Antibacterial Reagents Research Articles

Synthesis, Characterizationand Antibacterial Activity Studyof Para-substituted Derivatives of N -benzyl-3-methylbuten-2-enamides.

In order to deeply explorethe effect of para-substituentson the antibacterial activity ofN-benzyl-3-methylbuten-2-enamidederivatives,we elaborately synthesizedthreesuchpara-substituted derivatives(compounda: N-(4-hydroxybenzyl)-3-methylbut 2-enamide;compoundb:N-(4-isobutoxybenzyl)-3-methylbut-2-enamide;compoundc:N-(4-isopropoxybenzyl)-3-methylbut-2-enamide),of which thestructures were determined by ways of single crystal X-ray diffraction data analysis mainly. The antibacterial performance experiments showed thatcompounds a, band cwere evaluated for their antibacterial (Escherichia coli, Staphylococcus aureus,andEnterobacter aerogenes)activities.Among them, compounds a, band chavean effective antibacterial reagents forE.coliexhibiting MIC values of 0.01,0.01 and0.01g/mL, respectively, but inactive for E. aerogenes.In addition, compounds band chave better activity than compounda against S. aureuswithMIC values of 0.01 and0.02g/mL.These results provide an important basis for further study of the antibacterial properties and structure-activity relationship of these compounds, and are expected to provide valuable reference for the development of new antibacterial drugs.

Fabrication Methods, Structural, Surface Morphology and Biomedical Applications of MXene: A Review.

Recently, two-dimensional (2-D) layered materials have revealed outstanding properties and play a crucial role for numerous advanced applications. The emerging transition metal carbides and nitrides, known as MXene with empirical formula Mn+1XnTx, have generated widespread attention and demonstrated impressive potential in various fields. The fabrication of 2-D novel MXene and its composites and their characterizations are applicable to vast applications in different areas such as energy storage, gas sensors, catalysis, and biomedical applications. In this review, the main focus is on the various synthesis methods, their properties, and biomedical applications. This review provides detailed illustrations of MXenes for many biomedical applications, including bioimaging, drug delivery, therapies, biosensors, tissue engineering, and antibacterial reagents. The challenges and future prospects were highlighted in a comprehensive manner, and the existing problems and potential for MXene-based biomaterials were analyzed with the goal of accelerating their use in the biomedical field.

Long-term and high-efficiency capture of Escherichia coli using cellulose acetate nanofiber membrane functionalized with reactive 19 dye and polyhexamethylene biguanide

Cellulose acetate (CA) nanofibers have been popularly applied in various biomedical and textile products. In this work, a textile azo-dye Reactive Green 19 (RG19) was selected to be chemically coupled to the CA nanofiber membrane to form dyed CA nanofiber membrane (namely CA-RG19) and then poly(hexamethylene biguanide) (PHMB) as an antibacterial reagent was physically attached to the dyed CA nanofiber membrane, forming CA-RG19-PHMB nanofiber membrane. The nanofiber membranes were evaluated for their physical and mechanical properties, including functional group analysis, morphological characterization, and thermal stability assessment. To investigate the antibacterial properties of the nanofiber membrane, various concentrations of RG19 dye and PHMB were tested to evaluate the antibacterial efficiency (AE) against Escherichia coli of the membranes. It was found that the CA-RG19-PHMB nanofiber membrane exhibited an AE value of approximately 100 %, with the immobilization concentrations of RG19 dye and PHMB being 373.46 mg/g and 0.333 mg/g, respectively. The CA-RG19-PHMB nanofiber membrane showed 100 % antibacterial efficacy after 10 min against E. coli cells. Furthermore, the storage stability of the CA-RG19-PHMB nanofiber membrane remained at approximately 100 % of its initial antibacterial efficacy after 60 days, and it exhibited excellent antibacterial efficacy after five cycles.

Highly Crystalline Copper Aluminum-Layered Double Hydroxides with Intrinsic Fenton-Like Catalytic Activity for Robust Oral Health Management.

