A low-energy emulsification platform based on a Diet Coke-Mentos reaction-derived bubbly flow for formulating various emulsions as drug carriers.

The formulation of a drug using high-energy emulsification commonly causes drug deterioration. Exploiting the well-known Diet Coke-Mentos reaction (DCMR), a U-shaped tube reactor that can generate an eruption of bubbly flow that can serve as a low-energy emulsification platform, is proposed. The liquid in the U-tube reactor is a supersaturated solution of aqueous CO2, which mimics Diet Coke. When glass beads with rough surfaces, mimicking Mentos, are dropped into the carbonated water, an eruptive bubbly flow is spontaneously created, mediating effective emulsification at a compound water-oil interface. Experimental results demonstrate that DCMR-mediated bubbly flow may provide a versatile platform for the production of "oil-in-water" or "water-in-oil" droplets and Pickering emulsion composite particles as drug carriers. The DCMR-derived bubbly flow is generated without significant temperature elevation, so the activity of the drug to be emulsified is unaffected. In vivo results reveal the feasibility of using this low-energy emulsification platform to formulate an emulsion system that contains catalase, a temperature-sensitive oxidoreductase, to mitigate an experimentally formed paw inflammation in mice. The as-proposed emulsification platform is attractive for formulating numerous drug delivery systems on a small-scale in a customized manner to meet the needs of each individual for personalized medicine.

Biomimetic Engineering of a Scavenger-Free Nitric Oxide-Generating/Delivering System to Enhance Radiation Therapy.

Nitric oxide (NO) is a potent tumor-cell radiosensitizer but it can be readily scavenged by hemoglobin (Hb) in vivo. A biomimetic incubator that can generate and deliver NO in a scavenger (Hb)-free environment to enhance its radiosensitizing effect to maximize its efficacy in radiotherapy is proposed. This NO incubator comprises a poly(lactic-co-glycolic acid) (PLGA) hollow microsphere (HM) that contains an NO donor (NONOate) and a surfactant molecule (sodium caprate, SC) in its aqueous core. In acidic tumorous environments, the PLGA shell of the HM allows the penetration of protons from the outside, activating the hydrolytic cleavage of NONOate, spontaneously generating NO bubbles, which are immediately trapped/stabilized by SC. The SC-stabilized NO bubbles in the HM are then squeezed through the spaces of its PLGA matrices by the elevated internal pressure. Upon leaving the HM, the entrapped NO molecules may passively diffuse through their SC-stabilized/protected layer gradually to the tumor site, having a long-lasting radiosensitizing effect and inhibiting tumor growth. The entire process of NO generation and delivery is conducted in a scavenger (Hb)-free environment, mimicking the development of young ovoviviparous fish inside their mothers' bodies in the absence of predators before birth.