Environmental Engineering Reference
In-Depth Information
3-D kidney organoid proximal tubule culture was found to be suitable to detect
the toxicity of hydroxylated generation-5 PAMAM dendrimer and gold
nanoparticles [
18
]. While biochemistry assay, pathological examination and
metal content measurement in tissue might be interesting to understand in vivo
fate of metal nanoparticles. Intracellular stress response is often investigated with
H2DCF-DA (20,70-dichlorodihydrofluoresc(e) in diacetate) probe or mitochon-
drial membrane potential (MMP).
6.4 Analytical Techniques Used In Vitro and In Vivo
Studies
Deep understanding of factors like amount of nanoparticles reaching to the cells,
experimental conditions, and amount of nanoparticles/volume cell culture medium
containing the cell can improve the correlations between dose and response.
Equally important is technique selection.
In addition to particle sizing and aggregation stability assays performed in vitro
at different pH conditions and in relevant biological simulated fluid is an important
to predict their interaction in body. Many techniques are used to characterize
particle size, e.g. TEM, scanning electron microscopy (SEM), optical spectroscopy,
dynamic light scattering, laser diffractometry, and fluorescence polarization.
Mainly conclusions are based on results obtained from two techniques. Addition-
ally, each method possesses its own advantages and limitations. Large angle X-ray
diffraction (XRD) is mainly used to differentiate between crystalline and amor-
phous nature material while small angle X-ray scattering (SAXS) and small angle
neutron scattering (SANS) can be used to analyze particle size and shape of core
and shell structure. In many cases, multi-angle laser light scattering (MALLS) is
used together with UV-visible spectroscopy in field flow fractionation (FFF) for
size determination and separation.
Specific surface analysis methods are limited in number and can be employed to
analyze surface contaminants of nanoparticles by using one or many surface analysis
techniques like time-of-flight secondary ion mass spectrometry (ToF-SIMS), X-ray
photoelectron spectroscopy (XPS), X-ray fluorescence (XRF), energy dispersive
X-ray analysis (EDX), time-resolved fluorescence polarization anisotropy
(TRFPA) can size 1-10 nm particles may be sized with 0.1 nm resolution and
surface-enhanced Raman spectroscopy (SERS). These techniques can also be used
to identify impurities in products or determination of mass coverage by functiona-
lization. Metal content, metal based impurities can be detected by coupled plasma-
mass spectroscopy (ICP-MS), inductively coupled plasma-atomic emission spectros-
copy (ICPAES) but these methods have limitations over detection of size and shape.
Electrochemistry is widely used as an alternative characterization technique
to microscopy and spectroscopy. New electrochemical detection methods like
“nano-impacts” or “single nanoparticle collisions” offer in-situ detection of metal