As the main challenge of dental healthcare, oral infectious diseases are highly associated with the colonization of pathogenic microbes. However, current antibacterial treatments in the field of stomatology still lack a facile, safe, and universal approach. Herein, we report the controllable synthesis of copper aluminum-layered double hydroxides (CuAl-LDHs) with high Fenton-like catalytic activity, which can be utilized in the treatment of oral infectious diseases with negligible side effects. Our strategy can efficiently avoid the unwanted doping of other divalent metal ions in the synthesis of Cu-contained LDHs and result in the formation of binary CuAl-LDHs with high crystallinity and purity. Evidenced by experimental and theoretical results, CuAl-LDHs exhibit excellent catalytic ability toward the ·OH generation in the presence of H2O2 and hold strong affinity toward bacteria, endowing them with great catalytic sterilization against both Gram-positive and Gram-negative bacteria. As expected, these CuAl-LDHs provide outstanding treatments for mucosal infection and periodontitis by promoting wound healing and remodeling of the periodontal microenvironment. Moreover, toxicity investigation demonstrates the overall safety. Accordingly, the current study not only provides a convenient and economic strategy for treating oral infectious diseases but also extends the development of novel LDH-based Fenton or Fenton-like antibacterial reagents for further biomedical applications.

Characterization of tryptanthrin as an antibacterial reagent inhibiting Vibrio splendidus

Isolates of Vibrio splendidus are ubiquitously presented in various marine environments, and they can infect diverse marine culture animals, leading to high mortality and economic loss. Therefore, a control strategy of the infection caused by V. splendidus is urgently recommended. Tryptanthrin is a naturally extracted bioactive chemical with antimicrobial activity to other bacteria. In this study, the effects of tryptanthrin on the bacterial growth and virulence-related factors of one pathogenic strain V. splendidus AJ01 were determined. Tryptanthrin (10 μg/mL) could completely inhibit the growth of V. splendidus AJ01. The virulence-related factors of V. splendidus AJ01 were affected in the presence of tryptanthrin. Tryptanthrin resulted an increase in biofilm formation, but lead to reduction in the motility and hemolytic activity of V. splendidus cells. In the cells treated with tryptanthrin, two distinctly differentially expressed extracellular proteins, proteases and flagellum, were identified using SDS–PAGE combined with LC–MS. Real-time reverse transcriptase PCR confirmed that the genes involved in the flagellar formation and hemolysin decreased, whereas specific extracellular proteases and the genes involved in the biofilm formation were upregulated. Two previously annotated luxOVs genes were cloned, and their expression levels were analyzed at different cell densities. Molecular docking was performed to predict the interaction between LuxOVs and ATP/tryptanthrin. The two sigma-54-dependent transcriptional regulators showed similar ATP or tryptanthrin binding capacity but with different sites, and the direct competitive binding between ATP and tryptanthrin was present only in their binding to LuxO1. These results indicated that tryptanthrin can be used as a bactericide of V. splendidus by inhibiting the growth, bacterial flagella, and extracellular proteases, but increasing the biofilm. Sigma-54-dependent transcriptional regulator, especially the quorum sensing regulatory protein LuxO1, was determined to be the potential target of tryptanthrin.Key points• Tryptanthrin inhibited the growth of V. splendidus in a dose-dependent manner.• The effect of tryptanthrin on the virulence factors of V. splendidus was characterized.• LuxO was the potential target for tryptanthrin based on molecular docking.

Shining light on carbon dots: Toward enhanced antibacterial activity for biofilm disruption.

In spite of tremendous efforts dedicated to addressing bacterial infections and biofilm formation, the post-antibiotic ear continues to witness a gap between the established materials and an easily accessible yet biocompatible antibacterial reagent. Here we show carbon dots (CDs) synthesized via a single hydrothermal process can afford promising antibacterial activity that can be further enhanced by exposure to light. By using citric acid and polyethyleneimine as the precursors, the photoluminescence CDs can be produced within a one-pot, one-step hydrothermal reaction in only 2 h. The CDs demonstrate robust antibacterial properties against both Gram-positive and Gram-negative bacteria and, notably, a considerable enhancement of antibacterial effect can be observed upon photo-irradiation. Mechanistic insights reveal that the CDs generate singlet oxygen (1O2) when exposed to light, leading to an augmented reactive oxygen species level. The approach for disruption of biofilms and inhibition of biofilm formation by using the CDs has also been established. Our findings present a potential solution to combat antibacterial resistance and offer a path to reduce dependence on traditional antibiotics.

