Scanning Electron Microscopy-Based Approach to Understand the Mechanism Underlying the Adhesion of Dengue Viruses on Ceramic Hydroxyapatite Columns

Saito, Maiko; Kurosawa, Yae; Okuyama, Tsuneo

doi:10.1371/journal.pone.0053893

Cited by 12 publications

(8 citation statements)

References 19 publications

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“…Recently, the purification of dengue virus on Hap with 64% recovery was reported (Yae et al, ). The same research group investigated the fundamental mechanism of adsorption and desorption of dengue virus onto HAp media by scanning electron microscopy (SEM) (Saito et al, ). The dengue viruses bound to the HAp surface by electrostatic interactions, and, subsequently, temperature‐dependent virus envelope fusion was thought to occur.…”

Section: Chromatographymentioning

confidence: 99%

Improved virus purification processes for vaccines and gene therapy

Nestola

Peixoto

Silva

et al. 2015

Biotech & Bioengineering

113

106

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The downstream processing of virus particles for vaccination or gene therapy is becoming a critical bottleneck as upstream titers keep improving. Moreover, the growing pressure to develop cost-efficient processes has brought forward new downstream trains. This review aims at analyzing the state-of-the-art in viral downstream purification processes, encompassing the classical unit operations and their recent developments. Emphasis is given to novel strategies for process intensification, such as continuous or semi-continuous systems based on multicolumn technology, opening up process efficiency. Process understanding in the light of the pharmaceutical quality by design (QbD) initiative is also discussed. Finally, an outlook of the upcoming breakthrough technologies is presented.

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Section: Chromatographymentioning

confidence: 99%

Improved virus purification processes for vaccines and gene therapy

Nestola

Peixoto

Silva

et al. 2015

Biotech & Bioengineering

113

106

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“…Nevertheless, drug loading via co-precipitation onto CAP at the atomic scale is limited to physisorption, given that there is no ability to entrap the drug within the crystal lattice or have it chemically conjugated to the surface. On one hand, owing to the alternation of intensely charged multivalent species (Ca 2+ , PO 4 3− ) on the particle surface, CAP can relatively strongly bind a variety of organic molecules [ 22 , 23 , 24 ]. On the other hand, such strong binding usually does not stand in the way of a considerable amount of burst release that occurs in the first minutes of the contact of the material with the solution [ 25 ].…”

Section: Cap As a Tunable Drug Release Carrier And A Viscous Selfmentioning

confidence: 99%

Calcium Phosphate as a Key Material for Socially Responsible Tissue Engineering

Uskoković

2016

Materials

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Socially responsible technologies are designed while taking into consideration the socioeconomic, geopolitical and environmental limitations of regions in which they will be implemented. In the medical context, this involves making therapeutic platforms more accessible and affordable to patients in poor regions of the world wherein a given disease is endemic. This often necessitates going against the reigning trend of making therapeutic nanoparticles ever more structurally complex and expensive. However, studies aimed at simplifying materials and formulations while maintaining the functionality and therapeutic response of their more complex counterparts seldom provoke a significant interest in the scientific community. In this review we demonstrate that such compositional simplifications are meaningful when it comes to the design of a solution for osteomyelitis, a disease that is in its natural, non-postoperative form particularly prevalent in the underdeveloped parts of the world wherein poverty, poor sanitary conditions, and chronically compromised defense lines of the immune system are the norm. We show that calcium phosphate nanoparticles, which are inexpensive to make, could be chemically designed to possess the same functionality as a hypothetic mixture additionally composed of: (a) a bone growth factor; (b) an antibiotic for prophylactic or anti-infective purposes; (c) a bisphosphonate as an antiresorptive compound; (d) a viral vector to enable the intracellular delivery of therapeutics; (e) a luminescent dye; (f) a radiographic component; (g) an imaging contrast agent; (h) a magnetic domain; and (i) polymers as viscous components enabling the injectability of the material and acting as carriers for the sustained release of a drug. In particular, calcium phosphates could: (a) produce tunable drug release profiles; (b) take the form of viscous and injectable, self-setting pastes; (c) be naturally osteo-inductive and inhibitory for osteoclastogenesis; (d) intracellularly deliver bioactive compounds; (e) accommodate an array of functional ions; (f) be processed into macroporous constructs for tissue engineering; and (g) be naturally antimicrobial. All in all, we see in calcium phosphates the presence of a protean nature whose therapeutic potentials have been barely tapped into.

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“…Little has been reported on the drying technique best suited for the ultrastructural visualization of chromatography resin under scanning electron microscopy. There have been reports of the use of air drying , spray drying as well as the water‐to‐absolute ethanol dehydration technique . However, each one of the aforementioned techniques does not provide a sufficient level of drying for the visualization and characterization of an agarose bead on the nanometer scale.…”

Section: Introductionmentioning

confidence: 99%

Drying techniques for the visualisation of agarose‐based chromatography media by scanning electron microscopy

Nweke

Turmaine

McCartney

et al. 2017

Biotechnology Journal

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The drying of chromatography resins prior to scanning electron microscopy is critical to image resolution and hence understanding of the bead structure at sub-micron level. Achieving suitable drying conditions is especially important with agarose-based chromatography resins, as overdrying may cause artefact formation, bead damage and alterations to ultrastructural properties; and under-drying does not provide sufficient resolution for visualization under SEM. This paper compares and contrasts the effects of two drying techniques, critical point drying and freeze drying, on the morphology of two agarose based resins (MabSelect TM /d w ≈85 µm and Capto TM Adhere/d w ≈75 µm) and provides a complete method for both. The results show that critical point drying provides better drying and subsequently clearer ultrastructural visualization of both resins under SEM. Under this protocol both the polymer fibers (thickness ≈20 nm) and the pore sizes (diameter ≈100 nm) are clearly visible. Freeze drying is shown to cause bead damage to both resins, but to different extents. MabSelect resin encounters extensive bead fragmentation, whilst Capto Adhere resin undergoes partial bead disintegration, corresponding with the greater extent of agarose crosslinking and strength of this resin. While freeze drying appears to be the less favorable option for ultrastructural visualization of chromatography resin, it should be noted that the extent of fracturing caused by the freeze drying process may provide some insight into the mechanical properties of agarose-based chromatography media.

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Scanning Electron Microscopy-Based Approach to Understand the Mechanism Underlying the Adhesion of Dengue Viruses on Ceramic Hydroxyapatite Columns

Cited by 12 publications

References 19 publications

Improved virus purification processes for vaccines and gene therapy

Improved virus purification processes for vaccines and gene therapy

Calcium Phosphate as a Key Material for Socially Responsible Tissue Engineering

Drying techniques for the visualisation of agarose‐based chromatography media by scanning electron microscopy

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