Name: increasing cdna yields from single-cell quantities of mrna in standard laboratory reverse transcriptase reactions using acoustic microstreaming
Uploaded: 2011-07-11T13:00:00
Description: Watch this Scientific Journal Video about Increasing cDNA Yields from Single-cell Quantities of mRNA in Standard Laboratory Reverse Transcriptase Reactions using Acoustic Microstreaming at JoVE.com

This study was supported by the National Health and Medical Research Council of Australia (project grant no. 6288480) and the Scobie and Clare MacKinnon Trust.

1. Micromixing an RT Reaction
<ol>
	<li>Before performing an RT reaction with micromixing, equilibrate the micromixer to the desired temperature of the RT reaction.
		<ol>
				<li>Place the micromixer inside a 37&deg;C (or the temperature recommended by 	the RT supplier) incubator for at least 1 hour prior to the onset of the RT 	reaction.</li>
		</ol>
	</li>
	<li>Set up the RT mix according to the reverse transcriptase supplier's (e.g. MMTV-RT from Promega, Omniscript from Qiagen) instructions, except use single-cell ...

<ol>
	<li>Livesey, F. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Brief+Funct+Genomic+Proteomic.">Brief Funct Genomic Proteomic.</a> 2 (1), 31-31 (2003).</li><li>Aumann, T. D., Gantois, I., Egan, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Exp Neurol. 213 (2), 419-419 (2008).</li><li>Ottino, J. M., Wiggins, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Philos Transact A Math Phys Eng Sci. 362 (1818), 923-923 (2004).</li><li>Losey, M. W., Jackman, R. J., Firebaugh, S. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> J Microelectromech. Syst. 11, 709-709 (2002).</li><li>Bontoux, N., Dauphinot, L., Vitalis, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Lab Chip. 8 (3), 443-443 (2008).</li><li>Marcus, J. S., Anderson, W. F., Quake, S. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Anal Chem. 78 (9), 3084-3084 (2006).</li><li>Marcus, J. S., Anderson, W. F., Quake, S. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Anal Chem. 78 (3), 956-956 (2006).</li><li>Warren, L., Bryder, D., Weissman, I. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Proc Natl Acad Sci U S A. 103 (47), 17807-17807 (2006).</li><li>Jiao, Z. J., Huang, X. Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Microfluidics Nanofluidics. 6, 847-847 (2009).</li><li>Ahmed, D., Xiaole, M., Juluri, B. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Microfluidics Nanofluidics. 7, 727-727 (2009).</li><li>Paxton, W. F., O'Hara, M. J., Peper, S. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Anal Chem. 80, 4070-4070 (2008).</li><li>Autom, L. a. b. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> 11, 399-399 (2006).</li><li>Petkovic-Duran, K., Manasseh, R., Zhu, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> 47 (4), 827-827 (2009).</li><li>Boon, W. C., Petkovic-Duran, K., White, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> 50 (2), 116-116 (2011).</li><li>Liu, R. H., Lenigk, R., Druyor-Sanchez, R. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Anal Chem. 75 (8), 1911-1911 (1911).</li><li>Riley, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ann+Rev+Fluid+Mech.">Ann Rev Fluid Mech.</a> 33, 43-43 (2001).</li><li>Whitehill, J., Neild, A., Ng, T. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Applied Physics Letters. 96 (5), 053501-053501 (2010).</li></ol>

The method of application of micromixing to standard laboratory RT reactions described here can, of course, involve mRNA harvested via any method (e.g. cell lysis, laser capture microdissection). It can also comprise any brands or types of RT reagents, any temperature (within the tolerance of the materials of the micromixer), and any period of time. For example, we have observed improved cDNA yields from RT reactions comprising random hexamer or oligo-dT primers. It might also be applied to other biochemical transform...

