Biomedical Engineering Reference
In-Depth Information
8
In Vitro
St
udy for Nanomaterials
Seishiro Hirano and Karim Maghni
CONTENTS
8.1 Dose Metrics in
In Vitro
Study ................................................................. 153
8.2 Preparation of Nanoparticle Suspension ................................................ 156
8.3 Cell Type-Based Approach ....................................................................... 157
8.3.1 Macrophages/Monocytes ............................................................. 157
8.3.2 Lung and Bronchial Epithelial Cells ........................................... 158
8.3.3 Fibroblasts ....................................................................................... 158
8.3.4 Endothelial Cell and Heart/Cardiac Cells ................................. 158
8.3.5 Neural, Mesothelial, and Other Cells ......................................... 159
8.4 Nanomaterial-Based Approach ............................................................... 159
8.5 Implications and Recommendation for
In Vitro
Study ......................... 161
References ............................................................................................................. 162
8.1 Dose Metrics in
In Vitro
Study
Particles are taken up by cells through the process of phagocytosis or endo-
cytosis. Phagocytosis is a major pathway for natural immune-related cells
such as macrophages, monocytes, and neutrophils as a host defense mecha-
nism against microorganisms, whereas endocytosis occurs in all types of
cells. Phagocytosis of opsonized particles is initiated after cell membrane
receptors recognize ligands such as Fcγ and C3bi on the particles. Actin mol-
ecules are assembled and the cell membrane extends around the opsonized
particle like a zipper closure. On the other hand, endocytosis is initiated
by invagination of the cell membranes. In either case, the cell membrane is
finally pinched off and the particle is carried inside the cell. In general, parti-
cles >1 μm are taken up by phagocytosis and particles <200 nm by endocyto-
sis. The differences between phagocytosis and endocytosis are schematically
presented in Figure 8.1. Thus, nanoparticles are more likely taken up by cells
via the endocytic pathway unless they are agglomerated [1].
153
