Assay Techniques

In this video, we demonstrate an assay to establish the presence of phospholipase in the crude venom extract from Anthopleura dowii—a marine sea anemone. The assay utilizes an agarose gel diffusion technique, in which the enzyme phospholipase diffuses and breaks down phospholipids incorporated in the solid media in a radial manner.

In this video, we describe a cell chirality assay to determine the alignment bias of cells in a confined geometric boundary such as a ring micropattern. Chirality is an inherent property of most cell types and is determined by genetic and environmental factors. Knowing the chirality of a normal cell population can help to screen drug-treated cells.

This video describes a colorimetric assay to measure the mitochondrial citrate synthase activity assay present in the tissue homogenate of Drosophila.

In this video, we describe a colorimetric-based method to determine non-heme iron content in mouse liver tissue. Bathophenanthroline sulfonate is used as the chromogenic substrate in the presence of a reducing agent, which converts ferric iron to chelatable ferrous iron.

This video demonstrates a quantification technique for CO2 released during substrate oxidation using 14C-radiolabeled substrates. The released 14CO2 is trapped in an alkaline solution and quantified by a scintillation counter. The oxidation of different substrates varies between tissues and reflects the pathophysiological condition of the tissue.

In this video, we demonstrate a procedure to investigate septin organization on a glass-supported lipid bilayer in vitro using total internal reflection fluorescence microscopy.

This video describes the technique of studying the septin protein assembly on microspheres coated with lipid bilayers. This technique helps in understanding the curvature-dependent assemblies of protein on curved surfaces.

In this video, we demonstrate a screening assay to identify the efficacy of small-molecule nematicides against nematodes. Nematicides are considered effective if they cause a decrease in the number of mobile nematodes in the sample after exposure.

In this video, we describe a method for the detection of osteoblast-secreted calcium deposits using an anionic dye, Alizarin Red S. The cultured osteoblasts are first stained and then the dye is recovered for colorimetric quantification of calcium deposits or the degree of osteoblast mineralization.

In this video, we describe the larval contact assay to evaluate the toxicity of the dopamine receptor antagonist amitriptyline on the third instar stage larvae of mosquitoes, known vectors of several human infectious diseases. Assessing the larval mortality upon incubation with different amitriptyline concentrations over different time intervals helps determine its lethal concentration 50.

In this video, we demonstrate the topical testing assay to determine the toxicity of a potential insecticide on adult female mosquitoes. Using a dopamine receptor antagonist that causes lethal inhibition of neurotransmission in mosquitoes, this method describes a way to evaluate the toxic effects of insecticides upon topical application.

This video demonstrates a blood-feeding assay to evaluate the mortality and fecundity of test compounds with novel modes of action on female mosquitoes. This technique helps in screening new classes of insecticides to kill the resistant population of mosquitoes and control disease spread.

In this video, we demonstrate a cell-based protein aggregation assay using proteasome inhibitors, which block proteasome activity, preventing misfolded, mutant proteins, fused to a fluorescent label, from undergoing ubiquitin-dependent proteasomal degradation, leading to their accumulation within the cell cytoplasm. The protein aggregates are then visualized and quantified by fluorescence microscopy.

This video demonstrates a rapid bioassay for investigating endotoxin activity in a whole blood sample via a chemiluminescence-based method. This assay is a rapid and sensitive biomarker test for early-stage diagnosis of endotoxin-mediated sepsis.

This video describes the turbidimetric format of the Limulus amoebocyte lysate, or LAL, assay to estimate endotoxin contamination in PEGylated liposomal doxorubicin nano-formulations. The turbidity of the solution following the reaction of the endotoxin with the LAL reagent helps to estimate the endotoxin in the sample.

This video describes a gel-clot assay to determine the presence of bacterial endotoxins in nano-formulations using Limulus Amoebocyte Lysate derived from the blood cells of horseshoe crabs. The assay helps test for endotoxin contamination of pharmaceutical products, including nano-based formulations.

In this video, we demonstrate a high throughput assay for carbohydrate-active enzyme screening using insoluble chromogenic polymer hydrogel substrates. The enzyme degrades these substrates into a soluble colored product that can be quantified by measuring the color intensity of the product.

