Table 1.

Transport of polystyrene and polystyrene–polyethylene glycol nanoparticles in native or N-acetyl cysteine-treated cystic fibrosis sputum.

Surface chemistry	Diameter (nm)†	Zeta potential (mV)‡	Mucolytics	α §	Dw/<Deff>¶
COOH	217 ± 5	-59 ± 4	–	0.31	2600
			NAC	0.50	530
PEG	213 ± 6	-1 ± 4	–	0.70	85
			NAC	0.91	8
COOH	515 ± 7	-61 ± 1	–	0.31	1600
			NAC	0.41	1000
PEG	515 ± 16	-4 ± 1	–	0.46	350
			NAC	0.73	100

^†Measured by dynamic light scattering. Error values represent standard error of the mean.

^‡Measured at pH 7.0. Error values represent standard error of the mean.

^§Calculated by fitting data in Figures 1A & 3Ato <mean square displacement> = 4D_oτ^α, where D_o is diffusivity and α is anomalous exponent equal to or less than 1. The larger the deviation from 1, the higher the degree of hindrance to particle motion.

^¶D_w is the theoretical diffusivity of particles in water calculated from the Stokes–Einstein equation and <D_eff> is measured in cystic fibrosis sputum at time scale of 1 s. The D_w/<D_eff> ratio indicates by how many fold the transport of particles in cystic fibrosis sputum is slower than in pure water.

D_eff: Effective diffusivity; NAC: N-acetyl cysteine; PEG: Polyethylene glycol.