The use of nitric oxide (NO) is emerging as a promising, novel approach for the treatment of antibiotic resistant bacteria and biofilm infections. Depending on the concentration, NO can induce biofilm dispersal, increase bacteria susceptibility to antibiotic treatment, and induce cell damage or cell death via the formation of reactive oxygen or reactive nitrogen species. The use of NO is, however, limited by its reactivity, which can affect NO delivery to its target site and result in off-target effects. To overcome these issues, and enable spatial or temporal control over NO release, various strategies for the design of NO-releasing materials, including the incorporation of photo-activable, charge-switchable, or bacteria-targeting groups, have been developed. Other strategies have focused on increased NO storage and delivery by encapsulation or conjugation of NO donors within a single polymeric framework. This review compiles recent developments in NO drugs and NO-releasing materials designed for applications in antimicrobial or anti-biofilm treatment and discusses limitations and variability in biological responses in response to the use of NO for bacterial eradiation. 相似文献
Current wound healing treatments such as bandages and gauzes predominantly rely on passively protecting the wound and do not offer properties that increase the rate of wound healing. While these strategies are strong at protecting any infection after application, they are ineffective at treating an already infected wound or assisting in tissue regeneration. Next‐generation wound healing treatments are being developed at a rapid pace and have a variety of advantages over traditional treatments. Features such as gas exchange, moisture balance, active suppression of infection, and increased cell proliferation are all central to developing the next successful wound healing dressing. Electrospinning has already been shown to have the qualities required to be a key technique of next generation polymer‐based wound healing treatments. Combined with antimicrobial peptides (AMPs), electrospun dressings can indeed become a formidable solution for the treatment of both acute and chronic wounds. The literature on combining electrospinning and AMPs is now starting to increase and this review aims to give a comprehensive overview of the current developments that combine electrospinning technology and AMPs in order to make multifunctional fibers effective against infection in wound healing. 相似文献
Inspired by transient devices, transient self‐destroying micromotors that are propelled by metal–water/acid reactions and autonomously disappear after completing their tasks have emerged as promising tools for diverse applications. Such transient machines require careful selection of the metal matrix and well‐designed architectures for effective propulsion and customized functionality. In particular, recent advances in transient micromotors based on the active metals Zn, Fe, and Mg are introduced here. First, the fundamental design principles of transient micromotors are discussed. Then, their recent progress in environmental and biomedical applications is highlighted. 相似文献
A new biosensor is described for the detection of S‐nitrosothiols (RSNOs) based on their decomposition by immobilized glutathione peroxidase (GPx), an enzyme containing selenocysteine residue that catalytically produces nitric oxide (NO) from RSNOs. The enzyme is entrapped at the distal tip of a planar amperometric NO sensor. The new biosensor shows good sensitivity, linearity, reversibility, and response times towards various RSNO species in PBS buffer, pH 7.4 . In most cases, the response time is less than 5 min, and the response is linear up to 6 μM of the tested RSNO species. The lowest detection limit is obtained for S‐nitrosocysteine (CysNO), at approx. 0.2 μM. The biosensor's sensitivity is not affected by the addition of EDTA as a chelating agent; an advantage over other potential catalytic enzymes that contain copper ion centers, such as CuZn‐superoxide dismutase and xanthine oxidase. However, lifetime of the new sensor is limited, with sensitivity decrease of 50% after two days of use. Nonetheless, the new amperometric GPx based RSNO sensor could prove useful for detecting relative RSNO levels in biological samples, including whole blood. 相似文献
Nanogels (NGs) are 3‐dimensional (3D) networks composed of hydrophilic or amphiphilic polymer chains, allowing for effective and homogeneous encapsulation of drugs, genes, or imaging agents for biomedical applications. Polyethylenimine (PEI), possessing abundant positively charged amine groups, is an ideal platform for the development of NGs. A variety of effective PEI‐based NGs have been designed and much effort has been devoted to study the relationship between the structure and function of the NGs. In particular, PEI‐based NGs can be prepared either using PEI as the major NG component or using PEI as a crosslinker. This review reports the recent progresses in the design of PEI‐based NGs for gene and drug delivery and for bioimaging applications with a target focus to tackle the diagnosis and therapy of cancer. 相似文献
