Name: optimizing the use of a liquid handling robot to conduct a high throughput forward chemical genetics screen of arabidopsis thaliana
Uploaded: 2018-04-30T13:30:00
Description: Watch this Scientific Journal Video about Optimizing the Use of a Liquid Handling Robot to Conduct a High Throughput Forward Chemical Genetics Screen of Arabidopsis thaliana at JoVE.com

We thank Jozsef Stork, Mitchel Richmond, Jarrad Gollihue, and Andrea Sanchez for constructive and critical discussion. Dr. Sharyn Perry for the phenotypic photographs. This material is based upon work supported by the National Science Foundation under Cooperative Agreement No. 1355438.

1. Creating a Dilution Library
<ol>
	<li>Label 625 Dilution Library plates by hand, ensuring that they match to their corresponding plate from the chemical library. Additionally, connect in flow and out flow hoses to the Multichannel Tip Wash Automated Labware Positioner (ALP) by passing them through the Console Drive to the 5 Gallon Reservoir (see Table of Materials).</li>
	<li>Access the computer and turn on the wash pump through the connection of the Device Controller to the Multichannel Tip Wash AL...

<ol>
	<li>Blackwell, H. E., Zhao, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chemical+genetic+approaches+to+plant+biology.">Chemical genetic approaches to plant biology.</a> Plant Physiol. 133 (2), 448-455 (2003).</li><li>Dejonghe, W., Russinova, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Plant+chemical+genetics:+From+phenotype-based+screens+to+synthetic+biology.">Plant chemical genetics: From phenotype-based screens to synthetic biology.</a> Plant Physiol. 174 (1), 5-20 (2017).</li><li>McCourt, P., Desveaux, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Plant+chemical+genetics.">Plant chemical genetics.</a> New Phytol. 185 (1), 15-26 (2010).</li><li>Lumba, S., Cutler, S., McCourt, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Plant+nuclear+hormone+receptors:+A+role+for+small+molecules+in+protein-protein+interactions.">Plant nuclear hormone receptors: A role for small molecules in protein-protein interactions.</a> Annu Rev Cell Dev Biol. 26, 445-469 (2010).</li><li>Hicks, G. R., Raikhel, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Opportunities+and+challenges+in+plant+chemical+biology.">Opportunities and challenges in plant chemical biology.</a> Nat Chem Biol. 5 (5), 268-272 (2009).</li><li>De Rybel, B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+role+for+the+root+cap+in+root+branching+revealed+by+the+non-auxin+probe+naxillin.">A role for the root cap in root branching revealed by the non-auxin probe naxillin.</a> Nat Chem Biol. 8 (9), 798-805 (2012).</li><li>Koornneef, M., Meinke, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+development+of+Arabidopsis+as+a+model+plant.">The development of Arabidopsis as a model plant.</a> Plant J. 61 (6), 909-921 (2010).</li><li>Serrano, M., Kombrink, E., Meesters, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Considerations+for+designing+chemical+screening+strategies+in+plant+biology.">Considerations for designing chemical screening strategies in plant biology.</a> Front Plant Sci. 6, 131 (2015).</li><li>Yoshitani, N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+structure-based+strategy+for+discovery+of+small+ligands+binding+to+functionally+unknown+proteins:+Combination+of+in+silico+screening+and+surface+plasmon+resonance+measurements.">A structure-based strategy for discovery of small ligands binding to functionally unknown proteins: Combination of in silico screening and surface plasmon resonance measurements.</a> Proteomics. 5 (6), 1472-1480 (2005).</li><li>Macarron, R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Impact+of+high-throughput+screening+in+biomedical+research.">Impact of high-throughput screening in biomedical research.</a> Nat Rev Drug Discov. 10 (3), 188-195 (2011).</li><li>DeBolt, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Morlin,+an+inhibitor+of+cortical+microtubule+dynamics+and+cellulose+synthase+movement.">Morlin, an inhibitor of cortical microtubule dynamics and cellulose synthase movement.</a> Proc Natl Acad Sci U S A. 104 (14), 5854-5859 (2007).</li><li>Christian, M., Hannah, W. B., Luthen, H., Jones, A. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Identification+of+auxins+by+a+chemical+genomics+approach.">Identification of auxins by a chemical genomics approach.</a> J Exp Bot. 59 (10), 2757-2767 (2008).</li><li>Drakakaki, G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Clusters+of+bioactive+compounds+target+dynamic+endomembrane+networks+in+vivo.">Clusters of bioactive compounds target dynamic endomembrane networks in vivo.</a> PNAS. 108 (43), 17850-17855 (2011).</li><li>Armstrong, J. I., Yuan, S., Dale, J. M., Tanner, V. N., Theologis, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Identification+of+inhibitors+of+auxin+transcriptional+activation+by+means+of+chemical+genetics+in+Arabidopsis.">Identification of inhibitors of auxin transcriptional activation by means of chemical genetics in Arabidopsis.</a> Proc Natl Acad Sci U S A. 101 (41), 14978-14983 (2004).</li><li>Brown, L. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+small+molecule+with+differential+effects+on+the+PTS1+and+PTS2+peroxisome+matrix+import+pathways.">A small molecule with differential effects on the PTS1 and PTS2 peroxisome matrix import pathways.</a> Plant J. 65 (6), 980-990 (2011).</li><li>De Rybel, B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chemical+inhibition+of+a+subset+of+Arabidopsis+thaliana+GSK3-like+kinases+activates+brassinosteroid+signaling.">Chemical inhibition of a subset of Arabidopsis thaliana GSK3-like kinases activates brassinosteroid signaling.</a> Chem Biol. 16 (6), 594-604 (2009).</li><li>Arkin, M. R., Tang, Y., Wells, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Small-molecule+inhibitors+of+protein-protein+interactions:+progressing+toward+the+reality.">Small-molecule inhibitors of protein-protein interactions: progressing toward the reality.</a> Chem Biol. 21 (9), 1102-1114 (2014).</li><li>St Onge, R., Schlecht, U., Scharfe, C., Evangelista, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Forward+chemical+genetics+in+yeast+for+discovery+of+chemical+probes+targeting+metabolism.">Forward chemical genetics in yeast for discovery of chemical probes targeting metabolism.</a> Molecules. 17 (11), 13098-13115 (2012).</li><li>Vassilev, L. T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vivo+activation+of+the+p53+pathway+by+small-molecule+antagonists+of+MDM2.">In vivo activation of the p53 pathway by small-molecule antagonists of MDM2.</a> Science. 303 (5659), 844-848 (2004).</li><li>Zhao, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chemical+genetic+interrogation+of+natural+variation+uncovers+a+molecule+that+is+glycoactivated.">Chemical genetic interrogation of natural variation uncovers a molecule that is glycoactivated.</a> Nat Chem Biol. 3 (11), 716-721 (2007).</li><li>Walsh, T. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+emerging+field+of+chemical+genetics:+Potential+applications+for+pesticide+discovery.">The emerging field of chemical genetics: Potential applications for pesticide discovery.</a> Pest Manag Sci. 63 (12), 1165-1171 (2007).</li><li>. Seed Handling Available from: <a target="_blank" href="https://abrc.osu.edu/seed-handling">https://abrc.osu.edu/seed-handling</a> (2013)</li><li>Knoth, C., Salus, M. S., Girke, T., Eulgem, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+synthetic+elicitor+3,5-dichloroanthranilic+acid+induces+NPR1-dependent+and+NPR1-independent+mechanisms+of+disease+resistance+in+Arabidopsis.">The synthetic elicitor 3,5-dichloroanthranilic acid induces NPR1-dependent and NPR1-independent mechanisms of disease resistance in Arabidopsis.</a> Plant Physiol. 150 (1), 333-347 (2009).</li><li>Conway, M. K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Scalable+96-well+Plate+based+iPSC+culture+and+production+using+a+robotic+liquid+handling+system.">Scalable 96-well Plate based iPSC culture and production using a robotic liquid handling system.</a> J Vis Exp. , (2015).</li><li>Daniszewski, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Automated+cell+culture+systems+and+their+applications+to+human+pluripotent+stem+cell+studies.">Automated cell culture systems and their applications to human pluripotent stem cell studies.</a> SLAS Technol. , (2017).</li><li>Popa-Burke, I., Russell, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Compound+precipitation+in+high-concentration+DMSO+solutions.">Compound precipitation in high-concentration DMSO solutions.</a> J Biomol Screen. 19 (9), 1302-1308 (2014).</li><li>Partridge, F. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+automated+high-throughput+system+for+phenotypic+screening+of+chemical+libraries+on+C.+elegans+and+parasitic+nematodes.">An automated high-throughput system for phenotypic screening of chemical libraries on C. elegans and parasitic nematodes.</a> Cold Spring Harb Protoc. , (2017).</li></ol>

