How xMAP® Technology Advances Veterinary and Agricultural Research

New white paper reviews a host of recent studies based on xMAP® Technology

When Luminex scientists first created xMAP® Technology back in the 1990s, they couldn’t possibly have imagined the vast array of applications for which it would eventually be utilized. We are continually impressed with our users’ creativity and scientific vision as they bring multiplexing technology to numerous new research areas.

In this recent white paper, Multiplex Methods in Veterinary Medicine and Agriculture, our team explores several ways xMAP-based assays are used in veterinary medicine and agricultural science. There are a wide range of applications in this research area alone—including livestock and crop production, food and water safety, translational research, companion animal medicine, zoonotic disease, wildlife and ecosystem health, and more.

Adaptable, efficient multiplex assays

While this is a broad landscape representing enormous diversity, there is a common thread across these applications: they are all characterized by a need for highly accurate measurement of biochemical processes. xMAP Technology powers multiplex assays that can detect up to 500 analytes in a single, low-volume sample, making them more time and cost-efficient than traditional immunoassay methods. Specifically, in veterinary research, the ability to use small input volumes makes it possible to study birds and other small animal species.

The flexibility of xMAP Technology is one of the reasons it’s well-suited to so many different research uses. Along with our partners, we offer an extensive menu of commercially available assays, as well as the option to design custom assays for novel research applications.

Below are just a few examples of how xMAP is being used across veterinary and agricultural research:

  • Studying host immune proteins and infectious agents in veterinary research
  • Detecting foodborne pathogens, hormones, antibiotics, and other drugs in food safety testing
  • Measuring mycotoxins in feed
  • Differentiating viruses in plants
  • Evaluating water quality and other environmental substrates

Multiple studies with reliable results

The studies described in the white paper show how widely adaptable xMAP-based assays are, supporting research across multiple fields.

These studies also reveal how xMAP-based assays can bridge the gap between veterinary medicine and human health. Using xMAP Technology, investigators are determining appropriate animal models for human disease.

xMAP Technology is open-architecture—reducing time, labor, and costs compared to traditional methods—delivering reliable answers to complex questions. It offers the versatility to perform a wide range of multiplexing assays, from proteins to nucleic acids, on a single platform.

Download our free white paper to read more about how scientists are using xMAP-based assays to enhance their research in veterinary medicine and agricultural science.

Free White Paper: New Veterinary and Agricultural Applications with xMAP Technology

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The Year in Review—How COVID-19 Transformed Our World

Reflecting on a challenging year in global health

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As 2021 inches closer, many of us have begun our annual reflection, reviewing the events of the past year to gain perspective and shape the months ahead. Ordinarily, one might identify several themes that characterized the year—but in 2020, everything was filtered through the lens of the COVID-19 pandemic.

With tens of millions of cases and more than one million global deaths, the dramatic loss of life and complete societal and economic disruptions have created lasting changes in all of our lives. The pandemic changed how we work, interact with each other and our communities, teach our children, and measure our days.

Dedicating all available resources to address challenges

The pandemic also brought a beautiful side of humanity into focus: how we came together to fight for better health outcomes. At Luminex, this was a very personal lesson for us. Each day, we develop technologies and assays to improve clinical laboratory testing capabilities, and COVID-19 had a major impact on how we work together to quickly address time-sensitive challenges. In 2020, every member of the Luminex family worked diligently to develop, validate, manufacture, and support a host of new assays to facilitate SARS-CoV-2 detection and COVID-19 research.

Although developing these new solutions was an intense process, we knew our team was experienced, knowledgeable, and up to the challenge. We immediately recognized that building one assay wouldn’t overcome the enormous testing obstacles faced by labs around the world, so our goal was to develop a COVID-19 assay for every clinical testing platform in our portfolio. We wanted all Luminex customers to get the support they needed.

Creating a united front against COVID-19

By early March, our internal efforts were well underway. Later that same month, we received our first Emergency Use Authorization (EUA) from the US Food and Drug Administration (FDA) for a SARS-CoV-2 assay as part of our ® SARS-CoV-2 Assay” href=”https://investor.luminexcorp.com/news-releases/news-release-details/luminex-receives-fda-emergency-use-authorization-ariesr-sars-cov”>ARIES® SARS-CoV-2 Assay, and then, we received authorization for our ® Technology Users Battle COVID-19 with New Serology Assays” href=”/blog/xmap-technology-users-battle-covid-19-with-new-serology-assays/”>xMAP® community mobilized quickly against the pandemic, deploying research partners and colleagues in other organizations as they engaged in COVID-19 research. We were also honored to support webinars featuring scientists from the Icahn School of Medicine at Mount Sinai and Rush University Medical Center to help others learn from their developments.

