Nitric oxide-releasing amphiphiles are successfully synthesized through direct polymerization and are engineered as photoresponsive polymersomes for biomedical applications.
It
is of particular interest to develop new antibacterial agents
with low risk of drug resistance development and low toxicity toward
mammalian cells to combat pathogen infections. Although gaseous signaling
molecules (GSMs) such as nitric oxide (NO) and formaldehyde (FA) have
broad-spectrum antibacterial performance and the low propensity of
drug resistance development, many previous studies heavily focused
on nanocarriers capable of delivering only one GSM. Herein, we developed
a micellar nanoparticle platform that can simultaneously deliver NO
and FA under visible light irradiation. An amphiphilic diblock copolymer
of poly(ethylene oxide)-b-poly(4-((2-nitro-5-(((2-nitrobenzyl)oxy)methoxy)benzyl)(nitroso)amino)benzyl
methacrylate) (PEO-b-PNNBM) was successfully synthesized
through atom transfer radical polymerization (ATRP). The resulting
diblock copolymer self-assembled into micellar nanoparticles without
premature NO and FA leakage, whereas they underwent phototriggered
disassembly with the corelease of NO and FA. We showed that the NO-
and FA-releasing micellar nanoparticles exhibited a combinatorial
antibacterial performance, efficiently killing both Gram-negative
(e.g., Escherichia coli) and Gram-positive
(e.g., Staphylococcus aureus) bacteria
with low toxicity to mammalian cells and low hemolytic property. This
work provides new insights into the development of GSM-based antibacterial
agents.
The development of new antibacterial agents that can efficiently eradicate biofilms is of crucial importance to combat persistent and chronic bacterial infections. Herein, the fabrication of photoresponsive vesicles capable of the sequential release of nitric oxide (NO) and gentamicin sulfate (GS) is reported, which can not only efficiently disperse Pseudomonas aeruginosa (P. aeruginosa) PAO1 biofilm but also kill the planktonic bacteria. Well‐defined amphiphilic diblockcopolymers of poly(ethylene oxide)‐b‐poly(4‐((2‐nitrobenzyl)(nitroso)amino)benzyl methacrylate) (PNO) is first synthesized through atom transfer radical polymerization (ATRP). The PNO diblock copolymer self‐assembled into vesicles in aqueous solution, and a hydrophilic antibiotic of GS is subsequently encapsulated into the aqueous lumens of vesicles. The vesicles undergo visible light‐mediated N‐NO cleavage, releasing NO and disintegrating the vesicles with the release of the GS payload. The sequential release of NO and GS efficiently eradicate P. aeruginosa PAO1 biofilm and kill the liberated bacteria, showing a better antibiofilm effect than that of NO or GS alone.
Separation is one of the most energy-intensive processes in the chemical industry, and membrane-based separation technology contributes significantly to energy conservation and emission reduction. Additionally, metal-organic framework (MOF) materials have been widely investigated and have been found to have enormous potential in membrane separation due to their uniform pore size and high designability. Notably, pure MOF films and MOF mixed matrix membranes (MMMs) are the core of the “next generation” MOF materials. However, there are some tough issues with MOF-based membranes that affect separation performance. For pure MOF membranes, problems such as framework flexibility, defects, and grain orientation need to be addressed. Meanwhile, there still exist bottlenecks for MMMs such as MOF aggregation, plasticization and aging of the polymer matrix, poor interface compatibility, etc. Herein, corresponding methods are introduced to solve these problems, including inhibiting framework flexibility, regulating synthesis conditions, and enhancing the interaction between MOF and substrate. A series of high-quality MOF-based membranes have been obtained based on these techniques. Overall, these membranes revealed desired separation performance in both gas separation (e.g., CO2, H2, and olefin/paraffin) and liquid separation (e.g., water purification, organic solvent nanofiltration, and chiral separation).
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