FUTURE PLAN

1. The synthesis of a vesicle involving both biotin and i-motif.

Since we have generated two vesicles with biotin and i-motif respectively, we believe that these two functional moieties could co-exist on a single vesicle. In the next step, we will construct a vesicle involving both biotin and i-motif, which might realize targeted recognition and controlled release at the same time (Figure. 1).

Figure 1.A vesicle involving both biotin and i-motif.

Figure 2. The procedure of reductive amination. Adapted from ref 1.

2. The reduction of imine bond.

Although the using of reversible imine condensation provided our self-assembly system with the “self-error-correction” ability which led to the formation of the most thermodynamically stable species, it also brought unstability, as imine bond might break down in hydrolytic environment. In order to improve the stability of the vesicle, in the next step, we will conduct in-situ reduction with chemical-selective reductants such as sodium triacetoxyborohydride to reduce the imine bond to a more stable C-N bond 1 (Figure. 2).

3. The functionalization of vesicles with fusion proteins.

Since we have successfully loaded streptavidin onto the surface of vesicles, in the next step, we will make a fusion protein containing streptavidin and load it onto the surface of vesicles. Depending on the functional protein, we might achieve multiple functionalization of DNA vesicles such as induced apoptosis (achieved through Fas ligand 2) (Figure. 3) and cell-targeting (achieved through specific antibodies).

Figure 3. Principle model of induced apoptosis by a DNA vesicle loaded with Fas ligand. Adapted from ref 2.

Figure 4. The trapping of payload molecules.

4. The trapping of payload molecules.

Since the self-assembly of DNA vesicles does not require high temperature, it especially favors the co-assembly with heat-sensitive drug molecules. In the next step, we will co-assemble DNA three-way junctions with carefully selected payload molecules to trap payload in vesicles (Figure. 4).

The vesicle would serve as a prototype of drug carrier, which is able to realize targeted drug delivery and pH-controlled release, if the four steps mentioned above were achieved.