We report a simple method for the photothermal welding of nonwoven mats of electrospun nanofibers by introducing a near‐infrared (NIR) dye such as indocyanine green. By leveraging the strong photothermal effect of the dye, the nanofibers can be readily welded at their cross points or even over‐welded (i.e., melted and/or fused together) to transform the porous mat into a solid film upon exposure to a NIR laser. While welding at the cross points greatly improves the mechanical strength of a nonwoven mat of nanofibers, melting and fusion of the nanofibers can be employed to fabricate a novel class of photothermal papers for laser writing or printing without chemicals or toner particles. By using a photomask, we can integrate photothermal welding with the gas foaming technique to pattern and then expand nonwoven mats into 3D scaffolds with well‐defined structures. This method can be applied to different combinations of polymers and dyes, if they can be co‐dissolved in a suitable solvent for electrospinning. 相似文献
Nitrogen‐doped hollow cobalt oxide nanofibers (Co3O4 NFs) with both glucose catalytic activity and pH sensitivity were fabricated through core‐sheath electrospinning technique, followed by calcination. The as‐developed nitrogen‐doped hollow Co3O4 NFs were thoroughly characterized using various techniques, and then employed to fabricate a dual electrochemical sensor for both pH sensing and glucose sensing. The pH sensitivity of the developed nitrogen‐doped hollow Co3O4 NFs demonstrated a Nernst constant of 12.9–15.9 mV/pH in the pH range of 3.0~9.0 and 6.8–10.7 mV/pH in the pH range of 9.0~13.0, respectively. The developed hollow cobalt oxides nanofibers sensor also possesses glucose sensitivity of 87.67 μA mM?1 cm?2, the limit of detection of 0.38 μM (S/N=3), and an acceptable selectivity against several common interferents in non‐enzymatic glucose determination. High accuracy for monitoring glucose in human serum sample was also demonstrated. These features indicate that the as‐synthesized nitrogen‐doped hollow cobalt oxides nanofibers hold great potential in the development of a unique dual sensor for both solid‐state pH sensing and superior non‐enzymatic glucose sensing. 相似文献
A label‐free DNA biosensor based on three‐dimensional reduced graphene oxide (3D‐rGO) and polyaniline (PANI) nanofibers modified glassy carbon electrode (GCE) was successfully developed for supersensitive detection of breast cancer BRCA1. The results demonstrated that 3D‐rGO and PANI nanofibers had synergic effects for reducing the charge transfer resistance (Rct), meaning a huge enhancement in electrochemical activity of 3D‐rGO‐PANI/GCE. Probe DNA could be immobilized on 3D‐rGO‐PANI/GCE for special and sensitive recognition of target DNA (1.0×10?15–1.0×10?7 M) with a theoretical LOD of 3.01×10?16 M (3S/m). Furthermore, this proposed nano‐biosensor could directly detect BRCA1 in real blood samples. 相似文献
A novel method for highly efficient nitric oxide absorption by azole‐based ionic liquid was reported. The NO absorption capacity reached up to 4.52 mol per mol ionic liquid and is significant higher than the capacity other traditional absorbents. Moreover, the absorption of NO by this ionic liquid was reversible. Through a combination of experimental absorption, quantum chemical calculation, NMR and FT‐IR spectroscopic investigation, the results indicated that such high capacity originated from multiple‐site interactions between NO and the anion through the formation of NONOate with the chemical formula R1R2N?(NO?)?N=O, where R1 and R2 are alkyl groups. We believe that this highly efficient and reversible NO absorption by an azole‐based ionic liquid paves a new way for gas capture and utilization. 相似文献
Furoxans, or 1,2,5‐oxadiazole‐N‐oxides, are a class of nitric oxide (NO)‐donating compounds that release NO in response to thiol‐containing molecules. In this study, polymeric micelles bearing furoxan moieties are prepared from an amphiphilic block copolymer consisting of a hydrophobic furoxan‐bearing block and a hydrophilic poly(N‐acryloylmorpholine) block. The block copolymer is prepared using a combination of the reversible addition–fragmentation chain transfer polymerization and the copper‐catalyzed Huisgen cycloaddition techniques. The block copolymers form spherical micelles with a diameter of 50 nm by self‐assembly in water. The micelles release NO in response to cysteine and show improved stability against hydrolytic decomposition. Furthermore, the micelles show a synergistic anti‐proliferative effect with ibuprofen in human colon cancer cells.
