ACS Central Science最新文献

Tunability of functional properties in a continuous manner is desired but challenging to accomplish for organic solid-state materials. Herein, we describe a method for tuning optoelectronic properties of solid-state aggregates with narrow absorption bands. First, we systematically shift the absorption maxima of highly dipolar merocyanine dyes in solution by chemical alterations of their chromophore cores. This leaves their solid-state packing arrangements unchanged, affording similar J- and H-coupled aggregate absorption bands at different wavelengths. Next, mixing these isostructural dyes leads to a spectral fine-tuning of the mixed layers, which could be characterized as crystalline organic solid solutions and utilized in narrowband color-selective organic photodiodes. Finally, we devise a semiempirical model, which explains the observed spectral tuning in terms of the molecular exciton theory. Thus, we demonstrate narrowband absorbing solid-state aggregates spanning the wavelength range of 437–760 nm, whose absorption can be fine-tuned over 40% of the visible light range.

Spectral tuning of absorption properties for color sensing is achieved by design of isostructural compounds and binary mixtures thereof, which self-assemble into identical supramolecular aggregates.

Tunability of functional properties in a continuous manner is desired but challenging to accomplish for organic solid-state materials. Herein, we describe a method for tuning optoelectronic properties of solid-state aggregates with narrow absorption bands. First, we systematically shift the absorption maxima of highly dipolar merocyanine dyes in solution by chemical alterations of their chromophore cores. This leaves their solid-state packing arrangements unchanged, affording similar J- and H-coupled aggregate absorption bands at different wavelengths. Next, mixing these isostructural dyes leads to a spectral fine-tuning of the mixed layers, which could be characterized as crystalline organic solid solutions and utilized in narrowband color-selective organic photodiodes. Finally, we devise a semiempirical model, which explains the observed spectral tuning in terms of the molecular exciton theory. Thus, we demonstrate narrowband absorbing solid-state aggregates spanning the wavelength range of 437-760 nm, whose absorption can be fine-tuned over 40% of the visible light range.

Similar to conventional solids, porous materials have demonstrated rigid and flexible behaviors. Here, we show that flexible pores can be not just elastic but also plastic. By variation of the hydrogen-bonding ability and steric hindrance of ligand side groups, the energy difference and barrier between metastable states of a porous framework are fine-tuned to enable the plastic behavior. All metastable pore structures can transform to the target ones in atmospheres of the target guests with sufficiently high pressures, and all shaped pores can remain unchanged after guest removal, resulting in optimized host–guest recognitions for the target guests. Up to a 6-fold increase of adsorption selectivity and 9-fold increase of purification productivity for CO₂ capture and coalmine CH₄ upgrading, and even inversion of CO₂/C₂H₂ selectivity, have been achieved by reversible pore-shaping of a single plastic-pore adsorbent. The realization of plastic pores creates an opportunity for on-demand switching of adsorption and separation functions with optimized performances.

While porous materials possess rigid or flexible/elastic pores, a plastic pore is realized for the first time, which can be shaped by target guest molecules to meet needs of different applications.

Antibiotics save countless lives each year and have dramatically improved human health outcomes since their introduction in the 20th century. Unfortunately, bacteria are now developing resistance to antibiotics at an alarming rate, with many new strains of "superbugs" showing simultaneous resistance to multiple classes of antibiotics. To mitigate the global burden of antimicrobial resistance, we must develop new antibiotics that are broadly effective, safe, and highly stable to enable global access. In this manuscript, we report the development of polyacrylamide-based copolymers as a class of broad-spectrum antibiotics with efficacy against several critical pathogens. We demonstrate that these copolymer drugs are selective for bacteria over mammalian cells, indicating a favorable safety profile. We show that they kill bacteria through a membrane disruption mechanism, which allows them to overcome traditional mechanisms of antimicrobial resistance. Finally, we demonstrate their ability to rehabilitate an existing small-molecule antibiotic that is highly subject to resistance development by improving its potency and eliminating the development of resistance in a combination treatment. This work represents a significant step toward combating antimicrobial resistance.

