Photosensitizer‐Modified MnO2 Nanoparticles to Enhance Photodynamic Treatment of Abscesses and Boost Immune Protection for Treated Mice

The emergence of drug‐resistant bacteria and easy recurrence has been challenging in the clinical treatment of skin abscesses resulting from bacterial infections (e.g., by Staphylococcus aureus (S. aureus)). Herein, an antibacterial nanoagent capable of modulating the abscess microenvironment is designed to enhance photodynamic treatment of skin abscesses, and subsequently activate the immune system to effectively prevent abscess recurrence. In the system, manganese dioxide nanoparticles (MnO₂ NPs) with high catalytic reactivity toward H₂O₂ are modified with photosensitizer chlorine e6 (Ce6) and coated with polyethylene glycol (PEG). The obtained Ce6@MnO₂‐PEG NPs, by triggering the decomposition of lesion endogenous H₂O₂, are able to effectively relieve the hypoxic abscess microenvironment during S. aureus infection. The light‐triggered photodynamic bacterial killing effect could thus be remarkably enhanced, resulting in effective in vivo therapy of S. aureus‐induced skin abscesses. Interestingly, a notable pathogen‐specific immunological memory effect against future infection by the same species of bacteria is elicited after such treatment, owing to the release of bacterial antigens post photodynamic therapy (PDT) together with the adjuvant‐like function of manganese ions to activate the host immune system. This work thus presents a new type of photodynamic nanoagent particularly promising for highly effective light‐triggered abscess treatment and prevention of abscess recurrence.     

Eradication of Multi‐Drug Resistant Bacteria by a Novel Zn‐doped CuO Nanocomposite

Zinc‐doped copper oxide nanoparticles are synthesized and simultaneously deposited on cotton fabric using ultrasound irradiation. The optimization of the processing conditions, the specific reagent ratio, and the precursor concentration results in the formation of uniform nanoparticles with an average size of ≈30 nm. The antibacterial activity of the Zn‐doped CuO Cu_0.88Zn_0.12O in a colloidal suspension or deposited on the fabric is tested against Escherichia coli (Gram negative) and Staphylococcus aureus (Gram positive) bacteria. A substantial enhancement of 10 000 times in the antimicrobial activity of the Zn–CuO nanocomposite compared to the pure CuO and ZnO nanoparticles (NPs) is observed after 10 min exposure to the bacteria. Similar activities are observed against multidrug‐resistant bacteria (MDR), (i.e., Methicillin‐resistant S. aureus and MDR E. coli) further emphasizing the efficacy of this composite. Finally, the mechanism for this enhanced antibacterial activity is presented.     

Bioinspired Superhydrophobic Fe3O4@Polydopamine@Ag Hybrid Nanoparticles for Liquid Marble and Oil Spill

Fe₃O₄ nanoparticles (NPs) with Ag NPs evenly distributed on the surface are fabricated by using polydopamine (PDA) as the intermediate layer. Silanization and thiol chemistry are used to firmly combine the Fe₃O₄@ PDA core and outer surface Ag NPs. The spherical and hybrid nanoparticles are termed Fe₃O₄@PDA@Ag NPs, which possess a core–shell and hierarchical structure. After surface modification with 1H,1H,2H,2H‐perfluorodecanethiol, the hybrid Fe₃O₄@PDA@Ag NPs become highly hydrophobic. Slight rolling of a water droplet on the as‐prepared NPs causes the formation of a “liquid marble”, which is capable of performing remote actuation on various solid surfaces, such as glass sheet, paper, plastic, textile, and ceramic, and at the liquid–air interface using a permanent magnet. Liquid marbles with self‐assembled NPs on the liquid surface have potential to act as a miniaturized reactor for manipulation of inner liquid droplet with high positioning precision. In addition, the Fe₃O₄@PDA@Ag NPs are multifunctional and can be applied for oil/water separation and antibacterial purpose.     

