Table 1. Properties of VGD.

VGD	generation	capping group	number of charges	molecular weight	mass/charge	equivalent N/P ratioa
VGD Precursor
VGD1	n/a	adenine	2	640.3	320	n/a
VGD2	n/a	adenine and thymine	2	645.3	323	n/a
VGD3	n/a	thymine	2	780.5	390	n/a
Comb-Branched VGD
VGD4	G1	ethyl	10	2553	255	0.5
VGD5	G1	thymine	10	3105	311	1.0
VGD6	G2	thymine	26	7812	301	1.2
Spheroidal VGD
VGD7	G0	Methyl	6	1501	250	0.6
VGD8	G0	thymine	6	1300	217	0.7
VGD9	G1	ethyl	18	2687	149	1.0
VGD10	G1	thymine	18	4316	240	1.3
VGD11	G2	thymine	42	7947	189	1.0
VGD12	G3	ethyl	90	23 350	259	1.1
VGD13	G3	thymine	90	26 679	296	1.1
Control
PEI				25 000 (Mw)	43.0	2.4

^aMinimum N/P ratio required to condense plasmid DNA.