A platform integrating selective discrimination, imaging, and synergistic elimination of Gram-positive bacteria is urgently needed to address the problem of bacterial infection, especially those resulting from Gram-positive bacteria,. Aggregation-induced emission materials (AIEgens) have shown great promise for antimicrobial applications. Herein, three positively charged AIE-active cyclometalated iridium photosensitizers (Ir1–3) were rationally designed and synthesized. Selective discrimination and imaging of Gram-positive bacteria among Gram-positive bacteria, Gram-negative bacteria, and fungi were achieved with Ir1–3. Among three AIE-active cyclometalated iridium photosensitizers, Ir1 had the best antibacterial activity owing to the monoaromatic substituent of phenanthroline imidazole ligand to the main ligand, eliminating Gram-positive bacteria through its inherent antibacterial mechanism and bacterial photodynamic inactivation. Furthermore, Ir1 altered Gram-positive bacterial gene expression and was successfully applied to S. aureus-infected wound treatment. Due to the interaction between lipoteichoic acids (LTA) and our iridium-based AIEgens, our AIEgen photosensitizers realized selective discrimination, imaging, and synergistic elimination of Gram-positive bacteria.

BACKGROUND In the present study, lipases of TLL (lipase from Thermomyces lanuginosus), AOL (lipase from Aspergillus oryzae), RML (lipase from Rhizomucor miehei), BCL (lipase from Burkholderia cepacia), CALA (Candida antarctica lipase A) and LU (Lecitase® Ultra) were encapsulated into nucleotide‐hybrid metal coordination polymers (CPs). Enzyme concentration was optimized for encapsulation and the enzymatic properties of the obtained lipases were investigated. In addition, their performance in glycerolysis and esterification was evaluated, and glycerolysis conditions (water content, temperature and time) were optimized. RESULTS Hydrolysis activity over 10 000 U g−1 and activity recovery over 90% were observed from AOL@GMP/Tb, TLL@GMP/Tb and RML@GMP/Tb. GMP/Tb encapsulation (of AOL, TLL, RML and LU) improved their thermostability when incubated in air. The encapsulated lipases exhibited moderate [triacylglycerols (TAG) conversion 30–50%] and considerable glycerolysis activity (TAG conversion over 60%). TAG conversions from 69.37% to 82.35% and diacylglycerols (DAG) contents from 58.62% to 64.88% were obtained from CALA@GMP/metal samples (except for CALA@GMP/Cu). Interestingly, none of the encapsulated lipases initiated the esterification reaction. AOL@GMP/Tb, TLL@GMP/Tb, RML@GMP/Tb and CALA@GMP/Tb showed good reusability in glycerolysis, with 88.80%, 94.67%, 89.85% and 78.16% of their initial glycerolysis activity, respectively, remaining after five cycles of reuse. The relationships between temperature and TAG conversion were LnV0 = 6.5364–3.7943/T and LnV0 = 13.8820–6.4684/T for AOL@GMP/Tb and CALA@GMP/Tb, respectively; in addition, their activation energies were 31.55 and 53.78 kJ mol−1, respectively. CONCLUSION Most of the present encapsulated lipases exhibited moderate and considerable glycerolysis activity. In addition, AOL@GMP/Tb, TLL@GMP/Tb, RML@GMP/Tb and CALA@GMP/Tb exhibited good reusability in glycerolysis reactions and potential in practical applications. © 2022 Society of Chemical Industry.

An iridium(iii) complex-based mitochondria targeting phosphorescent probe for selectively detecting Cu2+ and Cys in aqueous solution, living cells and zebrafish has been developed.

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