Rational design, synthesis, and antimicrobial evaluation of novel 1,2,4-trizaole-substituted 1,3,4-oxadiazole derivatives with a dual thioether moiety.

In this paper, a series of novel 1,2,4-trizaole-substituted 1,3,4-oxadiazole derivatives with a dual thioether moiety were constructed. The synthetic compounds were characterized by 1H NMR, 13C NMR, HRMS, and single crystal diffraction. The antimicrobial activities of title compounds against fungi (Pyricutaria oryzae Cav., Phomopsis sp., Botryosphaeria dothidea, cucumber Botrytis cinerea, tobacco Botrytis cinerea, blueberry Botrytis cinerea) and bacteria (Xanthomonas oryzae pv. oryzicola, Xoc; Xanthomonas axonopodis pv. citri, Xac) revealed these compounds possessed excellent antibacterial activity through mycelial growth rate method and turbidity method, respectively. Among them, compounds 7a, 7d, 7g, 7k, 7l, and 7n had the antibacterial inhibition rate of 90.68, 97.86, 93.61, 97.70, 97.26, and 92.34%, respectively. The EC50 values of 7a, 7d, 7g, 7k, 7l, and 7n were 58.31, 48.76, 58.50, 40.11, 38.15, and 46.99μg/mL, separately, superior to that of positive control pesticide thiodiazole copper (104.26μg/mL). The molecular docking simulation of compound 7l and glutathione s-transferase also confirmed its good activity. The in vivo bioassay toward Xac infected citrus leaves was also performed to evaluate the potential of compounds as efficient antibacterial reagent. Further study of antibacterial mechanism was also carried out, including extracellular polysaccharide production, permeability of bacterial membrane, and scanning electron microscope observations. The excellent antibacterial activities of these compounds provided a strong support for its application for preventing and control plant diseases.

Copper-based nanodots as efficient biomimetic antibiotics for the treatment of oral bacterial infections

Oral infectious diseases caused by a variety of pathogenic bacteria seriously affect the quality of life. However, these diseases remain a clinical challenge because of the lack of simple, safe, and universal prophylactics. To address these limitations, we synthesize CuOx nanodots (CuOx NDs) with excellent Fenton-like reaction activity and utilize them in the treatment of oral bacterial infections. Different from other complicated approaches, CuOx NDs are rationally prepared using a facile one-pot aqueous synthesis. In the presence of H2O2, these well-developed CuOx NDs can efficiently catalyze the generation of hydroxyl radicals (·OH) around oral pathogens, leading to the death of various bacteria. Meanwhile, results of biosafety indicate the high biocompatibility and extremely low toxicity of these CuOx NDs. After understanding the admirable in vitro antibacterial effect of CuOx NDs in the presence of H2O2, we further explore their in vivo antibacterial performance on several classical animal models including oral mucosal wound model, intragingival bacteria-infected model, and the periodontal infection model. As expected, these CuOx NDs with wide-spectrum antibacterial activity can serve as high-performance antibacterial reagents for the treatment of various oral bacterial infections with the help of H2O2. In brief, current nanoplatform can act as efficient antibiotics against oral pathogens with broadening the biomedical applications of copper-based nanomaterials.

Herbal-Based Green Synthesis of TB-ZnO-TiO(II) Nanoparticles Composite From Terminalia bellirica: Characterization, Toxicity Assay, Antioxidant Assay, and Antimicrobial Activity.