With the ever‐increasing threat posed by the multi‐drug resistance of bacteria, the development of non‐antibiotic agents for the broad‐spectrum eradication of clinically prevalent superbugs remains a global challenge. Here, we demonstrate the simple supramolecular self‐assembly of structurally defined graphene nanoribbons (GNRs) with a cationic porphyrin (Pp4N) to afford unique one‐dimensional wire‐like GNR superstructures coated with Pp4N nanoparticles. This Pp4N/GNR nanocomposite displays excellent dual‐modal properties with significant reactive‐oxygen‐species (ROS) production (in photodynamic therapy) and temperature elevation (in photothermal therapy) upon light irradiation at 660 and 808 nm, respectively. This combined approach proved synergistic, providing an impressive antimicrobial effect that led to the complete annihilation of a wide spectrum of Gram‐positive, Gram‐negative, and drug‐resistant bacteria both in vitro and in vivo. The study also unveils the promise of GNRs as a new platform to develop dual‐modal antimicrobial agents that are able to overcome antibiotic resistance. 相似文献
Contact‐active antimicrobial polymer surfaces bear cationic charges and kill or deactivate bacteria by interaction with the negatively charged parts of their cell envelope (lipopolysaccharides, peptidoglycan, and membrane lipids). The exact mechanism of this interaction is still under debate. While cationic antimicrobial polymer surfaces can be very useful for short‐term applications, they lose their activity once they are contaminated by a sufficiently thick layer of adhering biomolecules or bacterial cell debris. This layer shields incoming bacteria from the antimicrobially active cationic surface moieties. Besides discussing antimicrobial surfaces, this feature article focuses on recent strategies that were developed to overcome the contamination problem. This includes bifunctional materials with simultaneously presented antimicrobial and protein‐repellent moieties; polymer surfaces that can be switched from an antimicrobial, cell‐attractive to a cell‐repellent state; polymer surfaces that can be regenerated by enzyme action; degradable antimicrobial polymers; and antimicrobial polymer surfaces with removable top layers. 相似文献
Autofluorescent microcapsules were assembled by covalent cross‐linking of polysaccharide alginate dialdehyde (ADA) derivative and cystamine dihydrochloride (CM) through a layer‐by‐layer (LBL) technique. The formulated Schiff base and disulfide bonds render capsules with pH‐ and redox‐responsive properties for pinpointed intracellular delivery based on the physiological difference between intracellular and extracellular environments. This simple and versatile method could be extended to other polysaccharide derivatives for the fabrication of autofluorescent nano‐ and micromaterials with dual stimuli response for biomedical applications. 相似文献
Chitosan has many useful intrinsic properties (e.g., non-toxicity, antibacterial properties, and biodegradability) and can be processed into high-surface-area nanofiber constructs for a broad range of sustainable research and commercial applications. These nanofibers can be further functionalized with bioactive agents. In the food industry, for example, edible films can be formed from chitosan-based composite fibers filled with nanoparticles, exhibiting excellent antioxidant and antimicrobial properties for a variety of products. Processing ‘pure’ chitosan into nanofibers can be challenging due to its cationic nature and high crystallinity; therefore, chitosan is often modified or blended with other materials to improve its processability and tailor its performance to specific needs. Chitosan can be blended with a variety of natural and synthetic polymers and processed into fibers while maintaining many of its intrinsic properties that are important for textile, cosmeceutical, and biomedical applications. The abundance of amine groups in the chemical structure of chitosan allows for facile modification (e.g., into soluble derivatives) and the binding of negatively charged domains. In particular, high-surface-area chitosan nanofibers are effective in binding negatively charged biomolecules. Recent developments of chitosan-based nanofibers with biological activities for various applications in biomedical, food packaging, and textiles are discussed herein. 相似文献
Nitric oxide (NO) levels in exhaled breath are a non‐invasive marker that can be used to diagnose various respiratory diseases and monitor a patient's response to given therapies. A portable and inexpensive device that can enable selective NO concentration measurements in exhaled breath samples is needed. Herein, the performance of an amperometric Pt‐Nafion‐based gas phase sensor for detection of NO in exhaled human nasal breath is examined. Enhanced selectivity over carbon monoxide and ammonia is achieved via an in‐line zinc oxide‐based filter. Exhaled nasal NO levels measured in 21 human samples with the sensor are shown to correlate well with those obtained using a chemiluminescence reference method (R2=0.9836). 相似文献
Hybrid nanofibers from chitosan or N‐carboxyethylchitosan (CECh) and silver nanoparticles (AgNPs) were prepared by electrospinning using HCOOH as a solvent. AgNPs were synthesized in situ in the spinning solution. HCOOH slowed down the cross‐linking of the polysaccharides with GA enabling the reactive electrospinning in the presence of poly(ethylene oxide) (PEO). EDX analyses showed that AgNPs are uniformly dispersed in the nanofibers. Since AgNPs hampered the cross‐linking of chitosan and CECh with GA in the hybrid fibers, the imparting of water insolubility to the fibers was achieved at a second stage using GA vapors. The surface of chitosan/PEO/AgNPs nanofibers was enriched in chitosan and 15 wt.‐% of the incorporated AgNPs were on the fiber surface as evidenced by XPS.