This video demonstrates an assay to screen enzymes effective in degrading complex polysaccharides in plant biomass using insoluble chromogenic biomass or ICB. The enzymes hydrolyze ICB to release soluble dye-linked oligosaccharides, and the enzyme activity is assessed by colorimetric analysis of the reaction product.

This video demonstrates a nuclear staining method to detect the cytotoxic effect of mitocan on drug-sensitive cancer cells and healthy variants. The double staining with DNA-binding dyes such as propidium iodide and Hoechst dye provides a clear distinction between the dead and live cells, thus helping to assess the cytotoxicity of the drug.

In this video, we perform an in vitro motility assay to analyze the actin-myosin interactions. The gliding movement of actin filaments on immobilized myosin molecules is visualized using fluorescence microscopy.

In this video, we perform an in vitro motility assay to analyze the actin-myosin interactions. The gliding movement of actin filaments on immobilized myosin molecules is visualized using fluorescence microscopy.

This video demonstrates the differential radial capillary action of ligand assay — a technique for systematic high-throughput screening of intracellular nucleotide second messenger-binding proteins. This technique allows for direct binding of the messengers to the overexpressed target protein in the cell lysate — bypassing the need for protein purification.

This video describes a degradation assay for misfolded proteins using cycloheximide treatment along with detergent fractionation. This method aids in studying the dynamics of misfolded proteins and uncovering the in-depth mechanisms of protein turnover.

This video describes an in vitro fluorescence-based microplate assay to study the degradation kinetics of a fluorescently-labeled misfolded luciferase mutant protein expressed in the nuclei of transfected mammalian cells. The assay involves the treatment of cells expressing the fluorescent mutant protein with a translation inhibitor and a proteasome inhibitor to assess the proteasome-mediated degradation of the misfolded protein.

The video demonstrates the luciferase assay used to quantify luciferase-tagged proteins. The assay uses an engineered luciferase enzyme composed of a large fragment that binds with the small fragment, which is conjugated with a protein of interest. The bound subunits form an active enzyme that, in the presence of the substrate, releases a luminescent signal. This signal is then quantified using a luminometer.

This video demonstrates an in vivo imaging-based assay to determine proteostasis decline due to aging. The assay uses Caenorhabditis elegans expressing polyglutamine YFP-fusion protein in body wall muscles to measure the age-associated aggregation of polyglutamine and induction of proteotoxicity, leading to paralysis.

In this video, we demonstrate the amplified luminescent proximity homogeneous assay—a bead-based proximity assay. It utilizes homogeneously-sized acceptor and donor beads, immobilized with two proteins that tend to interact to screen potential small molecules inhibiting protein interactions.

This video demonstrates an assay to monitor gut acidification in Drosophila flies. After the ingestion of food supplemented with a pH indicator dye, the acidification of the intestinal lumen results in a change in the color of the dye. Visual inspection of the digestive tract of the flies to examine the color change provides evidence of acidification.

This video describes a plate reader-based assay to measure mitochondrial calcium uptake in isolated mitochondria. The assay analyzes the fluorescence signal of a calcium-sensitive fluorescent dye to study the kinetics of mitochondrial calcium uptake and calcium overload.

This video describes a colorimetric method to quantify the soluble protein content in plant tissues. The method uses Coomassie Brilliant Blue G-250 dye, which interacts with the soluble protein to form a blue-colored stable protein-dye complex, proportional to the soluble protein content in the tissue.

This video describes the method to quantify the digestible carbohydrates present in plant tissues. This helps to collect data from various plant tissues to study nutritional ecology, plant-herbivore interactions, and food-web dynamics.

In this video, we demonstrate the luciferase assay to quantify the growth of the intracellular pathogen Toxoplasma gondii. Utilizing a strain of Toxoplasma that expresses luciferase enzyme after infecting the host cells, the luciferase activity is detected in the infected cell culture to determine the successful reproduction of the parasite.

