scholarly journals Antimicrobial Photoinactivation of In Situ Oral Biofilms by Visible Light Plus Water-Filtered Infrared A and Tetrahydroporphyrin-tetratosylate (THPTS)

2021 ◽  
Vol 9 (1) ◽  
pp. 145
Author(s):  
Lamprini Karygianni ◽  
Sandra Ruf ◽  
Elmar Hellwig ◽  
Marie Follo ◽  
Kirstin Vach ◽  
...  
Keyword(s):  
Untreated Control ◽  
Laser Scanning ◽  
Microbial Reduction ◽  
Laser Scanning Microscopy ◽  
Ex Situ ◽  
Confocal Laser ◽  
Initial Adhesion ◽  
Oral Biofilms ◽  
Deep Layers

The aim of this study was to examine the effect of aPDT with visual light (VIS) + water-filtered infrared A (wIRA) as a light source, and tetrahydroporphyrin-tetratosylate (THPTS) as a photosensitizer on in situ initial and mature oral biofilms. The samples were incubated, ex situ, with THPTS for two minutes, followed by irradiation with 200 mW cm − 2 VIS + wIRA for five minutes at 37 °C. The adherent microorganisms were quantified, and the biofilm samples were visualized using live/dead staining and confocal laser scanning microscopy (CLSM). The THPTS-mediated aPDT resulted in significant decreases in both the initially adherent microorganisms and the microorganisms in the mature oral biofilms, in comparison to the untreated control samples (>99.99% each; p = 0.018 and p = 0.0066, respectively). The remaining vital bacteria significantly decreased in the aPDT-treated biofilms during initial adhesion (vitality rate 9.4% vs. 71.2% untreated control, 17.28% CHX). Of the mature biofilms, 25.67% remained vital after aPDT treatment (81.97% untreated control, 16.44% CHX). High permeability of THPTS into deep layers could be shown. The present results indicate that the microbial reduction in oral initial and mature oral biofilms resulting from aPDT with VIS + wIRA in combination with THPTS has significant potential for the treatment of oral biofilm-associated diseases.

scholarly journals Bacterial colonization of enamel in situ investigated using fluorescence in situ hybridization

2009 ◽  
Vol 58 (10) ◽  
pp. 1359-1366 ◽  
Author(s):  
Ali Al-Ahmad ◽  
Marie Follo ◽  
Ann-Carina Selzer ◽  
Elmar Hellwig ◽  
Matthias Hannig ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Laser Scanning ◽  
Bacterial Colonization ◽  
Bacterial Species ◽  
Fusobacterium Nucleatum ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Actinomyces Naeslundii ◽  
Oral Biofilms

Oral biofilms are one of the greatest challenges in dental research. The present study aimed to investigate initial bacterial colonization of enamel surfaces in situ using fluorescence in situ hybridization (FISH) over a 12 h period. For this purpose, bovine enamel slabs were fixed on buccal sites of individual splints worn by six subjects for 2, 6 and 12 h to allow biofilm formation. Specimens were processed for FISH and evaluated with confocal laser-scanning microscopy, using probes for eubacteria, Streptococcus species, Veillonella species, Fusobacterium nucleatum and Actinomyces naeslundii. The number of adherent bacteria increased with time and all tested bacterial species were detected in the biofilm formed in situ. The general percentage composition of the eubacteria did not change over the investigated period, but the number of streptococci, the most frequently detected species, increased significantly with time (2 h: 17.7±13.8 %; 6 h: 20.0±16.6 %; 12 h: 24.7±16.1 %). However, ≤1 % of the surface was covered with bacteria after 12 h of biofilm formation in situ. In conclusion, FISH is an appropriate method for quantifying initial biofilm formation in situ, and the proportion of streptococci increases during the first 12 h of bacterial adherence.

scholarly journals Novel Broad-Spectrum Antimicrobial Photoinactivation ofIn SituOral Biofilms by Visible Light plus Water-Filtered Infrared A

2014 ◽  
Vol 80 (23) ◽  
pp. 7324-7336 ◽  
Author(s):  
L. Karygianni ◽  
S. Ruf ◽  
M. Follo ◽  
E. Hellwig ◽  
M. Bucher ◽  
...  
Keyword(s):  
Visible Light ◽  
Laser Scanning ◽  
Treatment Approach ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Pharmaceutical Treatment ◽  
Oral Biofilms ◽  
Biofilm Bacteria ◽  
Bovine Enamel