We won’t be sorry to leave 2020 in the past—and there are still challenges ahead as we move into the new year while continuing to fight the pandemic. However, even in the most difficult moments of this past year, we were struck by the dedication and tenacity of both our global workforce, as well as the clinical laboratory community at large, and we are honored to be part of the network of assay and technology developers supporting their unprecedented efforts.

We remain dedicated to supporting our customers and partners fighting the pandemic, which is why we have developed multiple flexible solutions for automating and facilitating SARS-CoV-2 testing and COVID-19 research needs. Click here to learn more about these solutions and stay informed on the most up-to-date COVID-19 testing information.

Learn more about Luminex's SARS-CoV-2 testing solutions.

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Training Tomorrow’s Custom Assay Development Experts: A Summer Internship Program Hosted by the LuminexPLORE Lab

UT Austin students share their experience working in our xMAP® Custom Assay Development lab this past summer

Internships in our industry aren’t particularly common, and they’re even harder to find in places like Austin, which isn’t really considered a biotech hub. However, it’s important to offer these types of programs so that students interested in a job in the life sciences field have an opportunity to explore career options that aren’t limited to academia. This is why we were so proud to offer an internship program in the LuminexPLORE Custom Assay Development Lab this past summer.

Atharwa Mankame and Chad Papenfuhs, two students at the University of Texas at Austin, spent several months working in the Custom Assay Development Lab where Development and Applications Scientist Jackie Surls, PhD, mentored them during the program. As they prepared to wrap up their internships, we asked for their feedback about their experience. They told us that they both enjoyed the program and were grateful to have had the opportunity to work on real projects while they were here.

“What’s unique about our internship opportunity is that we get to take on these projects,” Papenfuhs said, noting that he was able to work directly with customers. In one project, he helped to determine whether Luminex assays could be used to detect guide RNAs for a company running CRISPR gene editing workflows. “It’s been fun to have real responsibility in the biotech world,” he adds.

For his role, Mankame relied on his operations management focus at school to analyze process flows, identify bottlenecks, and make recommendations about how to streamline resource allocation. For example, he suggested that exploring options to help standardize the time it takes to review project contracts could allow the team to better predict when staff resources would be needed for new custom assay programs. He also mentioned that he appreciated the opportunity to present this and other projects he worked on while here to the Luminex team.

Both interns credit Jackie’s management style with fostering an interesting and challenging environment. “Jackie’s been great. She told me to take the initiative and go for it when I suggested projects,” Mankame says. “That allowed me to explore areas I wasn’t familiar with.”

“What’s unique about our internship opportunity is that we get to take on [customer] projects. It’s been fun to have real responsibility in the biotech world.”

— Chad Papenfuhs, UT Austin Student & LuminexPLORE Lab Intern

Looking to the future

When asked about their plans for their own careers, Mankame told us he intends to go to medical school and hopes to be able to consult on technology development once he’s a physician. Papenfuhs, who plans to complete a PhD in microbiology and then work in the biotech industry, is hopeful that the connections he made here will come in handy down the road. We’re not looking forward to saying goodbye to our interns, but we are so proud of everything they’ve accomplished during their time at Luminex.

As Mankame and Papenfuhs head back to full-time classes, they offered some advice to future interns: summer break is a great time for a training program, because there’s less competition between school coursework and the internship. This approach also lets interns spend bigger blocks of time in the lab, which Mankame notes is important to be able to see an assay all the way through.

We’re thankful to our interns for their valuable contributions during their time with us, and to our team members for helping make this important program such a success!

Although next year’s program is still a ways away, if you’re interested in learning more about the xMAP Technology our interns employed during their time here, we have a variety of in-depth resources to learn more about custom assay development. Download the xMAP® Cookbook, a collection of methods and protocols for developing multiplex assays, or click here to learn more about LuminexPLORE Lab, a custom services program designed to accelerate your research.