The Binary Effect on Methicillin‐Resistant Staphylococcus aureus of Polymeric Nanovesicles Appended by Proline‐Rich Amino Acid Sequences and Inorganic Nanoparticles

Prevalent research underscores efforts to engineer highly sophisticated nanovesicles that are functionalized to combat antibiotic‐resistant bacterial infections, especially those caused by methicillin‐resistant Staphylococcus aureus (MRSA), and that aid with wound healing or immunomodulation. This is especially relevant for patients who are susceptible to Staphylococcus aureus infections postoperatively. Here, antibacterial formulations are incorporated into polymeric, biocompatible vesicles called polymersomes (PsNPs) that self‐assemble via hydrophobic interactions of admixed aqueous and organic substances. Nano‐PsNPs are synthesized using a high molecular weight amphiphilic block copolymer, and are conjugated to include antimicrobial peptides (AMPs) along the peripheral hydrophilic region and silver nanoparticles (AgNPs) inside their hydrophobic corona. In vitro testing on bacterial and human cell lines indicates that finely tuned treatment concentrations of AMP and AgNPs in PsNPs synergistically inhibits the growth of MRSA without posing significant side effects, as compared with other potent treatment strategies. A ratio of silver‐to‐AMP of about 1:5.8 corresponding to ≈11.6 µg mL^?1 of silver nanoparticles and 14.3 × 10^?6 m of the peptide, yields complete MRSA inhibition over a 23 h time frame. This bacteriostatic activity, coupled with nominal cytotoxicity toward native human dermal fibroblast cells, extends the potential for AMP/AgNP polymersome therapies to replace antibiotics in the clinical setting.     

Synthesis of oleic acid-stabilized silver nanoparticles and analysis of their antibacterial activity

The development of new and simple green chemical methods for synthesizing colloidal solutions of functional nanoparticles is desirable for environment-friendly applications. In the present work, we report a feasible method for synthesizing colloidal solutions of silver nanoparticles (Ag NPs) based on the modified Tollens technique. The Ag NPs were stabilized by using oleic acid as a surfactant and were produced for the first time by the reduction of silver ammonium complex [Ag(NH₃)₂]⁺_(aq) by glucose with UV irradiation treatment. A stable and nearly monodisperse aqueous Ag NPs solution with average-sized particles (~ 9–10 nm) was obtained. The Ag NPs exhibited high antibacterial activity against both Gram-negative Escherichia Coli (E. coli) and Gram-positive Staphylococcus aureus bacteria. Electron microscopic images and analyses provided further insights into the interaction and bactericidal mechanism of the Ag NPs. The proposed method of synthesis is an effective way to produce highly bactericidal colloidal solutions for medical, microbiological, and industrial applications.     

Sono‐Immunotherapeutic Nanocapturer to Combat Multidrug‐Resistant Bacterial Infections

Antibiotic‐free methods hold particular promise for preventing and controlling multidrug‐resistant (MDR) bacterial infection via eradiation of bacteria and their pathogenic virulence. A facile and bioinspired strategy is presented for bridging antibacterial sonodynamic therapy and antivirulence immunotherapy. As a proof‐of‐concept, an antibody which neutralizes alpha‐toxin of methicillin‐resistant Staphylococcus aureus (MRSA) is genetically engineered on to the surface of cell membrane nanovesicles, which then undergo sonosensitizer encapsulation. Compared with conventional passive virulence absorption using natural red blood membrane, the highly active antibody–toxin interaction enables the nanovesicles to capture virulence more potently in vitro. Upon ultrasound activation, the sonosensitizers efficiently generate reactive oxygen species to kill bacteria and accelerate the virulence clearance. In vivo optical imaging shows that the antibody‐piloted nanocapturer can successfully locate MRSA infection and accurately distinguish the foci from sterile inflammation. In situ magnetic resonance imaging and oxyhemoglobin saturation detection visualize the treatment progression, revealing a complete sono‐immunotherapeutic eradication of MRSA myositis in mice. The first combination of antibacterial sonodynamic therapy and antivirulence immunotherapy, which promises a new way for antibiotic‐free nanotheranostics to robustly combat MDR bacterial infections, is presented.     