Background Terminalia bellirica leaf extractwas used as an herbal to get an aqueous extract of Tb-ZnO-TiO2 (zinc and titanium dioxide) nanoparticles composite, and this was subsequently subjected to an analysis of its antioxidant properties and possible antimicrobial activity againstgram-negative andgram-positive bacteria. Employing the 2,2-Diphenyl-1-picrylhydrazyl and hydrogen peroxide assay techniques for antioxidant properties.In addition to their biocompatibility, rapid biodegradability, and low toxicity, herbal-based nanoparticles (Tb-ZnO-TiO2 NPs composite) synthesized by T. bellirica have drawn a lot of interest as promising options for administering drugs and effective antimicrobial applications. Materials and methods The form and dimensions of the dispersion of the synthesized nanoparticles were investigated through scanning electron microscopy (SEM), Fourier Transform Infrared Spectroscopy, and UV-visible for particle characterization. Nanoparticles were analyzed for antimicrobial activity using the well diffusion method.Ascorbic acid and vitamin E were used as two separate controls for antioxidant assay with different concentrations, and also toxicity assay was done by using zebrafish embryos. Results Tb-ZnO-TiO2NPs composite were obtained as a powder, the X-beam diffraction (XRD) result revealed a small quantity of impurities and revealed that the structure was spherical in nature. A unique absorption peak for Tb-ZnO-TiO2 NPs composite may be seen in UV-Vis spectroscopywhich is in the region of 260 to 320 nm. The Tb-ZnO-TiO2NPs compositeantibacterial efficacy was evaluated and showed noted antibacterial activity and free radical scavenging activity with less toxicity. Conclusion The results demonstrated the Tb-ZnO-TiO2NPs composite has strong antioxidant qualities and enormous antibacterial activity obtained from T. bellirica extract. Therefore, the Tb-ZnO-TiO2NPs composite synthesized nanoparticles can be used in biomedical applications as an effective antioxidant and antibacterial reagent.

Fabrication of ε-Poly-L-lysine (ε-PL) modified electrospun antibacterial nanofibrous membranes for PM1.0 filtration

Segregating airborne particulate matters (PMs, especially PM1.0) with high transmissibility of bacterial and viral pathogens is crucial for ensuring outdoor breathing safety. Electrospun nanofiber membranes (ENMs) have shown great promise for this purpose. However, the application of traditional ENMs is usually plagued by bacterial growth causing severe public health concern. Although some research has been done to overcome this challenge by doping antibacterial materials, the potential negative effects of these materials on the human body cannot be ignored. In this study, the ε-Poly-L-lysine (ε-PL), a green broad-spectrum antibacterial reagent, was grafted onto the surface of polydopamine (PDA) coated polyacrylonitrile (PAN) ENM via addition of Schiff base and Michael reaction. Experimental results indicated that the introduction of the ε-PL is key to the antibacterial performance of the membranes, and the antibacterial efficacy of E. coli and B. subtilis can reach to 99.86 % and 99.99 % respectively. Even after 7 days, the antibacterial efficiency of membrane remained at a high level. Additionally, the uniform structure of membranes endowed it with a high filtration efficiency of 80.9 % for PM1.0 particles with a moderate transmembrane pressure drop (TMP) of 250 Pa and the corresponding quality factor is approximately 0.0066 Pa−1. This study has far-reaching implications for the design of green antibacterial nanofibrous membranes to realize the segregation of harmful PMs.

Organo-Ptii Complexes for Potent Photodynamic Inactivation of Multi-Drug Resistant Bacteria and the Influence of Configuration.

