Acoustically triggered microcannons, capable of loading and firing nanobullets (Nbs), are presented as powerful microballistic tools. Hollow conically shaped microcannon structures have been synthesized electrochemically and fully loaded with nanobullets made of silica or fluorescent microspheres, and perfluorocarbon emulsions, embedded in a gel matrix stabilizer. Application of a focused ultrasound pulse leads to the spontaneous vaporization of the perfluorocarbon emulsions within the microcannon and results in the rapid ejection of the nanobullets. Such Nbs "firing" at remarkably high speeds (on the magnitude of meters per second) has been modeled theoretically and demonstrated experimentally. Arrays of microcannons anchored in a template membrane were used to demonstrate the efficient Nbs loading and the high penetration capabilities of the ejected Nbs in a tissue phantom gel. This acoustic-microcannon approach could be translated into advanced microscale ballistic tools, capable of efficient loading and firing of multiple cargoes, and offer improved accessibility to target locations and enhanced tissue penetration properties.

Aqueous solutions containing alkaline salts of carboxylic or sulfonic amino acids represent candidate solvents with good potential for carbon dioxide (CO2) capture. In the present work, the CO2 reactions with potassium salts of glycine (aminoacetic acid) and taurine (2-aminoethanesulfonic acid) in aqueous solutions are investigated using a stirred-cell reactor. The reaction pathways are comprehensively described using the zwitterion and the termolecular mechanism. The investigated reactions belong to the fast pseudo-first-order reaction regime systems. The second-order rate constant for the CO2 reaction with potassium glycinate is determined, and its value at 303 K is evaluated to be 6.29 m3/(mol s). The liquid-side mass-transfer coefficient is estimated, and its value (0.006 cm/s) is consistent with those typical for stirred-cell reactors. Finally, it is determined that potassium glycinate promotes the activity of tertiary amines (e.g., N,N-diethylethanolamine).

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