This protocol is designed to aid researchers in accomplishing a forward chemical genetics screen on Arabidopsis. We provide representative results from a screen of 50,000 compounds (Figure 2 and Figure 3), one of the largest forward chemical genetics screens performed on Arabidopsis to date9,13,23. The use of a liquid handling robot enabled more efficient dilution libra...

In the past 20 years researchers in the field of plant biology have made great strides using chemical genetics approaches, both forward and reverse, improving our understanding of cell wall biosynthesis, the cytoskeleton, hormone biosynthesis and signaling, gravitropism, pathogenesis, purine biosynthesis, and endomembrane trafficking1,2,3,4,5. Employing forward chemical genetics techniques enables the identification of phenotypes of interest and allows researchers to understand the genotypic underpinnings of particular processes. Conversely, reverse chemical genetics seeks out chemicals that interact with a pre-determined protein target6. Arabidopsis has been at the forefront of these discoveries in plant biology because its genome is small, mapped, and annotated. It has a short generation time, and there are multiple mutant/reporter lines available to facilitate the identification of aberrant subcellular machinery7.
There are two major bottlenecks that slow the progress of forward chemical genetic screens, the initial screening process and determining the target of the compound of interest8. A major aid in increasing the speed of small molecule selection is the use of automation and automated equipment9. Liquid handling robots are an excellent tool for handling large libraries of small molecules and have been instrumental in driving progress in the biological sciences10. The protocol presented here is designed to alleviate the bottleneck associated with the screening process, enabling the identification of bioactive small molecules at a rapid rate. This technique decreases the burden of labor and time on behalf of the operator while also decreasing the economic cost to the principle investigator.
Thus far, most chemical libraries analyzed have held between 10,000 and 20,000 compounds, some with as many as 150,000 and some with as few as 709,11,12,13,14,15,16. The protocol introduced herein was implemented on a small molecule library of 50,000 compounds (see Table of Materials), one of the larger forward chemical genetics screens conducted on Arabidopsis to date. This protocol fits with the current trend towards increased efficiency and speed regarding forward chemical genetics, especially as it pertains to herbicide discovery, insecticide discovery, fungicide discover, drug discovery, and cancer biology17,18,19,20,21. Though implemented here with Arabidopsis, this protocol, could easily be adapted to cell cultures, spores, and potentially even insects in liquid medium within 96-, 384-, or 1536-well plates. Due to its small size, Arabidopsis is amenable to screening in 96 well plates. However, distributing seeds evenly among wells is a challenge. Hand seeding is accurate but labor intensive, and though there are devices designed to dispense seeds into 96-well plates, they are expensive to purchase. Here, we show how this step can be circumvented with just a small loss in accuracy.
The overall goal of this method was to make screening a large chemical library against Arabidopsis more manageable, without compromising accuracy, via the use of a liquid handling robot. The use of this method improves the efficiency of the researcher by decreasing the time taken to complete initial dilution series management and subsequent phenotypic screens, allowing quick visualization of samples under a dissecting microscope, and rapid identification of novel bioactive small molecules. Figure 1 depicts this protocol&#39;s key outcomes in 4 steps.
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/57393/57393fig1.jpg" /> 
Figure 1: Overall workflow of the forward chemical genetics screen. An overview of the protocol to be described with some detail for each of the 4 key steps. 1: Receiving the Chemical Library, 2: Making the Dilution Library, 3: Making the Screening Plates, and 4: Incubating and visualizing the Screening Plates. <a href="/files/ftp_upload/57393/57393fig1large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>