Near-Infrared Light-Mediated Cyclodextrin Metal–Organic Frameworks for Synergistic Antibacterial and Anti-Biofilm Therapies

Bacterial infections pose a significant threat to global public health; therefore, the development of novel therapeutics is urgently needed. Herein, a controllable antibacterial nanoplatform utilizing cyclodextrin metal–organic frameworks (CD-MOFs) as a template to synthesize ultrafine silver nanoparticles (Ag NPs) in their porous structure is constructed. Subsequently, polydopamine (PDA) is encapsulated on the CD-MOFs’ surface via dopamine polymerization to enhance the water stability and enable hyperthermia capacity. The resulting Ag@MOF@PDA generates localized hyperthermia and gradually releases Ag⁺ to achieve long-term photothermal-chemical bactericidal capability. The release rate of Ag⁺ can be accelerated by NIR-mediated heating in a controllable manner, quickly reaching the effective concentration and reducing the frequency of medication to avoid potential toxicity. In vitro experiments demonstrate that the combined antibacterial strategy can not only effectively kill both gram-negative and gram-positive bacteria, but also directly eradicate mature biofilms. In vivo results confirm that both bacterial- and biofilm-infected wounds treated with a combination of Ag@MOF@PDA and laser exhibit satisfactory recovery with minimal toxicity, displaying a superior therapeutic effect compared to other groups. Together, the results warrant that the Ag@MOF@PDA realizes synergistic antibacterial capacity and controllable release of Ag⁺ to combat bacterial and biofilm infections, providing a potential antibiotic-free alternative in the “post-antibiotic era.”     

The fabrication of the antibacterial paste based on TiO2 nanotubes and Ag nanoparticles-loaded TiO2 nanotubes powders

ABSTRACT

We successfully synthesised TiO₂ nanotubes (TNTs) and silver nanoparticles (Ag NPs)-loaded TiO₂ nanotubes paste. These were coated on a glass substrate by spin coating method, and their antibacterial activities were surveyed. The morphology of materials was defined by transmission electron microscopy (TEM) image; the crystalline structure and the composition of the materials were determined by X-ray diffraction (XRD) pattern and X-ray photoelectron spectroscopy (XPS). Vibrational properties of the molecules existing in the sample were investigated by Fourier transform infrared (FTIR) spectroscopy, and the transmittances of films were determined by UV–Vis transmittance spectroscopy. This research shows that the structure and morphology of TNTs did not change after they underwent the processes of paste preparing and film coating on a glass substrate. Furthermore, the transmittance of TNTs film (about 75%) is higher than Ag NPs-loaded TiO₂ nanotubes (Ag/TNTs) film (about 65%) in the visible region. Moreover, the antibacterial property of Ag/TNTs film shows its effectiveness against Escherichia coli bacteria, and the antibacterial efficiency is 99.06% for 24 h-incubation period in the dark condition.     

A facile method to prepare size-tunable silver nanoparticles and its antibacterial mechanism

The antibacterial effect of silver nanoparticles (denoted as Ag NPs) is closely related to size. This could partly explain why size controllable synthesis of Ag NPs for bactericidal application is drawing much attention. Thus, we establish a facile and mild route to prepare size-tunable Ag NPs with highly uniform morphologies and narrow size distributions. The as-prepared Ag NPs with averaged sizes of 2, 12 and 32?nm were characterized by transmission electron microscopy (TEM), ultraviolet–visible absorption spectroscopy (UV–vis), X-ray powder diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The antimicrobial effect of the as-prepared Ag NPs with different particles size was assessed by broth dilution and disk diffusion as well as measurement of optical density (OD₆₀₀). Moreover, their antibacterial mechanism was discussed in relation to morphology observation of microorganism by scanning electron microscopy (SEM) and to concentration detection of Ag⁺ by stripping voltammetry. It was found that the parameters such as reactant molar ratio, reaction time, dropping speed, and most of all, pH of the reactant solutions, have significant influences on size-regulation of Ag NPs. The as-prepared Ag NPs exhibit excellent antibacterial properties, and their antimicrobial activities increase with decreasing particles size. Besides, two kinds of mechanisms, i.e., contact action and release of Ag⁺, are responsible for the antimicrobial effect of Ag NPs.     