Interested in developing your own assays? Get started with the xMAP Cookbook

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Multiplex Bead Mixes Made Easy with an Excel-Based Bead Calculator

Whether you’re developing a multiplex assay for 500 different markers in one reaction or developing lower-plex assays, knowing how to make a multiplex bead mix from different types of bead stocks is critical for proper assay performance.

Unconjugated beads can be purchased as individual stocks at different concentrations of 12.5 or 2.5 million beads per mL. After coupling with different capture molecules for proteomic or genomic applications, we recommend resuspending coupled beads to a concentration of about 20 to 50 million beads/mL (<20,000 to 50,000 beads/µL), or less for proteomic vs. genomic applications respectively; see the xMAP® Cookbook for coupling protocols.

Choosing Your Beads

Whether coupling your own beads, or using MagPlex®-Avidin or MagPlex®-TAG beads, we recommend that the multiplex mix contains about 2,500 beads of each region per reaction in a user-defined volume. The Cookbook recommends that each bead region used for making a multiplex mix be at 50 or 75 beads/µL (50,000 or 75,000/mL) for different applications. As the plex of an assay increases and the volume of bead mix needed per reaction varies based on assay design, using the standard 50 or 75 beads/µL leads to errors with making a multiplex mix.

Determining Bead Stock Concentrations

When making multiplex assays, it is more efficient to have all the stocks at the same concentration and at concentrations other than the 50 or 75 beads/µL recommended. For example, in a 40-plex assay, if all the beads were at 1 million beads/mL, the same volume of each bead stock can be used to make a multiplex mix, rather than having to change the pipette volume 40 times to dispense the right amount of beads into the mix for each bead region.

No matter how capture molecules are coupled or bound to Luminex beads, the first step after attaching capture molecules is to confirm bead recovery and determine the bead concentration. The next step is to dilute all the bead preparations to the same bead concentration. While each bead preparation has a different concentration, getting them all to the same concentration can be easily calculated with the appropriate bead stock dilution calculator template.

Download the Coupled Bead Stock Dilution Calculator Template

Using the Multiplex Bead Mix Calculator

Once all of the bead stocks are adjusted to the same concentration, the bead mix calculator can be used to determine how to make a multiplex bead mix. The bead mix calculator eliminates potential calculation errors that can result from the unique needs of each experiment, including a varying number of bead regions per reaction (plex), final bead concentration of all the coupled bead stocks, and the specific volume of bead mix needed for each reaction. When using these variable parameters above certain plexes, there are different points where a concentration step will be needed to correctly make a multiplex mix. The bead mix calculator can indicate if concentrating is needed or not, and can let you know if you have enough beads to make a multiplex mix.

Download the Multiplex Bead Mix Calculator

Instructions on how to use these workbooks can be found in this video:

Tools for Calculating Bead Concentrations and Making Multiplex Bead Mixes

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Browse 1,200+ Partner Kits with xMAP® Kit Finder [Online Tool]
xMAP® Cookbook to Design Your Own Assays [Download]
View the xMAP Multiplexing Blog [Blog]

Multiplexing Provides Richer Information for Veterinary Testing

Cornell scientists use Luminex® technology to skip long ELISAs and advance diagnostic test interpretation

At Cornell University’s Animal Health Diagnostic Center (AHDC), scientists provide high-quality testing for a variety of animals while developing valuable new veterinary tests.

Dr. Bettina Wagner, a veterinarian and immunology expert serving as the AHDC’s Director of Serology, has built several important assays using xMAP® Technology. When she first joined the ADHC in 2006, she acquired a new Luminex® 100™ System, which proved so effective that she upgraded to the Luminex 200™. She now has four of these units—three in the AHDC and another in her research lab, where she performs much of her initial work on developing new assays.

Early in Dr. Wagner’s tenure at the AHDC, she established an xMAP-based test to replace western blot and ELISA tests for Borrelia burgdorferi, the pathogen responsible for most cases of Lyme disease.

“When we introduced the test in 2011, it was the first multiplex serological assay for veterinary species,” Wagner recalls. The bead-based test could be used across multiple species and, unlike its predecessor assays, offered more than just a ‘yes or no’ answer.

