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The overuse of antibiotics has led to the rapid development of multi-drug resistant bacteria, making antibiotics increasingly ineffective against bacterial infections. Consequently, there is an urgent need to develop alternative strategies to combat multi-drug-resistant bacterial infections. In this study, gold nanoparticles modified with ellagic acid (EA-AuNPs) were prepared using a simple and mild one-pot hydrothermal process. EA-AuNPs demonstrated high bactericidal efficacy and broad-spectrum antimicrobial activities against clinical isolates of the antibiotic-resistant ESKAPE pathogens. Furthermore, EA-AuNPs effectively disperse biofilms of multi-drug-resistant bacteria. Additionally, EA-AuNPs mitigated inflammatory responses at the bacterial infection sites. The combined bactericidal and anti-inflammatory treatment with EA-AuNPs resulted in faster curing of peritonitis caused by Staphylococcus aureus in mice compared to treatment with free EA or gentamicin. Moreover, transcriptome analysis revealed that EA-AuNPs exhibited a multi-targeting mechanism, making resistance development in pathogens more challenging than traditional antibiotics that recognize specific cellular targets. Overall, EA-AuNPs emerged as a promising antimicrobial agent against multi-drug-resistant bacterial infections.
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The oral microbiota develops within the first 2 years of childhood and becomes distinct from the parents by 4 years-of-age. The oral microbiota plays an important role in the overall health/symbiosis of the individual. Deviations from the state of symbiosis leads to dysbiosis and an increased risk of pathogenicity. Deviations can occur not only from daily life activities but also from orthodontic interventions. Orthodontic appliances are formed from a variety of biomaterials. Once inserted, they serve as a breeding ground for microbial attachment, not only from new surface areas and crevices but also from material physicochemical interactions different than in the symbiotic state. Individuals undergoing orthodontic treatment show, compared with untreated people, qualitative and quantitative differences in activity within the oral microbiota, induced by increased retention of supra- and subgingival microbial plaque throughout the treatment period. These changes are at the root of the main undesirable effects, such as gingivitis, white spot lesions (WSL), and more severe caries lesions. Notably, the oral microbiota profile in the first weeks of orthodontic intervention might be a valuable indicator to predict and identify higher-risk individuals with respect to periodontal health and caries risk within an otherwise healthy population. Antimicrobial coatings have been used to dissuade microbes from adhering to the biomaterial; however, they disrupt the host microbiota, and several bacterial strains have become resistant. Smart biomaterials that can reduce the antimicrobial load preventing microbial adhesion to orthodontic appliances have shown promising results, but their complexity has kept many solutions from reaching the clinic. 3D printing technology provides opportunities for complex chemical syntheses to be performed uniformly, reducing the cost of producing smart biomaterials giving hope that they may reach the clinic in the near future. The purpose of this review is to emphasize the importance of the oral microbiota during orthodontic therapy and to use innovative technologies to better maintain its healthy balance during surgical procedures.
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Hybrid-nanozymes are promising in various applications, but comprehensive comparison of hybrid-nanozymes composed of single-atoms or nanoparticles on the same support has never been made. Here, manganese-oxide nanosheets were loaded with Pt-single-atoms or differently-sized nanoparticles and their oxidase- and-peroxidase activities compared. High-resolution Transmission-Electron-Microscopy and corresponding Fast Fourier Transform imaging showed that Pt-nanoparticles (1.5 nm diameter) had no clear (111) crystal-planes, while larger nanoparticles had clear (111) crystal-planes. X-ray Photo-electron Spectroscopy demonstrated that unloaded nanosheets were composed of MnO2 with a high number of oxygen vacancies (Vo/Mn 0.4). Loading with 7.0 nm Pt-nanoparticles induced a change to Mn2O3, while loading with 1.5 nm nanoparticles increased the number of vacancies (Vo/Mn 1.2). Nanosheets loaded with 3.0 nm Pt-nanoparticles possessed similarly high catalytic activities as Pt-single-atoms. However, loading with 1.5 nm or 7.0 nm Pt-nanoparticles yielded lower catalytic activities. A model is proposed explaining the low catalytic activity of under- and over-sized Pt-nanoparticles as compared with intermediately-sized (3.0 nm) Pt-nanoparticles and single-atoms. Herewith, catalytic activities of hybrid-nanozymes composed of single-atoms and intermediately-sized nanoparticles are put a par, as confirmed here with respect to bacterial biofilm eradication. This conclusion facilitates a balanced choice between using Pt-single-atoms or nanoparticles in further development and application of hybrid-nanozymes.