A Hierarchical 3D Nanostructured Microfluidic Device for Sensitive Detection of Pathogenic Bacteria

Efficient capture and rapid detection of pathogenic bacteria from body fluids lead to early diagnostics of bacterial infections and significantly enhance the survival rate. We propose a universal nano/microfluidic device integrated with a 3D nanostructured detection platform for sensitive and quantifiable detection of pathogenic bacteria. Surface characterization of the nanostructured detection platform confirms a uniform distribution of hierarchical 3D nano‐/microisland (NMI) structures with spatial orientation and nanorough protrusions. The hierarchical 3D NMI is the unique characteristic of the integrated device, which enables enhanced capture and quantifiable detection of bacteria via both a probe‐free and immunoaffinity detection method. As a proof of principle, we demonstrate probe‐free capture of pathogenic Escherichia coli (E. coli) and immunocapture of methicillin‐resistant‐Staphylococcus aureus (MRSA). Our device demonstrates a linear range between 50 and 10⁴ CFU mL^?1, with average efficiency of 93% and 85% for probe‐free detection of E. coli and immunoaffinity detection of MRSA, respectively. It is successfully demonstrated that the spatial orientation of 3D NMIs contributes in quantifiable detection of fluorescently labeled bacteria, while the nanorough protrusions contribute in probe‐free capture of bacteria. The ease of fabrication, integration, and implementation can inspire future point‐of‐care devices based on nanomaterial interfaces for sensitive and high‐throughput optical detection.     

Preparation and characterization of polyoxometalate-Ag nanoparticles composite multilayer films

The multifunctional thin films (BW₁₂/Ag NPs)_n (BW₁₂ = BW₁₂O₄₀, NPs = nanoparticles) were prepared by layer-by-layer self-assembly method. The (BW₁₂/PEI-Ag⁺)_n (PEI = polyethylenimine) composite films were achieved through alternately depositing anionic BW₁₂ and cationic PEI-Ag⁺ complex. The deposition process of (BW₁₂/PEI-Ag⁺)₁₀ multilayer is linear layer-by-layer self-assembly. Under UV irradiation, Ag ions in (BW₁₂/PEI-Ag⁺)_n multilayer films were reduced photochemically into Ag NPs and (BW₁₂/Ag NPs)₁₀ films were obtained. Through UV-vis measurements, the presence of surface plasma absorption peak at 445 nm demonstrated the formation of silver NPs. The electrochemical and antibacterial activities of (BW₁₂/Ag NPs)_n films were investigated. The electrochemical results indicate that the glassy carbon electrode modified with (BW₁₂/Ag NP)_n film exhibits the electroreduction toward O₂. Moreover, the (BW₁₂/Ag NP)₁₀ multilayer films exhibit long-lasting antibacterial properties toward Escherichia coli (E. coli).     

Size-dependent antibacterial activities of silver nanoparticles against oral anaerobic pathogenic bacteria

Dental caries and periodontal disease are widespread diseases for which microorganism infections have been identified as the main etiology. Silver nanoparticles (Ag Nps) were considered as potential control oral bacteria infection agent due to its excellent antimicrobial activity and non acute toxic effects on human cells. In this work, stable Ag Nps with different sizes (~5, 15 and 55 nm mean values) were synthesized by using a simple reduction method or hydrothermal method. The Nps were characterized by powder X-ray diffraction, transmission electron microscopy and UV–vis absorption spectroscopy. The antibacterial activities were evaluated by colony counting assay and growth inhibition curve method, and corresponding minimum inhibitory concentration (MIC) against five anaerobic oral pathogenic bacteria and aerobic bacteria E. coli were determined. The results showed that Ag Nps had apparent antibacterial effects against the anaerobic oral pathogenic bacteria and aerobic bacteria. The MIC values of 5-nm Ag against anaerobic oral pathogenic bacteria A. actinomycetemcomitans, F. nuceatum, S. mitis, S. mutans and S. sanguis were 25, 25, 25, 50 and 50 μg/mL, respectively. The aerobic bacteria were more susceptible to Ag NPs than the anaerobic oral pathogenic bacteria. In the mean time, Ag NPs displayed an obvious size-dependent antibacterial activity against the anaerobic bacteria. The 5-nm Ag presents the highest antibacterial activity. The results of this work indicated a potential application of Ag Nps in the inhibition of oral microorganism infections.     