The video demonstrates the luciferase assay used to determine the efficacy of an antiparasitic chemical inhibitor against the intracellular pathogen Toxoplasma gondii. The study involves luciferase-expressing parasites invading the host cells to replicate and survive. The chemical inhibitor binds with the cysteine proteases of the parasite and inhibits replication. The luciferase activity detected is proportional to the fold changes in parasite growth, determining the drug's efficacy against...

This video demonstrates an in vitro protocol to study the Msp1-mediated removal of mislocalized TA proteins integrated into the lipid bilayer of liposomes. Msp1 and TA proteins are co-reconstituted into liposomes, and the ATP-dependent translocation of TA proteins is confirmed through affinity purification.

In this video, we describe a simple and robust method to determine the cytotoxic potential of a trypanocidal drug against a parasite, Trypanosoma cruzi, expressing the β-galactosidase enzyme. β-galactosidase serves as a cell lysis indicator, and its activity can be used to assess the effects of the drug.

In this video, we demonstrate an assay that investigates monoamine release mechanisms from the neurons of metabolically active ex vivo rat brain slices, when treated with test drugs. The assay demonstrates that neurostimulant drugs induce monoamine release via the cellular monoamine transporters, whereas high KCl concentration induces synaptic vesicle exocytosis-mediated vesicular monoamine release.

This video describes an in vivo method to screen the protective potential of neuroprotective test compounds in reducing polyQ aggregation in body wall muscle cells of nematodes and ameliorating aggregation-associated proteotoxicity.

In this video, we describe a method to evaluate the neuroprotective effect of a test compound, astragalan, on neuronal survival in Caenorhabditis elegans from polyQ-mediated neurotoxicity. The assay uses Caenorhabditis elegans expressing the abnormally expanded polyQ repeats fused to GFP in their ASH neurons to measure neuronal survival following test compound treatment.

This video describes an osmotic avoidance assay to examine chemoavoidance behavior in a transgenic worm model. Avoidance behavior is tested in a plate in the presence of a high-osmotic barrier and chemoattractant. The worms with a functional loss of neurons get attracted by the chemoattractant, cross the high-osmotic barrier, and become paralyzed in the trap zone because of the anesthetic solution.

This video describes a colorimetric assay for lactate measurement in cell lysates by using the lactate dehydrogenase enzyme. This enzyme converts lactate into pyruvate, along with the conversion of NAD to NADH that reacts with tetrazolium dyes and gives a colored product that can be measured spectrophotometrically to quantitate the lactate.

This video describes a colorimetric assay for quantitatively measuring pyruvate in the cellular fractions of Caenorhabditis elegans. Utilizing the hydrogen peroxide produced from the enzymatic reaction of pyruvate oxidase with cellular pyruvate, a chromogenic dye is oxidized to produce a colored product, measured using colorimetry to determine the pyruvate concentration.

This video describes a spectrophotometric assay for the estimation of glycogen synthase activity. The method relies on the reduction in the absorbance of NADH with time and indicates glycogen synthase activity.

In this video, we describe a qualitative spectrophotometric assay to determine the extent of branching in a glycogen sample with an uncharacterized structure. Comparing the absorbance maxima of the uncharacterized sample with that of polysaccharides with known branched structures indicates the presence of branching in the uncharacterized sample.

This video demonstrates the thiobarbituric acid reactive substances (TBARS) assay to assess oxidative stress in biological samples.

This video demonstrates the split luciferase complementation assay to detect protein-protein interactions. In this assay, the proteins of interest are tagged to small and large fragments of the luciferase enzyme. When the proteins interact, the large and small fragments combine to form an active enzyme complex, which in the presence of a specific substrate, releases bright luminescence that can be measured.

Source:Alessia J. Marchesan1, Guillermo Hernandez Ramirez11Renewable Resources, University of Alberta. This video demonstrates the technique for collecting a soil sample for hydraulic property analysis. The sampling area is cleared, and the top crust is evacuated. The sampling ring is then placed into the soil to collect the sample. The ring with the sample is then cleaned, labeled, packed, and transferred undisturbed for analysis.