<table border="1">
	<tbody>
		<tr>
			<th>Name of the reagent	</th>
			<th>Company	</th>
			<th>Catalogue number	</th>
			<th>Comments (optional)</th>
		</tr>
		
		<tr>
			<td>Total RNA was isolated from snap frozen acutely prepared adult mouse midbrain slices</td>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
		</tr>
		
		<tr>
			<td>PicoPure RNA Isolation Kit	</td>
			<td>Arcturus, CA, USA	</td>
			<td>KIT0204	</td>
			<td>The kit is now available from Applied Biosystems</td>
		</tr>
		
		<tr>
			<td>DNA-free DNase Treatment and Removal Reagents	</td>
			<td>Ambion	</td>
			<td>AM1906M</td>
			<td>&nbsp;</td>
		</tr>
		
		<tr>
			<td>Random hexamer primers	</td>
			<td>Promega	</td>
			<td>C1181</td>
			<td>&nbsp;</td>
		</tr>
		
		<tr>
			<td>AMV-RT	</td>
			<td>Promega	</td>
			<td>M5101</td>
			<td>&nbsp;</td>
		</tr>
		
		<tr>
			<td>dNTP set	</td>
			<td>Promega	</td>
			<td>U1240</td>
			<td>&nbsp;</td>
		</tr>
		
		<tr>
			<td>RNasin Ribonuclease Inhibitor	</td>
			<td>Promega	</td>
			<td>N2111</td>
			<td>&nbsp;</td>
		</tr>
		
		<tr>
			<td>Nuclease-Free Water	</td>
			<td>Promega	</td>
			<td>P1193</td>
			<td>&nbsp;</td>
		</tr>
		
		<tr>
			<td>SYBR Green PCR Master Mix	</td>
			<td>Applied Biosystem	</td>
			<td>4309155</td>
			<td>&nbsp;</td>
		</tr>
		
		<tr>
			<td>Hprt forward (20mer):CTT TGC TGA CCT GCT GGA TT</td>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
		</tr>
		
		<tr>
			<td>Hprt reverse (20mer):TAT GTC CCC CGT TGA CTG AT</td>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
		</tr>
		
		<tr>
			<td>Nurr1 forward (23mer):CAG CTC CGA TTT CTT AAC TCC AG</td>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
		</tr>
		
		<tr>
			<td>Nurr1 reverse (23mer):GGT GAG GTC CAT GCT AAA CTT GA</td>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
		</tr>
		
		<tr>
			<td>NanoDrop 1000 Spectrophotometer. </td>
			<td>Thermo Scientific</td>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
		</tr>
		
		<tr>
			<td>Corbett Rotor Gene RG-6000</td>
			<td>Corbett Life Science</td>
			<td>&nbsp;</td>
			<td>Corbett Life Science was acquired by QIAGEN in July 2008</td>
		</tr>
		
	</tbody>
</table>

increasing cdna yields from single-cell quantities of mrna in standard laboratory reverse transcriptase reactions using acoustic microstreaming

Correlating gene expression with cell behavior is ideally done at the single-cell level. However, this is not easily achieved because the small amount of labile mRNA present in a single cell (1-5% of 1-50pg total RNA, or 0.01-2.5pg mRNA, per cell 1) mostly degrades before it can be reverse transcribed into a stable cDNA copy. For example, using standard laboratory reagents and hardware, only a small number of genes can be qualitatively assessed per cell 2. One way to increase the efficiency of standard laboratory reverse transcriptase (RT) reactions (i.e. standard reagents in microliter volumes) comprising single-cell amounts of mRNA would be to more rapidly mix the reagents so the mRNA can be converted to cDNA before it degrades. However this is not trivial because at microliter scales liquid flow is laminar, i.e. currently available methods of mixing (i.e. shaking, vortexing and trituration) fail to produce sufficient chaotic motion to effectively mix reagents. To solve this problem, micro-scale mixing techniques have to be used 3,4. A number of microfluidic-based mixing technologies have been developed which successfully increase RT reaction yields 5-8. However, microfluidics technologies require specialized hardware that is relatively expensive and not yet widely available. A cheaper, more convenient solution is desirable. The main objective of this study is to demonstrate how application of a novel "micromixing" technique to standard laboratory RT reactions comprising single-cell quantities of mRNA significantly increases their cDNA yields. We find cDNA yields increase by approximately 10-100-fold, which enables: (1) greater numbers of genes to be analyzed per cell; (2) more quantitative analysis of gene expression; and (3) better detection of low-abundance genes in single cells. The micromixing is based on acoustic microstreaming 9-12, a phenomenon where sound waves propagating around a small obstacle create a mean flow near the obstacle. We have developed an acoustic microstreaming-based device ("micromixer") with a key simplification; acoustic microstreaming can be achieved at audio frequencies by ensuring the system has a liquid-air interface with a small radius of curvature 13. The meniscus of a microliter volume of solution in a tube provides an appropriately small radius of curvature. The use of audio frequencies means that the hardware can be inexpensive and versatile 13, and nucleic acids and other biochemical reagents are not damaged like they can be with standard laboratory sonicators.

