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A Novel Biocompatible Titaniuma??Gadolinium Quantum Dot as a Bacterial Detecting Agent with High Antibacterial Activity
摘要： In this study, the titanium–gadolinium quantum dots (TGQDs) were novel, first of its type to be synthesized, and fully characterized to date. Multiple physical characterization includes scanning electron microscopy (SEM), scanning electrochemical microscope (SCEM), x-ray fluorescence, spectrophotometry, and dynamic light scattering were carried out. The obtained results confirmed appropriate size and shape distributions in addition to processing optical features with high quantum yield. The synthesized TGQD was used as a fluorescent dye for bacterial detection and imaging by fluorescent microscopy and spectrophotometry, where TGQD stained only bacterial cells, but not human cells. The significant antibacterial activities of the TGQDs were found against a highly pathogenic bacterium (Staphylococcus aureus) and its antibiotic resistant strains (vancomycin and methicillin resistant Staphylococcus aureus) using growth curve analysis and determination of minimum inhibitory concentration (MIC) analysis. Live/dead cell imaging assay using phase-contrast microscope was performed for further confirmation of the antibacterial activity. Cell wall disruption and release of cell content was observed to be the prime mode of action with the reduction of cellular oxygen demand (OD).
关键词： titanium–gadolinium quantum dots,bacterial resistance,antibacterial activity,bacterial detection,SECM
更新于2025-09-23 15:19:57
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Peptide and drug functionalized fluorescent quantum dots for enhanced cell internalization and bacterial debilitation
摘要： This report illustrates a strategy for designing a nanoconjugate derived vector which efficiently delivers antimicrobial drug directly into bacterial cells. The nanoconjugate comprises of negatively charged CDTe@CdS quantum dot (QD) with its surface functionalized using cationic BP-100 (KKLFKKILKYL-amide); a known cell penetrating peptide (CPP), via electrostatic approach. The interactions between QD and CPP in QDs functionalized CPPs (QD-CPP) have been well analysed using fluorescence spectroscopy, gel electrophoresis and zeta potential analysis. The QD-CPP conjugate was internalized into Gram-negative (E. coli) as well as Gram positive (S. aureus) bacterial strains with confocal studies exhibiting a strong signal in tested microorganisms. Further, to check the applicability of QD-CPP conjugate, as a delivery vector for generating an effective therapeutics, ampicillin molecules were conjugated on QD-CPP surface to generate QD-CPP-Amp conjugate. The CPP and drug molecules on the surface of QDs were well quantified using HPLC data. It was observed that the internalization and bacterial debilitation of QD-CPP-Amp conjugate is two to four fold effective as compared to bare ampicillin. The morphological changes to the bacterial cells upon the treatment with QD-CPP-Amp conjugates, were noted with no cytotoxic effect on tested mammalian cell lines. The results inferred that the proposed QD-CPP vector provides a targeted and proficient approach for cellular internalization of cargo (drug) in bacterial cells with effective tracking through florescent QDs.
关键词： antibacterial,QD-CPP conjugate,bacterial internalization,quantum dots,cell penetrating peptide
更新于2025-09-23 15:19:57
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Ionic liquid assisted wet chemical synthesis CdS quantum dots and their structural, morphological, optical, electrochemical, photocatalytic, antibacterial and hemocompatibility characterization
摘要： In this work, CdS quantum dots were fabricated through the ionic liquid assisted wet chemical method to investigate the structural, optical response, electrochemical behaviour, photocatalytic, hemocompatibility and antibacterial studies for optoelectronic devices, supercapacitors, photocatalytic and biological applications. The synthesis powder has confirmed the formation of the cubic structure of the CdS material using the powder XRD pattern. Further, the Raman and FT-IR studies have supported the formation of the CdS synthesis. The XRD data and TEM image were employed to examine the lattice parameters like crystallite size, crystalline nature, lattice constant, d-spacing and volume of the unit cell and particle size. The broad optical absorption has been seen in the visible portion in the optical spectra. Using the Tauc plot from the optical absorption spectrum data, the optical band gap value of CdS NPs is computed as 2.74 eV and proved to be a narrow band gap material. Examining the electrochemical properties of CdS NPs revealed the redox behaviour, using CV characterization. The effect of the Indigo carmine (IC) and Congo red (CR) dye on the optical absorption, degradation irradiation time and photocatalytic efficiency of CdS NPs have been discussed. Antimicrobial studies of CdS NPs have been investigated.