PtII based organometallic photosensitizers (PSs) have emerged as novel potent photodynamic inactivation (PDI) reagents through their enhanced intersystem crossing (ISC) processes. Currently, few PtII PSs have been investigated as antibacterial materials, with relatively poor performances reported and with structure-activity relationships not well described. Herein, a pair of configurational isomers are reported of Bis-BODIPY (4,4-difluoro-boradizaindacene) embedded PtII PSs. The cis-isomer (cis-BBP) displayed enhanced 1O2 generation and better bacterial membrane anchoring capability as compared to the trans-isomer (trans-BBP). The effective PDI concentrations (efficiency > 99.9%) for cis-BBP in Acinetobacter baumannii (multi-drug resistant (MDR)) and Staphylococcus aureus are 400nM (12Jcm-2) and 100nM (18Jcm-2), respectively; corresponding concentrations and light doses for trans-BBP in the two bacteria are 2.50µM (30Jcm-2) and 1.50µM (18Jcm-2), respectively. The 50% and 90% minimum inhibitory concentration (MIC50 and MIC90) ratio of trans-BBP to cis-BBP is 22.22 and 24.02 in A. baumannii (MDR); 21.29 and 22.36 in methicillin resistant S. aureus (MRSA), respectively. Furthermore, cis-BBP displays superior in vivo antibacterial performance, with acceptable dark and photoinduced cytotoxicity. These results demonstrate cis-BBP is a robust light-assisted antibacterial reagent at sub-micromolecular concentrations. More importantly, configuration of PtII PSs should be an important issue to be considered in further PDI reagents design.

The Structure, Functions and Potential Medicinal Effects of Chlorophylls Derived from Microalgae.

Microalgae are considered to be natural producers of bioactive pigments, with the production of pigments from microalgae being a sustainable and economical strategy that promises to alleviate growing demand. Chlorophyll, as the main pigment of photosynthesis, has been widely studied, but its medicinal applications as an antioxidant, antibacterial, and antitumor reagent are still poorly understood. Chlorophyll is the most important pigment in plants and algae, which not only provides food for organisms throughout the biosphere, but also plays an important role in a variety of human and man-made applications. The biological activity of chlorophyll is closely related to its chemical structure; its specific structure offers the possibility for its medicinal applications. This paper reviews the structural and functional roles of microalgal chlorophylls, commonly used extraction methods, and recent advances in medicine, to provide a theoretical basis for the standardization and commercial production and application of chlorophylls.

Lipophilic AIEgens as the "Trojan Horse" with Discrepant Efficacy in Tracking and Treatment of Mycobacterial Infection.

The highly contagious tuberculosis is a leading infectious killer, which urgently requires effective diagnosis and treatment methods. To address these issues, three lipophilic aggregation-induced emission (AIE) photosensitizers (TTMN, TTTMN, and MeOTTMN) are selected to evaluate their labeling and antimicrobial properties in vitro and in vivo. These three lipophilic AIEgens preserve low cytotoxicity and achieve real-time and non-invasive visualization of the process of mycobacteria infection in vitro and in vivo. More importantly, these AIEgens can be triggered by white light to produce reactive oxygen species (ROS), which is a highly efficient antibacterial reagent. Among these AIEgens, the TTMN photosensitizerhas an outstanding antibacterial efficacy over the clinical first-line drug rifampicin at the same therapeutic concentration. Interestingly, this study also finds that TTMN can increase the expression of pro-inflammatory cytokines in the early stage of infection after light irradiation, indicating an additional pro-inflammatory role of TTMN. This work provides some feasibility basis for developing AIEgens-based agents for effectively destroying mycobacterium.

Self-Cross-Linkable Maleic Anhydride Terpolymer Coating with Inherent High Antimicrobial Activity and Low Cytotoxicity.

Developing coating materials with low cytotoxicity and high antimicrobial activity has been recognized as an effective way to prevent medical device-associated infections. In this study, a maleic anhydride terpolymer (PPTM) is synthesized and covalently attached to silicone rubber (SR) surface. The formed coating can be further cross-linked (SPM) through the self-condensation of pendent siloxane groups of terpolymer. No crack or delamination of SPM was observed after 500 cycles of bending and 7 day immersion in deionized water. The sliding friction force of a catheter was reduced by 50% after coating with SPM. The SPM coating without adding any extra antibacterial reagents can kill 99.99% of Staphylococcus aureus and Escherichia coli and also significantly reduce bacterial coverage, while the coating displayed no antimicrobial activity when maleic anhydride groups of SPM were aminated or hydrolyzed. The results of the repeated disinfection tests showed that the SR coated with SPM could maintain 87.3% bactericidal activity within 5 cycles. Furthermore, the SPM coating only imparted slight toxic effect (>85% viability) on L929 cells after 36 h of coculture, which is superior to the coating of aminated SPM conjugated with the antimicrobial peptide E6. The terpolymer containing maleic anhydride units have great potential as a flexible and durable coating against implant infections.

