Table 1 Longitudinal relaxation times (T1) of bulk water protons in the presence of bimodal nanosystems, concentration of Gd(III), and the respective relaxivities given per QDs and per Gd(III).

From: Hydrophilic Quantum Dots Functionalized with Gd(III)-DO3A Monoamide Chelates as Bright and Effective T1-weighted Bimodal Nanoprobes

QDs-Gd(III) chelates

Frequency and Temperature

T1 (ms)*

Relaxivity per QDs (mM−1·s−1)

Gd(III) Concentration (x 10−3 mM)

Relaxivity per Gd(III) (mM−1·s−1)

1/20

20 MHz – 25 °C

550

744

35.8

42

20 MHz – 37 °C

560

753

42

60 MHz – 37 °C

890

422

24

1/30

20 MHz – 25 °C

440

971

54.6

36

20 MHz – 37 °C

440

996

36

60 MHz – 37 °C

720

554

20

  1. *An error of ca. 10% was evaluated for the T1 measurements. The concentration of Gd(III) was obtained by ICP, as described in the Experimental Procedure section. The final QDs concentration, obtained from the absorption spectrum, was of approximately 2 μΜ in all the systems. Diamagnetic relaxation rates (R1) were 0.28 s−1 for 20 and 60 MHz (37 °C) and 0.33 s−1 for 20 MHz, 25 °C.
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