<table>
	<tbody>
		<tr>
			<td>Keyboard</td>
			<td>Local Provider</td>
			<td>N/A</td>
			<td>Used for protocol design and operating the Biomek FX</td>
		</tr>
		<tr>
			<td>Mouse</td>
			<td>Local Provider</td>
			<td>N/A</td>
			<td>Used for protocol design and operating the Biomek FX</td>
		</tr>
		<tr>
			<td>Computer Screen</td>
			<td>Local Provider</td>
			<td>N/A</td>
			<td>Used for protocol design and operating the Biomek FX</td>
		</tr>
		<tr>
			<td>Computer</td>
			<td>Local Provider</td>
			<td>N/A</td>
			<td>Used for protocol design and operating the Biomek FX</td>
		</tr>
		<tr>
			<td>DIVERSet Diverse Screening Library</td>
			<td>ChemBridge</td>
			<td>N/A</td>
			<td>Chemical library</td>
		</tr>
		<tr>
			<td>Biomek Software</td>
			<td>Beckman Coulter</td>
			<td>N/A</td>
			<td>Runs and designs the Biomek FX</td>
		</tr>
		<tr>
			<td>Device Controller</td>
			<td>Beckman Coulter</td>
			<td>719366</td>
			<td>Operates the water pump/tip washing station</td>
		</tr>
		<tr>
			<td>Stacker Carousel Pendent</td>
			<td>Beckman Coulter</td>
			<td>148240</td>
			<td>Manual operation of Biomek Stacker Carousel</td>
		</tr>
		<tr>
			<td>Biomek Stacker Carousel</td>
			<td>Beckman Coulter</td>
			<td>148520</td>
			<td>Rotary unit that houses all FX Stacker 10&#39;s</td>
		</tr>
		<tr>
			<td>FX Stacker 10</td>
			<td>Beckman Coulter</td>
			<td>148522</td>
			<td>Elevator unit that houses components for screen</td>
		</tr>
		<tr>
			<td>FX Stacker 10</td>
			<td>Beckman Coulter</td>
			<td>148522</td>
			<td>Elevator unit that houses components for screen</td>
		</tr>
		<tr>
			<td>FX Stacker 10</td>
			<td>Beckman Coulter</td>
			<td>148522</td>
			<td>Elevator unit that houses components for screen</td>
		</tr>
		<tr>
			<td>FX Stacker 10</td>
			<td>Beckman Coulter</td>
			<td>148522</td>
			<td>Elevator unit that houses components for screen</td>
		</tr>
		<tr>
			<td>Biomek FX</td>
			<td>Beckman Coulter</td>
			<td>https://www.beckman.com/liquid-handlers</td>
			<td>Robot that performs the desired operations</td>
		</tr>
		<tr>
			<td>Accuframe</td>
			<td>Artisan Technology Group</td>
			<td>76853-4</td>
			<td>Frames arm to place components corretly</td>
		</tr>
		<tr>
			<td>Framing Fixture</td>
			<td>Beckman Coulter</td>
			<td>719415</td>
			<td>Centers arm in the Accuframe</td>
		</tr>
		<tr>
			<td>Multichannel Tip Wash ALP</td>
			<td>Beckman Coulter</td>
			<td>719662</td>
			<td>Washes the tips after the ethanol bath</td>
		</tr>
		<tr>
			<td>Tip Loader ALP</td>
			<td>Beckman Coulter</td>
			<td>719356</td>
			<td>Pneumatically loads tips onto the arm</td>
		</tr>
		<tr>
			<td>Air Compressor</td>
			<td>Local Provider</td>
			<td>N/A</td>
			<td>Provides air for pneumatic tip loading</td>
		</tr>
		<tr>
			<td>MasterFlex Console Drive</td>
			<td>Cole-Parmer</td>
			<td>77200-65</td>
			<td>Pump used to circulate water through the Multichannel Tip Washer</td>
		</tr>
		<tr>
			<td>Air Hose</td>
			<td>Local Provider</td>
			<td>N/A</td>
			<td>Provides air from air compressor to Tip Loader</td>
		</tr>
		<tr>
			<td>Water Hose</td>
			<td>Local Provider</td>
			<td>N/A</td>
			<td>Provides water from 5 Gallon Reserviour to Tip Washer</td>
		</tr>
		<tr>
			<td>Static ALP&#39;s</td>
			<td>Beckman Coulter</td>
			<td>Comes with Biomek FX</td>
			<td>Supports equipment for the Screen</td>
		</tr>
		<tr>
			<td>5 Gallon Reserviour</td>
			<td>Local Provider</td>
			<td>N/A</td>
			<td>Recirculates the dirty water from cleaning the tips</td>
		</tr>
		<tr>
			<td>Grippers</td>
			<td>Beckman Coulter</td>
			<td>Comes with Biomek FX</td>
			<td>Grabs and moves the equipment to the correct places</td>
		</tr>
		<tr>
			<td>96-Channel 200 &#181;L Head</td>
			<td>Beckman Coulter</td>
			<td>Comes with Biomek FX</td>
			<td>Holds the 96 tips used within the screen</td>
		</tr>
		<tr>
			<td>AP96 P200 Pipette Tips</td>
			<td>Beckman Coulter</td>
			<td>717251</td>
			<td>Used to make the screening library</td>
		</tr>
		<tr>
			<td>96 Well Flat Bottom Plate</td>
			<td>Costar</td>
			<td>9018</td>
			<td>Aids in visulization of screen</td>
		</tr>
		<tr>
			<td>96 Well V-Bottom Plate</td>
			<td>Costar</td>
			<td>3897</td>
			<td>Aids in storing of dilution library</td>
		</tr>
		<tr>
			<td>AlumaSeal 96 Sealing Film</td>
			<td>MedSci</td>
			<td>F-96-100</td>
			<td>Seals for storage both the chemicle library and dilution library</td>
		</tr>
		<tr>
			<td>Plastic ziplock sandwich bags</td>
			<td>Local Provider</td>
			<td>N/A</td>
			<td>Used to ensure a humid environment for screen</td>
		</tr>
		<tr>
			<td>AP96 P20 Pipette Tips</td>
			<td>Beckman Coulter</td>
			<td>717254</td>
			<td>Used in the dilution library creation</td>
		</tr>
		<tr>
			<td>Growth Chamber</td>
			<td>Percival</td>
			<td>AR36L3</td>
			<td>Germinates seeds for phenotypic visulization</td>
		</tr>
		<tr>
			<td>Spatula</td>
			<td>Local Provider</td>
			<td>N/A</td>
			<td>Holds seeds to add into wells where liquid seeding failed seed adequatly</td>
		</tr>
		<tr>
			<td>Toothpick</td>
			<td>Local Provider</td>
			<td>N/A</td>
			<td>Pushes seeds from spatula to wells</td>
		</tr>
		<tr>
			<td>Murashige and Skoog Basal Salt Mixture</td>
			<td>PhytoTechnology Laboratories</td>
			<td>M524</td>
			<td>Add to MS media mixture</td>
		</tr>
		<tr>
			<td>MES Free Acid Monohydrate</td>
			<td>Fisher Scientific</td>
			<td>ICN19483580</td>
			<td>Added to MS media to decrease pH</td>
		</tr>
		<tr>
			<td>Agar Powder</td>
			<td>Alfa Aesar</td>
			<td>9002-18-0</td>
			<td>Increases thickness of media to support seed suspension</td>
		</tr>
		<tr>
			<td>5M KOH</td>
			<td>Sigma-Aldrich</td>
			<td>484016</td>
			<td>Increases pH to adequate levels</td>
		</tr>
		<tr>
			<td>1L Media Storage Bottle</td>
			<td>Corning</td>
			<td>1395-1L</td>
			<td>Holds enough media for a screen</td>
		</tr>
		<tr>
			<td>Polypropylene Centrifuge Tubes</td>
			<td>Corning</td>
			<td>431470</td>
			<td>Sterilizes seeds prior to vernilization</td>
		</tr>
		<tr>
			<td>pH Probe</td>
			<td>Davis Instruments</td>
			<td>YX-58825-26</td>
			<td>Used for making media</td>
		</tr>
		<tr>
			<td>ALPs (Automated Labware Positioners) Users Manual</td>
			<td>Beckman Coulter</td>
			<td>PN 987836</td>
			<td>Aids in setting up the accompaning equipment for the Biomek FX</td>
		</tr>
		<tr>
			<td>Biomek 2000 Stacker Carousel Users Guide</td>
			<td>Beckman Coulter</td>
			<td>609862-AA</td>
			<td>Aids in setting up the Stacker Carousel</td>
		</tr>
		<tr>
			<td>Biomek FX and FXP Laboratory Automation Workstations Users Manual</td>
			<td>Beckman Coulter</td>
			<td>PN 987834</td>
			<td>Used to frame the Multichannel Pod</td>
		</tr>
		<tr>
			<td>Biomek FXP Laboratory Automation Workstation Customer Startup Guide</td>
			<td>Beckman Coulter</td>
			<td>PN B32335AB</td>
			<td>Used to aid in setting up the Biomek FX</td>
		</tr>
		<tr>
			<td>Biomek Software User&#39;s Manual</td>
			<td>Beckman Coulter</td>
			<td>PN 987835</td>
			<td>Used to set up and understand the Software</td>
		</tr>
	</tbody>
</table>