Source: Léa Rubira1, Hélène Sturer1, Louise Combette1, Sandra Santini1, Stéphane Renaud1, Cyril Fersing1,21Nuclear medicine department, Institut régional du Cancer de Montpellier (ICM), Univ Montpellier, 2IBMM, Univ Montpellier, CNRS, ENSCMThis video demonstrates the safe, controlled infusion of a radiopharmaceutical using a peristaltic pump with a dual-line cassette system. The setup includes connecting saline and infusion lines, positioning the shielded vial, and initiating simultaneous...

Source:Anthony J. Yosick1,2, Christine Massie1, Emma Knapp2, Hani A. Awad1,2,31Department of Biomedical Engineering, University of Rochester, US2Center for Musculoskeletal Research, Department of Orthopedics, University of Rochester Medical Center, USA3Department of Orthopedics, University of Rochester Medical Center, USAThe video demonstrates fall-related wrist fractures using human cadaver forearms with varying bone densities. Specimens are standardized by removing upper soft tissue,...

In this video, we demonstrate an assay to visualize and quantify the cellular uptake of extracellular vesicles or EVs. This assay utilizes 3D fluorescent imaging using a confocal microscope and allows for distinguishing internalized EVs from ones adhered to the cell surface.

This video describes an invasion assay using a three-chambered array based on electrical impedance. This technique measures the invasive potential of cancer cells under the influence of soluble factors secreted by the resident stromal cells in tumor microenvironments.

In this video, we demonstrate a lysostaphin-based in vitro enzyme protection assay to quantify the Staphylococcus aureus internalization in A549 cells. The assay helps in qualitative, quantitative, and characterization studies of the intracellular bacterial load in the host cells.

In this video, we describe an in vitro osteoclastic resorption assay on calcium phosphate-coated cell culture plates cultured with human peripheral blood mononuclear cell-derived osteoclasts. The osteoclasts form a characteristic actin ring on the calcium phosphate-coated matrix of the cell culture plate and degrade the matrix within the actin ring region to release calcium and phosphate ions, resulting in the formation of distinct resorption pits within the degraded matrix.

In this video, we describe a phase separation assay, wherein intracellular proteins comprising intrinsically disordered regions fused to a photosensitive oligomerization domain are induced via blue-light exposure to self-associate into membrane-less liquid-like condensates.

This video demonstrates a modified microcarrier beads-based assay incorporating pericytes to study endothelial sprouting during the early stages of angiogenesis. The assay provides an in vitro experimental model to understand molecular mechanisms of angiogenesis and the effect of anti-angiogenetic therapeutics.

This video describes an in vitro assay to determine calcium-ionophore-induced hemolysis or lysis of red blood cells in a human sample. The assay measures the percentage of hemolysis by quantifying hemoglobin released from ruptured erythrocytes.

In this video, we demonstrate the Annexin V binding assay to measure the degree of eryptosis, erythrocyte programmed cell death, using fluorescent Annexin V staining. Apoptotic erythrocytes demonstrate phosphatidylserine translocation from the inner to the outer leaflet of the cell membrane, causing the fluorophore-tagged Annexin V to bind to the translocated phosphatidylserine, thereby emitting a fluorescent signal.

This video demonstrates an in vitro technique to assess iron bioavailability in complex food sources. The technique combines the simulation of human digestion along with iron uptake by differentiated Caco-2 cells. Intracellular ferritin formation acts as a marker for cellular iron uptake.

This video demonstrates an in vitro assay to indirectly measure intracellular glucose uptake. The assay uses a fluorescently-labeled glucose analog to establish a correlation between extracellular glucose depletion and intracellular glucose uptake.

In this video, we demonstrate an ex vivo technique to measure extracellular glucose analog depletion in harvested mouse organs. It involves incubating the mouse tissue in a solution containing fluorescently-labeled deoxyglucose, which is taken up by the cells. The glucose analog uptake can be indirectly determined by measuring the fluorescence of the incubated medium.

This video describes the measurement of aortic smooth muscle cell (SMC) contraction using electrical cell-substrate impedance sensing, or ECIS. ECIS measures the locomotion of cells and is a reliable method for measuring contractions.

