Breaching Bacterial Biofilm Barriers: Efficient Combinatorial Theranostics for Multidrug-Resistant Bacterial Biofilms with a Novel Penetration-Enhanced AIEgen Probe

PaAP-Activatable NIR Probe for Diagnosing, Imaging, and Discovering Small-Molecule Therapeutics against Implant-Associated Biofilm Infections

Biofilm formation on medical implants causes implant-associated infections (IAIs), leading to high morbidity and mortality. Developing molecular tools for precise biofilm detection, along with novel strategies and agents to target biofilm-related IAIs, is crucial for improving treatment options and patient outcomes. Pseudomonas aeruginosa aminopeptidase (PaAP), a key biofilm-associated virulence factor, is a promising target for combating infections. Here, we developed a PaAP-activatable near-infrared (NIR) fluorescent probe, Hcy-NEO-Leu, for real-time, specific, and sensitive detection of PaAP activity. This probe enables noninvasive imaging of the P. aeruginosa biofilm in vitro and in vivo. The probe also identified LY-58, a lycorine derivative that disrupts biofilm formation without affecting bacterial growth or mammalian cell viability, enhancing tobramycin penetration and overcoming antibiotic resistance. This study introduces LY-58 as a promising adjunctive therapy. In conclusion, the PaAP-activatable NIR imaging probe, combined with LY-58, offers innovative tools for the early diagnosis and effective treatment of IAIs.

Expanding Our Horizons: AIE Materials in Bacterial Research

Bacteria share a longstanding and complex relationship with humans, playing a role in protecting gut health and sustaining the ecosystem to cause infectious diseases and antibiotic resistance. Luminogenic materials that share aggregation-induced emission (AIE) characteristics have emerged as a versatile toolbox for bacterial studies through fluorescence visualization. Numerous research efforts highlight the superiority of AIE materials in this field. Recent advances in AIE materials in bacterial studies are categorized into four areas: understanding bacterial interactions, antibacterial strategies, diverse applications, and synergistic applications with bacteria. Initial research focuses on visualizing the unseen bacteria and progresses into developing strategies involving electrostatic interactions, amphiphilic AIE luminogens (AIEgens), and various AIE materials to enhance bacterial affinity. Recent progress in antibacterial strategies includes using photodynamic and photothermal therapies, bacterial toxicity studies, and combined therapies. Diverse applications from environmental disinfection to disease treatment, utilizing AIE materials in antibacterial coatings, bacterial sensors, wound healing materials, etc., are also provided. Finally, synergistic applications combining AIE materials with bacteria to achieve enhanced outcomes are explored. This review summarizes the developmental trend of AIE materials in bacterial studies and is expected to provide future research directions in advancing bacterial methodologies.

Enhancing Pathogen Detection in Implant-Related Infections through Chemical Antibiofilm Strategies: A Comprehensive Review

Implant-related infections (IRIs) represent a significant challenge to modern surgery. The occurrence of these infections is due to the ability of pathogens to aggregate and form biofilms, which presents a challenge to both the diagnosis and subsequent treatment of the infection. Biofilms provide pathogens with protection from the host immune response and antibiotics, making detection difficult and complicating both single-stage and two-stage revision procedures. This narrative review examines advanced chemical antibiofilm techniques with the aim of improving the detection and identification of pathogens in IRIs. The articles included in this review were selected from databases such as PubMed, Scopus, MDPI and SpringerLink, which focus on recent studies evaluating the efficacy and enhanced accuracy of microbiological sampling and culture following the use of chemical antibiofilm. Although promising results have been achieved with the successful application of some antibiofilm chemical pre-treatment methods, mainly in orthopedics and in cardiovascular surgery, further research is required to optimize and expand their routine use in the clinical setting. This is necessary to ensure their safety, efficacy and integration into diagnostic protocols. Future studies should focus on standardizing these techniques and evaluating their effectiveness in large-scale clinical trials. This review emphasizes the importance of interdisciplinary collaboration in developing reliable diagnostic tools and highlights the need for innovative approaches to improve outcomes for patients undergoing both single-stage and two-stage revision surgery for implant-related infections.

Nanotechnology-driven strategies to enhance the treatment of drug-resistant bacterial infections

The misuse of antibiotics has led to increased bacterial resistance, posing a global public health crisis and seriously endangering lives. Currently, antibiotic therapy remains the most common approach for treating bacterial infections, but its effectiveness against multidrug-resistant bacteria is diminishing due to the slow development of new antibiotics and the increase of bacterial drug resistance. Consequently, developing new a\ntimicrobial strategies and improving antibiotic efficacy to combat bacterial infection has become an urgent priority. The emergence of nanotechnology has revolutionized the traditional antibiotic treatment, presenting new opportunities for refractory bacterial infection. Here we comprehensively review the research progress in nanotechnology-based antimicrobial drug delivery and highlight diverse platforms designed to target different bacterial resistance mechanisms. We also outline the use of nanotechnology in combining antibiotic therapy with other therapeutic modalities to enhance the therapeutic effectiveness of drug-resistant bacterial infections. These innovative therapeutic strategies have the potential to enhance bacterial susceptibility and overcome bacterial resistance. Finally, the challenges and prospects for the application of nanomaterial-based antimicrobial strategies in combating bacterial resistance are discussed. This article is categorized under: Biology-Inspired Nanomaterials > Nucleic Acid-Based Structures Therapeutic Approaches and Drug Discovery > Nanomedicine for Infectious Disease.

