This work was supported by the Hygiene Fonds of the Medical University Graz. All subjects gave their informed consent. Institutional approval of the study protocol was obtained from the Medical University Graz.

1. Specimen collection
<ol>
 <li>Remove fixed palatal expanders after 4 months of intraoral service. Use NOLA Dry Field System to isolate the appliances before removing them (Figures 1 and 2).</li>
 <li>Use sterilized pliers, gloves and trays to remove expanders without adding contamination (Figures 3 and 4).</li>
 <li>Store objects in Sarstedt 120 ml vials at -20&deg;C. Take to laboratory on ice and process within 24 hours.</li>
</ol>
2. Biofilm fixation
<ol>
 <li>Scrape off biofilm flakes with a sterile scalpel, or collect pieces with sterile forceps.</li>
 <li>Add ice-cold 4% PFA solution until sample is well covered.</li>
 <li>Incubate the mixture at +4&deg;C (do not freeze) for 3 to 12 hours. Longer fixation times or higher fixation temperatures may render the cell envelopes of gram-negative cells less permeable to oligonucleotide probes.</li>
 <li>Remove PFA solution and wash with ice-cold 1X PBS. Repeat this step 2-3 times to remove residual PFA.</li>
 <li>Resuspend the sample in 1 vol. ice-cold 1X PBS and add 1 vol. ice-cold 96% (v/v) ethanol.</li>
 <li>Store the sample at -20&deg;C. Samples fixed according to this protocol can be stored for several months to years.</li>
</ol>
3. Dehydration of fixed Samples
<ol>
 <li>Apply 5-30 &mu;l of PFA-fixed sample material to a microscope slide.</li>
 <li>Dry at 46&deg;C for about 15 min or at room temperature for longer. Thaw the lysozyme and the formamide.</li>
 <li>Add 250 &mu;l of lysozyme (1mg/ml) at room temperature for 10 min, thus facilitating penetration of the probes into the cells by partial destruction of the cell walls.</li>
 <li>Dip slide into 50%, 80% and 96% (v/v) ethanol for 3 min each. The dehydrating effect of the ethanol concentration series will disintegrate the cell membranes.</li>
 <li>Dry the slides at 46&deg;C for 10 min.</li>
</ol>
4. In-situ hybridization
<ol>
 <li>Prepare 1 ml of fresh hybridization buffer (see Table 1 for concentrations). Formamide concentrations used in this study: 10% (EUBmix), 20% (Bac303, POGI, MUT590) or 45% (LGCmix).</li>
 <li>Thaw the oligonucleotide probe solutions. Thawed probes should be kept on ice and protected from light.</li>
 <li>Add 2 &mu;l of each probe to 200 &mu;l of hybridization buffer, mix well and apply the mixture to the dehydrated sample on a microscope slide.</li>
 <li>Place a piece of tissue paper into a square Petri dish and pour the remaining hybridization buffer onto the tissue paper.</li>
 <li>Immediately place the slide horizontally into the dish and close the dish. Incubate in an oven at 46&deg;C for 1-5 hours (90 min will suffice in most cases). The dish functions as a moisture chamber preventing evaporation of hybridization solution from the slide. In particular, evaporation of formamide can cause non-specific probe binding to non-target cells.</li>
 <li>Prepare 50 ml of washing buffer (see Table 2 for concentrations). Prepare the washing buffer in a 50 ml tube and preheat to 48&deg;C in a water bath. The washing step is performed at 48&deg;C.</li>
 <li>Remove the dish with the slide from the hybridization oven. Immediately wash off the hybridization buffer with a small volume of pre-warmed washing buffer, and transfer the slide into the remaining washing buffer.</li>
 <li>Place the tube containing the washing buffer and the slide back into the water bath and incubate at 48&deg;C for 10-15 min.</li>
 <li>Remove slide from the tube and dip into ice-cold ddH2O for 2-3 seconds to eliminate residual washing buffer.</li>
 <li>Air-dry the slide as quickly as possible (the use of compressed air is recommended). Fast drying will reduce probe dissociation.</li>
 <li>Dried slides can be stored in the dark at -20&deg;C for several weeks without significant loss of probe-conferred fluorescence signal.</li>
</ol>
5. Microscopy
<ol>
 <li>After FISH and washing, apply two drops of antifadent close to the left and right ends of a slide (frozen slices should be warmed to room temperature prior to this step).</li>
 <li>Place a microscope cover slip on top and wait until the antifadent has spread over the entire slide. Note that an excessive amount of antifadent can blur the microscope image.</li>
 <li>Observe the samples under a confocal laser scanning microscope equipped with suitable filters or lasers. We used a Leica TCS unit (HCX PL APO/63x; NA 1.2). Data can be analyzed with software such as IMARIS or AMIRA.</li>
 <li>Slides embedded in antifadent can be stored at +4&deg;C (do not freeze) for up to 7 days before the probe-conferred fluorescence begins to decline. Alternatively, the antifadent can be removed with ddH2O, and the dried slides can be stored at -20&deg;C for an extended period of time.</li>
</ol>
6. Representative Results:
