A Zinc Porphyrin Polymer as Efficient Bifunctional Catalyst for Conversion of CO 2 to Cyclic Carbonates

Dialdehyde cellulose films covalently crosslinked with porphyrin-based covalent organic polymers for photodynamic sterilization

Foodborne pathogens result in a great harm to human, which is an urgent problem to be addressed. Herein, a novel cellulose-based packaging films with excellent anti-bacterial properties under visible light were prepared. A porphyrin-based covalent organic polymer (Por-COPs) was constructed, then covalently grafted onto dialdehyde cellulose (DAC). The addition of Por-COPs enhanced the mechanical, hydrophobicity, and water resistance of the DAC-based composite films. DAC/Por-COP-2.5 film exhibited outstanding properties for the photodynamic inactivation of bacteria under visible light irradiation, delivering inactivation efficiencies of 99.90 % and 99.45 % towards Staphylococcus aureus and Escherichia coli within 20 min. The DAC/Por-COPs films efficiently generated •O2- and 1O2 under visible light, thereby causing oxidative stress to cell membranes for bacterial inactivation. The prepared composite film forms a protective barrier against bacterial contamination. Results guide the development of high performance and more sustainable packaging films for the food sector.

Palladium nanospheres-embedded metal-organic frameworks to enhance the ECL efficiency of 2,6-dimethyl-8-(3-carboxyphenyl)4,4'-difluoroboradiazene in aqueous solution for ultrasensitive Cu2+ detection

Nowadays, organic emitters suffer from insufficient electrochemiluminescence (ECL) efficiency in aqueous solutions, and their practical applications are severely restricted in the bio-sensing field. In this work, palladium nanospheres-embedded metal-organic frameworks (Pd@MOFs) were exploited to enhance the ECL efficiency of 2,6-dimethyl-8-(3-carboxyphenyl)4,4'-difluoroboradiazene (BET) prepared by a one-pot method in aqueous environment. First, the Pd@MOFs were generated via in situ reduction of Pd nanospheres anchored onto the MOFs, and fabricated by orderly coordination of palladium chloride (PdCl2) with 1,2,4,5-benzenetetramine (BTA) tetrahydrochloride. Then, the influence of protons on the ECL response of BET was studied in detail to obtain stronger ECL emission using potassium persulfate (K2S2O8) as co-reactant in aqueous environment. As a result, a 1.47-fold ECL efficiency enlargement of BET/K2S2O8 was harvested at the Pd@MOFs/GCE, where Ru(bpy)32+ behaved as a standard. Based on the fact that the ECL signals of the BET-covered Pd@MOFs modified glassy carbon electrode (simplified as BET/Pd@MOFs/GCE) can be quenched by Cu2+, the as-built ECL sensor showed a wide linear range (1.0-100.0 pM) and a limit of detection (LOD) as low as 0.12 pM. Hence, such research offers huge potential to promote the development of organic emitters in ECL biosensors and environmental monitoring.

Synthesis of a Rare Water-Soluble Silver(II)/Porphyrin and Its Multifunctional Therapeutic Effect on Methicillin-Resistant Staphylococcus aureus

Porphyrin derivatives are popular photodynamic therapy (PDT) agents; however, their typical insolubility in water has made it challenging to separate cells of organisms in a liquid water environment. Herein, a novel water-soluble 5,10,15,20-tetrakis(4-methoxyphenyl-3-sulfonatophenyl) porphyrin (TMPPS) was synthesized with 95% yield by modifying the traditional sulfonation route. The reaction of TMPPS with AgNO₃ afforded AgTMPPS an unusual Ag(II) oxidation state (97% yield). The free base and Ag(II) complex were characterized by matrix-assisted laser desorption ionization-mass spectroscopy, and ¹H nuclear magnetic resonance, Fourier-transform infrared, UV-vis, fluorescence, and X-ray photolectron spectroscopies. Upon 460 nm laser irradiation, AgTMPPS generated a large amount of ¹O₂, whereas no ⦁OH was detected. Antibacterial experiments on methicillin-resistant Staphylococcus aureus (MRSA) revealed that the combined action of Ag^Ⅱ ions and PDT could endow AgTMPPS with a 100% bactericidal ratio for highly concentrated MRSA (10⁸ CFU/mL) at a very low dosage (4 μM) under laser irradiation at 360 J/cm². Another PDT response was demonstrated by photocatalytically oxidizing 1,4-dihydronicotinamide adenine dinucleotide to NAD⁺ with AgTMPPS. The structural features of the TMPPS and AgTMPPS molecules were investigated by density functional theory quantum chemical calculations to demonstrate the efficient chemical and photodynamical effects of AgTMPPS for non-invasive antibacterial therapy.