Watch this Scientific Journal Video about Increasing cDNA Yields from Single-cell Quantities of mRNA in Standard Laboratory Reverse Transcriptase Reactions using Acoustic Microstreaming at JoVE.com

Increasing cDNA Yields from Single-cell Quantities of mRNA in Standard Laboratory Reverse Transcriptase Reactions using Acoustic Microstreaming

We describe a novel method for increasing cDNA yield from single-cell quantities of mRNA in otherwise standard laboratory reverse transcription reactions. The novelty resides in the use of a micromixer, which utilizes the phenomenon of acoustic microstreaming, to mix fluids at microliter scales more effectively than shaking, vortexing or trituration.

Correlating gene expression with cell behavior is ideally done at the single-cell level.  However, this is not easily achieved because the small amount of ...

increasing-cdna-yields-from-single-cell-quantities-mrna-standard

Research

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Bioengineering

Creating Transient Cell Membrane Pores Using a Standard Inkjet Printer

Bioprinting has a wide range of applications and significance, including tissue engineering, direct cell application therapies, and biosensor microfabrication.1-10 Recently, thermal inkjet printing has also been used for gene transfection.8,9 The thermal inkjet printing process was shown to temporarily disrupt the cell membranes without affecting cell viability. The transient pores in the membrane can be used to introduce molecules, which would otherwise be too large to pass through the membrane, into the cell cytoplasm.8,9,11
The application being demonstrated here is the use of thermal inkjet printing for the incorporation of fluorescently labeled g-actin monomers into cells. The advantage of using thermal ink-jet printing to inject molecules into cells is that the technique is relatively benign to cells.8, 12 Cell viability after printing has been shown to be similar to standard cell plating methods1,8. In addition, inkjet printing can process thousands of cells in minutes, which is much faster than manual microinjection. The pores created by printing have been shown to close within about two hours. However, there is a limit to the size of the pore created (~10 nm) with this printing technique, which limits the technique to injecting cells with small proteins and/or particles. 8,9,11
A standard HP DeskJet 500 printer was modified to allow for cell printing.3, 5, 8 The cover of the printer was removed and the paper feed mechanism was bypassed using a mechanical lever. A stage was created to allow for placement of microscope slides and coverslips directly under the print head. Ink cartridges were opened, the ink was removed and they were cleaned prior to use with cells. The printing pattern was created using standard drawing software, which then controlled the printer through a simple print command. 3T3 fibroblasts were grown to confluence, trypsinized, and then resuspended into phosphate buffered saline with soluble fluorescently labeled g-actin monomers. The cell suspension was pipetted into the ink cartridge and lines of cells were printed onto glass microscope cover slips. The live cells were imaged using fluorescence microscopy and actin was found throughout the cytoplasm. Incorporation of fluorescent actin into the cell allows for imaging of short-time cytoskeletal dynamics and is useful for a wide range of applications.13-15

A description of the methods used to convert an HP DeskJet 500 printer into a bioprinter. The printer is capable of processing living cells, which causes transient pores in the membrane. These pores can be utilized to incorporate small molecules, including fluorescent G-actin, into the printed cells.

Bioprinting has a wide range of applications and significance, including tissue engineering, direct cell application therapies, and biosensor ...