Scraping biofilm off fixed orthodontic appliances (Figure 5) yields suitable flakes (Figure 6) that can be hybridized directly onto coated glass slides for microscopy. In this way, different groups of orobiome bacteria can be identified in their natural three-dimensional environment by tagging bacterial rRNA with differently labeled specific probes (Figures 7 and 8). In Figure 7, biofilm was stained with EUBmix (green, all bacteria) and LGCmix (yellow, Firmicutes). Firmicutes appear in green, as they were stained with yellow and blue. In Figure 8, biofilm was stained with EUBmix (red, all bacteria), Bac303 (blue, Bacteroidetes) and POGI (yellow, Porphyromonas gingivalis). Porphyromonas gingivalis is shown in yellowish white, as all three probes bind to its DNA and the overlap of colors results in a white signal. Morphological differences between groups of bacteria can also be identified (Figures 9 and 10). Large clusters of coccoid bacteria are shown in Figure 9, where staining was performed with EUBmix (green, all bacteria). Different shapes of oral bacteria were visualized in Figure 10, where coccoid and filamentous bacteria can be distinguished by staining with EUBmix (red). Also, a typical mushroom-like structure of the biofilm can be processed via 3D modeling of the CLSM data (Figures 11 and 12) <a href="https://www.jove.com/files/ftp_upload/2967/Film1 Klug Santigli 01_2_JES_Web.mov">Click here to watch a movie of the 3D modeling.</a>
<img alt="Figure 1" src="/files/ftp_upload/2967/2967fig1.jpg" /> 
Figure 1. Fixed palatal expander in situ.
<img alt="Figure 2" src="/files/ftp_upload/2967/2967fig2.jpg" /> 
Figure 2. Nola Dry Field System.
<img alt="Figure 3" src="/files/ftp_upload/2967/2967fig3.jpg" /> 
Figure 3. Sterilized pliers, gloves and tray.
<img alt="Figure 4" src="/files/ftp_upload/2967/2967fig4.jpg" /> 
Figure 4. Removed expander.
<img alt="Figure 5" src="/files/ftp_upload/2967/2967fig5.jpg" /> 
Figure 5. Scraping off biofilm with a sterile scalpel.
<img alt="Figure 6" src="/files/ftp_upload/2967/2967fig6.jpg" /> 
Figure 6. Resin flakes directly hybridized onto coated glass slides.
<img alt="Figure 7" src="/files/ftp_upload/2967/2967fig7.jpg" /> 
Figure 7. CLSM image: differentiation of a specific bacterial group. 2D overlay of 3D CLSM stack data. Biofilm stained with EUBmix (green, all bacteria) and LGCmix (yellow, Firmicutes).
<img alt="Figure 8" src="/files/ftp_upload/2967/2967fig8.jpg" /> 
Figure 8. CLSM image: differentiation of a specific bacterial group. 2D overlay of 3D CLSM stack data. Biofilm stained with EUBmix (red, all bacteria), Bac303 (blue, Bacteroidetes) and POGI (yellow, Porphyromonas gingivalis).
<img alt="Figure 9" src="/files/ftp_upload/2967/2967fig9.jpg" /> 
Figure 9. CLSM image: differentiation of specific morphologies. 2D overlay of 3D CLSM stack data. Biofilm stained with EUBmix (green, all bacteria). Large clusters of coccoid bacteria (arrows).
<img alt="Figure 10" src="/files/ftp_upload/2967/2967fig10.jpg" /> 
Figure 10. CLSM images: differentiation of specific morphologies. 2D overlay of 3D CLSM stack data. Biofilm stained with EUBmix (red, all bacteria). Coccoid (arrow below) and filamentous bacteria (arrow above) can be distinguished.
<img alt="Figure 11" src="/files/ftp_upload/2967/2967fig11.jpg" /> 
Figure 11. Mushroom structure, 3D views from below. Stacks of biofilm flakes (scraped off the surface of an orthodontic appliance), stained with EUBmix and processed with IMARIS (CLSM image).
<img alt="Figure 11" src="/files/ftp_upload/2967/2967fig11.jpg" /> 
Figure 12. Mushroom structure, 3D side view. Stacks of biofilm flakes (scraped off the surface of an orthodontic appliance) processed with IMARIS (CLSM image).
<table border="1">
 <tbody>
 <tr>
 <td colspan="4">Hybridization buffer (200 &mu;l)</td>
 </tr>
 <tr>
 <td>Formamide concentration</td>
 <td>10%</td>
 <td>20%</td>
 <td>45%</td>
 </tr>
 <tr>
 <td>5 M NaCl</td>
 <td>36</td>
 <td>36</td>
 <td>36</td>
 </tr>
 <tr>
 <td>1 M Tris-HCl</td>
 <td>4</td>
 <td>4</td>
 <td>4</td>
 </tr>
 <tr>
 <td>2% SDS</td>
 <td>1</td>
 <td>1</td>
 <td>1</td>
 </tr>
 <tr>
 <td>FA</td>
 <td>20</td>
 <td>40</td>
 <td>90</td>
 </tr>
 <tr>
 <td>ddH2O</td>
 <td>138</td>
 <td>118</td>
 <td>68</td>
 </tr>
 <tr>
 <td>Any FISH probe</td>
 <td>2</td>
 <td>2</td>
 <td>2</td>
 </tr>
 </tbody>
</table>
Table 1. Constituents of hybridization buffer (concentrations in &mu;l).
<table border="1">
 <tbody>
 <tr>
 <td colspan="4">Washing buffer (50 ml)</td>
 </tr>
 <tr>
 <td>Formamide concentration</td>
 <td>10%</td>
 <td>20%</td>
 <td>45%</td>
 </tr>
 <tr>
 <td>5 M NaCl</td>
 <td>4500</td>
 <td>2150</td>
 <td>300</td>
 </tr>
 <tr>
 <td>1 M Tris-HCl</td>
 <td>1000</td>
 <td>1000</td>
 <td>1000</td>
 </tr>
 <tr>
 <td>0.5 M EDTA</td>
 <td>0</td>
 <td>500</td>
 <td>500</td>
 </tr>
 <tr>
 <td>ddH2O</td>
 <td>44 500</td>
 <td>46 350</td>
 <td>48 200</td>
 </tr>
 </tbody>
</table>
Table 2. Constituents of washing buffer (concentrations in &mu;l).
Movie 1. <a href="https://www.jove.com/files/ftp_upload/2967/Film1 Klug Santigli 01_2_JES_Web.mov">Click here to watch the movie.</a>

