MXene介导的近红外光热效应用于快速清除多种耐药菌以及菌膜

随着细菌耐药性的不断出现和加重,针对耐药菌感染和菌膜这类难以用传统抗生素治疗的临床医疗问题,需要发展新型高效快速的杀菌方法.本文采用新型二维材料MXene与近红外激光相结合,实现了在20 min内对细菌以及菌膜的快速高效杀除.为了测试该方案的广谱抗菌性,我们对包括耐药性的耐甲氧西林金黄色葡萄球菌(MRSA)和耐万古霉素...     

细菌纤维素抗菌复合材料的制备和应用

目的 综述细菌纤维素抗菌复合材料在国内外的研究和应用现状,以制备具有优异抗菌性能的细菌纤维素复合材料.方法 总结细菌纤维素抗菌复合材料的抗菌性及其最新合成方式,包括与无机抗菌剂、有机抗菌剂结合或添加抗生素等方式合成细菌纤维素抗菌复合材料,并进一步阐述细菌纤维素抗菌复合材料的应用领域.结论 细菌纤维素复合材料的抗菌性能优异,在医学、食品包装和净水等领域都有较大的应用潜力,有待进一步系统研究.     

Antibacterial Performance of a Cu-bearing Stainless Steel against Microorganisms in Tap Water

Tap water is one of the most commonly used water resources in our daily life. However, the increasing water contamination and the health risk caused by pathogenic bacteria, such as Staphylococcus aureus and Escherichia coli have attracted more attention. The mutualism of different pathogenic bacteria may diminish antibacterial effect of antibacterial agents. It was found that materials used for making pipe and tap played one of the most important roles in promoting bacterial growth. This paper is to report the performance of an innovative type 304 Cu-bearing stainless steel(304Cu SS) against microbes in tap water. The investigation methodologies involved were means of heterotrophic plate count, contact angle measurements, scanning electron microscopy for observing the cell and subtract surface morphology,atomic absorption spectrometry for copper ions release study, and confocal laser scanning microscopy used for examining live/dead bacteria on normal 304 stainless steel and 304 Cu SS. It was found that the surface free energy varied after being immersed in tap water with polar component and Cu ions release.The results showed 304 Cu SS could effectively kill most of the planktonic bacteria(max 95.9% antibacterial rate), and consequently inhibit bacterial biofilms formation on the surface, contributing to the reduction of pathogenic risk to the surrounding environments.     

Antibiotic-Free Antibacterial Strategies Enabled by Nanomaterials: Progress and Perspectives

Bacterial infection is one of the top ten leading causes of death globally and the worst killer in low-income countries. The overuse of antibiotics leads to ever-increasing antibiotic resistance, posing a severe threat to human health. Recent advances in nanotechnology provide new opportunities to address the challenges in bacterial infection by killing germs without using antibiotics. Antibiotic-free antibacterial strategies enabled by advanced nanomaterials are presented. Nanomaterials are classified on the basis of their mode of action: nanomaterials with intrinsic or light-mediated bactericidal properties and others that serve as vehicles for the delivery of natural antibacterial compounds. Specific attention is given to antibacterial mechanisms and the structure–performance relationship. Practical antibacterial applications employing these antibiotic-free strategies are also introduced. Current challenges in this field and future perspectives are presented to stimulate new technologies and their translation to fight against bacterial infection.     

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.     

季铵盐接枝聚膦腈微球的制备及抗菌活性

细菌感染引起的疾病问题在世界范围内引起广泛的关注。抗生素虽然能有效治疗细菌感染,但是不合理的使用及滥用会导致细菌产生耐药性。因此,解决细菌耐药性问题并研发出安全高效的非抗生素抗菌剂显得尤为迫切。通过在生物可降解型环交联型聚(环三膦腈-共-聚乙烯亚胺)微球(PHP)表面上接枝环氧丙基十二烷基二甲基氯化铵(DDEAC),成功制备了环交联型聚(环三膦腈-共-聚乙烯亚胺)接枝季铵盐微球(PHPD)。采用FTIR、XPS、TG、TEM和FESEM对微球的结构与形貌进行了表征分析,并研究了其抗菌活性和细胞毒性。实验结果表明,改性抗菌微球PHPD(50 μg/mL)对大肠杆菌(E.coli)和金黄色葡萄球菌(S.aureus)的抗菌率均达97.3%。复合材料克服了单独使用季铵盐DDEAC材料的高毒性缺陷,并且在实现高效抗菌的同时也具有很好的细胞相容性。因此,本研究对于开发安全高效的纳米抗菌剂具有一定的指导意义。      