Photoactivated Trifunctional Platinum Nanobiotics for Precise Synergism of Multiple Antibacterial Modes

Integrating multiple strategies of antibacterial mechanisms into one has been proven to have tremendous promise for improving antimicrobial efficiency. Hence, dual‐valent platinum nanoparticles (dvPtNPs) with a zero‐valent platinum core (Pt⁰) and bi‐valent platinum shell (Pt²⁺ ions), combining photothermal and photodynamic therapy, together with “chemotherapy,” emerge as spatiotemporally light‐activatable platinum nano‐antibiotics. Under near‐infrared (NIR) exposure, the multiple antibacterial modes of dvPtNPs are triggered. The Pt⁰ core reveals significant hyperthermia via effective photothermal conversion while an immediate release of chemotherapeutic Pt²⁺ ions occurs through hyperthermia‐initiated destabilization of metallic interactions, together with reactive oxygen species (ROS) level increase, thereby resulting in synergistic antibacterial effects. The precise cooperative effects between photothermal, photodynamic, and Pt²⁺ antibacterial effects are achieved on both Gram‐negative Escherichia coli and Gram‐positive methicillin‐resistant Staphylococcus aureus, where bacterial viability and colony‐forming units are significantly reduced. Moreover, similar results are observed in mice subcutaneous abscess models. Significantly, after NIR treatment, dvPtNP exhibits a more robust bacteria‐killing efficiency than other PtNP groups, owing to its integration of dramatic damage to the bacterial membrane and DNA, and alteration to ATP and ROS metabolism. This study broadens the avenues for designing and synthesizing antibacterial materials with higher efficiency.     

Biomimetic Nanosponges Suppress In Vivo Lethality Induced by the Whole Secreted Proteins of Pathogenic Bacteria

Polymeric nanoparticles coated with membrane of intact red blood cells have emerged as biomimetic toxin nanosponges (RBC‐NS) that absorb and neutralize bacterial virulence factors associated with numerous bacterial infections. Despite its promise, a clear correlation between in vitro neutralization of complex bacterial toxins and in vivo therapeutic efficacy remains elusive. In this study, the whole secreted proteins (wSP) of methicillin‐resistant Staphylococcus aureus (MRSA) are collected to induce lethality in mice. The wSP preserve the complexity of bacterial virulence profile while avoiding the intricacy and dynamics of infections by live bacteria. RBC‐NS are first quantified for their neutralization capacity against the hemolytic activity of MRSA wSP in vitro. Using a mouse model, in vivo studies further demonstrate that, by neutralizing the hemolytic activity, RBC‐NS confer significant survival benefits against wSP‐induced lethality. Furthermore, when mice are challenged with a sublethal dosage of MRSA supernatant, RBC‐NS reduce lung damages and inhibit the activation of nuclear factor kappa B in the spleen. These results provide a systematic evaluation of RBC‐NS toward the treatment of severe MRSA infections such as MRSA bacteremia and MRSA‐induced sepsis.     

Biosynthesis of Ag,Se, and ZnO nanoparticles with antimicrobial activities against resistant pathogens using waste isolate Streptomyces enissocaesilis

