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Antimicrobial effectiveness of grape seed extract against <i>Enterococcus faecalis</i> biofilm: A Confocal Laser Scanning Microscopy analysis
摘要： This study evaluated the antimicrobial effectiveness of 6.5% Vitis vinifera grape seed extract (GSE) against Enterococcus faecalis bio?lm using confocal laser scanning microscopy (CLSM). Saline solution (SS), 5.25% sodium hypochlorite (NaOCl) and 2% chlorhexidine (CHX) were used for comparison. Dentin discs were inoculated with E. faecalis strain establishing a 3-week-old bio?lm. Discs (n = 10) were exposed to 5.25% NaOCl, 2% CHX, 6.5% GSE and SS (negative control) for 10 min. Discs were stained with the ?uorescent LIVE/DEAD-BacLightTM dye and analysed using CLSM. The proportion of dead cells in bio?lm was analysed using one-way ANOVA and Tukey tests (P < 0.05). A higher proportion of dead cells was found in GSE group compared with CHX and SS (P < 0.05). NaOCl group was associated with the highest proportion of dead cells (P < 0.05). GSE presented antimicrobial activity against E. faecalis; however, NaOCl was the most effective irrigant solution. GSE was more effective than CHX and SS.
关键词： bio?lm,root canal irrigants,grape seed extract,confocal laser scanning microscopy,Enterococcus faecalis
更新于2025-09-12 10:27:22
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Enhanced transmitting and blocking filter design approach for laser scanning applications based on combining GSM and AFGSM methods
摘要： We present a novel and robust filter design method, developed for one-dimensional photonic crystal-based filters. Hybrid filter structures are presented comprising periodic and degenerated multilayered dielectric structures. The proposed approach provides significant flexibility in designing desired transmission band while offering widened stop-bands. In obtaining the transmission characteristics we utilize the Auxiliary Functions of Generalized Scattering Matrix Method (AFGSM), already proven to provide computational advantages in obtaining bandgap edge frequencies without solving an eigenvalue equation. With the proposed design strategy, we showcase its efficacy through designing four different filters that are utilized in laser scanning microscopy; namely a laser line filter at 800 nm wavelength for reflectance confocal microscopy, a band-pass filter at 400 nm wavelength for second harmonic generation microscopy, a laser block filter at 800 nm wavelength and a dichroic filter blocking 350-400 nm while transmitting higher wavelengths for multiphoton microscopy.
关键词： Multilayered Dielectrics,Optical Filters,Fabry-Perot Resonators,Auxiliary Functions of Generalized Scattering Matrix (AFGSM),Photonic Bandgaps (PBGs),Laser Scanning Microscopy (LSM)
更新于2025-09-12 10:27:22
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Assessing Fracture Surface Ductility by Confocal Laser Scanning Microscopy
摘要： Hitherto there is no generally accepted quantitative parameter which, on the one hand, would reliably characterize the ductility of the whole fracture surface, and, on the other hand, could be relatively quickly measured. This circumstance substantially affects the objectivity of the fractographic analysis which effectiveness is still strongly dependent on the experience and skills of an expert. Recent studies showed that the value of the normalized fracture surface area Rs can serve as the measure of the fracture surface ductility. This parameter can be evaluated by the quantitative confocal laser scanning microscopy (CLSM). In the present study we investigated the Rs value for the fracture surfaces of the low carbon steel specimens tested in the temperature range from 200 to -196 °C where the steel undergoes ductile-to-brittle transition accompanied by the alternation of the fracture mode from ductile to brittle. The temperature dependence of the Rs value is found to have a sigmoidal shape with the sharp drop in the range from 100 to -100 °C. It is demonstrated that the Rs is strongly correlated with the fracture surface appearance: the Rs decreases concurrently with increasing brittleness of the fracture surface.
