Silver Nanoparticle-Loaded Titanium-Based Metal-Organic Framework for Promoting Antibacterial Performance by Synergistic Chemical-Photodynamic Therapy.

The abuse of antibiotics leads to an increasing emergence of drug-resistant bacteria, which not only causes a waste of medical resources but also seriously endangers people's health and life safety. Therefore, it is highly desirable to develop an efficient antibacterial strategy to reduce the reliance on traditional antibiotics. Antibacterial photodynamic therapy (aPDT) is regarded as an intriguing antimicrobial method that is less likely to generate drug resistance, but its efficiency still needs to be further improved. Herein, a robust titanium-based metal-organic framework ACM-1 was adopted to support Ag nanoparticles (NPs) to obtain Ag NPs@ACM-1 for boosting antibacterial efficiency via synergistic chemical-photodynamic therapy. Apart from the intrinsic antibacterial nature, Ag NPs largely boost ROS production and thus improve aPDT efficacy. As a consequence, Ag NPs@ACM-1 shows excellent antibacterial activity under visible light illumination, and its minimum bactericidal concentrations (MBCs) against E. coli, S. aureus, and MRSA are as low as 39.1, 39.1, and 62.5 µg mL-1, respectively. Moreover, to expand the practicability of Ag NPs@ACM-1, two (a dense and a loose) Ag NPs@ACM-1 films were readily fabricated by simply dispersing Ag NPs@ACM-1 into heated aqueous solutions of edible agar and sequentially cooling through heating or freeze-drying, respectively. Notably, these two films are mechanically flexible and exhibit excellent antibacterial activities, and their antimicrobial performances can be well retained in their recyclable and remade films. As agar is nontoxic, degradable, inexpensive, and ecosustainable, the dense and loose Ag NPs@ACM-1 films are potent to serve as recyclable and degradable antibacterial plastics and antibacterial dressings, respectively.

Boosting Antibacterial Photodynamic Therapy in a Nanosized Zr MOF by the Combination of Ag NP Encapsulation and Porphyrin Doping.

Antibacterial photodynamic therapy (aPDT) is regarded as one of the most promising antibacterial therapies due to its nonresistance, noninvasion, and rapid sterilization. However, the development of antibacterial materials with high aPDT efficacy is still a long-standing challenge. Herein, we develop an effective antibacterial photodynamic composite UiO-66-(SH)2@TCPP@AgNPs by Ag encapsulation and 4,4',4″,4‴-(porphine-5,10,15,20-tetrayl)tetrakis(benzoic acid) (TCPP) dopant. Through a mix-and-match strategy in the self-assembly process, 2,5-dimercaptoterephthalic acid containing -SH groups and TCPP were uniformly decorated into the UiO-66-type framework to form UiO-66-(SH)2@TCPP. After Ag(I) impregnation and in situ UV light reduction, Ag NPs were formed and encapsulated into UiO-66-(SH)2@TCPP to get UiO-66-(SH)2@TCPP@AgNPs. In the resulting composite, both Ag NPs and TCPP can effectively enhance the visible light absorption, largely boosting the generation efficiency of reactive oxygen species. Notably, the nanoscale size enables it to effectively contact and be endocytosed into bacteria. Consequently, UiO-66-(SH)2@TCPP@AgNPs show a very high aPDT efficacy against Gram-negative and Gram-positive bacteria as well as drug-resistant bacteria (MRSA). Furthermore, the Ag NPs were firmly anchored at the framework by the high density of -SH moieties, avoiding the cytotoxicity caused by the leakage of Ag NPs. By in vitro experiments, UiO-66-(SH)2@TCPP@AgNPs show a very high antibacterial activity and good biocompatibility as well as the potentiality to promote cell proliferation.