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Carbon monoxide is a gasotransmitter that may be beneficial for vascular tissue engineering and regenerative medicine strategies because it can promote endothelial cell (EC) proliferation and migration by binding to heme‐containing compounds within cells. For example, CO may be beneficial for vascular cognitive impairment and dementia because many patients' disrupted blood–brain barriers do not heal naturally. However, control of the CO dose is critical, and new controlled delivery methods need to be developed. This study developed ultrasound‐sensitive microbubbles with a carefully controlled precipitation technique, loaded them with CO, and assessed their ability to promote EC proliferation and function. Microbubbles fabricated with perfluoropentane exhibited good stability at room temperature, but they could still be ruptured and release CO in culture with application of ultrasound. Microbubbles synthesized from the higher boiling point compound, perfluorohexane, were too stable at physiological temperature. The lower‐boiling point perfluoropentane microbubbles had good biocompatibility and appeared to improve VE‐cadherin expression when CO was loaded in the bubbles. Finally, tissue phantoms were used to show that an imaging ultrasound probe can efficiently rupture the microbubbles and that the CO‐loaded microbubbles can improve EC spreading and proliferation compared to control conditions without microbubbles as well as microbubbles without application of ultrasound. Overall, this study demonstrated the potential for use of these ultrasound‐sensitive microbubbles for improving blood vessel endothelialization. [ABSTRACT FROM AUTHOR]

One of the grand challenges underlying current direct air capture (DAC) technologies relates to the intensive energy cost for sorbent regeneration and CO2 release, making the massive scale (GtCO2/year) deployment required to have a positive impact on climate change economically unfeasible. This challenge underscores the critical need to develop new DAC processes with substantially reduced regeneration energies. Here, we report a photochemically‐driven approach for CO2 release by exploiting the unique properties of an indazole metastable‐state photoacid (mPAH). Our measurements on simulated and amino acid‐based DAC systems revealed the potential of mPAH to be used for CO2 release cycles by regulating pH changes and associated isomers driven by light. Upon irradiating with moderate intensity light, a ≈55 % and ≈68 % to ≈78 % conversion of total inorganic carbon to CO2 was found for the simulated and amino acid‐based DAC systems, respectively. Our results confirm the feasibility of on‐demand CO2 release under ambient conditions using light instead of heat, thereby providing an energy efficient pathway for the regeneration of DAC sorbents. [ABSTRACT FROM AUTHOR]

One of the grand challenges underlying current direct air capture (DAC) technologies relates to the intensive energy cost for sorbent regeneration and CO 2 release, making the massive scale (GtCO 2 /year) deployment required to have a positive impact on climate change economically unfeasible. This challenge underscores the critical need to develop new DAC processes with substantially reduced regeneration energies. Here, we report a photochemically-driven approach for CO 2 release by exploiting the unique properties of an indazole metastable-state photoacid (mPAH). Our measurements on simulated and amino acid-based DAC systems revealed the potential of mPAH to be used for CO 2 release cycles by regulating pH changes and associated isomers driven by light. Upon irradiating with moderate intensity light, a ≈55 % and ≈68 % to ≈78 % conversion of total inorganic carbon to CO 2 was found for the simulated and amino acid-based DAC systems, respectively. Our results confirm the feasibility of on-demand CO 2 release under ambient conditions using light instead of heat, thereby providing an energy efficient pathway for the regeneration of DAC sorbents., (© 2023 Wiley-VCH GmbH.)