The
overprescription and improper use of antibiotics have contributed
to the evolution of bacterial resistance, making it urgent to develop
alternative therapies and agents with better efficacy as well as less
toxicity to combat bacterial infections and keep new resistance from
developing. In this work, a novel light-activable nano-antibiotic
platform (TC-PCM@GNC-PND) was constructed by the incorporation of
gold nanocages (GNC) and two thermosensitive gatekeepers, phase-change
materials (PCM) and thermosensitive polymer poly(N-isopropylacrylamide-co-diethylaminoethyl methacrylate)
(PND), to realize precisely the synergy of photothermal and antimicrobial
drugs. GNC exhibits an excellent photothermal effect owing to its
strong absorbance in the near-infrared (NIR) region, and hollow interiors
make it a favorable vehicle for loading various antibiotics such as
tetracycline (TC). The release of the encapsulated drugs could be
precisely controlled by NIR light through the dual thermosensitive
interaction of liquid–solid transition of PCM and coil–granule
transition of PND, improving efficacy and alleviating side effects
with on-demand drug release. The thermosensitive hydrogel was formed
in situ upon application with body temperature, enhancing retention
of the antimicrobial agent in local infectious sites. Highly effective
ablation of bacteria is achieved both in vitro and in periodontitis
models with little toxicity owing to the synergy of photothermal effects
and chemotherapeutic drug release induced by NIR. This study could
provide guidance for the design of antibacterial materials and shed
substantial light on synergistic treatment.
Achieving nitrogen removal from domestic wastewater using anaerobic ammonium oxidation (anammox) has the potential to make wastewater treatment energy-neutral or even energy-positive. The challenge is to suppress the growth of nitrite-oxidizing bacteria (NOB). This study presents a promising method based on intermittent aeration with low dissolved oxygen to limit NOB growth, thereby providing an advantage to anammox bacteria to form a partnership with the ammonium-oxidizing bacteria (AOB). The results showed that NOB was successfully suppressed using that method, with the relative abundance of NOB maintained between 2.0–2.6%, based on Fluorescent in-situ Hybridization. Nitrogen could be effectively removed from domestic wastewater with anammox at a temperature above 20 °C, with an effluent total nitrogen (TN) concentration of 6.6 ± 2.7 mg/L, while the influent TN and soluble chemical oxygen demand were 62.6 ± 3.1 mg/L and 88.0 ± 8.1 mg/L, respectively.
Mineral granules in the mitochondria of bone‐forming cells are thought to be the origin of biomineral precursors, which are transported to extracellular matrices to initiate cell‐mediated biomineralization. However, no evidence has revealed how mitochondrial granules form. This study indicates that mitochondrial granules are initiated by transporting calcium and phosphorus clusters from the endoplasmic reticulum (ER) to mitochondria based on detailed observations of the continuous process of mouse parietal bone development as well as in vitro biomineralization in bone‐forming cells. Nanosized biomineral precursors (≈30 nm in diameter), which originate from mitochondrial granules, initiate intrafibrillar mineralization of collagen as early as embryonic day 14.5. Both in vivo and in vitro studies further reveal that formation of mitochondrial granules is induced by the ER. Elevated levels of intracellular calcium or phosphate ions, which can be induced by treatment with ionomycin and black phosphorus, respectively, accelerate formation of the calcium and phosphorus clusters on ER membranes and ultimately promote biomineralization. These findings provide a novel insight into biomineralization and bone formation.
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