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As a potential alternative to antibiotics, hyperbranched poly(ionic liquid)s (HPILs) have demonstrated significant potential in combating bacterial biofilms. However, their high cation density poses a high risk of toxicity, greatly limiting their in vivo applications. In this study, we constructed a biocompatible HPIL (HPIL-Glu) from a hyperbranched polyurea core with modified terminals featuring charge-convertible ionic liquids. These ionic liquid moieties consist of an ammonium-based cation and a gluconate (Glu) organic counter. HPIL-Glu could form a homogeneous nanoassembly in water and exhibited a pH-responsive charge conversion property. Under neutral conditions, Glu shielded the positively charged surface, minimizing the toxicity. In a mildly acidic environment, Glu protonation exposes cationic moieties to biofilm eradication. Comprehensive antimicrobial assessments demonstrate that HPIL-Glu effectively kills bacteria and promotes the healing of bacteria-infected chronic wounds. Furthermore, prolonged exposure to HPIL-Glu does not induce antimicrobial resistance.
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Cascade-reaction containers generating reactive oxygen species (ROS) as an alternative for antibiotic-based strategies for bacterial infection control, require endogenous oxygen-sources and ROS-generation close to or preferably inside target bacteria. Here, this is achieved by cetyltrimethylammonium-chloride (CTAC) assisted in situ metabolic labeling and incorporation of mesoporous SiO2-nanoparticles, dual-loaded with glucose-oxidase and Fe3O4-nanoparticles as cascade-reaction containers, inside bacterial cell walls. First, azide-functionalized d-alanine (D-Ala-N3) was inserted in cell wall peptidoglycan layers of growing Gram-positive pathogens. In Gram-negatives, this could only be achieved after outer lipid-membrane permeabilization, using a low concentration of CTAC. Low concentrations of CTAC had no adverse effect on in vitro blood clotting or hemolysis nor on the health of mice when blood-injected. Next, dibenzocyclooctyne-polyethylene-glycol modified, SiO2-nanoparticles were in situ click-reacted with d-Ala-N3 in bacterial cell wall peptidoglycan layers. Herewith, a two-step cascade-reaction is facilitated inside bacteria, in which glucose-oxidase generates H2O2 at endogenously-available glucose concentrations, while subsequently Fe3O4-nanoparticles catalyze generation of â¢OH from the H2O2 generated. Generation of â¢OH inside bacterial cell walls by dual-loaded mesoporous SiO2-nanoparticles yielded more effective in vitro killing of both planktonic Gram-positive and Gram-negative bacteria suspended in 10 % plasma than SiO2-nanoparticles solely loaded with glucose-oxidase. Gram-positive or Gram-negative bacterially induced sepsis in mice could be effectively treated by in situ pre-treatment with tail-vein injected CTAC and d-Ala-N3, followed by injection of dual-loaded cascade-reaction containers without using antibiotics. This makes in situ metabolic incorporation of cascade-reaction containers as described attractive for further investigation with respect to the control of other types of infections comprising planktonic bacteria. STATEMENT OF SIGNIFICANCE: In situ metabolic-incorporation of cascade-reaction-containers loaded with glucose-oxidase and Fe3O4 nanoparticles into bacterial cell-wall peptidoglycan is described, yielding ROS-generation from endogenous glucose, non-antibiotically killing bacteria before ROS inactivates. Hitherto, only Gram-positives could be metabolically-labeled, because Gram-negatives possess two lipid-membranes. The outer membrane impedes direct access to the peptidoglycan. This problem was solved by outer-membrane permeabilization using a quaternary-ammonium compound. Several studies on metabolic-labeling perform crucial labeling steps during bacterial-culturing that in real-life should be part of a treatment. In situ metabolic-incorporation as described, can be applied in well-plates during in vitro experiments or in the body as during in vivo animal experiments. Surprisingly, metabolic-incorporation proceeded unhampered in blood and a murine, bacterially-induced sepsis could be well treated.