optimizing the use of a liquid handling robot to conduct a high throughput forward chemical genetics screen of arabidopsis thaliana

Chemical genetics is increasingly being employed to decode traits in plants that may be recalcitrant to traditional genetics due to gene redundancy or lethality. However, the probability of a synthetic small molecule being bioactive is low; therefore, thousands of molecules must be tested in order to find those of interest. Liquid handling robotics systems are designed to handle large numbers of samples, increasing the speed with which a chemical library can be screened in addition to minimizing/standardizing error. To achieve a high-throughput forward chemical genetics screen of a library of 50,000 small molecules on Arabidopsis thaliana (Arabidopsis), protocols using a bench-top multichannel liquid handling robot were developed that require minimal technician involvement. With these protocols, 3,271 small molecules were discovered that caused visible phenotypic alterations. 1,563 compounds induced short roots, 1,148 compounds altered coloration, 383 compounds caused root hair and other, non-categorized, alterations, and 177 compounds inhibited germination.

The ability to accurately and efficiently characterize phenotypes based on the addition of small molecules at screening concentrations under a dissecting microscope is the end goal of this method of forward chemical genetics on Arabidopsis. The phenotypes observed when all 50,000 compounds had been screened was diverse and could be broken into several distinct classes (Figure 2). Figure 3A-F depicts exam...

Watch this Scientific Journal Video about Optimizing the Use of a Liquid Handling Robot to Conduct a High Throughput Forward Chemical Genetics Screen of Arabidopsis thaliana at JoVE.com

Optimizing the Use of a Liquid Handling Robot to Conduct a High Throughput Forward Chemical Genetics Screen of Arabidopsis thaliana

A high throughput screen of synthetic small molecules was conducted on the model plant species, Arabidopsis thaliana. This protocol, developed for a liquid handling robot, increases the speed of forward chemical genetics screens, accelerating the discovery of novel small molecules affecting plant physiology.

Optimizing the Use of a Liquid Handling Robot to Conduct a High Throughput Forward Chemical Genetics Screen of Arabidopsis thaliana

Chemical genetics is increasingly being employed to decode traits in plants that may be recalcitrant to traditional genetics due to gene redundancy or ...