<ol>
	<li>Sunde, P. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fluorescence+in+situ+hybridization+(FISH)+for+direct+visualization+of+bacteria+in+periapical+lesions+of+asymptomatic+root-filled+teeth.">Fluorescence in situ hybridization (FISH) for direct visualization of bacteria in periapical lesions of asymptomatic root-filled teeth.</a> Microbiology. 149, 1095-1102 (2003).</li><li>Sussman, M., Loya, Y., Fine, M., Rosenberg, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+marine+fireworm+Hermodice+carunculata+is+a+winter+reservoir+and+spring-summer+vector+for+the+coral-bleaching+pathogen+Vibrio+shiloi.">The marine fireworm Hermodice carunculata is a winter reservoir and spring-summer vector for the coral-bleaching pathogen Vibrio shiloi.</a> Environ. Microbiol. 5, 250-255 (2003).</li><li>Kolenbrander, P. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Communication+among+oral+bacteria.">Communication among oral bacteria.</a> Microbiol. Mol. Biol. Rev. 66, 486-505 (2002).</li><li>Zijnge, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Oral+biofilm+architecture+on+natural+teeth.">Oral biofilm architecture on natural teeth.</a> PLoS One. 5, e9321-e9321 (2010).</li><li>Thurnheer, T., Gmur, R., Giertsen, E., Guggenheim, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Automated+fluorescent+in+situ+hybridization+for+the+specific+detection+and+quantification+of+oral+streptococci+in+dental+plaque.">Automated fluorescent in situ hybridization for the specific detection and quantification of oral streptococci in dental plaque.</a> J. Microbiol. Methods. 44, 39-47 (2001).</li><li>Hojo, K., Nagaoka, S., Ohshima, T., Maeda, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bacterial+interactions+in+dental+biofilm+development.">Bacterial interactions in dental biofilm development.</a> J. Dent. Res. 88, 982-990 (2009).</li><li>Jung, D. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Visualization+of+initial+bacterial+colonization+on+dentine+and+enamel+in+situ.">Visualization of initial bacterial colonization on dentine and enamel in situ.</a> J. Microbiol. Methods. 81, 166-174 (2010).</li><li>Al-Ahmad, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bacterial+colonization+of+enamel+in+situ+investigated+using+fluorescence+in+situ+hybridization.">Bacterial colonization of enamel in situ investigated using fluorescence in situ hybridization.</a> J. Med. Microbiol. 58, 1359-1366 (2009).</li><li>Bryers, J. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Medical+biofilms.">Medical biofilms.</a> Biotechnol. Bioeng. 100, 1-18 (2008).</li><li>Cardinale, M., Vieira de Castro, J., Muller, H., Berg, G., Grube, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+situ+analysis+of+the+bacterial+community+associated+with+the+reindeer+lichen+Cladonia+arbuscula+reveals+predominance+of+Alphaproteobacteria.">In situ analysis of the bacterial community associated with the reindeer lichen Cladonia arbuscula reveals predominance of Alphaproteobacteria.</a> FEMS Microbiol. Ecol. 66, 63-71 (2008).</li><li>Aas, J. A., Paster, B. J., Stokes, L. N., Olsen, I., Dewhirst, F. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Defining+the+normal+bacterial+flora+of+the+oral+cavity.">Defining the normal bacterial flora of the oral cavity.</a> J. Clin. Microbiol. 43, 5721-5732 (2005).</li><li>Chin, M. Y., Busscher, H. J., Evans, R., Noar, J., Pratten, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Early+biofilm+formation+and+the+effects+of+antimicrobial+agents+on+orthodontic+bonding+materials+in+a+parallel+plate+flow+chamber.">Early biofilm formation and the effects of antimicrobial agents on orthodontic bonding materials in a parallel plate flow chamber.</a> Eur. J. Orthod. 28, 1-7 (2006).</li><li>Loy, A., Maixner, F., Wagner, M., Horn, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=probeBase--an+online+resource+for+rRNA-targeted+oligonucleotide+probes:+new+features+2007.">probeBase--an online resource for rRNA-targeted oligonucleotide probes: new features 2007.</a> Nucleic. Acids. Res. 35, (2007).</li><li>Diaz, P. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Molecular+characterization+of+subject-specific+oral+microflora+during+initial+colonization+of+enamel.">Molecular characterization of subject-specific oral microflora during initial colonization of enamel.</a> Appl. Environ. Microbiol. 72, 2837-2848 (2006).</li><li>Dige, I., Nilsson, H., Kilian, M., Nyvad, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+situ+identification+of+streptococci+and+other+bacteria+in+initial+dental+biofilm+by+confocal+laser+scanning+microscopy+and+fluorescence+in+situ+hybridization.">In situ identification of streptococci and other bacteria in initial dental biofilm by confocal laser scanning microscopy and fluorescence in situ hybridization.</a> Eur. J. Oral Sci. 115, 459-467 (2007).</li><li>Kolenbrander, P. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bacterial+interactions+and+successions+during+plaque+development.">Bacterial interactions and successions during plaque development.</a> Periodontology. 42, 47-79 (2000).</li><li>Kolenbrander, P. E., Palmer, R. J., Periasamy, S., Jakubovics, N. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Oral+multispecies+biofilm+development+and+the+key+role+of+cell-cell+distance.">Oral multispecies biofilm development and the key role of cell-cell distance.</a> Nat. Rev. Microbiol. 8, 471-480 (2010).</li><li>Chalmers, N. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Use+of+quantum+dot+luminescent+probes+to+achieve+single-cell+resolution+of+human+oral+bacteria+in+biofilms.">Use of quantum dot luminescent probes to achieve single-cell resolution of human oral bacteria in biofilms.</a> Appl. Environ. Microbiol. 73, 630-636 (2007).</li><li>Wecke, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+novel+technique+for+monitoring+the+development+of+bacterial+biofilms+in+human+periodontal+pockets.">A novel technique for monitoring the development of bacterial biofilms in human periodontal pockets.</a> FEMS Microbiol. Lett. 191, 95-101 (2000).</li><li>Moter, A., Gobel, U. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fluorescence+in+situ+hybridization+(FISH)+for+direct+visualization+of+microorganisms.">Fluorescence in situ hybridization (FISH) for direct visualization of microorganisms.</a> J. Microbiol. Methods. 41, 85-112 (2000).</li></ol>