Ag-MXene as peroxidase-mimicking nanozyme for enhanced bacteriocide and cholesterol sensing

Reactive oxygen species (ROS) are ideal alternative antibacterial reagents for rapid and effective sterilization. Although a variety of ROS-based antimicrobial strategies have been developed, many are still limited by their inefficiency. Herein, we report the synthesis of the Ag-MXene nanozyme, which have superior peroxidase-like activity for antibacterial applications. As a result, Ag-MXene nanozyme can efficiently increase the level of intracellular ROS, converting H2O2 into hydroxyl radicals that effectively kill both Gram-negative and Gram-positive bacteria and disrupting the bacterial biofilm formation. Moreover, a sensitive and selective colorimetric biosensor was constructed for assaying cholesterol based on the Ag-MXene’s prominent peroxidase-mimicking activity and the cholesterol oxidase cascade reaction. The biosensor exhibits high performance with a linear cholesterol detection range of 2–800 μM, and a detection limit of 0.6 μM. Ag-MXene nanozyme can be used for the rapid detection of cholesterol in serum without complicated sample pretreatment. Collectively, it is conceivable that the proposed Ag-MXene nanozyme could be used as a biocide and as a cholesterol sensor. This study provides a broad prospect for the rapid detection and sterilization of MXene nanozymes in the biomedical field.

Washable Antibacterial Modified Bio-based PA56 with High Toughness

An effective method was developed for the preparation of a washable antibacterial modified bio-based polyamide 56 (PA56) with high toughness by a simple reactive extrusion technique. In this work, polypentamethylene guanidine hydrochloride (PPMG), as a bio-based antibacterial reagent, was successfully grafted onto a bio-based PA56 polymer. The micromorphology of the samples was studied by scanning electron microscopy, which proved that the addition of ethylene-methyl acrylate-glycidyl methacrylate terpolymer (EMA) greatly improved the compatibility. In addition, the mechanical properties of the modified antibacterial bio-based polyamide were improved, especially the impact toughness of PA56-g-1.0 (1.0 wt % PPMG and 1.0 wt % EMA) could be 48% higher than pure PA56. When the content of PPMG was higher than 1.0%, the inhibition rates of the products against Escherichia coli and Staphylococcus aureus both reached over 99.99%, and such a high inhibition rate would still maintain after 30 washing times with hot water (90 °C) and detergent.

New quinazolone derivatives: Synthesis, Spectroscopic, X-ray, DFT calculation and Biological activity studies

Quinazolone is a type of heterocyclic scaffold with extensively biological activities. Many reports have shown that quinazolone derivatives played an important role as antidiabetic, antithrombotic, antiviral, antibacterial and antitumor reagents. Based on the broadly biological activities, a new series of quinazolone derivatives was designed and synthesized. These compounds were characterized by 1H-NMR, 13C-NMR and HRMS. Especially, compound 3f was cultured into single crystals, and the structure of compound 3f was also characterized by FT-IR and X-ray. In addition, the density functional theory (DFT) calculation of compound 3f was studied at the B3LYP/6-311 level. Finally, the antitumor activity of all the target compounds was evaluated by MTT assay.

Copper-based nanomaterials as peroxidase candidates for intelligent colorimetric detection and antibacterial applications

With natural polyphenol compound tannic acid (TA) as the ingredient, copper tannate (CuTA) nanolayer material was formed by self-assembly under the conditions of heating and copper ion. Copper ion and tannic acid could coordinate to form Cu–O–C structure which was similar to the Fe–N–C structure of natural heme enzymes. In addition, the obtained CuTA nanomaterial possessed excellent peroxidase-like catalytic activity and stability. Based on this excellent enzymatic activity, CuTA nanomaterials could be used for colorimetric detection of hydrogen peroxide with a smartphone and decomposition of organic dyes. Based on the structural characteristics and catalytic activity, the copper tannate nanozymes could also serve as potential antibacterial reagents to effectively inhibit the growth of gram-negative and positive bacteria in a low hydrogen peroxide level. This work may promote the exploration of novel peroxidase mimetics and broaden the applications of nanozymes.