The overall goal of this protocol is to perform a high throughput forward chemical genetics screen on Arabidopsis seedlings. With this method, we can efficiently and effectively discover novel small molecules that affect plant physiology. These discoveries will provide the foundation for further studies into physiological processes, such as cell wall synthesis.The main advantage of this technique is that tens of thousands of small molecules can be screened in a short period of time. Though this protocol is designed for the model plant species Arabidopsis, it can easily be adapted to other organisms, such as insects, microorganisms, or cell culture. We first had the idea for this protocol when we learned that the university's genomic center needed to find a home for a surplus liquid-handling robot.We immediately volunteered to take it off their hands. Prepare the dilution library and the Multichannel Tip Wash Automated Labware Positioner or ALP as described in the text protocol. Manually load the Stacker 10s attached to the stacker carousel.In Hotels A through D, first load one box of AP96 P20 pipette tips in Room One. Then, load four 96-well V-bottom plates in Rooms Two through Five with two upper plates containing stock concentrations from the ordered library and the other two lower plates empty. Additionally, load one box of AP96 P20 pipette tips in Room Six.Load four 96-well V-bottom plates in Rooms Seven through Nine with the two upper plates containing stock concentrations of the ordered library and the two lower plates empty. Set up the deck with 300 milliliters of water in the reservoir on P3, a 300-milliliter 70%ethanol bath on P7, the Tip Loader ALP, and the Multichannel Tip Wash ALP. Using the liquid-handling robot's operating software, present AP96 P20 pipette tips from the Stacker 10 and move them to the Tip Loader ALP.Present Room Two from Hotel A and separate all four 96-well V-bottom plates on the deck, placing the bottom two on P4 and P8 and the top two on P5 and P9.Load AP96 P20 pipette tips with the Tip Loader ALP onto the 96-channel 200-microliter head. Aspirate 90 microliters from the 300-milliliter water reservoir and dispense into the 96-well V-bottom dilution plate on P4.Repeat the step for the plate on P8.Mix the chemical library plate on P5 by repetitively aspirating and dispensing 15 microliters three times. Additionally, aspirate 10 microliters from the chemical library plate on P5 and dispense 10 microliters into the dilution plate on P4.Mix the solutions of the plate on P4 by repetitively aspirating and dispensing 50 microliters a total of three times.Once mixed, clean the AP96 P20 pipette tips by aspirating and dispensing 70 microliters of 70%ethanol from P7, then wash them in the Multichannel Tip Wash ALP by aspirating and dispensing a 110%volume of water four times. Repeat these steps for the second pair of plates on P8 and P9.Upon creating the second 96-well V-bottom dilution plate, stack the P9, P5, P8, and P4 plates in that order from bottom to top. Then, place the stack on one empty static ALP.Use either P1, P2, P6, P10, P11, P12, or P13. Repeat these steps until Room Five in Hotel A is empty, then start the process again upon reaching Room Six, moving new AP96 P20 pipette tips to the Tip Loader ALP and placing the used AP96 P20 pipette tips on an empty static ALP. Repeat the procedure until Room 9 of Hotel A is empty.In order to proceed to Hotel B, the plates and tips on the deck must be reloaded into Hotel A.Though the robot can work unsupervised, it is necessary to refill the water reservoir after each dilution cycle. If the cycle restarts with insufficient water, the robot will aspirate air and the chemicals will not be diluted. Manually refill the 300-milliliter water reservoir.The computer program can incorporate a pause detailing this message, requiring the user to hit Continue before carrying out the next step. Repeat the dilution steps for the remaining three Hotels. Manually add seeds to the media at a density of 0.1 gram per 100 milliliters.This density results in an average of 3-10 seeds per well of a 96-well plate. Manually place four 96-well flat-bottom plates in Rooms One and Two of Hotel A.Place a box of AP96 P250 pipette tips on the Tip Loader ALP, a 300-milliliter reservoir filled with the media-seed mixture on P3, and a 300-milliliter reservoir filled with 70%ethanol on P7.Using the operating software, present Rooms One and Two in Hotel A and separate the stacks of four plates. Place one plate on each of the empty static ALPs, then load AP96 P250 pipette tips on the 96-channel 200-microliter head.Aspirate 90 microliters from the 300-milliliter media-seed reservoir on P3 and dispense it into the first 96-well flat bottom plate. Repeat this process until all eight plates contain the media-seed mixture. Clean the AP96 P250 pipette tips by aspirating and dispensing 70 microliters from the 300-milliliter reservoir filled with 70%ethanol on P7.Wash the tips in the Multichannel Tip Wash ALP by aspirating and dispensing a 110%volume of water four times, then unload the tips at TL1.Finally, gather the plates by hand. Manually load a box of AP96 P250 pipette tips into Room One of Hotel A.Also, load two 96-well V-bottom dilution library plates into Rooms Two, Four, Six, and Eight. Load two 96-well flat-bottom screening plates into Rooms Three, Five, Seven, and Nine.Using the operating software, configure the deck to contain a wash reservoir of 300 milliliters of 70%ethanol at P7.The media-seed reservoir can be left on the deck at P3.Additionally, turn on the console drive through connection of the device controller to circulate water through the Multichannel Tip Wash ALP. This will turn off automatically at the end of the protocol. Present the AP96 P250 pipette tip box from Hotel A and move it to the Tip Loader ALP.Next, present the 96-well V-bottom dilution library plates from Room Two of Hotel A to the deck. Place one plate on static ALP P4 and one plate on P8.Then, present the 96-well flat-bottom screening plates from Room Three of Hotel A to the deck. Place one plate on static ALP P5 and one on P9.Load AP96 P250 pipette tips with the Tip Loader ALP onto the 96-channel 200-microliter head.Mix the 96-well V-bottom dilution plate on P4 by aspirating and dispensing 50 microliters three times. Following that, aspirate 10 microliters from this plate and dispense into the 96-well flat-bottom screening plate on P5.Mix the solutions in the plate at P5 by aspirating and dispensing 50 microliters three times. Clean the AP96 P250 pipette tips with ethanol by aspirating and dispensing 70 microliters of 70%ethanol from the reservoir at P7.Then, wash the tips in the Multichannel Tip Wash ALP by aspirating and dispensing a 110%volume of water four times.Repeat these steps for the second 96-well V-bottom dilution library plate and 96-well flat-bottom screening plate. Stack the two 96-well V-bottom dilution library plates together and the two 96-well flat-bottom screening plates together. Move the plates to the static ALPs.Then, repeat the process three times, adding diluted chemicals to screening plates a total of eight times. Finally, check the number of seeds in each well of the screening plates through visual confirmation. Supplement the wells with fewer than three seeds by addition of sterilized and vernalized seed.It is critical to ensure that the media in which the seedlings are growing does not dry out, as this will result in poor germination. Plates containing seedlings should be kept at high humidity or stored in desiccation-resistant containers. Incubate the 96-well flat-bottom screening plates for four days in an environmental chamber at 22 degrees Celsius on a 16/8 light/dark cycle in a desiccation-proof container.Visualize the 96-well flat-bottom screening plates under a dissecting microscope and record all aberrant phenotypes for further investigation. Examples of normal and aberrant phenotypes are no visible morphological abnormalities, brown root hairs, stunted root, severely stunted root, bleached, green mucilage, incomplete germination, and no germination. Visible phenotypes by percentage are displayed in a pie chart.Seedlings exhibited abnormalities in root morphology, pigmentation, root hairs, and germination. Also included is a variety of others, which include the production of green mucilage. Once mastered, this technique can greatly increase the efficiency and accuracy of large forward chemical genetic screens.While attempting this procedure, it is important to remember to sterilize and vernalize seed, refill the water reservoir during dilution steps, ensure samples are stored in desiccation-resistant containers, and that all imaging is done in flat-bottom plates. Depending on the physiological process you are interested in investigating, this initial screen can be followed up with additional assays to help determine the mode of action of each chemical. After watching this video, you should have a good understanding of how to use a liquid-handling robot to improve the efficiency and accuracy of a chemical genetic screen.