A Label-free Technique for the Spatio-temporal Imaging of Single Cell Secretions

Inter-cellular communication is an integral part of a complex system that helps in maintaining basic cellular activities. As a result, the malfunctioning of such signaling can lead to many disorders. To understand cell-to-cell signaling, it is essential to study the spatial and temporal nature of the secreted molecules from the cell without disturbing the local environment. Various assays have been developed to study protein secretion, however, these methods are typically based on fluorescent probes which disrupt the relevant signaling pathways. To overcome this limitation, a label-free technique is required.
In this paper, we describe the fabrication and application of a label-free localized surface plasmon resonance imaging (LSPRi) technology capable of detecting protein secretions from a single cell. The plasmonic nanostructures are lithographically patterned onto a standard glass coverslip and can be excited using visible light on commercially available light microscopes. Only a small fraction of the coverslip is covered by the nanostructures and hence this technique is well suited for combining common techniques such as fluorescence and bright-field imaging.
A multidisciplinary approach is used in this protocol which incorporates sensor nanofabrication and subsequent biofunctionalization, binding kinetics characterization of ligand and analyte, the integration of the chip and live cells, and the analysis of the measured signal. As a whole, this technology enables a general label-free approach towards mapping cellular secretions and correlating them with the responses of nearby cells.

Inter-cellular communication is critical for controlling various physiological activities within and outside the cell. This paper describes a protocol for measuring the spatio-temporal nature of single cell secretions. To achieve this, a multidisciplinary approach is used which integrates label-free nanoplasmonic sensing with live cell imaging.

Inter-cellular communication is an integral part of a complex system that helps in maintaining basic cellular activities. As a result, the malfunctioning ...

An Ultrahigh-throughput Microfluidic Platform for Single-cell Genome Sequencing

Sequencing technologies have undergone a paradigm shift from bulk to single-cell resolution in response to an evolving understanding of the role of cellular heterogeneity in biological systems. However, single-cell sequencing of large populations has been hampered by limitations in processing genomes for sequencing. In this paper, we describe a method for single-cell genome sequencing (SiC-seq) which uses droplet microfluidics to isolate, amplify, and barcode the genomes of single cells. Cell encapsulation in microgels allows the compartmentalized purification and tagmentation of DNA, while a microfluidic merger efficiently pairs each genome with a unique single-cell oligonucleotide barcode, allowing &gt;50,000 single cells to be sequenced per run. The sequencing data is demultiplexed by barcode, generating groups of reads originating from single cells. As a high-throughput and low-bias method of single-cell sequencing, SiC-seq will enable a broader range of genomic studies targeted at diverse cell populations.

Single-cell sequencing reveals genotypic heterogeneity in biological systems, but current technologies lack the throughput necessary for the deep profiling of community composition and function. Here, we describe a microfluidic workflow for sequencing &gt;50,000 single-cell genomes from diverse cell populations.

Sequencing technologies have undergone a paradigm shift from bulk to single-cell resolution in response to an evolving understanding of the role of ...

A Converging Strategy for the Generation of a Virtually Sequenced cDNA Library from Unreferenced Pacific Oysters

The access to biological material of reference species, which were used previously in key experiments such as in the development of novel cell lines or genome sequencing projects, are often difficult to provide for further studies or third parties due to the consumptive nature of the samples. Although now widely distributed over the Pacific coasts of Asia, Australia and North America, individual Pacific oyster specimens are genetically quite diverse and are therefore not directly suitable as the starting material for gene libraries. In this article, we demonstrate the use of unreferenced Pacific oyster specimens obtained from regional seafood markets to generate cDNA libraries. These libraries were then compared to the publicly available oyster genome, and the closest related library was selected using the mitochondrial reference genes Cytochrome C Oxidase subunit I (COX1) and NADH Dehydrogenase (ND). The suitability of the generated cDNA library is also demonstrated by cloning and expression of two genes encoding the enzymes UDP-glucuronic acid dehydrogenase (UGD) and UDP-xylose synthase (UXS), which are responsible for the biosynthesis of UDP-xylose from UDP-glucose.

We describe a strategy for how to use RNA samples from unreferenced Pacific oyster specimens, and evaluate the genetic material by comparison with publicly available genome data to generate a virtually sequenced cDNA library.

The access to biological material of reference species, which were used previously in key experiments such as in the development of novel cell lines or ...

