Table 2.
Quality of the information provided by different techniques (and parameters evaluated) in each of the steps involved in the bioconjugation of AuNPs.a
| Technique | Purpose of the evaluation (parameter)a,b |
|||
|---|---|---|---|---|
| 1 | 2 | 3 | 4 | |
| TEM | ++++ (d) | - (dns) | ND | ND |
| UV/VIS | ++++ (λLSPR) | ++ (ΔλLSPR) | ++ (ΔλLSPR) | ++ (520/650 nm) |
| DLS | ++++ (dh, PI) | +++ (Δdh, PI) | ++ (Δdh, PI) | - |
| ζ-potential | ++ (ζ) | ++ (Δζ) | + (Δζ) | ND |
| FTIR | ++ (υ) | - | ND | ND |
| Colloidal stability (titration) | ++ (Ccrit) | ++++ (ΔCcrit) | AuNP-cit: ++++ AuNP-MUA: -(ΔCcrit) |
ND |
| Colloidal stability (end-point) | - | ++++ (520/650 nm) | AuNP-cit: ++++ AuNP-MUA: -(520/650 nm) |
++ (520/650 nm) |
| Electrochemistry | - | ++++ (dns) (ΔEp, k0) |
AuNP-cit: ++++ (ΔEp, k0) | ND |
| Electrophoresis | - | ++++ (ΔRf) | AuNP-cit: -AuNP-MUA: ++++ (ΔRf) | ++ (ΔRf) |
| SEC | - | ++++ (Ve) | AuNP-cit: ++++ AuNP-MUA: ++++ (Ve, ΔVe) |
++++ (Ve, ΔVe) |
a
Based on the nomenclature used in Figure 1. 1) Characterization of AuNP-cit. 2) ligand exchange (cit → MUA) evaluation. 3) Ab immobilization on AuNP-cit and AuNP-MUA. 4) Comparison between proteins immobilized on AuNP-cit.
b
From “+” (poor/ambiguous) to “++++” (conclusive), “-”: not relevant information. “ND”: experiment not done. “dns”: data not shown.