Osteogenic and antimicrobial nanoparticulate calcium phosphate and poly-(d,l-lactide-co-glycolide) powders for the treatment of osteomyelitis

Development of a material for simultaneous sustained and localized delivery of antibiotics and induction of spontaneous regeneration of hard tissues affected by osteomyelitis stands for an important clinical need. In this work, a comparative analysis of the bacterial and osteoblastic cell response to two different nanoparticulate carriers of clindamycin, an antibiotic commonly prescribed in the treatment of bone infection, one composed of calcium phosphate and the other comprising poly-(D,L-lactide-co-glycolide)-coated calcium phosphate, was carried out. Three different non-cytotoxic phases of calcium phosphate, exhibiting dissolution and drug release profiles in the range of one week to two months to one year, respectively, were included in the analysis: monetite, amorphous calcium phosphate and hydroxyapatite. Spherical morphologies and narrow size distribution of both types of nanopowders were confirmed in transmission and scanning electron microscopic analyses. The antibiotic-containing powders exhibited sustained drug release contingent upon the degradation rate of the carrier. Assessment of the antibacterial performance of the antibiotic-encapsulated powders against Staphylococcus aureus, the most common pathogen isolated from infected bone, yielded satisfactory results both in broths and on blood agar plates for all the analyzed powders. In contrast, no cytotoxic behavior was detected upon the incubation of the antibiotic powders with the osteoblastic MC3T3-E1 cell line for up to three weeks. The cells were shown to engage in a close contact with the antibiotic-containing particles, irrespective of their internal or surface phase composition, polymeric or mineral. At the same time, both types of particles upregulated the expression of osteogenic markers osteocalcin, osteopontin, Runx2 and protocollagen type I, suggesting their ability to promote osteogenesis and enhance remineralization of the infected site in addition to eliminating the bacterial source of infection.     

聚苯胺的抗菌性及其机制

进行了聚苯胺溶出液、聚苯胺粉末和聚苯胺复合漆膜的抗菌性实验,用FT-IR检测了溶出液的成分,研究了本征态聚苯胺和掺杂态聚苯胺对大肠杆菌、金黄色葡萄球菌、白色念珠菌和枯草芽孢菌的抗菌性能及其随作用时间的变化,研究了与聚苯胺作用前后细菌的形貌变化以及聚苯胺的抗菌机制。     

Thermal-Disrupting Interface Mitigates Intercellular Cohesion Loss for Accurate Topical Antibacterial Therapy

Bacterial infections remain a leading threat to global health because of the misuse of antibiotics and the rise in drug-resistant pathogens. Although several strategies such as photothermal therapy and magneto-thermal therapy can suppress bacterial infections, excessive heat often damages host cells and lengthens the healing time. Here, a localized thermal managing strategy, thermal-disrupting interface induced mitigation (TRIM), is reported, to minimize intercellular cohesion loss for accurate antibacterial therapy. The TRIM dressing film is composed of alternative microscale arrangement of heat-responsive hydrogel regions and mechanical support regions, which enables the surface microtopography to have a significant effect on disrupting bacterial colonization upon infrared irradiation. The regulation of the interfacial contact to the attached skin confines the produced heat and minimizes the risk of skin damage during thermoablation. Quantitative mechanobiology studies demonstrate the TRIM dressing film with a critical dimension for surface features plays a critical role in maintaining intercellular cohesion of the epidermis during photothermal therapy. Finally, endowing wound dressing with the TRIM effect via in vivo studies in S. aureus infected mice demonstrates a promising strategy for mitigating the side effects of photothermal therapy against a wide spectrum of bacterial infections, promoting future biointerface design for antibacterial therapy.     