Establishing Single-Cell Based Co-Cultures in a Deterministic Manner with a Microfluidic Chip

Cell co-culture assays have been widely used for studying cell-cell interactions between different cell types to better understand the biology of diseases including cancer. However, it is challenging to clarify the complex mechanism of intercellular interactions in highly heterogeneous cell populations using conventional co-culture systems because the heterogeneity of the cell subpopulation is obscured by the average values; the conventional co-culture systems can only be used to describe the population signal, but are incapable of tracking individual cells behavior. Furthermore, conventional single-cell experimental methods have low efficiency in cell manipulation because of the Poisson distribution. Microfabricated devices are an emerging technology for single-cell studies because they can accurately manipulate single cells at high-throughput and can reduce sample and reagent consumption. Here, we describe the concept and application of a microfluidic chip for multiple single-cell co-cultures. The chip can efficiently capture multiple types of single cells in a culture chamber (~46%) and has a sufficient culture space useful to study the cells&#39; behavior (e.g., migration, proliferation, etc.) under cell-cell interaction at the single-cell level. Lymphatic endothelial cells and oral squamous cell carcinoma were used to perform a single-cell co-culture experiment on the microfluidic platform for live multiple single-cell interaction studies.

This report describes a microfluidic chip-based method to set up a single cell culture experiment in which high-efficiency pairing and microscopic analysis of multiple single cells can be achieved.

Cell co-culture assays have been widely used for studying cell-cell interactions between different cell types to better understand the biology of diseases ...

Increasing Durability of Dissociated Neural Cell Cultures Using Biologically Active Coralline Matrix

Cultures of dissociated hippocampal neuronal and glial cells are a valuable experimental model for studying neural growth and function by providing high cell isolation and a controlled environment. However, the survival of hippocampal cells in vitro is compromised: most cells die during the first week of culture. It is therefore of great importance to identify ways to increase the durability of neural cells in culture.
Calcium carbonate in the form of crystalline aragonite derived from the skeleton of corals can be used as a superior, active matrix for neural cultures. By nurturing, protecting, and activating glial cells, the coral skeleton enhances the survival and growth of these cells in vitro better than other matrices.
This protocol describes a method for cultivating hippocampal cells on a coralline matrix. This matrix is generated by attaching grains of coral skeletons to culture dishes, flasks, and glass coverslips. The grains assist in improving the environment of the cells by introducing them to a fine three-dimensional (3D) environment to grow on and to form tissue-like structures. The 3D environment introduced by the coral skeleton can be optimized for the cells by grinding, which enables control over the size and density of the grains (i.e., the matrix roughness), a property that has been found to influence glial cells activity. Moreover, the use of grains makes the observation and analysis of the cultures easier, especially when using light microscopy. Hence, the protocol includes procedures for generation and optimization of the coralline matrix as a tool to improve the maintenance and functionality of neural cells in vitro.

Dissociated hippocampal cell culture is a pivotal experimental tool in neuroscience. Neural cell survival and function in culture is enhanced when coralline skeletons are used as matrices, due to their neuroprotective and neuromodulative roles. Hence, neural cells grown on coralline matrix show higher durability, and thereby are more adequate for culturing.

Cultures of dissociated hippocampal neuronal and glial cells are a valuable experimental model for studying neural growth and function by providing high ...

Primary Clarification of CHO Harvested Cell Culture Fluid using an Acoustic Separator

Primary clarification is an essential step in a biomanufacturing process for the initial removal of cells from therapeutic products within the harvested cell culture fluid. While traditional methods like centrifugation or filtration are widely implemented for cell removal, the equipment for these processes have large footprints and operation can involve contamination risks and filter fouling. Additionally, traditional methods may not be ideal for continuous bioprocessing schemes for primary clarification. Thus, an alternate application using acoustic (sound) waves was investigated to continuously separate cells from the cell culture fluid. Presented in this study is a detailed protocol for using a bench-scale acoustic wave separator (AWS) for the primary separation of culture fluid containing a monoclonal IgG1 antibody from a CHO cell bioreactor harvest. Representative data are presented from the AWS and demonstrate how to achieve effective cell clarification and product recovery. Finally, potential applications for AWS in continuous bioprocessing are discussed. Overall, this study provides a practical and general protocol for the implementation of AWS in primary clarification for CHO cell cultures and further describes its application potential in continuous bioprocessing.

Presented here is a protocol for the primary clarification of CHO cell culture using an acoustic separator. This protocol can be used for the primary clarification of shake flask cultures or bioreactor harvests and has the potential application for continuous clarification of the cell bleed material during perfusion bioreactor operations.