optimizing-use-liquid-handling-robot-to-conduct-high-throughput

Research

JoVE Journal

Bioengineering

Adaptation of a Haptic Robot in a 3T fMRI

Functional magnetic resonance imaging (fMRI) provides excellent functional brain imaging via the BOLD signal 1 with advantages including non-ionizing radiation, millimeter spatial accuracy of anatomical and functional data 2, and nearly real-time analyses 3. Haptic robots provide precise measurement and control of position and force of a cursor in a reasonably confined space. Here we combine these two technologies to allow precision experiments involving motor control with haptic/tactile environment interaction such as reaching or grasping. The basic idea is to attach an 8 foot end effecter supported in the center to the robot 4 allowing the subject to use the robot, but shielding it and keeping it out of the most extreme part of the magnetic field from the fMRI machine (Figure 1).
The Phantom Premium 3.0, 6DoF, high-force robot (SensAble Technologies, Inc.) is an excellent choice for providing force-feedback in virtual reality experiments 5, 6, but it is inherently non-MR safe, introduces significant noise to the sensitive fMRI equipment, and its electric motors may be affected by the fMRI's strongly varying magnetic field. We have constructed a table and shielding system that allows the robot to be safely introduced into the fMRI environment and limits both the degradation of the fMRI signal by the electrically noisy motors and the degradation of the electric motor performance by the strongly varying magnetic field of the fMRI. With the shield, the signal to noise ratio (SNR: mean signal/noise standard deviation) of the fMRI goes from a baseline of &tilde;380 to &tilde;330, and &tilde;250 without the shielding. The remaining noise appears to be uncorrelated and does not add artifacts to the fMRI of a test sphere (Figure 2). The long, stiff handle allows placement of the robot out of range of the most strongly varying parts of the magnetic field so there is no significant effect of the fMRI on the robot. The effect of the handle on the robot's kinematics is minimal since it is lightweight (&tilde;2.6 lbs) but extremely stiff 3/4" graphite and well balanced on the 3DoF joint in the middle. The end result is an fMRI compatible, haptic system with about 1 cubic foot of working space, and, when combined with virtual reality, it allows for a new set of experiments to be performed in the fMRI environment including naturalistic reaching, passive displacement of the limb and haptic perception, adaptation learning in varying force fields, or texture identification 5, 6.

The adaptation and use of a haptic robot in a 3T fMRI is described.

Functional magnetic resonance imaging (fMRI) provides excellent functional brain imaging via the BOLD signal 1 with advantages including non-ionizing ...

High-throughput Protein Expression Generator Using a Microfluidic Platform

Rapidly increasing fields, such as systems biology, require the development and implementation of new technologies, enabling high-throughput and high-fidelity measurements of large systems. Microfluidics promises to fulfill many of these requirements, such as performing high-throughput screening experiments on-chip, encompassing biochemical, biophysical, and cell-based assays1. Since the early days of microfluidics devices, this field has drastically evolved, leading to the development of microfluidic large-scale integration2,3. This technology allows for the integration of thousands of micromechanical valves on a single device with a postage-sized footprint (Figure 1). We have developed a high-throughput microfluidic platform for generating in vitro expression of protein arrays (Figure 2) named PING (Protein Interaction Network Generator). These arrays can serve as a template for many experiments such as protein-protein 4, protein-RNA5 or protein-DNA6 interactions.
The device consist of thousands of reaction chambers, which are individually programmed using a microarrayer. Aligning of these printed microarrays to microfluidics devices programs each chamber with a single spot eliminating potential contamination or cross-reactivity Moreover, generating microarrays using standard microarray spotting techniques is also very modular, allowing for the arraying of proteins7, DNA8, small molecules, and even colloidal suspensions. The potential impact of microfluidics on biological sciences is significant. A number of microfluidics based assays have already provided novel insights into the structure and function of biological systems, and the field of microfluidics will continue to impact biology.

We present a microfluidic approach for the expression of protein arrays. The device consists of thousands of reaction chambers controlled by micro-mechanical valves. The microfluidic device is mated to a microarray-printed gene library. These genes are then transcribed and translated on-chip, resulting in a protein array ready for experimental use.

Rapidly increasing fields, such as systems biology, require the development and implementation of new technologies, enabling high-throughput and ...

High-throughput Synthesis of Carbohydrates and Functionalization of Polyanhydride Nanoparticles

Transdisciplinary approaches involving areas such as material design, nanotechnology, chemistry, and immunology have to be utilized to rationally design efficacious vaccines carriers. Nanoparticle-based platforms can prolong the persistence of vaccine antigens, which could improve vaccine immunogenicity1. Several biodegradable polymers have been studied as vaccine delivery vehicles1; in particular, polyanhydride particles have demonstrated the ability to provide sustained release of stable protein antigens and to activate antigen presenting cells and modulate immune responses2-12.
The molecular design of these vaccine carriers needs to integrate the rational selection of polymer properties as well as the incorporation of appropriate targeting agents. High throughput automated fabrication of targeting ligands and functionalized particles is a powerful tool that will enhance the ability to study a wide range of properties and will lead to the design of reproducible vaccine delivery devices.
The addition of targeting ligands capable of being recognized by specific receptors on immune cells has been shown to modulate and tailor immune responses10,11,13 C-type lectin receptors (CLRs) are pattern recognition receptors (PRRs) that recognize carbohydrates present on the surface of pathogens. The stimulation of immune cells via CLRs allows for enhanced internalization of antigen and subsequent presentation for further T cell activation14,15. Therefore, carbohydrate molecules play an important role in the study of immune responses; however, the use of these biomolecules often suffers from the lack of availability of structurally well-defined and pure carbohydrates. An automation platform based on iterative solution-phase reactions can enable rapid and controlled synthesis of these synthetically challenging molecules using significantly lower building block quantities than traditional solid-phase methods16,17.
Herein we report a protocol for the automated solution-phase synthesis of oligosaccharides such as mannose-based targeting ligands with fluorous solid-phase extraction for intermediate purification. After development of automated methods to make the carbohydrate-based targeting agent, we describe methods for their attachment on the surface of polyanhydride nanoparticles employing an automated robotic set up operated by LabVIEW as previously described10. Surface functionalization with carbohydrates has shown efficacy in targeting CLRs10,11 and increasing the throughput of the fabrication method to unearth the complexities associated with a multi-parametric system will be of great value (Figure 1a).

In this article, a high throughput method is presented for the synthesis of oligosaccharides and their attachment to the surface of polyanhydride nanoparticles for further use in targeting specific receptors on antigen presenting cells.

Transdisciplinary approaches involving areas such as material design, nanotechnology, chemistry, and immunology have to be utilized to rationally design ...