Disruption of biofilms in periodontal disease through the induction of phase transition by cationic dextrans.

Biofilm of oral pathogenic microorganisms induced by their multiplication and coaggregation would lead to periodontitis. In biofilms, the extracellular polymeric substances (EPS) as a protective shield encapsulates the individual bacteria, protecting them against attack. To alleviate periodontal disease, disrupting the EPS of pathogenic bacteria is crucial and challenging. Based on the sufficient capacity of disorganizing EPS of our designed cationic dextrans, we hypothesized that these polymers could be competent in relieving periodontitis. We validated that cationic dextrans could induce the phase transition of EPS in biofilms, especially the Porphyromonas gingivalis (P. gingivalis), a keystone periodontal pathogen, thus effectively destroying biofilm in vitro. More importantly, satisfactory in vivo treatment was achieved in a rat periodontal disease model. In summary, the study exploited a practical and effective strategy to treat periodontitis with cationic dextrans' powerful biofilm-controlling potential. STATEMENT OF SIGNIFICANCE: Periodontal disease is closely related to dental plaque biofilms on the tooth surface. The biofilm forms gel structures and shields the bacteria underneath, thus protecting oral pathogens from traditional anti-bacterial reagents. Due to limited penetration into gel, the efficacy of these reagents in biofilm elimination is restricted. Our designed cationic dextran could wipe out the coverage of gel-like EPS to disperse encapsulated bacteria. Such superior capacity endowed them with satisfactory effect in disrupting biofilm. Notably, in a rat periodontitis model, cationic dextrans dramatically suppressed alveolar bone loss and alleviated periodontal inflammation by controlling dental plaque. Given the increasing global concerns about periodontal disease, it's worth expanding the application of cationic dextrans both scientifically and clinically.

Antibody conjugated Au/Ir@Cu/Zn-MOF probe for bacterial lateral flow immunoassay and precise synergistic antibacterial treatment

Staphylococcus aureus is one of the most prevalent threats to public health. Rapid detection with high sensitivity and targeted killing is crucial to curb its spread. Herein, a metal-bearing nanocomposite, consisting of a bimetallic nanoparticle and a metal-organic framework (Au/Ir@Cu/Zn-MOF) was constructed. Upon conjugation with anti-S. aureus antibody, this nanocomposite (Ab-Au/Ir@Cu/Zn-MOF) was exploited for its dual functions, i.e. as a reporting probe in a lateral flow immunoassay and a high efficiency antibacterial reagent. Benefiting from the enrichment of Au/Ir NPs by the Cu/Zn-MOF, the Au/Ir@Cu/Zn-MOF-based lateral flow immunoassay sensor exhibited a visual limit of detection of 103 CFU/mL, which was100 times more sensitive than Au/Ir-based sensor. Moreover, the Ab-Au/Ir@Cu/Zn-MOF probe possessed synergistic photothermal-chemodynamic bactericidal effect that specifically targeted against S. aureus. Under a co-treatment by H2O2 (0.4 mM) and 808 nm near infrared irradiation (1 W/cm2, 5 min), complete sterilization of 5 × 105–106 CFU/mL S. aureus was achieved at a nanocomposite concentration as low as 6.25 μg/mL. The superior antibacterial efficiency was attributable to the three-fold properties of the Ab-Au/Ir@Cu/Zn-MOF probe: (1) enhanced multi-enzyme mimicking activities that promote reactive oxygen species generation, (2) high photothermal activity (efficiency of 53.70%), and (3) bacteria targeting ability via the antibody coating. By changing the antibody, this nanocomposite can be tailored to target a wide range of bacteria species, for detection and for precise antibacterial treatment.