Inhalable mucin-permeable nanomicelles deliver antibiotics for effective treatment of chronic pneumonia.

Pseudomonas aeruginosa (P. aeruginosa) pneumonia can have serious physiological consequences, particularly when P. aeruginosa biofilms are formed. Although inhaled therapy is preferred, inhaled drugs tend to get trapped by pulmonary mucus, which hinders efficient antibiotic permeability through mucus and biofilms. In this study, we prepare poly[2-(pentamethyleneimino)ethyl methacrylate]-block-poly[2-(N-oxide-pentamethyleneimino)ethyl methacrylate] (PPEMA-b-PPOEMA) micelles loaded with azithromycin (AZM) using reversible addition-fragmentation chain transfer (RAFT) polymerization to achieve effective treatment of P. aeruginosa pneumonia. The zwitterionic structure on the surface of the micelle facilitates the successful traversal of the mucus and optimal concentration within the biofilm. Furthermore, the protonation of piperidine in the polymer enables the micelles to exhibit a positive charge in the acidic environment of a bacterial infection, enhancing AZM's interaction with the bacterium. Both in vivo and in vitro experiments demonstrate that this transmucosal zwitterionic polymer, in combination with a charge reversal strategy, effectively promotes the enrichment of micelles at the site of bacterial infection, thereby increasing the number of antibiotics reaching the bacterial interior and demonstrating remarkable antibacterial synergy. Overall, this work offers a promising approach for trans-airway drug delivery in the treatment of pneumonia.

Precise antibiotic delivery to the lung infection microenvironment boosts the treatment of pneumonia with decreased gut dysbiosis.

Bacterial pneumonia is a common disease with significant health risks. However, the overuse antibiotics in clinics face challenges such as inadequate targeting and limited drug utilization, leading to drug resistance and gut dysbiosis. Herein, a dual-responsive lung inflammatory tissue targeted nanoparticle (LITTN), designed for targeting lung tissue and bacteria, is screened from a series of prepared nanoparticles consisting of permanent cationic lipids, acid-responsive lipids, and reactive oxygen species-responsive and phenylboronic acid-modified lipids with different surface properties. Such nanoparticle is further verified to enhance the adsorption of vitronectin in serum. Additionally, the optimized nanoparticle exhibits more positive charge and coordination of boric acid with cis-diol in the infected microenvironment, facilitating electrostatic interactions with bacteria and biofilm penetration. Importantly, the antibacterial efficiency of dual-responsive rifampicin-loaded LITTN (Rif@LITTN) against methicillin-resistant staphylococcus aureus is 10 times higher than that of free rifampicin. In a mouse model of bacterial pneumonia, the intravenous administration of Rif@LITTN could precisely target the lungs, localize in the lung infection microenvironment, and trigger the responsive release of rifampicin, thereby effectively alleviating lung inflammation and reducing damage. Notably, the targeted delivery of rifampicin helps protect against antibiotic-induced changes in the gut microbiota. This study establishes a new strategy for precise delivery to the lung-infected microenvironment, promoting treatment efficacy while minimizing the impact on gut microbiota. STATEMENT OF SIGNIFICANCE: Intravenous antibiotics play a critical role in clinical care, particularly for severe bacterial pneumonia. However, the inability of antibiotics to reach target tissues causes serious side effects, including liver and kidney damage and intestinal dysbiosis. Therefore, achieving precise delivery of antibiotics is of great significance. In this study, we developed a novel lung inflammatory tissue-targeted nanoparticle that could target lung tissue after intravenous administration and then target the inflammatory microenvironment to trigger dual-responsive antibiotics release to synergistically treat pneumonia while maintaining the balance of gut microbiota and reducing the adverse effects of antibiotics. This study provides new ideas for targeted drug delivery and reference for clinical treatment of pneumonia.

A Single-Component Dual Donor Enables Ultrasound-Triggered Co-release of Carbon Monoxide and Hydrogen Sulfide.

The development of dual gasotransmitter donors can not only provide robust tools to investigate their subtle interplay under pathophysiological conditions but also optimize therapeutic efficacy. While conventional strategies are heavily dependent on multicomponent donors, we herein report an ultrasound-responsive water-soluble copolymer (PSHF) capable of releasing carbon monoxide (CO) and hydrogen sulfide (H2 S) based on single-component sulfur-substituted 3-hydroxyflavone (SHF) derivatives. Interestingly, sulfur substitution can not only greatly improve the ultrasound sensitivity but also enable the co-release of CO/H2 S under mild ultrasound irradiation. The co-release of CO/H2 S gasotransmitters exerts a bactericidal effect against Staphylococcus aureus and demonstrates anti-inflammatory activity in lipopolysaccharide-challenged macrophages. Moreover, the excellent tissue penetration of ultrasound irradiation enables the local release of CO/H2 S in the joints of septic arthritis rats, exhibiting superior therapeutic efficacy without the need for any antibiotics.