关键词： quantitative fractography,normalized surface area,confocal laser scanning microscopy,low-carbon steel,fracture surface
更新于2025-09-12 10:27:22
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Reconstruction of image sequences from ungated and scanning-aberrated laser scanning microscopy images of the beating heart
摘要： Fluorescence laser-scanning microscopy is a well-established imaging technique in biology, available in many imaging facilities to investigate structures within live animal embryos such as zebrafish. Laser scanning microscopes (LSM) are limited when used to study dynamic heart morphology or function. Despite their ability to resolve static cardiac structures, the fast motion of the beating heart introduces severe artifacts in the scanned images and gating the acquisitions to the heartbeat is difficult to implement on traditional microscopes. Furthermore, although alternative high-speed imaging instruments exist, they are not widely available (due to cost or hardware complications), putting dynamic cardio-vascular imaging off-limits for many researchers. Here, we propose a method that allows imaging the beating heart on conventional LSMs. Our approach takes a set of images containing scanning aberrations, each triggered at an arbitrary time in the cardiac cycle, and assembles an image sequence that covers a single cardiac heartbeat. The steps are: (i) frame sorting by solving a traveling salesman problem; (ii) heartbeat duration estimation; and (iii) scan-delay compensation via space-time resampling. We characterize the performance of our method on synthetic data under several light intensities and scanning speeds. We further illustrate our method's applicability on experimental images acquired in live zebrafish larvae, and show that the reconstruction quality approaches that of fast, state-of-the-art microscopes. Our technique opens the possibility of using LSMs to carry out studies of cardiac dynamics, without the need for prospective gating or fast microscopes.
关键词： cardiac imaging,scanning aberration compensation,laser scanning microscopy,zebrafish imaging,fast microscopy,combinatorial optimization,traveling salesman problem,image and video sampling,Computational microscopy,confocal microscopy
更新于2025-09-11 14:15:04
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In Situ Monitoring of the Antibacterial Activity of a Copper–Silver Alloy Using Confocal Laser Scanning Microscopy and pH Microsensors
摘要： The antibacterial efficacy of a copper–silver alloy coating under conditions resembling build up of dry surface bacterial biofilms is successfully demonstrated according to US EPA test methods with a ≥99.9% reduction of test organisms over a 24 h period. A tailor-made confocal imaging protocol is designed to visualize in situ the killing of bacterial biofilms at the copper–silver alloy surface and monitor the kinetics for 100 min. The copper–silver alloy coating eradicates a biofilm of Gram-positive bacteria within 5 min while a biofilm of Gram-negative bacteria are killed more slowly. In situ pH monitoring indicates a 2-log units increase at the interface between the metallic surface and bacterial biofilm; however, the viability of the bacteria is not directly affected by this raise (pH 8.0–9.5) when tested in buffer. The OH? production, as a result of the interaction between the electrochemically active surface and the bacterial biofilm under environmental conditions, is thus one aspect of the contact-mediated killing of the copper–silver alloy coating and not the direct cause of the observed antibacterial efficacy. The combination of oxidation of bacterial cells, release of copper ions, and local pH raise characterizes the antibacterial activity of the copper–silver alloy-coated dry surface.
关键词： bacterial biofilms,confocal laser scanning microscopy,copper–silver alloy,electroplating,antibacterial activity
更新于2025-09-11 14:15:04
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A Simple and Rapid Staining Technique for Sex Determination of Trichinella Larvae Parasites by Confocal Laser Scanning Microscopy
摘要： The roundworms of Trichinella genus are worldwide distributed and their prevalence in nature is high. Trichinella genus parasites are the causative agents of foodborne zoonosis trichinellosis. The main prevention and control of the infection are meat inspection by the magnetic stirrer method for the detection of Trichinella larvae in muscle samples. The treatment can be effective if the parasite is discovered early in the intestinal phase. Once the Trichinella larva has reached the muscle tissue, the parasite remains therein and there is no treatment for this life cycle stage. The Trichinella species is dioecious with separate male and female individuals. The developed staining technique that uses confocal laser scanning microscopy (CLSM) displays sufficient results for Trichinella larvae examination and this protocol is applicable to study the internal and external structures and for the sex determination of T. britovi and T. spiralis larvae samples. In the present study, a luminescent derivative was synthesized and used for staining of T. spiralis and T. britovi larvae samples for the examination by CLSM. Various fixatives, such as AFA, 70% ethanol, and Bouin’s and Carnoy’s solutions were tested for sample preparation. The synthesized luminescent compound demonstrates best visualization results for samples fixed in Bouin’s fixative.
