Fig2. Application of the pop-up pirate for DDS: a comparative scheme.
Pop-up pirate (Fig.1) is the toy which Japanese Takara Tommy started to sale in 1975. We first put a doll in a barrel.(Fig. 1a). The barrel of this toy has holes to stab a swords. Then we stab swords to the barrel one by one (Fig. 1b). When a player stabs the specific point on the barrel, the doll jumps out (Fig. 1c). The player who made the doll jump out is a loser. We think it interesting that the doll pops up only when the sword is stabbed in a specific position. The specific position changes at every games.
We intended to tie this phenomenon to a scientific field. What will happen if we can realize a pop-up pirate on a nano-scale ? The nano-pop-up-pirate is regarded as a nano-robot which release a substances or trigger a mechanical movement by selectively recognizing a specific molecular information. The applications for molecular information amplification and drug delivery system (DDS) will be possible, which is scientifically and technically significant. DDS (drug delivery system) is a general technique to transport a drug to an internal target part in the body or to control quantity of drug in the target part appropriately. In this system, we have three important points: no release of a drug before transporting the drug to the affected part, the targeting to an affected part, and release controlled by a specific stimulation. In comparison with a conventional drug transit technology, we can expect suppression of expression of the specific action, decrease in the burdens on patient by the reduction of the dose, reduced side effects, reduced medical expenses, and low cost. DDS materials made of the DNA-silica hybrids, which will be developed based on the present study, will be applicable for DDS systems with high stability and low cost (Fig. 2).
Fig. 3. The goals of our project
A purpose of this study is to fabricate a pop-up pirate on the nano-scale. We synthesize colloidal particles and use them as the nano-doll and nano-barrel. We then combine the doll- and the barrel-particle by hybridization of the ssDNAs grafted on the particles. Finally we observe the release (pop-up) of the doll-particle in response to specific stimulation (adding "sword DNA" with fully complementary base sequence with the barrel DNA). We divide our goals into the 5 steps as shown in Fig. 3.