关键词： Semiconductor,Electrochemical properties,Photocatalyst,Antibacterial Properties,Optical properties
更新于2025-09-23 15:19:57
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The antibacterial effect of potassium-sodium niobate ceramics based on controlling piezoelectric properties
摘要： The implant infection is one of the most serious postsurgical complications of medical device implantation. Therefore, the development of biocompatible materials with improved antibacterial properties is of great importance. It might be a new insight to apply the intrinsic electrical properties of biomaterials to solve this problem. Here, potassium-sodium niobate piezoceramics (K0.5Na0.5NbO3, KNN) with different piezoelectric constants were prepared, and the microstructures and piezoelectric properties of these piezoceramics were evaluated. Moreover, the antibacterial effect and biocompatibility of these piezoceramics were assayed. Results showed that these piezoceramics were able to decrease the colonies of bacteria staphylococcus aureus (S. aureus), favor the rat bone marrow mesenchymal stem cells (rBMSCs) proliferation and promote the cell adhesion and spreading. The above effects were found closely related to the surface positive charges of the piezoceramics, and the sample bearing the most positive charges on its surface (sample 80KNN) had the best performance in both antibacterial effect and biocompatibility. Based on our work, it is feasible to develop biocompatible antibacterial materials by controlling piezoelectric properties.
关键词： Positive charges,Biocompatibility,Potassium-sodium niobate,Antibacterial property
更新于2025-09-23 15:19:57
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Antimicrobial propensity of ultrananocrystalline diamond films with embedded silver nanodroplets
摘要： Ultrananocrystalline diamond (UNCD) layers exhibit excellent mechanical properties and combine chemical inertness with good biological compatibility. Therefore, UNCD is considered a promising material for coating of implants. In this work we present the preparation of thin UNCD films with embedded silver nanodroplets that provide antimicrobial property, addressing another important topic concerning implant surgery, namely the risk of a life threatening bacterial infection. UNCD layers were prepared by microwave plasma-assisted chemical vapor deposition on a silicon substrate. Afterwards, a thin film of silver was deposited on top and treated by rapid thermal annealing (RTA) leading to dewetting and formation of silver nanodroplets on the surface. A second UNCD deposition with a short duration between 5 and 30 min was applied for capping the silver nanoparticles with a thin layer. The sample surfaces were characterized after each step by atomic force microscopy and scanning electron microscopy. The composition of the final samples, including the depth of the incorporated Ag nanodroplets, was analyzed by Auger electron spectroscopy. The impact of the silver layer thickness and the RTA temperature on the nanodroplet morphology was investigated. It was found that after 10 min of capping deposition the silver particles were completely covered with UNCD. In order to study the release of silver ions, the UNCD/Ag/UNCD samples were submerged in deionized water for 7 days at 37 °C, followed by detection of the silver concentration in the aqueous samples by inductively coupled plasma mass spectrometry. The determined concentration was strongly dependent on the thickness of the capping UNCD layer, exhibiting the highest silver content for the sample with the thinnest capping layer. Thus, the UNCD layer thickness can be utilized to control the amount of Ag ions released into the surrounding environment. The antibacterial properties were investigated with bacterial assays of the Gram-negative Escherichia coli and Gram-positive Bacillus subtilis bacteria that were exposed to the samples. All silver containing samples showed significant antimicrobial propensity, whereas the different capping thicknesses affected the time-course dependent antibacterial efficiency.
