Table 1. Physico-chemical characteristics of as-synthesized and post-capped CNPs in hydrated states.
| Nanoparticles | Descrition | Precursor: passivator ratio (w/w) | Dispersibility | Preparation temperature, time* | Post synthesis processing** | DLS (nm) | Zeta (mV) | PDI | Functionality | Surface charge |
|---|---|---|---|---|---|---|---|---|---|---|
| CNP-Pristine | No-passivation | 1:0 | Water | 270 °C; 30 min | Probe sonication; filtration | 46 ± 17 | −17 ± 02 | 0.26 | Bare, Carboxylate, –OH, etc. | Negative |
| CNP-PEG 400 | Pre-passivation | 1:10 | water | 270 °C; 40 min | Probe sonication; filtration | 37 ± 04 | −27 ± 01 | 0.47 | –OH | Negative |
| CNP-PEG 1 K | Pre-passivation | 1:10 | water | 270 °C; 40 min | Probe sonication; filtration | 08 ± 01 | −22 ± 04 | 0.53 | –OH | Negative |
| CNP-PEG 4.6 K | Pre-passivation | 1:10 | water | 270 °C; 40 min | Probe sonication; filtration | 139 ± 07 | −27 ± 03 | 0.22 | –OH | Negative |
| CNP-PEG 10k | Pre-passivation | 1:10 | water | 270 °C; 40 min | Probe sonication; filtration | 28 ± 03 | −22 ± 02 | 0.23 | –OH | Negative |
| CNP-PEG 20k | Pre-passivation | 1:10 | water | 270 °C; 40 min | Probe sonication; filtration | 02 ± 01 | −24 ± 03 | 0.48 | –OH | Negative |
| CNP-Bis-MPA | Post-passivation | 1:10 | water | 270 °C; 30 min then RT | Probe sonication; filtration; incubation | 190 ± 80 | −25 ± 01 | 0.66 | –OH | Negative |
| CNP-PAMAM− | Post-passivation | 1:10 | water | 270 °C; 30 min then RT | Probe sonication; filtration; incubation | 200 ± 50 | −35 ± 01 | 0.55 | –COOH | Negative |
| CNP-PAMAM+ | Post-passivation | 1:10 | water | 270 °C; 30 min then RT | Probe sonication; filtration; incubation | 243 ± 19 | 26 ± 05 | 0.56 | –NH2 | positive |
| CNP-PolyLys | Post-passivation | 1:10 | water | 270 °C; 30 min then RT | Probe sonication; filtration; incubation | 219 ± 22 | 16 ± 06 | 0.64 | –NH2 | Positive |
| CNP-PEI | Post-passivation | 1:10 | water | 270 °C; 30 min then RT | Probe sonication; filtration; incubation | 41 ± 21 | 09 ± 01 | 0.60 | –NH2 | Positive |
Percent distribution of hydrodynamic diameters (number averaged, nm, 0.2 μM nanopure water) and polydispersity indexes were obtained from dynamic light scattering (DLS).
*Preparation temperature and time: Pre-passivated particles were prepared at 270 °C followed by post synthetic processing; whereas post-passivated particles were incubated with the passivating agent at ambient temperature.
**Post synthesis processing: 20-minute probe sonication; Amp 1, On: 2 Sec, Off: 1 Sec, followed by filtration through 0.2 μ cellulosic membrane.