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Peptidoglicano , Espécies Reativas de Oxigênio , Sepse , Animais , Espécies Reativas de Oxigênio/metabolismo , Sepse/tratamento farmacológico , Sepse/metabolismo , Camundongos , Nanopartículas/química , Dióxido de Silício/química , Bactérias Gram-Positivas/efeitos dos fármacos , Bactérias Gram-Negativas/efeitos dos fármacosRESUMO
Background: Bone-anchored maxillary protraction (BAMP) aims to correct midfacial deficiencies, with proven positive skeletal changes without potential unwanted side effects. However, the influence of BAMP treatment on facial soft tissues, particularly in subjects with complete unilateral cleft lip, alveolus, and palate (CUCLAP), remains unclear. Methods: This single-center longitudinal cohort study examined the effects of 1.5 years of BAMP treatment on facial soft tissues in growing subjects with complete unilateral cleft lip, alveolus, and palate. The sample consisted of 25 patients, age range 9.7 to 12.6 years. Three-dimensional surface models derived from CBCT scans were superimposed on stable structures of the anterior cranial base and on the occipital area posterior of the foramen magnum to assess three-dimensional changes due to growth and BAMP therapy. Results: The results revealed a moderate positive correlation (Pearson's correlation coefficient from 0.203 to 0.560) between changes in hard tissue and soft tissue; some correlations were found to be weak (<0.300). Linear changes in soft tissue following BAMP were in the same direction as skeletal changes, showing downward, forward, and outward displacement. The only exception was in the vertical dimension. The lower facial third showed a slight but significant reduction, mainly in lip length (-1.2 mm), whereas the middle facial third showed a small increase (1.1 mm). Conclusions: It was concluded that during BAMP, soft tissue changes occur in the same direction as skeletal changes, although with a larger variability and less pronounced effects.
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BACKGROUND: External apical root resorption (EARR) is a frequently observed adverse event in patients undergoing fixed appliance therapy. Assessing the patients' risk during treatment is important, as certain factors are assumed to be associated with an increased likelihood of occurrence. However, their predictive value remains limited, making evidence-based clinical decision-making challenging for orthodontists. To address this issue, the Dutch Association of Orthodontists (NvVO) developed a clinical practice guideline (CPG) for EARR in accordance with the AGREE II instrument (Appraisal of Guidelines for Research and Evaluation II) in 2018. The aim of this study is to get insight into the actual utilization and the practical implementation of the guideline among orthodontists. The hypothesis to be tested was that after its introduction, clinical practice for EARR has changed towards the recommendations in the CPG. OBJECTIVE: To investigate the use of the 2018 clinical practice guidelines for EARR among orthodontists 3 years after its introduction. METHODS: A questionnaire using a 7-point Likert scale was developed concerning four domains of EARR described in the guideline. The questionnaire was piloted, finalised, and then distributed digitally among Dutch orthodontists. REDCap was used for data collection, starting with an invitation email in June 2021, followed by two reminders. Effect was tested by the Mann-Whitney U test, and the influence of demographic variables was analysed. RESULTS: Questionnaires were sent out to all 275 and completed by 133 (response rate 48%); N = 59 females and N = 73 males were included; 81% had their training in the Netherlands, 89% had ≥ 6 years of work experience, and 89% worked in private orthodontic practice. One hundred thirty orthodontists (98.5%) reported changes in clinical practice. The biggest positive change in clinical behaviour regarding EARR occurred if EARR was diagnosed during treatment. Sex, clinical experience, country of specialist training, and working environment of the respondents did not affect clinical practices regarding EARR. CONCLUSIONS: This questionnaire demonstrated that, 3 years after introduction of the guideline, orthodontists improved their self-reported clinical practices to a more standardised management of root resorption. None of the demographic predictors had a significant effect on the results.
