Fig. 2

The assembly and characterization of nanovaccines. a Schematic diagram for the assembly of nanovaccines. In the assembly of nanovaccine, the molecular ratio between PRBS and RBD protein was 5:2. The molecular ratio between PRBS and HIV plasmid was 59:2. b TEM images of PRBS-RBD protein nanovaccine. c TEM images of PRBS-HIV plasmid nanovaccine. d DLS exhibited that the hydrate size of PRBS-RBD protein nanovaccine was around 300 nm e DLS exhibited that the hydrate size of PRBS-HIV plasmid nanovaccine was around 350 nm. f The average zeta potential of PRBS-RBD protein nanovaccine was 0 mV. g The average zeta potential of PRBS-HIV plasmid nanovaccine was -10 mV. h Standard calorimetric titrations of 0.108 μM RBD protein into 0.029 μM PRBS solution at 25 ℃. i Standard calorimetric titrations of 3.03 μM HIV DNA plasmid into 7.06 μM PRBS solution at 25 ℃. j The thermodynamic parameters of PRBS-RBD protein nanovaccine and PRBS-HIV plasmid nanovaccine such as equilibrium dissociation constant (Kd), Gibbs free energy (ΔG), enthalpy changes (ΔH), entropy changes (ΔS) and binding stoichiometry (N). (k) The fitting data of ITC from PRBS-RBD protein nanovaccine. ΔG, ΔH, − TΔS represented Gibbs free energy of binding (blue), enthalpy changes (green), entropy changes (red). l The fitting data of ITC from PRBS-HIV plasmid nanovaccine. ΔG, ΔH, − TΔS represented Gibbs free energy of binding (blue), enthalpy changes (green), entropy changes (red). m The structure mode of PRBS-RBD protein nanovaccine. Left part: RBD and PRBS were marked by grey and cyan. Right part: PRBS was depicted by sticks (C, cyan; N, blue; O, red and H, hydrogen). Residues were depicted by sticks (C, royal blue; N, blue; O, red and H, hydrogen). Hydrogen bonds were shown by yellow dotted lines. The length of bond (Å) was shown in the figure. n The structure mode of PRBS-HIV plasmid nanovaccine. Left part: HIV plasmid and PRBS were marked by grey and cyan. Right part: PRBS was depicted by sticks (C, cyan; N, blue; O, red and H, hydrogen). The nucleotides of HIV plasmid were depicted by sticks (C, royal blue; N, blue; O, red and H, hydrogen). The location of hydrophobic interaction was shown by a red dot. Water bridges were shown as black dotted lines. The length of bond (Å) was shown in the figure