“This test gives more information than the previous testing for Lyme,” she adds. “It can quantify antibodies to three specific antigenic proteins of the pathogen with broad linear range. Differences in antibody pattern against the three proteins can also tell us whether an infection is early or chronic, and it can evaluate treatment success as antibodies decline,” she says. The test also includes a marker to examine vaccine success and antibody titers.

Taking advantage of the many applications of xMAP Technology

Around the same time she created the test for B. burgdorferi, Dr. Wagner began a USDA-funded project to develop monoclonal antibodies for equine immunological molecules. She designed a multiplex cytokine assay—the first available for horses—using xMAP Technology. “We have run this assay for many years for the equine research community,” she adds.

Following the success of these initial projects, Dr. Wagner and her team continue to design additional multiplex tests. Most recently, Wagner and her team developed a test to detect antibodies associated with COVID-19 in felines, which they tested on cat samples collected from veterinarians in New York City.

“Luminex technology is great—we use it every day,” Dr. Wagner says. “Multiplexing is very important for us. We can offer advanced interpretation by using multiple targets, so it is an experiment life-saver for many samples where we simply don’t have enough volume to run several separate assays.”

Find detailed instructions on developing your own assays.

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Luminex Licensed Technologies Partner Spotlight: EpiCypher

EpiCypher delivers high-quality reagents for epigenetics and chromatin research

As one of Luminex’s Licensed Technologies Partners, EpiCypher is one of many companies that uses xMAP® Technology to deliver important solutions for improving research and molecular diagnostics.

Based out of the Research Triangle Park in North Carolina, EpiCypher is a biotechnology company that helps scientists push the boundaries of research in chromatin regulation, chromatin mapping, and epigenetics. They do this through the development and production of modified recombinant nucleosomes, and have leveraged this technology for a wide range of quantitative chromatin assays.

To find out more about how xMAP Technology supports EpiCypher’s developments, we spoke with Leslie Shannon, Marketing Communications Manager, Keli Rodriguez, Lab Manager, and Carolina Lin, Research Associate.

What does EpiCypher do?

Founded in 2012, EpiCypher aims to address the growing need for high-quality epigenetic reagents. They pioneered the production of recombinant designer nucleosomes (dNucs™), which contain defined post-translational modifications (PTMs) and recapitulate the natural nucleosome structure observed in vivo, making them ideal substrates for a variety of chromatin assays.

One application of dNucs is SNAP-ChIP™ Spike-in technology, which uses panels of DNA-barcoded dNucs as spike-in controls to examine antibody specificity (on- and off-target binding) and efficiency (percent pulldown relative to input) during a ChIP-seq workflow. Spike-ins can also be used for data normalization, highlighting the utility of these reagents for chromatin profiling.

In addition to developing and commercializing reagents, EpiCypher scientists also contribute research. “Our goal is to not only bring our customers cutting-edge epigenomic technologies, but also serve as a research partner,” says Leslie. “We have a unique business model that allows us to work with other scientists, either through collaborations, services, or projects, to answer challenging research questions.”

Why are nucleosome controls important for epigenetic research?

“Nucleosome controls offer a physiologically relevant measurement of success to epigenetic research,” Leslie says. For instance, histone PTM antibodies for ChIP assays are commonly tested using modified histone peptide arrays, which lack the nucleosome context. “Compared to our SNAP-ChIP Spike-in Controls, the histone peptide arrays didn’t accurately predict antibody specificity on chromatin in ChIP experiments. We also found cross-reactivity to other PTMs in many commercial ‘ChIP-grade’ antibodies. Overall, we concluded that nucleosome context is essential for identifying antibodies with reliable on-target performance in ChIP-seq.”

This revelation led to an initiative by the EpiCypher science team to leverage SNAP-ChIP controls to screen for reliable histone PTM antibodies for ChIP-seq experiments. “The SNAP-ChIP Spike-in Controls identify next-generation antibodies that are truly ‘ChIP-grade,’” Leslie mentions.

How is EpiCypher using Luminex technology?

The EpiCypher team needed an efficient technique to rapidly screen and identify candidate antibodies for final testing against SNAP-ChIP Spike-ins in a ChIP experiment. “It was costly and time-consuming to test all antibodies in standard ChIP workflows against SNAP-ChIP Spike-ins. Luminex offered a cheaper and faster way of performing these tests,” Leslie says.