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Ortodontistas , Guias de Prática Clínica como Assunto , Reabsorção da Raiz , Humanos , Feminino , Masculino , Padrões de Prática Odontológica , Países Baixos , Inquéritos e Questionários , Adulto , Ápice Dentário/patologia , Fidelidade a DiretrizesRESUMO
Dispersal of infectious biofilms increases bacterial concentrations in blood. To prevent sepsis, the strength of a dispersant should be limited to allow the immune system to remove dispersed bacteria from blood, preferably without antibiotic administration. Biofilm bacteria are held together by extracellular polymeric substances that can be degraded by dispersants. Currently, comparison of the strength of dispersants is not possible by lack of a suitable comparison parameter. Here, a biofilm dispersal parameter is proposed that accounts for differences in initial biofilm properties, dispersant concentration and exposure time by using PBS as a control and normalizing outcomes with respect to concentration and time. The parameter yielded near-identical values based on dispersant-induced reductions in biomass or biofilm colony-forming-units and appeared strain-dependent across pathogens. The parameter as proposed is largely independent of experimental methods and conditions and suitable for comparing different dispersants with respect to different causative strains in particular types of infection.
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Antimicrobial-resistant bacterial infections threaten to become the number one cause of death by the year 2050. Since the speed at which antimicrobial-resistance develops is exceeding the pace at which new antimicrobials come to the market, this threat cannot be countered by making more, new and stronger antimicrobials. Promising new antimicrobials should not only kill antimicrobial-resistant bacteria, but also prevent development of new bacterial resistance mechanisms in strains still susceptible. Here, PAMAM-dendrimers are clustered using glutaraldehyde to form megamers that are core-loaded with ciprofloxacin and functionalized with HA-SNO. Megamers are enzymatically disintegrated in an acidic pH, as in infectious biofilms, yielding release of ciprofloxacin and NO-generation by HA-SNO. NO-generation does not contribute to the killing of planktonic Gram-positive Staphylococcus aureus and Gram-negative Pseudomonas aeruginosa, but in a biofilm-mode of growth short-lived NO-assisted killing of both ciprofloxacin-susceptible and ciprofloxacin-resistant bacterial strains by the ciprofloxacin released. Repeated sub-culturing of ciprofloxacin-susceptible bacteria in presence of ciprofloxacin-loaded and HA-SNO functionalized PAMAM-megamers does not result in ciprofloxacin-resistant variants as does repeated culturing in presence of ciprofloxacin. Healing of wounds infected by a ciprofloxacin-resistant S. aureus variant treated with ciprofloxacin-loaded, HA-SNO functionalized megamers proceed faster through NO-assisted ciprofloxacin killing of infecting bacteria and stimulation of angiogenesis.