Nanoparticles (NPs) are gaining special interest due to their recent applications as antimicrobial agents to defeat the massive threat of resistant pathogens. This study focused on the utilisation of Streptomyces isolate S12 purified from waste discharge soil in the biological synthesis of silver (Ag), selenium (Se), and zinc oxide (ZnO) NPs. The isolate S12 was related to Streptomyces enissocaesilis according to 16S rRNA sequence analysis, morphological characteristics, and biochemical reactions. The cell‐free supernatant has been used for the synthesis of Ag, Se, and ZnO NPs. The synthesised NPs were characterised using ultraviolet–visible spectroscopy, dynamic light scattering (DLS), transmission electron microscopy, and Fourier transform infrared spectroscopy. The biogenic NPs were evaluated for antimicrobial effects against different Gram‐positive and Gram‐negative resistant isolates using the broth microdilution method. They showed antibacterial effect against standard and resistant isolates; Bacillus cereus, Staphylococcus aureus ATCC 29213, S. aureus S1.1, methicillin resistant S. aureus (MRSA 303, 402 and 807), Escherichia coli ATCC 12435, E. coli E7, Klebsiella pneumoniae ATCC 51503, K. pneumoniae K5, K112, Pseudomonas aeruginosa PAO1, and P. aeruginosa P8. This study showed the green synthesis of various NPs using Streptomyces isolate S12 which demonstrated diverse activities against multi‐drug resistant isolates.Inspec keywords: nanoparticles, nanofabrication, silver, selenium, zinc compounds, II‐VI semiconductors, wide band gap semiconductors, nanomedicine, biomedical materials, microorganisms, cellular biophysics, antibacterial activity, RNA, molecular biophysics, molecular configurations, ultraviolet spectra, visible spectra, biochemistry, light scattering, transmission electron microscopy, Fourier transform infrared spectraOther keywords: Gram‐positive resistant isolates, Gram‐negative resistant isolates, broth microdilution method, Bacillus cereus, Staphylococcus aureus ATCC 29213, S. aureus S1.1, methicillin resistant S. aureus MRSA 303, methicillin resistant S. aureus MRSA 402, methicillin resistant S. aureus MRSA 807, Escherichia coli ATCC 12435, E. coli E7, Klebsiella pneumoniae ATCC 51503, K. pneumoniae K5, Pseudomonas aeruginosa PAO1, P. aeruginosa P8, green synthesis, Streptomyces isolate S12, multidrug resistant isolates, Ag, Se, ZnO, biogenic NPs, Fourier transform infrared spectroscopy, transmission electron microscopy, dynamic light scattering, ultraviolet‐visible spectroscopy, cell‐free supernatant, biochemical reactions, morphological characteristics, 16S rRNA sequence analysis, biological synthesis, waste discharge soil, Streptomyces isolate S12 purification, antimicrobial agents, waste isolate Streptomyces enissocaesilis, resistant pathogens, antimicrobial activities, nanoparticles     

An extended spectrum bactericidal titanium dioxide (TiO<Subscript>2</Subscript>) coating for metallic implants: in vitro effectiveness against MRSA and mechanical properties

Implant infections remain feared and severe complications after total joint arthroplasty. The incidence of multi-resistant pathogens, causing such infections, is rising continuously, and orthopaedic surgeons are confronted with an ever-changing resistance pattern. Anti-infectious surface coatings aim for a high local effective concentration and a low systemic toxicity at the same time. Antibacterial efficacy and biomechanical stability of a novel broad-spectrum anti-infectious coating is assessed in the present study. Antibacterial efficacy of a sol–gel derived titanium dioxide (TiO₂) coating for metal implants with and without integrated copper ions as antibiotic agent was assessed against methicillin resistant Staphylococcus aureus (MRSA 27065). Both bacterial surface adhesion and growth of planktonic bacteria were assessed with bare and various TiO₂-coated Ti6Al4V metal discs. Furthermore, bonding strength of the TiO₂ surface coating, using standard testing procedures, as well as surface roughness were determined. We found a significant reduction of the bacterial growth rate for the coatings with integrated copper ions, with highest reduction rates observed for a fourfold copper TiO₂-coating. Pure TiO₂ without integrated copper ions did not reduce bacterial growth compared to uncoated Ti6Al4V. The coating was not detached from the substrate by standard adhesive failure testing, which indicated an excellent durability of the implant coating. The TiO₂ coating with integrated copper ions could offer a new strategy for preventing implant-associated infections, with antibacterial properties not only against the most common bacteria causing implant infections but also against multiresistant strains such as MRSA.     

