A modified starch-based adhesive including a starch-based adhesive and an additive, the additive including a dendron, a sugar unit bound to the dendron, and an antimicrobial agent bound to the dendron and, a method of synthesizing the additive including providing a dendron, binding a linker molecule to the dendron, binding a sugar unit to the linker molecule, and binding an antimicrobial agent to the linker molecule.