关键词： benzanthrone dye,fixatives,confocal laser scanning microscopy,Trichinella larvae sex determination,Bouin’s fixative
更新于2025-09-11 14:15:04
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A blue fluorescent labeling technique utilizing micro- and nanoparticles for tracking in LIVE/DEAD® stained pathogenic biofilms of Staphylococcus aureus and Burkholderia cepacia
摘要： Strategies that target and treat biofilms are widely applied to bacterial cultures using popular live/dead staining techniques with mostly red or green fluorescent markers (eg, with SYTO? 9, propidium iodide, fluorescein). Therefore, visualizing drugs or micro- and nanoparticulate delivery systems to analyze their distribution and effects in biofilms requires a third fluorescent dye that does not interfere with the properties of the live/dead markers. The present study establishes and evaluates a model for tracking polymeric particles in fluorescently stained biological material. To this end, poly(d,l-lactide-co-glycolide) (PLGA)-based micro- and nanoparticles were used as well-established model systems, which, because of their favorable safety profiles, are expected to play important future roles with regard to drug delivery via inhalation. PLGA was covalently and stably labeled with 7-amino-4-methyl-3-coumarinylacetic acid (AMCA), after which blue fluorescent poly(ethylene glycol)-block-PLGA (PEG-PLGA) particles were prepared using a mixture of fluorescent AMCA-PLGA and PEG-PLGA. Because chitosan is known to reduce negative surface charge, blue fluorescent PEG-PLGA-particles with chitosan were also prepared. These micro- and nanoparticles were physicochemically characterized and could be clearly distinguished from live/dead stained bacteria in biofilms using confocal laser scanning microscopy.
关键词： 7-amino-4-methyl-3-coumarinylacetic acid,cystic fibrosis,PEG,PLGA,chitosan,hydrodynamic diameter,confocal laser scanning microscopy
更新于2025-09-09 09:28:46
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Bismuth Ferrite Second Harmonic Nanoparticles for Pulmonary Macrophage Tracking
摘要： Recently, second harmonic generation (SHG) nanomaterials have been generated that are efficiently employed in the classical (NIR) and extended (NIR-II) near infrared windows using a multiphoton microscope. The aim was to test bismuth ferrite harmonic nanoparticles (BFO-HNPs) for their ability to monitor pulmonary macrophages in mice. BFO-loaded MH-S macrophages are given intratracheally to healthy mice or BFO-HNPs are intranasally instilled in mice with allergic airway inflammation and lung sections of up to 100 μM are prepared. Using a two-photon-laser scanning microscope, it is shown that bright BFO-HNPs signals are detected from superficially localized cells as well as from deep within the lung tissue. BFO-HNPs are identified with an excellent signal-to-noise ratio and virtually no background signal. The SHG from the nanocrystals can be distinguished from the endogenous collagen–derived SHG around the blood vessels and bronchial structures. BFO-HNPs are primarily taken up by M2 alveolar macrophages in vivo. This SHG imaging approach provides novel information about the interaction of macrophages with cells and the extracellular matrix in lung disease as it is capable of visualizing and tracking NP-loaded cells at high resolution in thick tissues with minimal background fluorescence.
关键词： two-photon-laser scanning microscopy,macrophages,third harmonic generation,nanoparticles,second harmonic generation
更新于2025-09-04 15:30:14