Designing a Bio-responsive Robot from DNA Origami

Nucleic acids are astonishingly versatile. In addition to their natural role as storage medium for biological information1, they can be utilized in parallel computing2,3 , recognize and bind molecular or cellular targets4,5 , catalyze chemical reactions6,7 , and generate calculated responses in a biological system8,9. Importantly, nucleic acids can be programmed to self-assemble into 2D and 3D structures10-12, enabling the integration of all these remarkable features in a single robot linking the sensing of biological cues to a preset response in order to exert a desired effect.
Creating shapes from nucleic acids was first proposed by Seeman13, and several variations on this theme have since been realized using various techniques11,12,14,15 . However, the most significant is perhaps the one proposed by Rothemund, termed scaffolded DNA origami16. In this technique, the folding of a long (&gt;7,000 bases) single-stranded DNA 'scaffold' is directed to a desired shape by hundreds of short complementary strands termed 'staples'. Folding is carried out by temperature annealing ramp. This technique was successfully demonstrated in the creation of a diverse array of 2D shapes with remarkable precision and robustness. DNA origami was later extended to 3D as well17,18 .
 
The current paper will focus on the caDNAno 2.0 software19 developed by Douglas and colleagues. caDNAno is a robust, user-friendly CAD tool enabling the design of 2D and 3D DNA origami shapes with versatile features. The design process relies on a systematic and accurate abstraction scheme for DNA structures, making it relatively straightforward and efficient.
In this paper we demonstrate the design of a DNA origami nanorobot that has been recently described20. This robot is 'robotic' in the sense that it links sensing to actuation, in order to perform a task. We explain how various sensing schemes can be integrated into the structure, and how this can be relayed to a desired effect. Finally we use Cando21 to simulate the mechanical properties of the designed shape. The concept we discuss can be adapted to multiple tasks and settings.

DNA origami is a powerful method for fabricating precise nanoscale objects by programming the self-assembly of DNA molecules. Here, we describe how DNA origami can be utilized to design a robotic robot capable of sensing biological cues and responding by shape shifting, subsequently relayed to a desired effect.

Nucleic acids are astonishingly versatile. In addition to their natural role as storage medium for biological information1, they can be utilized in ...

High-throughput, Automated Extraction of DNA and RNA from Clinical Samples using TruTip Technology on Common Liquid Handling Robots

TruTip is a simple nucleic acid extraction technology whereby a porous, monolithic binding matrix is inserted into a pipette tip. The geometry of the monolith can be adapted for specific pipette tips ranging in volume from 1.0 to 5.0 ml. The large porosity of the monolith enables viscous or complex samples to readily pass through it with minimal fluidic backpressure. Bi-directional flow maximizes residence time between the monolith and sample, and enables large sample volumes to be processed within a single TruTip. The fundamental steps, irrespective of sample volume or TruTip geometry, include cell lysis, nucleic acid binding to the inner pores of the TruTip monolith, washing away unbound sample components and lysis buffers, and eluting purified and concentrated nucleic acids into an appropriate buffer. The attributes and adaptability of TruTip are demonstrated in three automated clinical sample processing protocols using an Eppendorf epMotion 5070, Hamilton STAR and STARplus liquid handling robots, including RNA isolation from nasopharyngeal aspirate, genomic DNA isolation from whole blood, and fetal DNA extraction and enrichment from large volumes of maternal plasma (respectively).

TruTip is a simple nucleic acid extraction technology whereby a porous, monolithic binding matrix is inserted into a pipette tip. Consequently, the sample preparation format is compatible with most liquid handling instruments, and can be used for many medium to high-throughput clinical applications and sample types.

TruTip is a simple nucleic acid extraction  technology whereby a porous, monolithic binding matrix is inserted into a  pipette tip. The geometry of the ...

Optimizing Attachment of Human Mesenchymal Stem Cells on Poly(&#949;-caprolactone) Electrospun Yarns

Research into biomaterials and tissue engineering often includes cell-based in vitro investigations, which require initial knowledge of the starting cell number. While researchers commonly reference their seeding density this does not necessarily indicate the actual number of cells that have adhered to the material in question. This is particularly the case for materials, or scaffolds, that do not cover the base of standard cell culture well plates. This study investigates the initial attachment of human mesenchymal stem cells seeded at a known number onto electrospun poly(&#949;-caprolactone) yarn after 4 hr in culture. Electrospun yarns were held within several different set-ups, including bioreactor vessels rotating at 9 rpm, cell culture inserts positioned in low binding well plates and polytetrafluoroethylene (PTFE) troughs placed within petri dishes. The latter two were subjected to either static conditions or positioned on a shaker plate (30 rpm). After 4 hr incubation at 37&#160;oC, 5% CO2, the location of seeded cells was determined by cell DNA assay. Scaffolds were removed from their containers and placed in lysis buffer. The media fraction was similarly removed and centrifuged &#8211; the supernatant discarded and pellet broken up with lysis buffer. Lysis buffer was added to each receptacle, or well, and scraped to free any cells that may be present. The cell DNA assay determined the percentage of cells present within the scaffold, media and well fractions. Cell attachment was low for all experimental set-ups, with greatest attachment (30%) for yarns held within cell culture inserts and subjected to shaking motion. This study raises awareness to the actual number of cells attaching to scaffolds irrespective of the stated cell seeding density.

Optimizing Attachment of Human Mesenchymal Stem Cells on Poly(&amp;#949;-caprolactone) Electrospun Yarns

This article describes a range of set-ups for seeding human mesenchymal stem cells onto materials, in this case electrospun yarns, that do not cover the base of standard culture well plates in order to maximize and quantify the number of cells that initially attach compared to the known seeding density.

Research into biomaterials and tissue engineering often includes cell-based in vitro investigations, which require initial knowledge of the starting cell ...

Use of a High-throughput In Vitro Microfluidic System to Develop Oral Multi-species Biofilms

There are few high-throughput in vitro systems which facilitate the development of multi-species biofilms that contain numerous species commonly detected within in vivo oral biofilms. Furthermore, a system that uses natural human saliva as the nutrient source, instead of artificial media, is particularly desirable in order to support the expression of cellular and biofilm-specific properties that mimic the in vivo communities. We describe a method for the development of multi-species oral biofilms that are comparable, with respect to species composition, to supragingival dental plaque, under conditions similar to the human oral cavity. Specifically, this methods article will describe how a commercially available microfluidic system can be adapted to facilitate the development of multi-species oral biofilms derived from and grown within pooled saliva. Furthermore, a description of how the system can be used in conjunction with a confocal laser scanning microscope to generate 3-D biofilm reconstructions for architectural and viability analyses will be presented. Given the broad diversity of microorganisms that grow within biofilms in the microfluidic system (including Streptococcus, Neisseria, Veillonella, Gemella, and Porphyromonas), a protocol will also be presented describing how to harvest the biofilm cells for further subculture&#160;or DNA extraction and analysis. The limits of both the microfluidic biofilm system and the current state-of-the-art data analyses will be addressed. Ultimately, it is envisioned that this article will provide a baseline technique that will improve the study of oral biofilms and aid in the development of additional technologies that can be integrated with the microfluidic platform.