In this video, we describe an in vitro method to evaluate the allergic potential of an antigen to induce basophil degranulation. β-hexosaminidase is used as an index of chemical mediator release, and the enzyme activity of β-hexosaminidase is measured using a fluorogenic substrate.

In this video, we demonstrate a rapid, single-addition assay to assess cell viability in patient-derived organoids upon treatment with a test agent using intracellular ATP levels as a marker for cellular metabolic activity. The intracellular ATP levels are measured using the luciferase/luciferin reaction, where the emitted light intensity indicates the cellular viability and, in turn, the test agent's growth-inhibitory potency.

This video describes the technique of visualizing oxidative stress in cultured organoids. This work helps in understanding the level of oxidative stress due to ROS accumulation in the various cell types present in an organoid after treatment with different ROS modulators.

This video demonstrates a flow cytometry assay to quantify the ROS levels in 3D intestinal organoids obtained from GFP-expressing transgenic mice. This method provides an in vitro experimental model to investigate the efficacy of test compounds on ROS production.

In this video, we demonstrate a method to evaluate the effect of osmolytes on the formation of bacterial persisters. The bacterial cells are first exposed to osmolytes to induce osmotic stress, triggering persister formation, then treated with antibiotics to enumerate the persisters.

This video demonstrates a fluorescence microscopy-based method to study bacterial competition at the single-cell level. This method provides insights into the structure and function of bacterial communities.

This video describes the virus plaque assay of the infectious herpes simplex virus or HSV. The diluted viral particles are inoculated to the monolayer of epithelial cells. Upon incubation, the virus forms plaques and is counted visually to determine the infectious virus titer.

In this video, the TUNEL assay is performed to detect the presence of apoptotic cells in a sample. The study involves using a special DNA polymerase - terminal deoxynucleotidyl transferase - that catalyzes the addition of labeled dUTPs to the 3' terminus of fragmented DNA, which can be observed and identified under a fluorescence microscope.

This video describes an in vitro Caspase-3/7 luminescent assay to quantify cell death or apoptosis. The assay measures luminescence produced following caspase-3/7 cleavage of a pro-luminescent DEVD substrate. The luminescence generated is proportional to caspase-3/7 activity.

This video demonstrates an immunostaining technique to visualize apoptotic cell engulfment in the homogenized embryonic cells of Drosophila melanogaster. This method provides insights into cellular physiology by determining the extent of apoptotic cell engulfment.

In this video, we demonstrate the efferocytosis assay to study the clearance of apoptotic cells using confocal microscopy. Efferocytosis is a multi-step process where apoptotic cells are engulfed by phagocytes and degraded within vesicles called efferosomes. This protocol provides a method to visualize internalized and non-internalized portions of individual apoptotic cells and quantify efferocytosis.

In this video, we demonstrate that in the presence of a phosphodiester inhibitor, the oocyte cell cycle is arrested at prophase-I, during which transcribed mRNAs are stored in the absence of translation. After the release of the inhibitor, oocyte maturation resumes, and the cells enter metaphase. The signal of reporter mRNA fused with the target gene in metaphase-I indicates the activation of translational machinery and protein expression.

This video describes an in vitro fluorometric assay to assess the effects of artificial tear formulations on the cellular metabolic activity of corneal epithelial cells using resazurin-based Alamar blue solution. A non-toxic formulation maintains the cells in a healthy, metabolically active state, facilitating the reduction of resazurin into a highly fluorescent resorufin.

This video describes a confocal microscopy imaging-based assay to measure mitochondrial calcium uptake in cultured cells. The assay uses the calcium-sensitive fluorescent dye Rhod-2/AM to measure the mitochondrial calcium in permeabilized cultured cells.

This video discusses the fluorescence leakage assay to study the interactions of cell-penetrating peptides with cell membranes using cell membrane mimics — large unilamellar vesicles, or LUVs, encapsulated with a fluorescent dye and a quencher.

This video demonstrates an assay technique for assessing the calcification of the aortic valve interstitial cells in vitro. The assay helps to quantify the calcium concentration using the arsenazo III reagent, a calcium-sensitive dye that reacts with calcium ions to form a purple-colored calcium-arsenazo complex.

