Table 2.

Characterization techniques used to evaluate physicochemical properties of IONPs.

Techniques	Evaluation
Infrared spectroscopy (IR)	Nature of surface functionalization
Nuclear magnetic resonance spectroscopy (NMR)	Longitudinal and transverse relaxivity; Structure conformation
Superconducting quantum interference device (SQUID); Vibrating sample magnetometry (VSM)	Magnetic properties
Electron microscopy (transmission, TEM; scanning, SEM)	Morphology, crystallinity, size distribution, composition
X-ray diffraction (XRD)	Crystal structure, size
Dynamic light scattering (DLS)	Hydrodynamic diameter
Zeta potential measurement	Surface charge
Thermal analysis (differential scanning calorimetry, thermogravimetric analysis, etc.)	Surface coverage, thermal stability, nature of surface functionalization, carrier-drug interaction
Mass spectroscopy	Molecular weight
Fluorescence correlation spectroscopy	Dimension, binding kinetics of hydrodynamic
Surface-enhanced Raman scattering	Size distribution, electronic characteristics
Circular dichroism	Thermal constancy
Scanning tunnelling microscopy; Small-angle X-ray scattering	Shape heterogeneity, size and size navigation
Atomic force microscopy	Shape heterogeneity