Ultrafine Silver Nanoparticles Embedded in Cyclodextrin Metal‐Organic Frameworks with GRGDS Functionalization to Promote Antibacterial and Wound Healing Application

The challenge of bacterial infection increases the risk of mortality and morbidity in acute and chronic wound healing. Silver nanoparticles (Ag NPs) are a promising new version of conventional antibacterial nanosystem to fight against the bacterial resistance in concern of the drug discovery void. However, there are several challenges in controlling the size and colloidal stability of Ag NPs, which readily aggregate or coalesce in both solid and aqueous state. In this study, a template‐guided synthesis of ultrafine Ag NPs of around 2 nm using water‐soluble and biocompatible γ‐cyclodextrin metal‐organic frameworks (CD‐MOFs) is reported. The CD‐MOF based synthetic strategy integrates AgNO₃ reduction and Ag NPs immobilization in one pot achieving dual functions of reduced particle size and enhanced stability. Meanwhile, the synthesized Ag NPs are easily dispersible in aqueous media and exhibit effective bacterial inhibition. The surface modification of cross‐linked CD‐MOF particles with GRGDS peptide boosts the hemostatic effect that further enhances wound healing in synergy with the antibacterial effect. Hence, the strategy of ultrafine Ag NPs synthesis and immobilization in CD‐MOFs together with GRGDS modification holds promising potential for the rational design of effective wound healing devices.     

Biocompatible Conjugated Polymer Nanoparticles for Efficient Photothermal Tumor Therapy

Conjugated polymers (CPs) with strong near‐infrared (NIR) absorption and high heat conversion efficiency have emerged as a new generation of photothermal therapy (PTT) agents for cancer therapy. An efficient strategy to design NIR absorbing CPs with good water dispersibility is essential to achieve excellent therapeutic effect. In this work, poly[9,9‐bis(4‐(2‐ethylhexyl)phenyl)fluorene‐alt‐co‐6,7‐bis(4‐(hexyloxy)phenyl)‐4,9‐di(thiophen‐2‐yl)‐thiadiazoloquinoxaline] (PFTTQ) is synthesized through the combination of donor–acceptor moieties by Suzuki polymerization. PFTTQ nanoparticles (NPs) are fabricated through a precipitation approach using 1,2‐distearoyl‐ sn ‐glycero‐3‐phosphoethanolamine‐N‐[methoxy(polyethylene glycol)‐2000] (DSPE‐PEG₂₀₀₀) as the encapsulation matrix. Due to the large NIR absorption coefficient (3.6 L g^‐1 cm^‐1), the temperature of PFTTQ NP suspension (0.5 mg/mL) could be rapidly increased to more than 50 °C upon continuous 808 nm laser irradiation (0.75 W/cm²) for 5 min. The PFTTQ NPs show good biocompatibility to both MDA‐MB‐231 cells and Hela cells at 400 μg/mL of NPs, while upon laser irradiation, effective cancer cell killing is observed at a NP concentration of 50 μg/mL. Moreover, PFTTQ NPs could efficiently ablate tumor in in vivo study using a Hela tumor mouse model. Considering the large amount of NIR absorbing CPs available, the general encapsulation strategy will enable the development of more efficient PTT agents for cancer or tumor therapy.     

Titanium Incorporation into Zr‐Porphyrinic Metal–Organic Frameworks with Enhanced Antibacterial Activity against Multidrug‐Resistant Pathogens

This study uses metal–organic frameworks (MOFs) alone without any added antibacterial ingredients as the nonantibiotic agent for photodynamic therapy (PDT) of chronic wounds infected by multidrug‐resistant (MDR) bacteria. Nanoparticles (NPs) of MOFs (PCN‐224) are incorporated with titanium through a facile cation exchange strategy. The obtained bimetallic PCN‐224(Zr/Ti) shows greatly enhanced photocatalytic performance for the generation of reactive oxygen species under visible light, which is responsible for the effective antibacterial activities. The PCN‐224(Zr/Ti) NPs are loaded onto lactic‐co‐glycolic acid nanofibers to prepare a wound dressing, which shows high biocompatibility and minimal cytotoxicity. The wound dressing is efficient for PDT‐based in vivo healing of the chronic wound infected by MDR bacteria. Most importantly, this work does not involve any additional antibacterial agents, which is facile, low cost, and in particular, greatly explores the potential of MOFs as a powerful nonantibiotic agent in PDT.