This video describes the technique for recording the epileptiform activity of rhinal cortex-hippocampus organotypic slices ex vivo using electrophysiology or EEG set-up. This helps to study the dynamics and progression of epileptogenesis and screen potential therapeutic targets to treat epilepsy.

This video describes a non-contact co-culture wound healing assay to evaluate the migratory capacity of murine myoblasts. This helps to understand signal-sending and signal-receiving components of the paracrine non-canonical Wnt signaling interactions in vitro.

The video demonstrates the comet assay for detecting DNA damage following exposure to harmful agents. Under alkaline conditions, the DNA unwinds and denatures, and upon electrophoresis, the undamaged and damaged DNA migrate differently in the agarose gel, forming a comet-shaped structure. The slowly migrating undamaged DNA forms the circular comet head, while the rapidly migrating damaged DNA fragments form the elongated comet tail.

This video demonstrates an in vitro technique for estimating amino acid uptake by bone marrow-derived stromal cells. Na+-dependent amino acid transporters mediate the uptake of radiolabeled amino acids inside the cells, and the cellular uptake is estimated by measuring the radioactivity.

In this video, we demonstrate the process of real-time monitoring of cellular events, including the proliferation of adherent cells, via a cellular impedance assay. Here, the adherent cells act as insulators, restricting the current flow between the electrodes and increasing the impedance.

In this video, we discuss the correlation between the CIT50 and the multiplicity of viral infections. The virus-infected cells display cytopathic effects, causing their death and detachment from the gold microelectrode, which in turn, reduces the impedance.

This video describes a cellular impedance-based technique to study the survival kinetics of viruses that induce cytopathic effects. The method measures the electrical impedance of virus-infected adherent cells pre-treated with saline.

This video demonstrates the development of an ex vivo model of choroidal sprouting to study ocular microvascular angiogenesis. The assay involves culturing mouse eye explants containing the choroid tissue attached to the sclera and retinal pigment epithelium under specific conditions that promote choroidal microvascular sprouting.

This video describes a cell-based reporter assay to determine the estrogenic activity of plant-derived compounds. A compound with estrogen-like activity mimics its binding to estrogen receptors and drives downstream reporter enzyme gene transcription. The reporter enzyme generates bioluminescence in a reaction, indicating the estrogenic activity of the compound.

This video describes the time-resolved Förster resonance energy transfer or TR-FRET assay to determine endogenous protein phosphorylation with the help of donor and acceptor fluorophores tagged on antibodies specific to a test protein. This technique is designed to measure the phosphorylation of test proteins in cell lysates.

In this video, we describe a luminescence-based method to assess the neurotoxicity of neurite outgrowth-promoting small molecule compounds on the viability of hNPC-derived neurons. The assay measures intracellular ATP level, an indicator of cell viability, to evaluate neurotoxicity following test compound treatment.

Source:Piera Lalli1, Elisabetta Quilico1, Chiara Busso1, Marta Andrighetti1, Cristina Graziano1, Paola Pisani2, Marco A. Minetto11Division of Physical Medicine and Rehabilitation, Department of Surgical Sciences, University of Turin.2Institute of Clinical Physiology, National Research Council.This video demonstrates the radiofrequency echographic multi-spectrometry (REMS) technique for assessing bone mineral density (BMD). The patient is positioned supine, and ultrasound gel is applied to the...

Source:Li Xiaoming1, Liu Xiao1, Li Haiyang1, Cai Xiaohua1, Ou Jianping11Center for Reproductive Medicine, The Third Affiliated Hospital of Sun Yat-sen University.This video demonstrates the percutaneous aspiration of epididymal spermatozoa from a patient with azoospermia, a condition characterized by the absence of spermatozoa in the semen. The procedure involves disinfecting the scrotal area, aspirating epididymal fluid using a syringe with a specialized culture solution and processing the...