No conflicts of interest declared.

The protocol herein described is a highly workable approach to staining biofilms collected from hard materials. Sampling and hybridization are the most critical steps. During sampling, care must be taken that slices of adequate thickness are collected to ensure that the biofilm structure remains intact. During hybridization, it is essential to avoid excessive fluctuations in temperature, thus avoiding non-specific binding, or loss of binding, of the fluorescently labeled probes. This FISH protocol is an elegant method to stain normal heterogeneous biofilm directly on glass slides without disrupting its composition. The slides can immediately be used for microscopy without a need to move the sample once again. In this way, an improvement over staining in tubes is achieved by less shear force being applied to the biofilm. Slices &gt; 50 &mu;m thick can be prepared and investigated in this fashion.

<table border="1">
	<tbody>
		<tr>
			<th>Oligonucleotides</th>
			<th>Target organism</th>
			<th>Fluorochrome</th>
		</tr>
		<tr>
			<td>EUB338 - 338III</td>
			<td>Eubacteria</td>
			<td>Cy3</td>
		</tr>
		<tr>
			<td>LGC354 A-C</td>
			<td>Firmicutes</td>
			<td>FITC</td>
		</tr>
		<tr>
			<td>Bac303</td>
			<td>Bacteroidetes</td>
			<td>Cy5</td>
		</tr>
		<tr>
			<td>Mut590</td>
			<td>Streptococcus mutans</td>
			<td>FITC</td>
		</tr>
		<tr>
			<td>POGI</td>
			<td>Porphyromonas gingivalis</td>
			<td>FITC</td>
		</tr>
	</tbody>
</table>
Table 3. Oligonucleotides (refer to probeBase13 for details).
<table border="1">
	<tbody>
		<tr>
			<th>Component</th>
			<th>Company</th>
			<th>Comments</th>
		</tr>
		<tr>
			<td>4% paraformaldehyde</td>
			<td>&nbsp;</td>
			<td>4% solution in PBS</td>
		</tr>
		<tr>
			<td>1 x PBS</td>
			<td>&nbsp;</td>
			<td>3 x solution prepared</td>
		</tr>
		<tr>
			<td>ddH2O</td>
			<td>Millipore</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Ethanol (100%)</td>
			<td>Merck</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Lysozyme</td>
			<td>Roth</td>
			<td>100 mg/ml stock solution</td>
		</tr>
		<tr>
			<td>Formamide</td>
			<td>Roth</td>
			<td>99.5% solution</td>
		</tr>
		<tr>
			<td>5 M NaCl</td>
			<td>Roth</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>1 M Tris-HCl</td>
			<td>Roth</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>2% SDS</td>
			<td>Roth</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>FISH probes (oligonucleotides)</td>
			<td>Invitrogen, Sigma</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>ProLong Gold antifadent</td>
			<td>Invitrogen</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Nail polish</td>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<th>Equipment</th>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Incubator</td>
			<td>Thermo Scientific</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Water bath</td>
			<td>IKA Tez</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>50 ml tubes</td>
			<td>Sarstedt</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Polysine-coated slides</td>
			<td>Thermo Scientific</td>
			<td>&nbsp;</td>
		</tr>
	</tbody>
</table>
Table 4. Materials and equipment.