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Anti-Infecciosos , Staphylococcus aureus Resistente à Meticilina , Infecções Estafilocócicas , Camundongos , Animais , Ciprofloxacina/farmacologia , Antibacterianos/farmacologia , Ácido Hialurônico/farmacologia , Testes de Sensibilidade Microbiana , Infecções Estafilocócicas/tratamento farmacológico , Resistência Microbiana a Medicamentos , Anti-Infecciosos/farmacologia , Biofilmes , Concentração de Íons de Hidrogênio , Pseudomonas aeruginosaRESUMO
Alveolar bone grafting (ABG) is a critical surgical intervention in patients with a cleft of the alveolus, aimed at reconstructing the alveolar ridge to facilitate proper eruption, periodontal support, and alignment of adjacent permanent teeth. The optimal timing for ABG remains debated, with late secondary ABG between the ages of 9 and 11 being widely adopted. This study compared the palatal shapes of 28 children at a mean age of 9.5 years (SD = 0.7) who underwent early secondary ABG at a mean age of 2.1 years (SD = 0.6) or 33 children at a mean age of 10.8 years (SD = 1.5) who underwent late secondary ABG at a mean age of 8.6 years (SD = 1.3) to 60 non-cleft controls at a mean age of 8.6 years (SD = 1.2). The palatal shapes were captured with 239 landmarks digitized on the palate on a digital model. Utilizing geometric morphometric methods, i.e., generalized Procrustes superimpositions, principal component analysis, and permutation tests, we assessed the impact of ABG timing on palatal morphology. The first five principal components (PCs) explained 64.1% of the total shape variability: PC1 = 26.1%; PC2 = 12%; PC3 = 11.9%; PC4 = 7.8%; and PC5 = 6.4%. The Procrustes distance between both cleft groups and the control group was more than twice as large as the Procrustes distance between the early ABG and late ABG groups. Nonetheless, all intergroup differences were statistically significant. Our findings suggest that early ABG has a limited negative effect on palatal shape, providing comparable outcomes to late ABG. The study highlights the potential suitability of early ABG, challenging conventional practices and encouraging further exploration into its long-term effects on maxillary growth.
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BACKGROUND: Post-traumatic stress disorder (PTSD) sufferers show problematic patterns of Internet use such as fear of missing out (FOMO) and sharing misinformation and fake news. This study aimed to investigate these associations in survivors of the 2008 earthquake in Wenchuan, China. METHODS: A self-reported survey was completed by 356 survivors of the Wenchuan earthquake. A mediated structural equation model was constructed to test a proposed pattern of associations with FOMO as a mediator of the relationship between PTSD symptoms and belief in fake news, as well as moderators of this pathway. RESULTS: PTSD was directly associated with believing fake news (ß = 0.444, p < .001) and with FOMO (ß = 0.347, p < .001). FOMO mediated the association between PTSD and fake news belief (ß = 0.373, p < .001). Age moderated the direct (ß = 0.148, t = 3.097, p = .002) and indirect (ß = 0.145, t = 3.122, p = .002) pathways, with effects more pronounced with increasing age. Gender was also a moderator, with the indirect effect present in females but not in males (ß = 0.281, t = 6.737, p < .001). CONCLUSION: Those with higher PTSD symptoms are more likely to believe fake news and this is partly explained by FOMO. This effect is present in females and not males and is stronger in older people. Findings extend knowledge of the role of psychological variables in problematic Internet use among those with PTSD.
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Terremotos , Transtornos de Estresse Pós-Traumáticos , Masculino , Feminino , Humanos , Idoso , Transtornos de Estresse Pós-Traumáticos/epidemiologia , Transtornos de Estresse Pós-Traumáticos/psicologia , Estudos Transversais , Desinformação , Sobreviventes/psicologia , China/epidemiologia , Fatores de RiscoRESUMO
OBJECTIVE: To provide a critical overview of the effect of various orthodontic and/or dentofacial orthopedic interventions on three-dimensional volumetric changes in the upper airway. MATERIALS AND METHODS: Four databases were searched for clinical studies concerning 3D volumetric assessments based on CBCT before and after orthodontics interventions. The quality of the studies was assessed using the quality assessment tool of the National Heart, Lung and Blood Institute. After the use of inclusion and exclusion criteria, the pre-and post-treatment volumes were used to visualize the effect of various orthodontics interventions. RESULTS: A total of 48 studies were included in this review and none of which were RCTs. The quality of all included studies was assessed as medium. Overall, there is a tendency for an increase in airway volumes after various orthodontic interventions, except for studies concerning extraction therapy with fixed appliances in adults, in which both increases and decreases in airway volumes have been reported. CONCLUSION: Orthodontic treatment by growth modification and non-extraction therapy with fixed appliances, regardless of the malocclusion, generally showed positive effects on the airway volume. Orthodontic treatment in combination with extractions does not provide an unambiguous insight. A consensus on the methodology of the airway measurement and nomenclature is urgently needed in order to gain insight into the effect of different interventions on three-dimensional airway changes. CLINICAL RELEVANCE: Various orthodontic treatments do not negatively influence the upper airway volume. However, extraction therapy in adults should be chosen with caution, especially in subjects belonging to a group susceptible to airway obstruction.
