Table 1.

Equivalent circuit elements, their boundaries, and average fitted values for each skin treatment, at t_0, t_mid, and t_f. The range for each parameter was determined based on values in literature [4,17], as well as considering the total impedance (see Equation (1) and Figure 2b). Values are reported as avg. ± std. dev. across N = 14 subjects.

		Rsub [kΩ cm2]	Repi [kΩ cm2]	Cepi [nF cm−2]	Rgel [kΩ cm2]	Rct [kΩ cm2]	Cdl [nF cm−2]	Model Fit ${\mathit{\chi }}^2$ (×102)
Lower-Upper Parameter bounds		0.05–5.00	0.10–500	0.10–500	0.05–5.00	0.5–5.0 × 103	1.0–1.0 × 105	—
No Treatment	t 0	0.71 ± 0.16	86.38 ± 29.43	242.62 ± 148.41	0.87 ± 0.46	(1.31 ± 1.27) × 103	5.38 ± 2.19	3.75 ± 0.71
	tmid	0.74 ± 0.19	47.07 ± 33.09	27.98 ± 26.86	1.07 ± 0.90	147.93 ± 101.27	63.42 ± 25.62	2.18 ± 1.85
	tf	0.71 ± 0.20	40.90 ± 30.70	34.70 ± 19.11	0.72 ± 0.42	66.54 ± 31.96	36.29 ± 15.24	3.09 ± 0.84
Abrasive Tape	t 0	0.70 ± 0.20	6.61 ± 5.02	4.95 ± 3.73	0.59 ± 0.13	2.90 ± 2.39	7.00 ± 2.90	2.97 ± 0.75
	tmid	0.72 ± 0.18	1.80 ± 1.45	8.49 ± 2.46	0.59 ± 0.11	3.30 ± 2.66	10.50 ± 6.56	0.27 ± 0.08
	tf	0.67 ± 0.22	2.27 ± 1.39	28.28 ± 20.65	0.76 ± 0.48	1.26 ± 0.49	12.23 ± 4.27	0.36 ± 0.18
Salicylic Acid	t 0	0.79 ± 0.14	69.43 ± 30.09	97.63 ± 76.73	0.65 ± 0.14	675.80 ± 501.10	9.97 ± 5.40	4.72 ± 0.97
	tmid	0.77 ± 0.18	48.39 ± 32.86	47.81 ± 27.09	1.17 ± 1.02	17.67 ± 14.97	9.88 ± 9.54	0.97 ± 0.05
	tf	0.77 ± 0.16	35.97 ± 33.36	44.74 ± 31.84	1.36 ± 1.18	12.76 ± 9.71	7.70 ± 3.40	1.15 ± 0.49
µNeedle Array	t 0	0.81 ± 0.14	81.56 ± 31.34	29.46 ± 22.32	0.67 ± 0.17	807.42 ± 394.97	5.05 ± 2.17	4.15 ± 1.40
	tmid	0.74 ± 0.18	46.50 ± 35.41	24.59 ± 21.80	1.19 ± 1.09	92.16 ± 60.74	9.50 ± 5.52	2.62 ± 1.34
	tf	0.71 ± 0.16	35.36 ± 32.01	33.65 ± 28.34	0.91 ± 0.67	72.29 ± 30.89	5.38 ± 2.19	1.22 ± 0.40