oral biofilm analysis of palatal expanders by fluorescence in-situ hybridization and confocal laser scanning microscopy

Confocal laser scanning microscopy (CLSM) of natural heterogeneous biofilm is today facilitated by a comprehensive range of staining techniques, one of them being fluorescence in situ hybridization (FISH).1,2 We performed a pilot study in which oral biofilm samples collected from fixed orthodontic appliances (palatal expanders) were stained by FISH, the objective being to assess the three-dimensional organization of natural biofilm and plaque accumulation.3,4 FISH creates an opportunity to stain cells in their native biofilm environment by the use of fluorescently labeled 16S rRNA-targeting probes.4-7,19 Compared to alternative techniques like immunofluorescent labeling, this is an inexpensive, precise and straightforward labeling technique to investigate different bacterial groups in mixed biofilm consortia.18,20 General probes were used that bind to Eubacteria (EUB338 + EUB338II + EUB338III; hereafter EUBmix),8-10 Firmicutes (LGC354 A-C; hereafter LGCmix),9,10 and Bacteroidetes (Bac303).11 In addition, specific probes binding to Streptococcus mutans (MUT590)12,13 and Porphyromonas gingivalis (POGI)13,14 were used. The extreme hardness of the surface materials involved (stainless steel and acrylic resin) compelled us to find new ways of preparing the biofilm. As these surface materials could not be readily cut with a cryotome, various sampling methods were explored to obtain intact oral biofilm. The most workable of these approaches is presented in this communication. Small flakes of the biofilm-carrying acrylic resin were scraped off with a sterile scalpel, taking care not to damage the biofilm structure. Forceps were used to collect biofilm from the steel surfaces. Once collected, the samples were fixed and placed directly on polysine coated glass slides. FISH was performed directly on these slides with the probes mentioned above. Various FISH protocols were combined and modified to create a new protocol that was easy to handle.5,10,14,15 Subsequently the samples were analyzed by confocal laser scanning microscopy. Well-known configurations3,4,16,17 could be visualized, including mushroom-style formations and clusters of coccoid bacteria pervaded by channels. In addition, the bacterial composition of these typical biofilm structures were analyzed and 2D and 3D images created.

Watch this Scientific Journal Video about Oral Biofilm Analysis of Palatal Expanders by Fluorescence In-Situ Hybridization and Confocal Laser Scanning Microscopy at JoVE.com

Oral Biofilm Analysis of Palatal Expanders by Fluorescence In-Situ Hybridization and Confocal Laser Scanning Microscopy

We present a protocol for structural and compositional analysis of natural oral biofilm from orthodontic appliances with in situ hybridization (FISH) and confocal laser scanning microscopy (CLSM). Oral biofilm samples were collected from palatal expanders, scraping acrylic-resin flakes off their surface and referring them for molecular processing.

Confocal laser scanning microscopy (CLSM) of natural heterogeneous biofilm is today facilitated by a comprehensive range of staining techniques, one of ...

oral-biofilm-analysis-palatal-expanders-fluorescence-situ

Research

JoVE Journal

Medicine

15.9K vues.  Medical University of Graz. Nous présentons un protocole pour l'analyse structurelle et compositionnelle du biofilm naturel d'administration orale à partir d'appareils orthodontiques In situ

Vidéo: Oral Biofilm Analysis of Palatal Expanders by Fluorescence In-Situ Hybridization and Confocal Laser Scanning Microscopy

Probe-based Confocal Laser Endomicroscopy of the Urinary Tract: The Technique

Probe-based confocal laser endomicroscopy (CLE) is an emerging optical imaging technology that enables real-time in vivo microscopy of mucosal surfaces during standard endoscopy. With applications currently in the respiratory1 and gastrointestinal tracts,2-6 CLE has also been explored in the urinary tract for bladder cancer diagnosis.7-10 Cellular morphology and tissue microarchitecture can be resolved with micron scale resolution in real time, in addition to dynamic imaging of the normal and pathological vasculature.7
The probe-based CLE system (Cellvizio, Mauna Kea Technologies, France) consists of a reusable fiberoptic imaging probe coupled to a 488 nm laser scanning unit. The imaging probe is inserted in the working channels of standard flexible and rigid endoscopes. An endoscope-based CLE system (Optiscan, Australia), in which the confocal endomicroscopy functionality is integrated onto the endoscope, is also used in the gastrointestinal tract. Given the larger scope diameter, however, application in the urinary tract is currently limited to ex vivo use.11 Confocal image acquisition is done through direct contact of the imaging probe with the target tissue and recorded as video sequences. As in the gastrointestinal tract, endomicroscopy of the urinary tract requires an exogenenous contrast agent&mdash;most commonly fluorescein, which can be administered intravenously or intravesically. Intravesical administration is a well-established method to introduce pharmacological agents locally with minimal systemic toxicity that is unique to the urinary tract. Fluorescein rapidly stains the extracellular matrix and has an established safety profile.12 Imaging probes of various diameters enable compatibility with different caliber endoscopes. To date, 1.4 and 2.6 mm probes have been evaluated with flexible and rigid cystoscopy.10 Recent availability of a &lt; 1 mm imaging probe13 opens up the possibility of CLE in the upper urinary tract during ureteroscopy. Fluorescence cystoscopy (i.e. photodynamic diagnosis) and narrow band imaging are additional endoscope-based optical imaging modalities14 that can be combined with CLE to achieve multimodal imaging of the urinary tract. In the future, CLE may be coupled with molecular contrast agents such as fluorescently labeled peptides15 and antibodies for endoscopic imaging of disease processes with molecular specificity.

