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The sequestration of hydroxyapatite nanoparticles by human monocyte-macrophages in a compartment that allows free diffusion with the extracellular environment

Paper ID Volume ID Publish Year Pages File Format Full-Text
7899 568 2011 13 PDF Available
Title
The sequestration of hydroxyapatite nanoparticles by human monocyte-macrophages in a compartment that allows free diffusion with the extracellular environment
Abstract

Calcium phosphate and hydroxyapatite nanoparticles are extensively researched for medical applications, including bone implant materials, DNA and SiRNA delivery vectors and slow release vaccines. Elucidating the mechanisms by which cells internalize nanoparticles is fundamental for their long-term exploitation. In this study, we demonstrate that hydrophilic hydroxyapatite nanoparticles are sequestered within a specialized compartment called SCC (surface-connected compartment). This membrane-bound compartment is an elaborate labyrinth-like structure directly connected to the extracellular space. This continuity is demonstrated by in vivo 2-photon microscopy of ionic calcium using both cell-permeable and cell-impermeable dyes and by 3-D reconstructions from serial block-face SEM of fixed cells. Previously, this compartment was thought to be initiated specifically by exposure of macrophages to hydrophobic nanoparticles. However, we show that the SCC can be triggered by a much wider range of nanoparticles. Furthermore, we demonstrate its formation in A549 human lung epithelial cells, which are considerably less phagocytic than macrophages. EDX shows that extensive amounts of hydroxyapatite nanoparticles can be sequestered in this manner. We propose that SCC formation may be a means to remove large amounts of foreign material from the extracellular space, followed by slow degradation, may be to avoid excessive damage to surrounding cells or tissues.

Keywords
Serial block-face SEM (SBFSEM); Surface-connected compartment; Hydroxyapatite; Nanoparticles; Human monocyte-macrophages; 3D reconstruction
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The sequestration of hydroxyapatite nanoparticles by human monocyte-macrophages in a compartment that allows free diffusion with the extracellular environment
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Publisher
Database: Elsevier - ScienceDirect
Journal: Biomaterials - Volume 32, Issue 35, December 2011, Pages 9470–9482
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us