关键词： antibacterial material,ultrananocrystalline diamond films,silver nanodroplets
更新于2025-09-19 17:15:36
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Recent Developments about Conductive Polymer Based Composite Photocatalysts
摘要： Conductive polymers have been widely investigated in various applications. such as polyaniline (PANI), polypyrrole (PPy), poly(3,4-ethylenedioxythiophene) (PEDOT)), and polythiophene (PTh) have been loaded with various semiconductor nanomaterials to prepare the composite photocatalysts. However, a critical review of conductive polymer-based composite photocatalysts has not been available yet. Therefore, in this review, we summarized the applications of conductive polymers in the preparation of composite photocatalysts for photocatalytic degradation of hazardous chemicals, antibacterial, and photocatalytic hydrogen production. Various materials were systematically surveyed to illustrate their preparation methods, morphologies, and photocatalytic performances. The synergic effect between conductive polymers and semiconductor nanomaterials were observed for a lot of composite photocatalysts. The band structures of the composite photocatalysts can be analyzed to explain the mechanism of their enhanced photocatalytic activity. The incorporation of conductive polymers can result in signi?cantly improved visible-light driven photocatalytic activity by enhancing the separation of photoexcited charge carriers, extending the light absorption range, increasing the adsorption of reactants, inhibiting photo-corrosion, and reducing the formation of large aggregates. This review provides a systematic concept about how conductive polymers can improve the performance of composite photocatalysts.
关键词： synergic effect,degradation,photo-corrosion,photogenerated electron,antibacterial,hydrogen production,photocatalyst,conductive polymer
更新于2025-09-19 17:15:36
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Bacterial killing efficacy of synthesized rod shaped cuprous oxide nanoparticles using laser ablation technique
摘要： Recent interests with copper nanoparticles (Cu-NPs) has arisen because of its low cost and antibacterial properties, as it may be one of the very important alternatives to silver NPs. Pulsed laser ablation of a solid target (copper) in liquid media is used to synthesize colloidal oxide copper (Cu2O and CuO NPs) NPs. These oxides of copper NPs were synthesized using Nd:YAG laser energy to maintain a 40 mJ/pulse wavelength at 1064 nm. During the synthesis of colloidal NPs only two conditions were opted, employing double distilled water (without PEG) and 10% preparation of PEG. Both NPs were prepared under the similar parameters such as optimized instrument settings, laser energy and time of laser exposure (1 h ablation). Further, these copper oxide NPs were characterized by advance technologies including UV–visible, X-ray diffraction, transmission electron microscopy and attenuated total reflection Fourier transform infrared spectroscopy techniques. The significant antibacterial properties of synthesized materials were also observed. The cuprous oxide NPs, showed remarkable antibacterial effect conducted using disc diffusion techniques. The minimum inhibitory concentration and minimum bactericidal concentration of synthesized Cu2O NPs were recorded as 120 and 140 μg/L respectively against Staphylococcus aureus used as positive control. Therefore, based on the findings of present study Cu2O NPs can be exploited as stable antimicrobial agents for multipurpose uses.
关键词： Polyethylene glycol,Laser ablation,Antibacterial,UV–visible,Copper oxide NPs
更新于2025-09-19 17:13:59
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Hierarchical Micro/Mesoporous Copper Structure with Enhanced Antimicrobial Property via Laser Surface Texturing
摘要： Copper (Cu) and its alloys have been shown to eradicate a wide range of multidrug-resistant microbes upon direct contact. In this study, a facile one-step laser texturing (LT) process is demonstrated to effectively enhance the bactericidal properties of copper surfaces via concurrent selective modification of surface topography and chemistry of laser textured copper (LT-Cu). Surface morphology and elemental composition are analyzed via field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), and Raman spectroscopy. Surface area and pore size of LT-Cu is determined by Barrett–Joyner–Halenda (BJH) and Brunauer–Emmett–Teller (BET) analysis. It reveals direct formation of mesoporous structures with higher surface oxide (Cu2O and CuO), which provide a highly stable superhydrophilic property to the LT-Cu surfaces. The antibacterial properties of LT-Cu are tested against pathogenic bacterial strains with different concentrations including Pseudomonas aeruginosa, and methicillin-resistant Staphylococcus aureus (MRSA USA300) at 105 CFU mL?1, and Escherichia coli and Staphylococcus aureus at high bacterial concentrations of 108 CFU mL?1 using standard contact killing tests. The analysis shows that LT-Cu needs 40, 90, 60, and 120 min to completely eradicate the respective bacterial strain. The LT-Cu causes membrane damage to the bacterial cells immediately after exposure. Furthermore, the biocompatibility of LT-Cu is investigated by in vitro immune-staining assays with mammary stromal fibroblasts and T4-2 cells.