To effectively analyze these large sets of antibodies, they first conjugate nucleosome panels to Luminex xMAP beads so the beads denote PTM identities. Then, they add an antibody of interest. “We run the reaction on the Luminex FLEXMAP 3D® to detect what nucleosome or nucleosomes bind to the antibody,” Keli explains. If 90% of antibody-bound nucleosomes are attached to the expected PTM of interest, then it is approved for further testing in ChIP with SNAP-ChIP Spike-ins.

After screening hundreds of antibodies, EpiCypher identified a collection of the highest-performing ChIP antibodies—this data will be published by the end of this year, which will allow researchers to be able to more easily identify the best antibodies for future ChIP experiments.

Why does multiplexing matter for EpiCypher’s work?

Multiplexing was a key feature EpiCypher scientists were looking for as they evaluated options for screening antibodies. “Some of the other assays we ran prior to utilizing xMAP took a lot longer,” Keli explains. “The Luminex workflow gives a lot of information in a very short period of time.”

By multiplexing, EpiCypher can test an antibody against an entire panel of modified nucleosomes in one reaction. “It’s a great feature to be able to work with 500 different analytes in a single well, using extremely low volumes for each reaction,” Carolina says.

Another advantage: the system’s robustness. The team performs all the washes typically used in ChIP assays, thus replicating key experimental steps that are necessary to predict an antibody’s performance using SNAP-ChIP Spike-ins. “The beads are able to withstand all these different reagents and stringent wash conditions,” Carolina adds.

As a result, EpiCypher’s Luminex-based antibody screening method can be adapted for a range of buffer washes, and can be applied for antibody testing across different assays—this flexibility will be helpful when the EpiCypher team expands multiplex testing to their other genomic mapping assays.

“We are developing similar nucleosome controls for CUT&RUN and CUT&Tag experiments, and plan to use Luminex for those as well, so we can identify top-performing antibodies for these novel chromatin profiling assays,” Keli concludes.

Multiplexing offers significant advantages over traditional methods for delivering reliable answers to complex questions. Whether it’s saving time and resources for researchers like our partners at EpiCypher, or accelerating discovery for large-scale screening projects, there’s a multiplex solution that can meet the needs of your workflow.

Are you interested in developing, manufacturing, and commercializing your own multiplex assay on an efficient, flexible, and widely-adopted platform? Contact us here.

To learn more about EpiCypher’s latest technologies, check out their website at: epicypher.com

Are you interested in developing, manufacturing, and commercializing your own multiplex assay on an efficient, flexible, and widely-adopted platform?

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For COVID-19 Detection and Epidemiology, xMAP® Technology Offers Unique Advantages

Multiplex serology tests have yielded impressive results, showing promise for use in the COVID-19 pandemic.

For COVID-19 Detection and Epidemiology, xMAP<sup>®</sup> Technology Offers Unique Advantages
xMAP-based serology tests have been widely implemented for the detection of pathogenic bacteria, viruses, and parasites. In the COVID-19 era, xMAP Technology has helped build several new multiplex serology tests designed to detect antibodies to different SARS-CoV-2 antigens.

To demonstrate how these tests may make a difference, we’ve summarized how some xMAP-based serology tests have been used for clinical lab applications, as well as for epidemiology and surveillance.

Providing multiplex results you can rely on

One of the earliest applications of a multiplexed xMAP serological assay involved the screening of HIV antibodies in dried blood spot specimens for early detection of HIV exposure in neonates. Developed by Bellisario et al., this assay was able to simultaneously measure antibodies to three different purified recombinant HIV-1 antigens (p24, gp120, and gp160). The extra specificity of this assay meant it could distinguish 92 previously tested newborn specimens as either HIV-negative or HIV-positive, and was also able to clearly differentiate anti-HIV-1 blood spot controls (zero, low, and high) from the CDC.

In another application, Wu et al. used the xMAP platform to develop a sensitive, rapid, high-throughput multiplexed serological assay for identifying specific IgG antibodies to nine hemorrhagic fever viruses. Performance data with clinical serum samples demonstrated sensitivities of 90.7–98.04% and specificities of >90% for all but two of the viruses.

Waterboer et al. developed a multiplexed serological immunoassay that could simultaneously detect antibodies against 100 in situ affinity–purified recombinant human papillomavirus (HPV) proteins. Their assay could measure antibodies at serum dilutions of >1:1,000,000 and demonstrated high reproducibility and excellent concordance with single-plex ELISAs.