ABSTRACTAntimicrobial photodynamic therapy (APDT) has gained increased attention as an alternative treatment approach in various medical fields. However, the effect of APDT using visible light plus water-filtered infrared A (VIS + wIRA) on oral biofilms remains unexplored. For this purpose, initial and mature oral biofilms were obtainedin situ; six healthy subjects wore individual upper jaw acrylic devices with bovine enamel slabs attached to their proximal sites for 2 h or 3 days. The biofilms were incubated with 100 μg ml−1toluidine blue O (TB) or chlorin e6 (Ce6) and irradiated with VIS + wIRA with an energy density of 200 mW cm−2for 5 min. After cultivation, the CFU of half of the treated biofilm samples were quantified, whereas following live/dead staining, the other half of the samples were monitored by confocal laser scanning microscopy (CLSM). TB- and Ce6-mediated APDT yielded a significant decrease of up to 3.8 and 5.7 log10CFU for initial and mature oral biofilms, respectively. Quantification of the stained photoinactivated microorganisms confirmed these results. Overall, CLSM revealed the diffusion of the tested photosensitizers into the deepest biofilm layers after exposure to APDT. In particular, Ce6-aided APDT presented elevated permeability and higher effectiveness in eradicating 89.62% of biofilm bacteria compared to TB-aided APDT (82.25%) after 3 days. In conclusion, antimicrobial photoinactivation using VIS + wIRA proved highly potent in eradicating oral biofilms. Since APDT excludes the development of microbial resistance, it could supplement the pharmaceutical treatment of periodontitis or peri-implantitis.

scholarly journals Microscope-Based Imaging Platform for Large-Scale Analysis of Oral Biofilms

2012 ◽  
Vol 78 (24) ◽  
pp. 8703-8711 ◽  
Author(s):  
L. Karygianni ◽  
M. Follo ◽  
E. Hellwig ◽  
D. Burghardt ◽  
M. Wolkewitz ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Large Scale ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Wide Field ◽  
Bacterial Composition ◽  
Entire Area ◽  
Content Type ◽  
Oral Biofilms

ABSTRACTA microscopic method for noninvasively monitoring oral biofilms at the macroscale was developed to describe the spatial distribution of biofilms of different bacterial composition on bovine enamel surfaces (BES). For this purpose, oral biofilm was grownin situon BES that were fixed at approximal sites of individual upper jaw acrylic devices worn by a volunteer for 3 or 5 days. Eubacteria,Streptococcusspp., andFusobacterium nucleatumwere stained using specific fluorescencein situhybridization (FISH) probes. The resulting fluorescence signals were subsequently tested by confocal laser scanning microscopy (CLSM) and monitored by an automated wide-field microscope-based imaging platform (Scan∧R). Automated image processing and data analysis were conducted by microscope-associated software and followed by statistical evaluation of the results. The full segmentation of biofilm images revealed a random distribution of bacteria across the entire area of the enamel surfaces examined. Significant differences in the composition of the microflora were recorded across individual as well as between different enamel surfaces varying from sparsely colonized (47.26%) after 3 days to almost full surface coverage (84.45%) after 5 days. The enamel plates that were positioned at the back or in the middle of the oral cavity were found to be more suitable for the examination of biofilms up to 3 days old. In conclusion, automated microscopy combined with the use of FISH can enable the efficient visualization and meaningful quantification of bacterial composition over the entire sample surface. Due to the possibility of automation, Scan∧R overcomes the technical limitations of conventional CLSM.

Effects of antimicrobial agents on oral biofilms in a saliva-conditioned flowcell

Biofilms ◽  
2004 ◽  
Vol 1 (1) ◽  
pp. 5-12 ◽  
Author(s):  
J. S. Foster ◽  
P. C. Pan ◽  
P. E. Kolenbrander
Keyword(s):  
Laser Scanning ◽  
Antimicrobial Agents ◽  
Cetylpyridinium Chloride ◽  
Oral Bacteria ◽  
Laser Scanning Microscopy ◽  
Cellular Damage ◽  
Confocal Laser ◽  
Oral Biofilms

Oral bacteria form mixed-species biofilms known as dental plaque. Growth of these complex microbial communities is often controlled with the use of antimicrobial mouthrinses. Novel laboratory methods for testing the efficacy of antimicrobials in situ are necessary to complement current clinical testing protocols. In this study, we examined the effects of antimicrobial agents on a streptococcal biofilm grown in a saliva-conditioned flowcell. The flowcell coupled with confocal laser scanning microscopy enabled examination of growing oral biofilms in situ without disruption of the microbial community. Biofilms composed of Streptococcus gordonii DL1 were grown in an in vitro flowcell and treated with several commercially available antimicrobial mouthrinses containing essential oils, triclosan, cetylpyridinium chloride/domiphen or chlorhexidine. The results of this study revealed varying abilities of the antimicrobial agents to cause cellular damage on the growing biofilm in situ. This study therefore demonstrated the usefulness of the flowcell in the rapid assessment of antimicrobial efficacy.