Antibacterial activity of electrospun polymer mats with incorporated narrow diameter single-walled carbon nanotubes

Polymer coatings featuring nonleaching antibacterial agents are needed to significantly reduce bacterial colonization and subsequent biofilm formation. Previously, single-walled carbon nanotubes (SWNTs) have been reported to be strong antimicrobial agents that kill microbes on contact. However, the antibacterial activity of freestanding polymer mats with a low weight percent of incorporated SWNTs has not been demonstrated. In this study, four different weight percents of well characterized, small diameter (0.8 nm) SWNTs were incorporated into electrospun polysulfone (PSf) mats. Electrospun PSf-SWNT mats were observed to be flexible and composed of continuous, cylindrical, and randomly oriented fibers. SEM micrographs revealed that SWNT ends were distributed along the longitudinal fiber axis. Loss of bacteria (Escherichia coli) viability was observed to directly correlate to increased SWNT incorporation within the mat, ranging from 18% for 0.1 wt % SWNTs to 76% for 1.0 wt % SWNTs. Time-dependent bacterial cytotoxicity studies indicated that the antimicrobial action of the PSf-SWNT mats occurs after a short contact time of 15 min or less. This study demonstrates the potential applicability of electrospun PSf-SWNT mats as antibacterial coatings.     

Tailoring the Surface and Composition of Nanozymes for Enhanced Bacterial Binding and Antibacterial Activity

With the advantages of diverse structures, tunable enzymatic activity, and high stability, nanozymes are widely used in medicine, chemistry, food, environment, and other fields. As an alternative to traditional antibiotics, nanozymes attract more and more attention from the scientific researchers in recent years. Developing nanozymes-based antibacterial materials opens up a new avenue for the bacterial disinfection and sterilization. In this review, the classification of nanozymes and their antibacterial mechanisms are discussed. The surface and composition of nanozymes are critical for the antibacterial efficacy, which can be tailored to enhance both the bacterial binding and the antibacterial activity. On the one hand, the surface modification of nanozymes enables binding and targeting of bacteria that improves the antibacterial performance of nanozymes including the biochemical recognition, the surface charge, and the surface topography. On the other hand, the composition of nanozymes can be modulated to achieve enhanced antibacterial performance including the single nanozyme-mediated synergistic and multiple nanozymes-mediated cascade catalytic antibacterial applications. In addition, the current challenges and future prospects of tailoring nanozymes for antibacterial applications are discussed. This review can provide insights into the design of future nanozymes-based materials for the antibacterial treatments.     

Multifunctional implant coatings providing possibilities for fast antibiotics loading with subsequent slow release

The possibility to fast-load biomimetic hydroxyapatite coatings on surgical implant with the antibiotics Amoxicillin, Gentamicin sulfate, Tobramycin and Cephalothin has been investigated in order to develop a multifunctional implant device offering sustained local anti-bacterial treatment and giving the surgeon the possibility to choose which antibiotics to incorporate in the implant at the site of surgery. Physical vapor deposition was used to coat titanium surfaces with an adhesion enhancing gradient layer of titanium oxide having an amorphous oxygen poor composition at the interface and a crystalline bioactive anatase TiO₂ composition at the surface. Hydroxyapatite (HA) was biomimetically grown on the bioactive TiO₂ to serve as a combined bone in-growth promoter and drug delivery vehicle. The coating was characterized using scanning and transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. The antibiotics were loaded into the HA coatings via soaking and the subsequent release and antibacterial effect were analyzed using UV spectroscopy and examination of inhibition zones in a Staphylococcus aureus containing agar. It was found that a short drug loading time of 15 min ensured antibacterial effects after 24 h for all antibiotics under study. It was further found that the release processes of Cephalothin and Amoxicillin consisted of an initial rapid drug release that varied unpredictably in amount followed by a reproducible and sustained release process with a release rate independent of the drug loading times under study. Thus, implants that have been fast-loaded with drugs could be stored for ~10 min in a simulated body fluid after loading to ensure reproducibility in the subsequent release process. Calculated release rates and measurements of drug amounts remaining in the samples after 22 h of release indicated that a therapeutically relevant dose could be achieved close to the implant surface for about 2 days. Concluding, the present study provides an outline for the development of a fast-loading slow-release surgical implant kit where the implant and the drug are separated when delivered to the surgeon, thus constituting a flexible solution for the surgeon by offering the choice of quick addition of antibiotics to the implant coating based on the patient need. U. Brohede and J. Forsgren have contributed equally.     

