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. Author manuscript; available in PMC: 2015 Jan 15.
Published in final edited form as: Biomaterials. 2009 Sep 1;30(32):6451–6459. doi: 10.1016/j.biomaterials.2009.07.067

Fig. 4.

Fig. 4

Au-spermidine-DNA stored at 4°C or Au-protamine-DNA particles stored at 25°C or 60°C for 1, 2, or 3 months and then administered to mice as aged vaccine. Y-axis represents immuno-titer of Hepatitis B core antigen “cAg” (middle panel) or surface antigen “sAg” (bottom panel) relative to animals treated with control (standard HepB protein vaccine) [8, 25–26]. Protamine samples significantly different than their corresponding matched set of spermidine controls by Students t-test statistic are indicated with an asterisk (p < 0.050). Gel analysis (top panel) of these time and temperature treatments revealed retention of substantial intact supercoiled and open circle DNA forms for several months. Legend: OC = open coil DNA; SC = supercoiled DNA; t-0 = non-degraded sample; con4-1 = control at 4°C for 1 month; con4-2 = control at 4°C for 2 months; con4-3 = control at 4°C for 3 months; Prt25-1 = protamine at 25°C for 1 month; Prt25-2 = protamine at 25°C for 2 months; Prt25-3 = protamine at 25°C for 3 months; Prt60-1 = protamine at 60°C for 1 month; Prt60-2 = protamine at 60°C for 2 months; Prt60-3 = protamine at 60°C for 3 months.