Table 2. Different gradient conditions and their impact on synapse formation and neurite orientation across the main channel.

WJC	Experiment	C0,NGF	C0,B27	C0,insulin	∇NGF	∇B27	∇insulin	Slope a	SD a	R	NDrel
µm		ng/ml	% (v/v)	µg/ml	ng/ml/mm	%/mm	µg/ml/mm	1/mm	1/mm		(Nright-Nleft)/Nleft
1000	0B27pNGF-53	216.0	0.0	0.0	52.6	0.0	0.0	NA	NA	NA	∼0%
	2B27	0.0	2.0	4.0	0.0	0.0	0.0	0.022	0.009	0.02	−8%
	2B27pNGF-53	216.0	2.0	4.0	52.6	0.0	0.0	−0.520	0.009	0.58	−12%
	2B27pNGF-100	432.1	2.0	4.0	105.1	0.0	0.0	0.106	0.011	0.17	−14%
	2B27pNGF-200	864.2	2.0	4.0	210.2	0.0	0.0	0.644	0.010	0.77	−24%
	12B27	0.0	6.5	13.0	0.0	1.6	3.2	0.523	0.012	0.65	42%
	12B27pNGF-53	216.0	6.5	13.0	52.6	1.6	3.2	0.704	0.003	0.75	27%
150	12B27pNGF-53	277.0	8.3	16.6	234.1	7.0	14.0	0.871	0.006	0.93	122%

W_JC: Junction channel length, C_{0, XXX}: Maximal concentration of molecule XXX, ∇: gradient, a: gradient slope factor extracted from linear trend curve fits on synapse puncta in the main channel, SD: standard deviation, n = 5, ND_rel: Relative neurite difference, N: neurite frequency, NA: non applicable, right: hydrogel layers LA 1 & LA 2, left: hydrogel layers LA 3 & LA 4.