Primary clarification is an essential step in a biomanufacturing process for the initial removal of cells from therapeutic products within the harvested ...

Standard Test Method ASTM D 7998-19 for the Cohesive Strength Development of Wood Adhesives

The properties of cured wood adhesives are difficult to study because of the loss of water and other components to the wood, the influence of wood on the adhesive cure, and the effect of adhesive penetration on the wood interphase; thus, normal testing of a neat adhesive film is generally not useful. Most tests of wood adhesive bond strength are slow, laborious, can be strongly influenced by the wood and do not provide information on the kinetics of cure. Test method ASTM D 7998-19, however, can be used for fast evaluation of the strength of wood bonds. The use of a smooth, uniform, and strong wood surface, like maple face-veneer, and sufficient bonding pressure reduces the adhesion and wood strength effects on bond strength. This method has three main applications. The first is to provide consistent data on bond strength development. The second is to measure the dry and wet strengths of bonded lap shear samples. The third is to better understand the adhesive heat resistance by quickly evaluating thermal sensitivity and distinguishing between thermal softening and thermal degradation.

We present a procedure, ASTM D7998-19, for a rapid and more consistent evaluation of both dry and wet strength of adhesive bonds on wood. The method can also be used to provide information on strength development as a function of temperature and time or strength retention up to 250 &#176;C.

The properties of cured wood adhesives are difficult to study because of the loss of water and other components to the wood, the influence of wood on the ...

Magnetic-, Acoustic-, and Optical-Triple-Responsive Microbubbles for Magnetic Hyperthermia and Pothotothermal Combination Cancer Therapy

The precision delivery of anti-cancer agents which aim for targeted and deep-penetrated delivery as well as a controlled release at the tumor site has been challenged. Here, we fabricate iron oxide nanoparticle shelled microbubbles (NSMs) through self-assembly, synergizing magnetic, acoustic, and optical responsiveness in one nanotherapeutic platform. Iron oxide nanoparticles serve as both magnetic and photothermal agents. Once intravenously injected, NSMs can be magnetically guided to the tumor site. Ultrasound triggers the release of iron oxide nanoparticles, facilitating the penetration of nanoparticles deep into the tumor due to the cavitation effect of microbubbles. Thereafter, magnetic hyperthermia and photothermal therapy can be performed on the tumor for combinational cancer therapy, a solution for cancer resistance due to the tumor heterogeneity. In this protocol, the synthesis and characterization of NSMs including structural, chemical, magnetic and acoustic properties were performed. In addition, the anti-cancer efficacy by thermal therapy was investigated using in vitro cell cultures. The proposed delivery strategy and combination therapy holds great promise in cancer treatment to improve both delivery and anticancer efficacies.

Presented here is a protocol for the fabrication of iron oxide nanoparticle-shelled microbubbles (NSMs) through self-assembly, synergizing magnetic, acoustic, and optical responsiveness in one nanotherapeutic platform for magnetic hyperthermia and photothermal combination cancer therapy.

The precision delivery of anti-cancer agents which aim for targeted and deep-penetrated delivery as well as a controlled release at the tumor site has ...

Single-Cell Optical Action Potential Measurement in Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes

Conventional intracellular microelectrode techniques to quantify cardiomyocyte electrophysiology are extremely complex, labor intensive, and typically carried out in low throughput. Rapid and ongoing expansion of induced pluripotent stem cell (iPSC) technology presents a new standard in cardiovascular research and alternate methods are now necessary to increase throughput of electrophysiological data at a single cell level. VF2.1Cl is a recently derived voltage sensitive dye which provides a rapid single channel, high magnitude response to fluctuations in membrane potential. It possesses kinetics superior to those of other existing voltage indicators and makes available functional data equivalent to that of traditional microelectrode techniques. Here, we demonstrate simplified, non-invasive action potential characterization in externally paced human iPSC derived cardiomyocytes using a modular and highly affordable photometry system.

Here we describe optical acquisition and characterization of action potentials from induced pluripotent stem cell derived cardiomyocytes using a high-speed modular photometry system.

Conventional intracellular microelectrode techniques to quantify cardiomyocyte electrophysiology are extremely complex, labor intensive, and typically ...