PEEK) and titanium dioxide (TiO2) nanoparticles on 316L stainless steel substrates. The suspensions of TiO2 nanoparticles and PEEK microparticles for EPD were prepared in ethanol. PEEK-TiO2 composite coatings were optimized using suspensions containing 6wt% PEEK-TiO2 in ethanol with a 3:1 ratio of PEEK to TiO2 in weight and by applying a potential difference of 30 V for 1 minute. A heat-treatment process of the optimized PEEK-TiO2 composite coatings was performed at 335°C for 30 minutes with a heating rate of 10°Cminto densify the deposits. The EPD coatings were microstructurally evaluated by scanning electron microscopy (SEM). It was demonstrated that EPD is a convenient and rapid method to fabricate PEEK/TiO2 coatings on stainless steel which are interesting for biomedical applications.


2015 ◽  
Vol 638 ◽  
pp. 27-30 ◽  
Author(s):  
Stefan Ioan Voicu ◽  
Alexandru Muhulet ◽  
Iulian Antoniac ◽  
Marijana Simina Corobea

This paper presents a comparative study of cellulose acetate membranes, respectively nitrocellulose membranes, synthesized under the same conditions for the retention of proteins from aqueous solutions. It has also been studied the hydrodynamic behavior of the membranes, measuring water, respectively ethanol flow rates, and the retention of proteins. The membranes have been characterized by scanning electron microscopy in order to study the morphological differences.


2014 ◽  
Vol 614 ◽  
pp. 47-51
Author(s):  
Hella Mahjoub ◽  
Codruța Sarosi ◽  
Olga Orasan ◽  
Aniela Saplonţai-Pop

Synthetic Polymers, both organic and inorganic, are used in a wide variety of biomedical applications. The polymers can be biodegradable or nondegradable. Chitosan (CH), which is a naturally biodegradable, non-toxic biopolymer obtained by the deacetylation of chitin, has been demonstrated to have an intrinsic activity against a wide spectrum of bacteria, filamentous fungi and yeast. Several investigators have studied reinforced tricalcium phosphate (TCP), Chitosan, polymethylmethacrylate (PMMA)/methyl methacrylate (MMA) as potential cement. In fact addition of TCP with chitosan to the cement can improve biocompatibility and also enhance the mechanical properties of the cement because of its both biocompatibility and osteoconductivity properties. Crystalline phase and microstructure of the cement with hydroxyapatite - poly (methyl-methacrylate) were characterized by scanning electron microscopy (SEM; FEI Company), with the purpose to draw solid conclusions about the influence of the particles size, form and uniform mixing on the chemical process. We acquired PMMA sorted according to granulometric size.


Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6554
Author(s):  
James Alexander ◽  
Huan Dong ◽  
Deepa Bose ◽  
Ali Abdelhafeez Hassan ◽  
Sein Leung Soo ◽  
...  

Titanium oxide layers were produced via a novel catalytic ceramic conversion treatment (CCCT, C3T) on Ti-6Al-4V. This CCCT process is carried out by applying thin catalytic films of silver and palladium onto the substrate before an already established traditional ceramic conversion treatment (CCT, C2T) is carried out. The layers were characterised using scanning electron microscopy, X-ray diffraction, transmission electron microscopy; surface micro-hardness and reciprocating tribological performance was assessed; antibacterial performance was also assessed with s. aureus. This CCCT has been shown to increase the oxide thickness from ~ 5 to ~ 100 µm, with the production of an aluminium rich layer and agglomerates of silver and palladium oxide surrounded by vanadium oxide at the surface. The wear factor was significantly reduced from ~ 393 to ~ 5 m3/N·m, and a significant reduction in the number of colony-forming units per ml of Staphylococcus aureus on the CCCT surfaces was observed. The potential of the novel C3T treatment has been demonstrated by comparing the performance of C3T treated and untreated Ti6Al4V fixation pins through inserting into simulated bone materials.


2001 ◽  
Vol 7 (S2) ◽  
pp. 132-133
Author(s):  
D.J. Stokes ◽  
S.M. Rea ◽  
A.E. Porter ◽  
S.M. Best ◽  
W. Bonfield

The ability of ESEM to image insulating and/or moist specimens without the need for the removal of volatile components or the application of a conductive coating has significantly increased the potential range of experiments and observations that can be performed at the high resolution of electron microscopy. Such a technological advance has particularly important implications for the study of soft matter, complex fluids and biological specimens.An important area of study to which ESEM can be readily applied is that of materials for biomedical applications. Hydroxyapatite (HA) ceramics and HA/polymer composites (e.g. HAPEX™) are being developed for use as synthetic scaffolds in bone tissue engineering. The bioactivity of these materials is dependent upon such factors as phase composition, chemical composition, surface activity, crystallinity and microstructure. Using ESEM it is possible to obtain surface-sensitive, specimen-dependent secondary electron images (in the absence of specimen coating), yielding potentially new perspectives on microstructure to complement information derived from other techniques.


Author(s):  
Sharmila C ◽  
Ranjith Kumar R ◽  
Chandar Shekar B

 Objective: Synthesis of silver nanoparticles (AgNPs) using a simple, cost-effective and environmentally friendly green route approach and to study the antibacterial activity of AgNPs against human pathogens.Methods: Green route approach is used to synthesize AgNPs using Psidium guajava leaf extract. Fourier transform infrared (FTIR) was used to identify the presence of the functional group. X-ray diffraction (XRD) was used to analyze the structure of prepared AgNPs. Energy dispersive X-ray was used to the characteristic to the composition of the prepared nanoparticles. Size and morphology of the prepared AgNPs were investigated using field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) analysis. Antibacterials efficiency of prepared AgNPs was tested against Escherichia coli and Staphylococcus aureus by well diffusion methods.Results: FTIR study shows the presence of different functional groups present in the leaves mediated AgNPs. The XRD studies yield diffraction peaks corresponding to face-centered cubic structure of Ag crystals. Spherical shaped AgNPs with a particle size of about ~55 nm were evidenced using FESEM and TEM analysis. Energy dispersive spectrum of the synthesized AgNPs confirms the presence of silver in the prepared nanoparticles. From UV-VIS analysis it is shown that the absorption band was red-shifted from 430 nm to 456 nm. The prepared AgNPs shows good antibacterial activity against E. coli and S. aureus.Conclusions: P. guajava leaf extract is a potential reducing agent to synthesize AgNPs. The green synthesis approach provides cost-effective and eco-friendly nanoparticles, which could be used in biomedical applications.


2019 ◽  
Vol 12 (04) ◽  
pp. 1950062
Author(s):  
Zhongyan Gao ◽  
Qiang Ding ◽  
Qizhi Diao ◽  
Zhongying Guan ◽  
Biqiong Liu

Considering the high interests and concerns in regards to quantum dots (QDs), their properties and applications, this paper presents highly photoluminescent amino-functionalized carbon QDs which were prepared via a simple one-step method developed directly from pine needle. They were characterized by X-ray powder diffraction, photoluminescence (PL), UV-Vis diffused reflectance spectra, transmission electron microscope and scanning electron microscopy. These carbon QDs show strong and stable PL, which is dependent on excitation wavelength. The intense PL under longer excitation wavelength and excellent bioactivities suggest they can be used for biomedical applications due to its high photostability and biocompatibility.


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