Probe-based confocal laser endomicroscopy enables real-time microscopy of the human urinary tract during cystoscopy, providing dynamic, intravital imaging of pathological states such as bladder cancer with cellular resolution. Endomicroscopy may augment the diagnostic accuracy of standard white light endoscopy and provide intraoperative image guidance to improve surgical resection.

Probe-based  confocal laser endomicroscopy (CLE) is an emerging optical imaging technology  that enables real-time in vivo microscopy of mucosal surfaces ...

Clinicopathological Analysis of miRNA Expression in Breast Cancer Tissues by Using miRNA In Situ Hybridization

In this article, we describe a detailed protocol for miRNA detection in breast cancer tissue using in situ hybridization with a digoxigenin-labelled LNA (Locked Nucleic Acid) probe. The probe was recognized by anti-DIG alkaline phosphatase antibodies and later developed using alkaline phosphatase substrate producing fluorescence signals. Here we utilized miRNA in situ hybridization (MISH) technique to analyze expression of miR-489 in tissues from breast cancer patients. This technique can detect the localization of miRNA of interest in individual tissue samples. This technique can be used to compare the expression of desired miRNA in tumor tissue with that in adjacent normal tissue and to identify the specific structures responsible for expressing this miRNA. This technique can be very useful in answering certain clinical questions, such as role of specific miRNA in the development of cancer. Our results indicate that mammary epithelial cells express significantly higher levels of miR-489 than adjacent tumor cells.

Clinicopathological Analysis of miRNA Expression in Breast Cancer Tissues by Using miRNA In Situ Hybridization

Here we present a protocol to detect miRNA expression in breast cancer patient samples using miRNA in situ hybridization.

In this article, we describe a detailed protocol for miRNA detection in breast cancer tissue using in situ hybridization with a digoxigenin-labelled LNA ...

Oral Biofilm Sampling for Microbiome Analysis in Healthy Children

Oral biofilm and its molecular analysis provide a basis for investigating various dental research and clinical questions. Knowledge of biofilm composition leads to a better understanding of cariogenic and periopathogenic mechanisms. Microbial changes taking place in the oral cavity during childhood are of interest for several reasons. The evolution of the child oral microbiota and shifts in its composition need to be analyzed further to understand and possibly prevent the onset of disease. At the same time, advanced knowledge of the natural composition of oral biofilm is needed. Early stages of caries-free permanent dentition with healthy gums provide a widely unaffected subgingival habitat that can serve as an in situ baseline for studying features of oral health and disease. Analysis of children's oral biofilm during different stages in life is thus an important theme in the field. Modern molecular analysis methods can provide comprehensive information about the bacterial diversity of such biofilms. To enable microbiota data comparison, it is important to standardize each step in the procedure for molecular data generation. This procedure spans from clinical sampling, Next Generation Sequencing (NGS), bioinformatic data processing, to taxonomic interpretation. One of the most critical factors here is biofilm sampling. Sampling in children is even more challenging in particular due to limited space in subgingival areas. We thus focus on the use of paper points for subgingival sampling. This article provides a detailed protocol for oral biofilm sampling of the subgingival sulcus, the mucosa, and saliva in children.

Changes in the oral microbiome throughout childhood are of growing interest. Comparison of different microbiome studies reveals a lack of standardized sampling protocols. Limited space makes sampling the sound subgingival sulcus of children challenging. Paper point sampling is presented here in detail as the method of choice for this area.

Oral biofilm and its molecular analysis provide a basis for investigating various dental research and clinical questions. Knowledge of biofilm composition ...

Second Harmonic Generation Signals in Rabbit Sclera As a Tool for Evaluation of Therapeutic Tissue Cross-linking (TXL) for Myopia

Methods to strengthen tissue by introducing chemical bonds (non-enzymatic cross-linking) into structural proteins (fibrillar collagens) for therapy include photochemical cross-linking and tissue cross-linking (TXL) methods. Such methods for inducing mechanical tissue property changes are being employed to the cornea in corneal thinning (mechanically weakened) disorders such as keratoconus as well as the sclera in progressive myopia, where thinning and weakening of the posterior sclera occurs and likely contributes to axial elongation. The primary target proteins for such tissue strengthening are fibrillar collagens which constitute the great majority of dry weight proteins in the cornea and sclera. Fortuitously, fibrillar collagens are the main source of second harmonic generation signals in the tissue extracellular space. Therefore, modifications of the collagen proteins, such as those induced through cross-linking therapies, could potentially be detected and quantitated through the use of second harmonic generation microscopy (SHGM). Monitoring SHGM signals through the use of a laser scanning microscopy system coupled with an infrared excitation light source is an exciting modern imaging method that is enjoying widespread usage in the biomedical sciences. Thus, the present study was undertaken in order to evaluate the use of SHGM microscopy as a means to measure induced cross-linking effects in ex vivo rabbit sclera, following an injection of a chemical cross-linking agent into the sub-Tenon&#39;s space (sT), an injection approach that is standard practice for causing ocular anesthesia during ophthalmologic clinical procedures. The chemical cross-linking agent, sodium hydroxymethylglycinate (SMG), is from a class of cosmetic preservatives known as formaldehyde releasing agents (FARs). Scleral changes following reaction with SMG resulted in increases in SHG signals and correlated with shifts in thermal denaturation temperature, a standard method for evaluating induced tissue cross-linking effects.