Antibiotics save countless lives each year and have dramatically improved human health outcomes since their introduction in the 20th century. Unfortunately, bacteria are now developing resistance to antibiotics at an alarming rate, with many new strains of “superbugs” showing simultaneous resistance to multiple classes of antibiotics. To mitigate the global burden of antimicrobial resistance, we must develop new antibiotics that are broadly effective, safe, and highly stable to enable global access. In this manuscript, we report the development of polyacrylamide-based copolymers as a class of broad-spectrum antibiotics with efficacy against several critical pathogens. We demonstrate that these copolymer drugs are selective for bacteria over mammalian cells, indicating a favorable safety profile. We show that they kill bacteria through a membrane disruption mechanism, which allows them to overcome traditional mechanisms of antimicrobial resistance. Finally, we demonstrate their ability to rehabilitate an existing small-molecule antibiotic that is highly subject to resistance development by improving its potency and eliminating the development of resistance in a combination treatment. This work represents a significant step toward combating antimicrobial resistance.

Polyacrylamide-based copolymers function as broad-spectrum antibiotics via a membrane disruption mechanism. They can prevent or delay the onset of resistance and rehabilitate existing antibiotics.

Similar to conventional solids, porous materials have demonstrated rigid and flexible behaviors. Here, we show that flexible pores can be not just elastic but also plastic. By variation of the hydrogen-bonding ability and steric hindrance of ligand side groups, the energy difference and barrier between metastable states of a porous framework are fine-tuned to enable the plastic behavior. All metastable pore structures can transform to the target ones in atmospheres of the target guests with sufficiently high pressures, and all shaped pores can remain unchanged after guest removal, resulting in optimized host-guest recognitions for the target guests. Up to a 6-fold increase of adsorption selectivity and 9-fold increase of purification productivity for CO₂ capture and coalmine CH₄ upgrading, and even inversion of CO₂/C₂H₂ selectivity, have been achieved by reversible pore-shaping of a single plastic-pore adsorbent. The realization of plastic pores creates an opportunity for on-demand switching of adsorption and separation functions with optimized performances.

Neutrophil extracellular traps (NETs) are DNA networks released by neutrophils, first described as a defense response against pathogens but have since been associated with numerous inflammatory diseases. Diverse physical material properties have been shown to promote NET formation. Herein, we report the discovery that the charge of self-assembled peptide hydrogels predictably modulates the formation of NETs in vivo within the implanted material. Positively charged gels induce rapid NET release, whereas negatively charged gels do not. This differential immune response to our self-assembled peptide gels enabled the development of a material platform that allows rheostat-like modulation over the degree of NET formation with anatomical and locoregional control.

Self-assembled peptide-based hydrogel strategy for controlling the formation of neutrophil extracellular traps (NETs) in vivo with anatomical and locoregional precision, and the ability to regulate the degree of the response.

Neutrophil extracellular traps (NETs) are DNA networks released by neutrophils, first described as a defense response against pathogens but have since been associated with numerous inflammatory diseases. Diverse physical material properties have been shown to promote NET formation. Herein, we report the discovery that the charge of self-assembled peptide hydrogels predictably modulates the formation of NETs in vivo within the implanted material. Positively charged gels induce rapid NET release, whereas negatively charged gels do not. This differential immune response to our self-assembled peptide gels enabled the development of a material platform that allows rheostat-like modulation over the degree of NET formation with anatomical and locoregional control.

Mitochondrial targeting has emerged as an attractive method for antitumor treatment. However, most of the mitochondria targeted drugs focused on inhibiting tumor cells, while their potential for activation of immune responses in the tumor microenvironment has rarely been described. In this study, we report a photosensitive iridium complex MitoIrL2, which enabled the simultaneous mitochondrial modulation of macrophages and tumor cells to achieve synergistic antitumor immunity. The adjustment of the mitochondrial respiratory chain, HIF-1α, and the NF-κB pathway in macrophages drove the metabolic reprogramming from oxidative phosphorylation (OXPHOS) to glycolysis, converting protumor M2 into the antitumor M1 phenotype. Downregulated expression of immunosuppressive checkpoint SIRPα has also been observed on macrophages. Meanwhile, the mitochondrial targeting MitoIrL2 enhanced the immunogenic cell death of tumor cells and reversed the immunosuppressive tumor microenvironment, which activated the systemic immune response and established long-term immune memory in vivo. This work illustrates a promising strategy to simultaneously regulate macrophages toward the antitumor phenotype and enhance immunogenic cell death in tumor cells for synergistic antitumor immunotherapy.

A mitochondrial targeting iridium photosensitizer could achieve direct immune activation of both macrophages and tumor cells, synergistically enhancing antitumor immunity via mitochondrial modulation.

Academia and industry see mixed results replacing fluorinated chemicals in refrigeration, textiles, and ion-exchange membranes.