Novel aminothiazoximone-corbelled ethoxycarbonylpyrimidones with antibiofilm activity to conquer Gram-negative bacteria through potential multitargeting effects

The emergence of drug-resistant microorganisms threatens human health, and it is usually exacerbated by the formation of biofilm, which forces the development of new antibacterial agents with antibiofilm activity. In this work, a novel category of aminothiazoximone-corbelled ethoxycarbonylpyrimidones (ACEs) was designed and synthesized, and some of the prepared ACEs showed potent bioactivity against the tested bacteria. In particular, imidazolyl ACE 6c showed better inhibitory activity towards Acinetobacter baumannii and Escherichia coli with MIC values both of 0.0066 mmol/L than norfloxacin. It was also revealed that imidazolyl ACE 6c not only possessed inconspicuous hemolytic rate and cytotoxicity, low drug resistance and no risk of penetrating the blood-brain barrier, but also exhibited obvious biofilm inhibition and eradication activities. The preliminary mechanism research suggested that imidazolyl ACE 6c could induce metabolic dysfunction by deactivating lactate dehydrogenase and promote the accumulation of reactive oxygen species to decrease the reduced glutathione and ultimately cause oxidative damage in bacteria. Furthermore, ACE 6c was also found that could insert into DNA to form the supramolecular complex of 6c-DNA and trigger cell death. The multidimensional effect might promote bacterial cell rupture, leading to the leakage of intracellular content. These findings manifested that novel imidazolyl ACE 6c as a potential multitargeting antibacterial agent with potent antibiofilm activity could provide new possibility for the treatment of refractory biofilm-intensified bacterial infections.

Development of a Water-Soluble Fluorescent Probe Based on Natural Flavylium for Mercury(II) Ion Detection and Clinical Antidote Evaluation

The health hazard posed by Hg2+ makes it imperative to develop a fast and convenient means for detecting Hg2+ in water samples and living objects. While fluorescence sensing technology is considered a promising candidate, the poor water solubility and fluorescence quenching in aqueous solutions of most existing probes limit their practical application. To overcome this, we developed a natural flavylium-inspired fluorescent probe with excellent water solubility. Our probe demonstrated outstanding performance of high sensitivity (LOD = 0.47 nM), fast response (<10 min), and great selectivity for Hg2+. Notably, we validated its applicability in real water, urine samples, and living cells. Furthermore, the probe was successfully applied to evaluate the effectiveness of antidotes for clinical Hg2+ poisoning.

Targeted pH-responsive chitosan nanogels with Tanshinone IIA for enhancing the antibacterial/anti-biofilm efficacy

Persistent bacterial infection caused by biofilms is one of the most serious problems that threatened human health. The development of antibacterial agents remains a challenge to penetrate biofilm and effectively treat the underlying bacterial infection. In the current study, chitosan-based nanogels were developed for encapsulating the Tanshinone IIA (TA) to enhance the antibacterial and anti-biofilm efficacy against Streptococcus mutans (S. mutans). The as-prepared nanogels (TA@CS) displayed excellent encapsulation efficiency (91.41 ± 0.11 %), uniform particle sizes (393.97 ± 13.92 nm), and enhanced positive potential (42.27 ± 1.25 mV). After being coated with CS, the stability of TA under light and other harsh environments was greatly improved. In addition, TA@CS displayed pH responsiveness, allowing it to selectively release more TA in acidic conditions. Furthermore, the positively charged TA@CS were equipped to target negatively charged biofilm surfaces and efficiently penetrate through biofilm barriers, making it promising for remarkable anti-biofilm activity. More importantly, when TA was encapsulated into CS nanogels, the antibacterial activity of TA was enhanced at least 4-fold. Meanwhile, TA@CS inhibited 72 % of biofilm formation at 500 μg/mL. The results demonstrated that the nanogels constituted CS and TA had antibacterial/anti-biofilm properties with synergistic enhanced effects, which will benefit pharmaceutical, food, and other fields.

Photo-Activable Organosilver Nanosystem Facilitates Synergistic Cancer Theranostics

Anticancer drug development is important for human health, yet it remains a tremendous challenge. Photodynamic therapy (PDT), which induces cancer cell apoptosis via light-triggered production of reactive oxygen species, is a promising method. However, it has minimal efficacy in subcellular targeting, hypoxic microenvironments, and deep-seated malignancies. Here, we constructed a breast cancer photo-activable theranostic nanosystem through the rational design of a synthetic lysosomal-targeted molecule with multifunctions as aggregation-induced near-infrared (NIR) emission, a photosensitizer (PDT), and organosilver (chemotherapy) for NIR imaging and synergistic cancer therapy. The synthetic molecule could self-assemble into nanoparticles (TPIMBS NPs) and be stabilized with amphiphilic block copolymers for enhanced accumulation in tumor sites through passive targeting while reducing the leakage in normal tissues. Through photochemical internalization, TPIMBS NPs preferentially concentrated in the lysosomes of cancer cells and generated reactive oxygen species (ROS) upon light irradiation, resulting in lysosomal rupture and release of PSs to the cytosol, which led to cell apoptosis. Further, the photoinduced release of Ag⁺ from TPIMBS NPs could act as chemotherapy, significantly improving the overall therapeutic efficacy by synergistic effects with PDT. This research sheds fresh light on the creation of effective cancer treatments.

Functional insights to the development of bioactive material for combating bacterial infections

The emergence of antibiotic-resistant "superbugs" poses a serious threat to human health. Nanomaterials and cationic polymers have shown unprecedented advantages as effective antimicrobial therapies due to their flexibility and ability to interact with biological macromolecules. They can incorporate a variety of antimicrobial substances, achieving multifunctional effects without easily developing drug resistance. Herein, this article discusses recent advances in cationic polymers and nano-antibacterial materials, including material options, fabrication techniques, structural characteristics, and activity performance, with a focus on their fundamental active elements.