关键词： laser texturing,copper,hydrophilic,antibacterial,contact killing,copper oxide
更新于2025-09-19 17:13:59
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Blend biopolymeric nanofibrous scaffolds of cellulose acetate/?μ-polycaprolactone containing metallic nanoparticles prepared by laser ablation for wound disinfection applications
摘要： Laser ablation technique was utilized to synthesize versatile metallic nanoparticles including ZnO, Ag and CuO which were incorporated into the blend matrix of cellulose Acetate (CA) and ε-polycaprolactone (PCL) nano?brous scaffold. The compositional, microstructural and morphological behaviors for the obtained nano?bers were investigated using X-ray diffraction (XRD), Fourier Transformed Infrared, Transmission Electron Microscope (TEM) and Field Emission-Scanning Electron Microscope (FESEM). The cell viability and antibacterial activity were investigated against Staphylococcus aureus (S. aureus) and Escherichia coli (E-coli). TEM micrographs refer that while CuONPs were involved in the middle of CA/PCL ?brous scaffold with diameters around 160 nm. The morphological investigations indicated the scaffolds were con?gured in a non-oriented form with diameters 0.45–0.9 μm in the case of ZnONPs involved in blend matrix ?bers. The ratio of viable cells displays that compositions are biocompatible, while the antibacterial activity of both AgNPs and CuONPs showed an inhibition zone around 11.2.3 ± 2.2 mm and 9.4 ± 1.2 mm respectively. Bio-blend polymers matrices carrying nanoparticles could be tailored for a plethora of biomedical applications upon their compositions.
关键词： Laser ablation,CuO,Antibacterial,Ag nanoparticles,Wound healing,Blend polymer
更新于2025-09-19 17:13:59
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Fabrication and Deposition of Copper and Copper Oxide Nanoparticles by Laser Ablation in Open Air
摘要： The proximity of the “post-antibiotic era”, where infections and minor injuries could be a cause of death, there are urges to seek an alternative for the cure of infectious diseases. Copper nanoparticles and their huge potential as a bactericidal agent could be a solution. In this work, Cu and Cu oxide nanoparticles were synthesized by laser ablation in open air and in argon atmosphere using 532 and 1064 nm radiation generated by nanosecond and picosecond Nd:YVO4 lasers, respectively, to be directly deposited onto Ti substrates. Size, morphology, composition and the crystalline structure of the produced nanoparticles have been studied by the means of field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), the energy dispersive spectroscopy of X-rays (EDS), selected area electron diffraction (SAED) and X-ray diffraction (XRD). The UV-VIS absorbance of the thin layer of nanoparticles was also measured, and the antibacterial capacity of the obtained deposits tested against Staphylococcus aureus. The obtained deposits consisted of porous coatings composed of copper and copper oxide nanoparticles interconnected to form chain-like aggregates. The use of the argon atmosphere contributed to reduce significantly the formation of Cu oxide species. The synthesized and deposited nanoparticles exhibited an inhibitory effect upon S. aureus.
关键词： copper nanoparticles,laser ablation,antibacterial effects
更新于2025-09-19 17:13:59