3-D imaging of cells using a confocal laser scanning microscope and digital image processing

1988 ◽  
Vol 46 ◽  
pp. 96-97
Author(s):  
Thomas M. Jovin ◽  
Michel Robert-Nicoud ◽  
Donna J. Arndt-Jovin ◽  
Thorsten Schormann
Keyword(s):  
Laser Scanning ◽  
Confocal Laser Scanning Microscope ◽  
Laser Scanning Microscopy ◽  
Confocal Laser Scanning ◽  
Confocal Laser ◽  
Scanning Microscope ◽  
Laser Scanning Microscope ◽  
Biochemical Processes ◽  
Adjacent Structures

Light microscopic techniques for visualizing biomolecules and biochemical processes in situ have become indispensable in studies concerning the structural organization of supramolecular assemblies in cells and of processes during the cell cycle, transformation, differentiation, and development. Confocal laser scanning microscopy offers a number of advantages for the in situ localization and quantitation of fluorescence labeled targets and probes: (i) rejection of interfering signals emanating from out-of-focus and adjacent structures, allowing the “optical sectioning” of the specimen and 3-D reconstruction without time consuming deconvolution; (ii) increased spatial resolution; (iii) electronic control of contrast and magnification; (iv) simultanous imaging of the specimen by optical phenomena based on incident, scattered, emitted, and transmitted light; and (v) simultanous use of different fluorescent probes and types of detectors.We currently use a confocal laser scanning microscope CLSM (Zeiss, Oberkochen) equipped with 3-laser excitation (u.v - visible) and confocal optics in the fluorescence mode, as well as a computer-controlled X-Y-Z scanning stage with 0.1 μ resolution.

scholarly journals Influence of Aging on Corrosion Behaviour of the 6061 Cast Aluminium Alloy

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1821
Author(s):  
Ting He ◽  
Wei Shi ◽  
Song Xiang ◽  
Chaowen Huang ◽  
Ronald G. Ballinger
Keyword(s):  
Aluminium Alloy ◽  
Laser Scanning ◽  
Corrosion Behaviour ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Kelvin Probe ◽  
Force Microscopy ◽  
The Matrix ◽  
6061 Aluminium Alloy

The influence of AlFeSi and Mg2Si phases on corrosion behaviour of the cast 6061 aluminium alloy was investigated. Scanning Kelvin probe force microscopy (SKPFM), electron probe microanalysis (EPMA), and in situ observations by confocal laser scanning microscopy (CLSM) were used. It was found that Mg2Si phases were anodic relative to the matrix and dissolved preferentially without significantly affecting corrosion propagation. The AlFeSi phases’ influence on 6061 aluminium alloy local corrosion was greater than that of the Mg2Si phases. The corroded region width reached five times that of the AlFeSi phase, and the accelerating effect was terminated as the AlFeSi dissolved.

scholarly journals In Situ 3D-Imaging of the Inner Ear Synapses with a Cochlear Implant

Life ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 301
Author(s):  
Kathrin Malfeld ◽  
Nina Armbrecht ◽  
Holger A. Volk ◽  
Thomas Lenarz ◽  
Verena Scheper
Keyword(s):  
Cochlear Implant ◽  
Inner Ear ◽  
Laser Scanning ◽  
3D Imaging ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Sensory Cells ◽  
Residual Hearing ◽  
Preparation Methods

In recent years sensorineural hearing loss was found to affect not exclusively, nor at first, the sensory cells of the inner ear. The sensory cells’ synapses and subsequent neurites are initially damaged. Auditory synaptopathies also play an important role in cochlear implant (CI) care, as they can lead to a loss of physiological hearing in patients with residual hearing. These auditory synaptopathies and in general the cascades of hearing pathologies have been in the focus of research in recent years with the aim to develop more targeted and individually tailored therapeutics. In the current study, a method to examine implanted inner ears of guinea pigs was developed to examine the synapse level. For this purpose, the cochlea is made transparent and scanned with the implant in situ using confocal laser scanning microscopy. Three different preparation methods were compared to enable both an overview image of the cochlea for assessing the CI position and images of the synapses on the same specimen. The best results were achieved by dissection of the bony capsule of the cochlea.

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