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Má Oclusão , Tomografia Computadorizada de Feixe Cônico Espiral , Adulto , Humanos , Má Oclusão/terapiaRESUMO
Treatment of acute bacterial meningitis is difficult due to the impermeability of the blood-brain barrier, greatly limiting the antibiotic concentrations that can be achieved in the brain. Escherichia coli grown in presence of iron-oxide magnetic nanoparticles secrete large amounts of magnetic outer-membrane vesicles (OMVs) in order to remove excess Fe from their cytoplasm. OMVs are fully biomimetic nanocarriers, but can be inflammatory. Here, non-inflammatory magnetic OMVs were prepared from an E. coli strain in which the synthesis of inflammatory lipid A acyltransferase was inhibited using CRISPR/Cas9 mediated gene knockout. OMVs were loaded with ceftriaxone (CRO) and meso-tetra-(4-carboxyphenyl)porphine (TCPP) and magnetically driven across the blood-brain barrier for sonodynamic treatment of bacterial meningitis. ROS-generation upon ultrasound application of CRO- and TCPP-loaded OMVs yielded similar ROS-generation as by TCPP in solution. In vitro, ROS-generation by CRO- and TCPP-loaded OMVs upon ultrasound application operated synergistically with CRO to kill a hard-to-kill, CRO-tolerant E. coli strain. In a mouse model of CRO-tolerant E. coli meningitis, CRO- and TCPP-loaded OMVs improved survival rates and clinical behavioral scores of infected mice after magnetic targeting and ultrasound application. Recurrence did not occur for at least two weeks after arresting treatment.
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Antibacterianos , Meningites Bacterianas , Animais , Camundongos , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Escherichia coli , Espécies Reativas de Oxigênio , Ceftriaxona/farmacologia , Ceftriaxona/uso terapêutico , Meningites Bacterianas/tratamento farmacológico , Proteínas da Membrana Bacteriana ExternaRESUMO
Bacterially induced sepsis requires rapid bacterial detection and identification. Hours count for critically ill septic patients, while current culture-based detection requires at least 10 h up to several days. Here, we apply a microfluidic device equipped with a bacterially activated, macrophage-membrane-coating on nanowired-Si adsorbent surfaces for rapid, bacterial detection and Gram-identification in bacterially contaminated blood. Perfusion of suspensions of Gram-negative or Gram-positive bacteria through a microfluidic device equipped with membrane-coated adsorbent surfaces detected low (<10 CFU/mL) bacterial levels. Subsequent, in situ fluorescence-staining yielded Gram-identification for guiding antibiotic selection. In mixed Escherichia coli and Staphylococcus aureus suspensions, Gram-negative and Gram-positive bacteria were detected in the same ratios as those fixed in suspension. Results were validated with a 100% correct score by blinded evaluation (two observers) of 15 human blood samples, spiked with widely different bacterial strains or combinations of strains, demonstrating the potential of the platform for rapid (1.5 h in total) diagnosis of bacterial sepsis.