Source: Elettra Leo1, Luiza H.D. Cardoso1, Sabine Schmitt1, Erich Gnaiger11Oroboros InstrumentsThis video explains how oxygen flux is used to assess mitochondrial respiration in living and permeabilized mammalian cells. It demonstrates the sequential use of digitonin, metabolic substrates, ADP, an uncoupler, and an inhibitor to characterize different respiratory states. The resulting oxygen flux profile reveals mitochondrial function and energy-coupling efficiency under defined conditions.

This video describes an immunoassay technique using fluorescent magnetic beads or microspheres coupled with different antigens to simultaneously detect various antibody isotypes in a serum sample. The assay is helpful in understanding seroconversion during an infection or post-vaccination.

In this video, we demonstrate an immunoprecipitation assay, called the VLP capture assay, to isolate antigen-displaying virus-like particles, or VLPs, from a sample. The antigen binds with specific antibodies bound to magnetic beads, forming an immobilized antigen-antibody complex that is later separated and stored for further analysis.

This video demonstrates a sensitive quantification technique of protein phosphorylation using a single-molecule pull-down assay. The functionalization of polyethylene glycol-biotin and the use of labeled antibodies increases the detection of phosphorylated tyrosine with specificity.

This video demonstrates the in vitro method for SUMOylation of substrate proteins using a sequential enzyme cascade. Further, the SUMOylated status of the protein is identified using the electrophoresis and immunoblotting technique.

In this video, we show the HiBit-RBD bioreporter system-based assay for detecting SARS-CoV-2 neutralizing antibodies. This system targets the viral RBD domain by using a bioluminescent reporter system containing HiBiT fused to the RBD domain.

In this video, we demonstrate an in vitro colorimetric assay to detect the presence of neutralizing antibodies against alkaline phosphatase-expressing recombinant adeno-associated virus serotype 6 (rAAV6) vectors in sheep serum samples. The assay utilizes the reaction between the AAV encoding a human placental alkaline phosphatase gene and its substrate to generate an insoluble purple product.

This video demonstrates a highly sensitive immunofluorescence-based assay for detecting PM2.5-induced oxidative damage in the hearts of zebrafish embryos by measuring the levels of 8-OHdG and γH2AX, which indicate DNA damage and double-strand DNA breaks, respectively.

This video demonstrates the technique of assessing neuronal death in rhinal cortex-hippocampus organotypic slices. Neuronal death occurs via evolving epileptic seizures — resembling in vivo epilepsy — and is detected through dual-staining of the dead cells using propidium iodide and immunofluorescence.

This video demonstrates the detection of chemically conjugated antibody-antigen complexes via the sandwich enzyme-linked immunosorbent assay, or ELISA, technique. The captured antibody binds to the specific epitope of the antigen of the antibody-antigen conjugate, which can be later visualized using an enzyme-linked secondary antibody.

In this video, we demonstrate an EGFP-based immunofluorescence assay to identify the efficacy of target proteins on the neurite outgrowth of primary cortical neurons. The primary neurons are transfected with a fluorescent protein, EGFP, and a target protein, and then an immunoassay is performed to investigate the effect of the target protein on neurite outgrowth.

In this video, we demonstrate the electrochemiluminescence immunoassay for the quantitation of target protein levels in different samples. This assay is based on the luminescence produced in the electrochemical reaction. The intensity of light emitted is proportional to the quantity of the target protein in the sample.

Source:Jake Griner1, Arwen Wedgeworth2, Brenton Puckett2, Kacey Idouchi1, Slivia Guglietta2, Carsten Krieg11Department of Pathology and Laboratory Medicine, Medical University of South Carolina.2Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina.The video describes the preparation of a tissue sample for imaging mass cytometry. The tissue is first processed to unmask the antigen epitopes, permeabilize the cells, and block non-specific antibody binding...

Source:Sathish Muthu1,2,31Orthopaedic Research Group, Coimbatore.2Department of Biotechnology, Faculty of Engineering, Karpagam Academy of Higher Education.3Department of Orthopaedics, Government Medical College.This video demonstrates the preparation of high-quality Platelet-Rich Plasma (PRP) by screening for platelet count, collecting and centrifuging blood, and isolating platelets. This PRP is used in therapeutic applications for tissue regeneration and healing.