Antibacterial applications of elemental nanomaterials

The emergence and spread of antimicrobial resistance call for the development of antibacterial substances that may be able to circumvent the resistance mechanisms of bacteria. To this end, intensive research efforts have been directed toward non-antibiotic materials with antibacterial potency. In particular, single-element inorganic nanomaterials have demonstrated promising activity against bacteria, and prominent examples of single-element inorganic nanomaterials include silver (Ag) nanoparticles, 0-, 1- and 2-dimensional carbon nanomaterials, and 2-dimensional black phosphorous (BP) nanosheets. With activity modes distinct from those of commercial antibiotics, these single-element inorganic nanomaterials have demonstrated activity against antibiotic-resistant bacterial strains and may delay the emergence of resistance in bacteria. In this review, we focus on silver (Ag) nanoparticles, 0-, 1- and 2-dimensional carbon nanomaterials, and 2-dimensional black phosphorous (BP) nanosheets, and discuss their antibacterial potency, factors that influence their antibacterial performances, as well as their cytotoxicity to mammalian cells.     

Antibacterial activity of SPIONs versus ferrous and ferric ions under aerobic and anaerobic conditions: a preliminary mechanism study

In modern medicine, major attention has been paid to superparamagnetic iron oxide nanoparticles (SPIONs). Recent studies have shown the antibacterial properties of SPIONs against some Gram‐positive and Gram‐negative bacterial strains. These nanoparticles (NPs) can bind to bacterial membranes via hydrophobic or electrostatic interactions and pass through cell barriers. In this study, the authors evaluated the antibacterial activity of magnetic NPs in comparison with ferrous and ferric ions. The level of reactive oxygen species (ROS) in the treated Staphylococcus aureus and Escherichia coli bacteria were directly measured by fluorometric detection. The results showed that iron ions and SPIONs had significant dependent antimicrobial activities. SPIONs showed greater inhibitory effects than ferrous and ferric ions against the growth of treated bacterial strains under anaerobic conditions, while in aerobic conditions, ferrous showed the strongest antibacterial activity. In anaerobic conditions, they observed the greatest ROS formation and lowest minimum inhibitory concentration in the SPION‐treated group in comparison with the other groups. It seems that the release of iron ions from SPIONs and subsequent activation of ROS pathway are the main antibacterial mechanisms of action. Nevertheless, the greater antibacterial effect of SPIONs in anaerobic conditions represents other mechanisms involved in the antibacterial activity of these NPsInspec keywords: nanomagnetics, antibacterial activity, hydrophobicity, nanoparticles, superparamagnetism, biomedical materials, iron compounds, membranes, nanobiotechnologyOther keywords: ferrous ions, anaerobic conditions, superparamagnetic iron oxide nanoparticles, antibacterial properties, bacterial membranes, electrostatic interactions, bacterial strains, aerobic conditions, SPION‐treated group, antibacterial effect, cell barriers, 2′,7′‐dichlorodihydrofluorescein diacetate, reactive oxygen species, fluorometric detection, Staphylococcus aureus, Escherichia coli     

Antibacterial burst-release from minimal Ag-containing plasma polymer coatings

Biomaterials releasing silver (Ag) are of interest because of their ability to inhibit pathogenic bacteria including antibiotic-resistant strains. In order to investigate the potential of nanometre-thick Ag polymer (Ag/amino-hydrocarbon) nanocomposite plasma coatings, we studied a comprehensive range of factors such as the plasma deposition process and Ag cation release as well as the antibacterial and cytocompatible properties. The nanocomposite coatings released most bound Ag within the first day of immersion in water yielding an antibacterial burst. The release kinetics correlated with the inhibitory effects on the pathogens Pseudomonas aeruginosa or Staphylococcus aureus and on animal cells that were in contact with these coatings. We identified a unique range of Ag content that provided an effective antibacterial peak release, followed by cytocompatible conditions soon thereafter. The control of the in situ growth conditions for Ag nanoparticles in the polymer matrix offers the possibility to produce customized coatings that initially release sufficient quantities of Ag ions to produce a strong adjacent antibacterial effect, and at the same time exhibit a rapidly decaying Ag content to provide surface cytocompatibility within hours/days. This approach seems to be favourable with respect to implant surfaces and possible Ag-resistance/tolerance built-up.     