Respond to outbreaks with trusted technology

xMAP bead-based serological assays have also been implemented in outbreak situations. Ayouba et al. developed a multiplexed serological assay for the Zaire Ebola virus using nine recombinant proteins. The performance of the assay was evaluated with 94 positive and 108 negative samples, and revealed high sensitivity and specificity. Additionally, this high-throughput xMAP assay was extremely cost-effective when compared to the single-plex ELISA ($4 vs. $54 for each sample), and could therefore be easily and economically implemented to screen large sample volumes in an outbreak situation.

In addition to pathogen identification, detection of serological markers can provide additional information to estimate recent and past exposure to the pathogen. xMAP-based multiplex serological assays have been well-established in epidemiology for surveillance purposes.

Customized immunoassays for serosurveillance

To monitor vaccine-preventable diseases, Caboré et al. developed a pentaplex immunoassay for the simultaneous detection of IgG antibodies against diphtheria, tetanus, pertussis toxins, and other pertussis antigens. Their assay demonstrated good correlation with ELISA, a low intra- and inter-assay variability score, and was successfully implemented for performing large serosurveillance/seroprevalence studies.

O’Hearn et al. developed a similar multiplexed assay to detect IgG antibodies against Lassa, Ebola, Marburg, Rift Valley fever, and Crimean-Congo hemorrhagic fever viruses, as well as pan-assays for flaviviruses and alphaviruses. Their study highlights the importance of surveillance, as the results revealed that in addition to Lassa virus (which is endemic in West Africa), other strains of viruses are also responsible for hemorrhagic fever, but often go undetected, and ultimately, untreated.

Applying xMAP Technology to the COVID-19 pandemic

To aid in the detection of COVID-19, Luminex recently received Emergency Use Authorization for an xMAP-based antibody assay to help identify individuals who were exposed and developed an immune response to SARS-CoV-2. The xMAP® SARS-CoV-2 Multi-Antigen IgG Assay provides highly specific and sensitive results by targeting three different antigens and using an algorithm to determine positivity.

(EUA) – In Vitro Diagnostic Use Under Emergency Use Authorization. This test has not been FDA cleared or approved. This test has been authorized by the FDA under an EUA for use by authorized laboratories.

To learn more about clinical applications of xMAP-based serology tests, check out our recent white paper (luminexcorp.com/?wpdmdl=42265).

Free White Paper: xMAP Technology: A Benchmark for Serological Testing

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How to Reduce Coupling Variability with Luminex Bead Assays

Top 10 tips for a successful coupling process

If you’re designing a new multiplex bead-based assay or adding new targets to an existing xMAP® Technology-based assay, the coupling process required to add a protein or an antibody can seem daunting. We’re here to help!

While the Luminex custom assay development service can help you with coupling, we believe that anyone who knows their way around the lab can perform successful coupling reactions. It is very straightforward, and carefully following the xMAP Cookbook recipes can make all the difference.

If you’ve never performed coupling before, or if you’ve done it in the past and noticed problems, there are a few common issues that can be easily worked through.

Variability is the number one issue to avoid. Let’s say you’re performing a coupling confirmation assay to verify coupling efficiency. If there’s a really low signal, this could indicate an issue with the coupling process. As a general guideline, we recommend 5 micrograms per million beads, but always encourage users to do a titration to check the optimal concentration to put on the bead.

Low signal can also be a sign that there is a reagent quality issue. If you’re using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC) that has degraded, you may experience poor coupling efficiency. This is a common problem. Take care of those EDC vials! Be sure to store EDC in the freezer with a desiccant.

Over-vortexing can also cause problems. We recommend that xMAP users vortex and sonicate to make sure the beads are in homogenous suspension, but over-vortexing can lead to clumping, which will affect coupling.