Second Harmonic Generation Signals in Rabbit Sclera As a Tool for Evaluation of Therapeutic Tissue Cross-linking TXL for Myopia

This protocol describes techniques for evaluating chemical cross-linking of the rabbit sclera using&#160;second harmonic generation imaging and differential scanning calorimetry.

Methods to strengthen tissue by introducing chemical bonds (non-enzymatic cross-linking) into structural proteins (fibrillar collagens) for therapy ...

Oral Biofilm Formation on Different Materials for Dental Implants

Dental implants and their prosthetic components are prone to bacterial colonization and biofilm formation. The use of materials that provides low microbial adhesion may reduce the prevalence and progression of peri-implant diseases. In view of the oral environment complexity and oral biofilm heterogeneity, microscopy techniques are needed that can enable a biofilm analysis of the surfaces of teeth and dental materials. This article describes a series of protocols implemented for comparing oral biofilm formation on titanium and ceramic materials for prosthetic abutments, as well as the methods involved in oral biofilms analyses at the morphological and cellular levels. The in situ model to evaluate oral biofilm formation on titanium and zirconia materials for dental prosthesis abutments as described in this study provides a satisfactory preservation of the 48 h biofilm, thereby demonstrating methodological adequacy. Multiphoton microscopy allows the analysis of an area representative of the biofilm formed on the test materials. In addition, the use of fluorophores and the processing of the images using multiphoton microscopy allows the analysis of the bacterial viability in a very heterogeneous population of microorganisms. The preparation of biological specimens for electron microscopy promotes the structural preservation of biofilm, images with good resolution, and no artifacts.

Here, we present a protocol to evaluate oral biofilm formation on titanium and zirconia materials for dental prosthesis abutments, including the analysis of bacterial cells viability and morphological characteristics. An in situ model associated with powerful microscopy techniques is used for the oral biofilm analysis.

Dental implants and their prosthetic components are prone to bacterial colonization and biofilm formation. The use of materials that provides low ...

Oral Health Assessment by Lay Personnel for Older Adults

Oral health is an often-undervalued contributor to overall health. The literature, however, underscores the myriad of systemic diseases influenced by oral health, including type II diabetes, heart disease, and atherosclerosis. Thus, assessments of oral health, called oral screenings, have a significant role in assessing risk of disease, managing disease, and even improving disease by oral care. Here we present a method to assess oral health quickly and consistently across time. The protocol is simple enough for non-oral health professionals such as students, family, and caregivers. Useful for any age of patient, the method is particularly key for older individuals who are often at risk of inflammation and chronic disease. Components of the method include existing oral health assessment scales and inventories, which are combined to produce a comprehensive assessment of oral health. Thus, oral characteristics assessed include intraoral and extraoral structures, soft and hard tissues, natural and artificial teeth, plaque, oral functions such as swallowing, and the impact this oral health status has on the patient&#39;s quality of life. Advantages of this method include its inclusion of measures and perceptions of both the observer and patient, and its ability to track changes in oral health over time. Results acquired are quantitative totals of questionnaire and oral screening items, which can be summed for an oral health status score. The scores of successive oral screenings can be used to track the progression of oral health across time and guide recommendations for both oral and overall health care.

The goal of this protocol is to enable non-dental professionals to assess oral health status for research or health-screening purposes. Aspects assessed include lips, tongue, soft and hard tissues, natural and artificial teeth, oral cleanliness, plaque, swallowing, and impact of oral health on quality of life.

Oral health is an often-undervalued contributor to overall health. The literature, however, underscores the myriad of systemic diseases influenced by oral ...

Visualizing Membrane Ruffle Formation using Scanning Electron Microscopy

Membrane ruffling is the formation of motile plasma membrane protrusions containing a meshwork of newly polymerized actin filaments. Membrane ruffles may form spontaneously or in response to growth factors, inflammatory cytokines, and phorbol esters. Some of the membrane protrusions may reorganize into circular membrane ruffles that fuse at their distal margins and form cups that close and separate into the cytoplasm as large, heterogeneous vacuoles called macropinosomes. During the process, ruffles trap extracellular fluid and solutes that internalize within macropinosomes. High-resolution scanning electron microscopy (SEM) is a commonly used imaging technique to visualize and quantify membrane ruffle formation, circular protrusions, and closed macropinocytic cups on the cell surface. The following protocol describes the cell culture conditions, stimulation of the membrane ruffle formation in vitro, and how to fix, dehydrate, and prepare cells for imaging using SEM. Quantification of membrane ruffling, data normalization, and stimulators and inhibitors of membrane ruffle formation are also described. This method can help answer key questions about the role of macropinocytosis in physiological and pathological processes, investigate new targets that regulate membrane ruffle formation, and identify yet uncharacterized physiological stimulators as well as novel pharmacological inhibitors of macropinocytosis.