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Bactérias , Sepse , Humanos , Suspensões , Dispositivos Lab-On-A-Chip , Escherichia coli , Macrófagos , Sepse/diagnósticoRESUMO
Eradication of infectious biofilms is becoming increasingly difficult due to the growing number of antibiotic-resistant strains. This necessitates development of nonantibiotic-based, antimicrobial approaches. To this end, we designed a heterocatalytic metal-organic framework composed of zirconium 1,4-dicarboxybenzene (UiO-66) with immobilized Pt nanoparticles (Pt-NP/UiO-66). Pt-NP/UiO-66 enhanced singlet-oxygen generation compared with Pt nanoparticles or UiO-66, particularly in an acidic environment. Singlet-oxygen generation degraded phosphodiester bonds present in eDNA gluing biofilms together and therewith dispersed biofilms. Remaining biofilms possessed a more open structure. Concurrently, Pt-NP/UiO-66 stimulated macrophages to adapt a more M1-like, "fighting" phenotype, moving faster toward their target bacteria and showing increased bacterial killing. As a combined effect of biofilm dispersal and macrophage polarization, a subcutaneous Staphylococcus aureus biofilm in mice was more readily eradicated by Pt-NP/UiO-66 than by Pt nanoparticles or UiO-66. Therewith, heterocatalytic Pt-NP/UiO-66 metal-organic frameworks constitute a nonantibiotic-based strategy to weaken protective matrices and disperse infectious biofilms, while strengthening macrophages in bacterial killing.
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Doenças Transmissíveis , Estruturas Metalorgânicas , Camundongos , Animais , Estruturas Metalorgânicas/farmacologia , Estruturas Metalorgânicas/química , Biofilmes , Antibacterianos/farmacologia , Antibacterianos/química , Bactérias , Oxigênio/farmacologiaRESUMO
In radiology research soft tissues are often simulated on bone specimens using liquid materials such as water, or gel-like materials, such as ballistic gel. This study aimed to test the effect of hydration on the anatomical form of dry craniofacial bone specimens. Sixteen human dry skulls and 16 mandibles were scanned with an industrial scanner in dry conditions and after water embedding. Ten skulls were also embedded for different time periods (5 or 15 min). The subsequent 3D surface models were best-fit superimposed and compared by calculating mean absolute distances between them at various measurement areas. There was a significant, primarily enlargement effect of hydration on the anatomical form of dry skeletal specimens as detected after water embedding for a short time period. The effect was smaller in dry skulls (median 0.20 mm, IQR 0.17 mm) and larger in mandibles (median 0.56 mm, IQR 0.57 mm). The effect of different water embedding times was negligible. Based on the present findings, we suggest to shortly hydrate the skeletal specimens prior to reference model acquisition so that they are comparable to hydrated specimens when liquid materials are used as soft-tissue simulants for various radiologic research purposes.
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Mandíbula , Crânio , Humanos , Crânio/diagnóstico por imagem , Mandíbula/diagnóstico por imagem , ÁguaRESUMO
Exposure of infectious biofilms to dispersants induces high bacterial concentrations in blood that may cause sepsis. Preventing sepsis requires simultaneous biofilm dispersal and bacterial killing. Here, self-targeting DCPA(2-(4-((1,5-bis(octadecenoyl)1,5-dioxopentan-2-yl)carbamoyl)pyridin-1-ium-1-yl)acetate) liposomes with complexed water were self-assembled with ciprofloxacin loaded in-membrane and PEGylated as a lipid-membrane component, together with bromelain loaded in-core. Inside biofilms, DCPA-H2O and PEGylated ciprofloxacin became protonated, disturbing the balance in the lipid-membrane to cause liposome-burst and simultaneous release of bromelain and ciprofloxacin. Simultaneous release of bromelain and ciprofloxacin enhanced bacterial killing in Staphylococcus aureus biofilms as compared with free bromelain and/or ciprofloxacin. After tail-vein injection in mice, liposomes accumulated inside intra-abdominal staphylococcal biofilms. Subsequent liposome-burst and simultaneous release of bromelain and ciprofloxacin yielded degradation of the biofilm matrix by bromelain and higher bacterial killing without inducing septic symptoms as obtained by injection of free bromelain and ciprofloxacin. This shows the advantage of simultaneous release from liposomes of bromelain and ciprofloxacin inside a biofilm.
