TABLE 1.

Experimental and Theoretical Stokes–Einstein Diffusion Coefficients for CNTs and Small Molecules

	apparent diffusion coefficient, Da (m2/s in PBS pH = 7.4)	diameter of HepG2 spheroid (μm)	ζ potential or molecular charge (mV) (in PBS pH = 7.4)	Stokes–Einstein diffusion coefficient, D (m2/s in tissue)
CNT-TGFβ1-FITC	(1.5 ± 0.2) × 10−13	141.9 ± 5.6	−8.4 ± 0.31	5.7 × 10−16
CNT-FITC	(0.9 ± 0.3) × 10−14	170.8 ± 4.5	−0.01 ± 0.001	5.7 × 10−16
TGFβ1	(2.5 ± 0.3) × 10−13	147.2 ± 5.0	−4.7 ± 0.02	5.7 × 10−15
RhB	(5.9 ± 0.3) × 10−13	139.7 ± 2.7	positive	1.8 × 10−14
FITC	(1.6 ± 0.3) × 10−14	136.4 ± 2.4	negative	4.1 × 10−14