Macropinocytosis is a highly conserved endocytic process initiated by the formation of F-actin-rich sheet-like membrane projections, also known as membrane ruffles. Increased rate of macropinocytotic solute internalization has been implicated in various pathological conditions. This protocol presents a method to quantify membrane ruffle formation in vitro using scanning electron microscopy.

Membrane ruffling is the formation of motile plasma membrane protrusions containing a meshwork of newly polymerized actin filaments. Membrane ruffles may ...

Interphase Fluorescence in situ Hybridization of Bone Marrow Smears of Multiple Myeloma

Fluorescence in situ hybridization (FISH) detection is an indispensable method in genetic risk stratification in multiple myeloma (MM), which is one of the most common hematological malignancies. The identifying characteristic of MM is accumulated malignant plasma cells in bone marrow. FISH reports for MM mainly focus on purified or identified clonal plasma cells, rather than all nucleated cells, by sorting with anti-CD138 magnetic beads or marking with cytoplasmic immunoglobulin light chain &#954; or &#955;. Bone marrow interphase nuclei are usually obtained from fresh bone marrow cells. However, satisfactory enrichment of plasma cell specimens requires large amounts of fresh heparin anti-coagulated bone marrow, which cannot be obtained in the case of difficult bone marrow extraction or a bone marrow dry tap. Herein, we establish a novel method to improve the success of FISH detection on stained or unstained bone marrow smears. Bone marrow smears are easier to obtain than anticoagulated bone marrow specimens.

Interphase Fluorescence in situ Hybridization of Bone Marrow Smears of Multiple Myeloma

Here, we present a protocol for improving the success of interphase fluorescence in situ hybridization detection on bone marrow smears from multiple myeloma patients.

Fluorescence in situ hybridization (FISH) detection is an indispensable method in genetic risk stratification in multiple myeloma (MM), which is one of ...

Semi-Automated Planimetric Quantification of Dental Plaque Using an Intraoral Fluorescence Camera

Dental plaque accumulation is quantified using clinical indices or, otherwise, the planimetric plaque index (PPI),&#160;which measures the relative area of a tooth that is covered by plaque deposits. Compared to clinical indices, the PPI has a higher discriminatory power, but traditional planimetry is a time-consuming analysis, as the plaque-covered and clean tooth areas have to be determined manually for each image using image-processing software. Here, we present a method for the semi-automated planimetric quantification of dental plaque, which allows for the rapid processing of up to 1,000 images simultaneously. The method exploits the enhanced contrast between disclosed plaque, sound tooth surfaces, and soft tissues in fluorescence images acquired with an intraoral camera. Careful execution of the clinical procedures and accurate image acquisition are crucial steps for the successful semi-automated identification of the plaque-covered areas. The method is suitable for planimetry on sound facial and oral tooth surfaces, on most composite resin restorations, and on teeth with orthodontic brackets, but not on metallic restorations. Compared to traditional PPI recordings, semi-automated planimetry considerably reduces the amount of time spent on the analysis, as well as the subjective human input, thus increasing the reproducibility of planimetric measurements.

This study presents a semi-automated digital image analysis procedure for the planimetric quantification of disclosed dental plaque based on images acquired with an intraoral fluorescence camera. The method allows for the rapid and reliable quantification of dental plaque in the research environment.

Dental plaque accumulation is quantified using clinical indices or, otherwise, the planimetric plaque index (PPI),&#160;which measures the relative area ...

Capturing Oral Submucous Fibrosis Tissue Samples for Spatial-Omics Analysis

Isolation of Cells with Morphological and Spatial Information from Oral Submucous Fibrosis Samples by Laser Capture Microdissection

Oral submucous fibrosis (OSF) is a common type of potentially malignant disorder in the oral cavity. The atrophy of epithelium and fibrosis of the lamina propria and the submucosa are often found on histopathological slides. Epithelial dysplasia, epithelial atrophy, and senescent fibroblasts have been proposed to be associated with the malignant transformation of OSF. However, because of the heterogeneity of potentially malignant oral disorders and oral squamous cell carcinoma, it is difficult to identify the specific molecular mechanisms of malignant transformation in OSF. Here, we present a method to obtain a small number of epithelial or mesenchymal cells carrying morphological data and spatial information by laser capture microdissection on formalin-fixed paraffin-embedded tissue slides. Using a microscope, we can precisely capture microscale (~500 cells) dysplastic or atrophic epithelial tissue and fibrotic subepithelial tissue. The extracted cells can be evaluated by genome or transcriptome sequencing to acquire genomic and transcriptomic data with morphological and spatial information. This approach removes the heterogeneity of bulk OSF tissue sequencing and the interference caused by cells in non-lesioned areas, allowing for precise spatial-omics analysis of OSF tissue.

Author Spotlight: Unlocking the Mysteries of Oral Potential Malignancies 

Laser capture microdissection of oral submucous fibrosis tissues allows for precise extraction of cells from histological regions of interest for the analysis of multi-omics data with morphological and spatial information.

Oral submucous fibrosis (OSF) is a common type of potentially malignant disorder in the oral cavity. The atrophy of epithelium and fibrosis of the lamina ...