Use of a High-throughput In Vitro Microfluidic System to Develop Oral Multi-species Biofilms

The goal of this methods paper is to describe the use of a microfluidic system for the development of multi-species biofilms that contain species typically identified in human supragingival dental plaque.&#160;Methods to describe biofilm architecture, biofilm viability, and an approach to harvest biofilm for culture-dependent or culture-independent analyses are highlighted.

There are few high-throughput in vitro systems which facilitate the development of multi-species biofilms that contain numerous species commonly detected ...

Generation of Scalable, Metallic High-Aspect Ratio Nanocomposites in a Biological Liquid Medium

The goal of this protocol is to describe the synthesis of two novel biocomposites with high-aspect ratio structures. The biocomposites consist of copper and cystine, with either copper nanoparticles (CNPs) or copper sulfate contributing the metallic component. Synthesis is carried out in liquid under biological conditions (37 &#176;C) and the self-assembled composites form after 24 hr. Once formed, these composites are highly stable in both liquid media and in a dried form. The composites scale from the nano- to micro- range in length, and from a few microns to 25 nm in diameter. Field emission scanning electron microscopy with energy dispersive X-ray spectroscopy (EDX) demonstrated that sulfur was present in the NP-derived linear structures, while it was absent from the starting CNP material, thus confirming cystine as the source of sulfur in the final nanocomposites. During synthesis of these linear nano- and micro-composites, a diverse range of lengths of structures is formed in the synthesis vessel. Sonication of the liquid mixture after synthesis was demonstrated to assist in controlling average size of the structures by diminishing the average length with increased time of sonication. Since the formed structures are highly stable, do not agglomerate, and are formed in liquid phase, centrifugation may also be used to assist in concentrating and segregating formed composites.

Here we present a protocol to synthesize novel, high-aspect ratio biocomposites under biological conditions and in liquid media. The biocomposites scale from nanometers to micrometers in diameter and length, respectively. Copper nanoparticles (CNPs) and copper sulfate combined with cystine are the key components for the synthesis.

The goal of this protocol is to describe the synthesis of two novel biocomposites with high-aspect ratio structures. The biocomposites consist of copper ...

Automated Robotic Liquid Handling Assembly of Modular DNA Devices

Recent advances in modular DNA assembly techniques have enabled synthetic biologists to test significantly more of the available &#34;design space&#34; represented by &#34;devices&#34; created as combinations of individual genetic components. However, manual assembly of such large numbers of devices is time-intensive, error-prone, and costly. The increasing sophistication and scale of synthetic biology research necessitates an efficient, reproducible way to accommodate large-scale, complex, and high throughput device construction.
Here, a DNA assembly protocol using the Type-IIS restriction endonuclease based Modular Cloning (MoClo) technique is automated on two liquid-handling robotic platforms. Automated liquid-handling robots require careful, often times tedious optimization of pipetting parameters for liquids of different viscosities (e.g. enzymes, DNA, water, buffers), as well as explicit programming to ensure correct aspiration and dispensing of DNA parts and reagents. This makes manual script writing for complex assemblies just as problematic as manual DNA assembly, and necessitates a software tool that can automate script generation. To this end, we have developed a web-based software tool, http://mocloassembly.com, for generating combinatorial DNA device libraries from basic DNA parts uploaded as Genbank files. We provide access to the tool, and an export file from our liquid handler software which includes optimized liquid classes, labware parameters, and deck layout. All DNA parts used are available through Addgene, and their digital maps can be accessed via the Boston University BDC ICE Registry. Together, these elements provide a foundation for other organizations to automate modular cloning experiments and similar protocols.
The automated DNA assembly workflow presented here enables the repeatable, automated, high-throughput production of DNA devices, and reduces the risk of human error arising from repetitive manual pipetting. Sequencing data show the automated DNA assembly reactions generated from this workflow are ~95% correct and require as little as 4% as much hands-on time, compared to manual reaction preparation.

Here, an automated workflow to perform modular DNA &#34;device&#34; assembly using a modular cloning DNA assembly method on liquid-handling robots is presented. The protocol uses an intuitive software tool for generating liquid handler picklists for combinatorial DNA device library generation, which we demonstrate using two liquid handling platforms.

Recent advances in modular DNA assembly techniques have enabled synthetic biologists to test significantly more of the available &#34;design space&#34; ...

Synthesis of Biocompatible Liquid Crystal Elastomer Foams as Cell Scaffolds for 3D Spatial Cell Cultures

Here, we present a step-by-step preparation of a 3D, biodegradable, foam-like cell scaffold. These scaffolds were prepared by cross-linking star block co-polymers featuring cholesterol units as side-chain pendant groups, resulting in smectic-A (SmA) liquid crystal elastomers (LCEs). Foam-like scaffolds, prepared using metal templates, feature interconnected microchannels, making them suitable as 3D cell culture scaffolds. The combined properties of the regular structure of the metal foam and of the elastomer result in a 3D cell scaffold that promotes not only higher cell proliferation compared to conventional porous templated films, but also better management of mass transport (i.e., nutrients, gases, waste, etc.). The nature of the metal template allows for the easy manipulation of foam shapes (i.e., rolls or films) and for the preparation of scaffolds of different pore sizes for different cell studies while preserving the interconnected porous nature of the template. The etching process does not affect the chemistry of the elastomers, preserving their biocompatible and biodegradable nature. We show that these smectic LCEs, when grown for extensive time periods, enable the study of clinically relevant and complex tissue constructs while promoting the growth and proliferation of cells.

This study presents a methodology to prepare 3D, biodegradable, foam-like cell scaffolds based on biocompatible side-chain liquid crystal elastomers (LCEs). Confocal microscopy experiments show that foam-like LCEs allow for cell attachment, proliferation, and the spontaneous alignment of C2C12s myoblasts.

Here, we present a step-by-step preparation of a 3D, biodegradable, foam-like cell scaffold. These scaffolds were prepared by cross-linking star block ...