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Bromelaínas , Sepse , Animais , Camundongos , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Biofilmes , Ciprofloxacina/farmacologia , Lipídeos , Lipossomos , Testes de Sensibilidade Microbiana , Polietilenoglicóis , Prótons , Sepse/tratamento farmacológicoRESUMO
Antibiotic-loaded PEG/PAE-based micelles are frequently considered for eradicating infectious biofilms. At physiological pH, PEG facilitates transport through blood. Near an acidic infection-site, PAE becomes protonated causing micellar targeting to a biofilm. However, micellar penetration and accumulation is confined to the surface region of a biofilm. Especially matured biofilms also possess hypoxic regions. We here designed dual-responsive PEG/PAE-b-P(Lys-NBCF) micelles, responding to both acidity and low oxygen-saturation level in matured biofilms. Dual, pH- and hypoxia-responsive micelles targeted and accumulated evenly over the depth of 7- to 14-days old biofilms. Delineation demonstrated that pH-responsiveness was responsible for targeting of the infection-site and accumulation of micelles in the surface region of the biofilm. Hypoxia-responsiveness caused deep penetration in the biofilm. Dual, pH- and hypoxia-responsive micelles loaded with ciprofloxacin yielded more effective, synergistic eradication of 10-days old, matured Staphylococcus aureus biofilms underneath an abdominal imaging-window in living mice than achieved by ciprofloxacin in solution or single, pH- or hypoxia responsive micelles loaded with ciprofloxacin. Also, wound-healing after removal of window and its frame proceeded fastest after tail-vein injection of ciprofloxacin-loaded, dual, pH- and hypoxia-responsive micelles. Concluding, pH- and hypoxia-responsiveness are both required for eradicating mature biofilms and advancing responsive antibiotic nanocarriers to clinical application. STATEMENT OF SIGNIFICANCE: pH-responsive antibiotic nanocarriers have emerged as a possible new strategy to prevent antimicrobial-resistant bacterial infections from becoming the leading cause of death. In this paper, we show that commonly studied, pH-responsive micellar nanocarriers merely allow self-targeting to an infectious biofilm, but do not penetrate deeply into the biofilm. The dual-responsive (acidic pH- and hypoxia) antibiotic-loaded micelles designed here not only self-target to an infectious biofilm, but also penetrate deeply. The in vitro and in vivo advantages of dual-responsive nanocarriers are most obvious when studied in infectious biofilms grown for 10 viz a viz the 2 days, usually applied in the literature. Significantly, clinical treatment of bacterial infection usually starts more than 2 days after appearance of the first symptoms.
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Antibacterianos , Infecções Estafilocócicas , Camundongos , Animais , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Micelas , Biofilmes , Ciprofloxacina/farmacologia , Ciprofloxacina/uso terapêutico , Infecções Estafilocócicas/tratamento farmacológico , Concentração de Íons de Hidrogênio , HipóxiaRESUMO
Extracellular outer-membrane vesicles (OMVs) are attractive for use as drug nanocarriers, because of their high biocompatibility and ability to enter cells. However, widespread use is hampered by low yields. Here, a high-yield method for magnetic harvesting of OMVs from Escherichia coli is described. To this end, E. coli are grown in the presence of magnetic iron-oxide nanoparticles (MNPs). Uptake of MNPs by E. coli is low and does not increase secretion of OMVs. Uptake of MNPs can be enhanced through PEGylation of MNPs. E. coli growth in the presence of PEGylated MNPs increases bacterial MNP-uptake and OMV-secretion, accompanied by upregulation of genes involved in OMV-secretion. OMVs containing MNPs can be magnetically harvested at 60-fold higher yields than achieved by ultracentrifugation. Functionally, magnetically-harvested OMVs and OMVs harvested by ultracentrifugation are both taken-up in similar numbers by bacteria. Uniquely, in an applied magnetic field, magnetically-harvested OMVs with MNPs accumulate over the entire depth of an infectious biofilm. OMVs harvested by ultracentrifugation without MNPs only accumulate near the biofilm surface. In conclusion, PEGylation of MNPs is essential for their uptake in E. coli and yields magnetic OMVs allowing high-yield magnetic-harvesting. Moreover, magnetic OMVs can be magnetically targeted to a cargo delivery site in the human body.