Table 2.
Potential analytical techniques for the characterization of corona formation on M/NPs, their strengths and limitations
| Techniques | Corona Information | Sample states | Strengths | Limitations |
|---|---|---|---|---|
| UV–vis | Binding of protein corona to M/NPs | Particles | High reproducible and precision. nondestructive | Not suitable for qualification, susceptible to sample matrix, low sensitivity |
| DLS | Binding of coronas to M/NPs | Particles | Rapid and reproducible measurement of many nanoparticles, nondestructive | Not suitable for qualification and quantification, not suitable for heterogeneous particles |
| Fluorescence microscopy | Binding of coronas to M/NPs | Particles | High sensitive and good for real–time detection | Requirements for fluorescence labeling |
| TEM | Interactions between M/NPs and corona | Particles | High spatial resolution | Not suitable for qualification and quantification |
| SEM | Interactions between M/NPs and corona | Particles | High spatial resolution | Low particle population, poor qualification and quantification |
| AFM | Interactions between M/NPs and corona | Particles | High spatial resolution, possibility for 3D imaging | Poor efficiency |
| EDX | Elemental, especially metal elemental distribution | Particles | High efficiency | Not suitable for organic elements |
| Raman | Structures of organic substances, such as natural organic matters, lipids, persistent organic pollutants | Particles | Broad coverage of both organic and inorganic species | Low spatial resolution |
| FTIR | Structures of organic substances, such as natural organic matters, lipids, persistent organic pollutants | Particles | Good repeatability, high flexibility | Low accuracy and sensitivity, not available for inorganic species |
| ICP–MS | Compositions of metal or metal ions | Acid digested solution | High sensitivity and accuracy, quantification | Not suitable for organic compounds |
| TOF–SIMS | Structures of organic substances, such as natural organic matters, lipids, persistent organic pollutants, proteins | Particles | 3D profile with high mass resolution and spatial resolution | Poor quantification, not suitable for unknown compounds, requirements for samples |
| GC–MS | Compositions of hydrophobic and volatile organic compounds, such as flame retardants, lubricants and plasticizers and persistent organic pollutants | Solvent extracted solution | High sensitivity and reproducibility | Not suitable for thermally labile compounds |
| LC–MS | Compositions of thermally labile coronas, such as proteins, lipids, peptides | Enzyme digested or solvent extracted solution | Broad coverage of compounds, high sensitivity and accuracy | Requirements for multistep sample pretreatment, ex situ analysis |
| CE–MS | Compositions of thermally labile coronas, such as proteins and metabolites | Enzyme digested or solvent extracted solution | High resolution and selectivity | Not suitable for direct analysis of high molecular proteins, limited loading capacity |