Synergistic Chemotherapy and Photodynamic Therapy of Endophthalmitis Mediated by Zeolitic Imidazolate Framework‐Based Drug Delivery Systems

Endophthalmitis, derived from the infections of pathogens, is a common complication during the use of ophthalmology‐related biomaterials and after ophthalmic surgery. Herein, aiming at efficient photodynamic therapy (PDT) of bacterial infections and biofilm eradication of endophthalmitis, a pH‐responsive zeolitic imidazolate framework‐8‐polyacrylic acid (ZIF‐8‐PAA) material is constructed for bacterial infection–targeted delivery of ammonium methylbenzene blue (MB), a broad‐spectrum photosensitizer antibacterial agent. Polyacrylic acid (PAA) is incorporated into the system to achieve higher pH responsiveness and better drug loading capacity. MB‐loaded ZIF‐8‐PAA nanoparticles are modified with AgNO₃/dopamine for in situ reduction of AgNO₃ to silver nanoparticles (AgNPs), followed by a secondary modification with vancomycin/NH₂‐polyethylene glycol (Van/NH₂‐PEG), leading to the formation of a composite nanomaterial, ZIF‐8‐PAA‐MB@AgNPs@Van‐PEG. Dynamic light scattering, transmission electron microscopy, and UV–vis spectral analysis are used to explore the nanoparticles synthesis, drug loading and release, and related material properties. In terms of biological performance, in vitro antibacterial studies against three kinds of bacteria, i.e., Escherichia coli, Staphylococcus aureus, and methicillin‐resistant S. aureus, suggest an obvious superiority of PDT/AgNPs to any single strategy. Both in vitro retinal pigment epithelium cellular biocompatibility experiments and in vivo mice endophthalmitis models verify the biocompatibility and antibacterial function of the composite nanomaterials.     

Development of compartmentalized antibacterial systems based on encapsulated alliinase

Allicin, an organic compound produced via the transformation of biologically inactive alliin by alliinase, an enzyme found in garlic, combines a strong antibacterial effect with suppressed development of bacterial resistance. However, because of the high reactivity and volatility, controlled in-situ production of allicin that mimics the natural synthesis is essential to achieve desired therapeutic effects. In this work, the spray-drying technique was employed for encapsulation of alliinase into polymer micro-carriers with an emphasis on the effect of process parameters, i.e., drying temperature, nozzle type, choice of the carrier materials, on the activity of encapsulated alliinase in soluble maltodextrin and swellable chitosan microparticles. The results show that maltodextrin is a suitable carrier for the effective protection of alliinase against thermal stress. On the other hand, we can control allicin production and release from chitosan carriers with immobilized alliinase by variation of the cross-linker amount. Antibacterial activity of in-situ formed allicin vapors was confirmed against Escherichia coli bacterial strain using customized sample holders preventing physical contact of powder sample with the inoculated agar plate.     

日光驱动纳米纤维膜的制备及其抑菌性能研究

目的 为了研究低耗能、低成本的食品保鲜方法,创建一种可日光驱动的抗菌纳米纤维膜.方法 通过静电纺丝技术结合光敏性化学物质制备聚乙烯醇(PVA)纳米纤维膜,通过扫描电镜、傅里叶红外光谱、热重分析、水接触角、耐水试验、活性氧的释放以及抑菌试验对纳米纤维膜进行表征.结果 光敏性物质二苯甲酮四羧酸二酐(BTDA)成功地接枝在PVA纳米纤维膜上,并在日光驱动下,可以释放活性氧,对致病菌具有杀灭作用.结论 该纳米纤维膜在日光的驱动下,可以有效地产生活性氧,从而杀灭微生物,因此可以在食品抗菌包装方面有新的应用.     

In vitro study on infectious ureteral encrustation resistance of Cu-bearing stainless steel

Cu-bearing stainless steel has been found to have obvious inhibition performance against encrustation in vitro. This study was aiming to further investigate the inhibitory effect of a Cu-bearing stainless steel(316 L-Cu SS) on the infectious encrustation based on its antimicrobial activity. The encrustation in presence of bacteria, antibacterial performance, urease production and Ca and Mg precipitation were examined by scanning electron microscopy, antibacterial assay, enzyme-linked immunosorbent assay and inductively coupled plasma-mass spectrometry, respectively. It was found that 316 L-Cu SS could inhibit the formation of bacterial biofilm due to the release of Cu~(2+) ions and then decrease the urease amount splitting by bacteria, which produced a neutral environment with pH around 7. However, more encrustations coupled with bacterial biofilms on the surface of comparison stainless steel(316 L SS) with an alkaline environment were recorded. It can thus be seen that the 316 L-Cu SS highlights prominent superiority against encrustation in the presence of microorganisms.