To help you streamline the bead coupling process, here are our top 10 tips for reducing variability:

  1. Microspheres are light-sensitive. There’s no need to couple in the dark, but cover tubes in foil during incubation steps. If exposed to light for too long, the beads will photobleach.
  2. When resuspending the uncoupled beads in the coupling tube, make sure you have vortexed and sonicated the beads. Bead loss is often due to not mixing the beads well.
  3. There is such a thing as too much vortexing and sonicating. Stick to the recommended recipe to avoid bead clumping.
  4. Make sure you are using the tubes specified in the xMAP Cookbook, as tube type can have an impact on coupling efficiency. We recommend:
    1. USA Scientific® (Catalog # 1415-2500), or
    2. Eppendorf™ Protein LoBind (Catalog # 022431081)
  5. Make sure you have an appropriate magnet for the tube type containing your beads. The right kind will pull the beads to one side, not split them between both sides, or leave beads floating in the tube.
  6. Magnets can lose magnetism if not taken care of properly (e.g., do not store magnets on top of each other).
  7. Embrace single-use 10 mg EDC vials. Bulk EDC is hygroscopic, so it readily absorbs moisture from the air. Over time, the EDC degrades, which greatly diminishes coupling efficiency.
  8. When performing wash steps, make sure you place the beads on the magnet for at least 30 to 60 seconds for typical couplings. For large-scale coupling, visually check to ensure beads have been pulled. If they haven’t, wait an additional 30 to 60 seconds.
  9. When washing and aspirating beads, be careful not to disturb the beads to avoid having them stick to the transfer pipette.
  10. If using automation, check bead recovery before and after coupling. Ensure automation is optimally set up to avoid significant bead loss.

Please feel free to reach out with any questions. We’re confident that you can master the science of bead coupling!

Learn how LuminexPLORE can help your lab!

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Webinar: Mount Sinai Scientists Design Multiplex COVID-19 Antibody Test

Implementing xMAP® Technology allows for faster, more accurate results

When the global outbreak hit the US, the Icahn School of Medicine at Mount Sinai in New York City published some of the earliest COVID-19 studies in the US. It’s no surprise then that scientists at Mount Sinai were among the first to develop an antibody test. Using xMAP® Technology to design this test allowed them to make the most of its high-throughput multiplexing capabilities, fast results, and low sample input requirements.

This antibody test was the focus of a recent LabRoots webinar presented by Dr. Susan Zolla-Pazner, a Professor of Medicine at Mount Sinai. Developed by Dr. Zolla-Pazner’s team, the assay targets two SARS-CoV-2 antigens—the full spike protein and its receptor binding domain (RBD)—and uses two bead sets, each designed to bind to antibodies associated with one of these antigens. In the webinar, they presented the results from their validation study, which demonstrated that their test could provide robust signals for both antigens from plasma and serum using positive and negative COVID-19 samples.

Compared to ELISAs, this xMAP-based antibody test had significantly higher sensitivity—in some cases five to ten times higher. ELISA-based testing also led to more false negative results than the multiplex assay, according to Dr. Zolla-Pazner.

The webinar also discussed additional advantages of the xMAP assay, including:

  • xMAP beads can be coated with antigen ahead of time and stored for at least a month, making preparation more convenient and efficient.
  • Luminex beads require 20-fold less antigen compared to ELISAs, resulting in significant cost savings.
  • The xMAP assay delivers results for both spike and RBD antibodies in less than two hours, while ELISA plates can only detect one antibody at a time, and the complete workflow from prep to results for ELISAs takes two days.

Dr. Zolla-Pazner also shared results from additional studies that were enabled by the multiplex assay. For example, she showed that it was possible to track rising antibody levels over time by testing longitudinal specimens from the same patient, which will be extremely useful for characterizing the long-term immune response to COVID-19. Using the same method from her team’s original xMAP assay, she analyzed isotyping data to investigate differences in the IgG and IgM immune response. These results could inform donor selection for convalescent plasma therapy.

Watch the entire webinar here, or view Luminex’s COVID-19 testing resources here.

Watch the entire presentation with Dr. Zolla-Pazner.

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xMAP® Technology Users Battle COVID-19 with New Serology Assays

Designed and built by researchers around the world, xMAP® assays shine light on the antibody response to SARS-CoV-2.

xMAP<sup>®</sup> Technology Users Battle COVID-19 with New Serology Assays

Our xMAP® Technology empowers researchers to build their own assays quickly, creatively, and effectively. Designed and built by researchers around the world, xMAP® assays shine light on the antibody response to SARS-CoV-2. If you haven’t seen the studies, they are well worth your time. Here, we provide a quick overview of some of the latest studies using xMAP to address the pandemic.

Identifying SARS-CoV-2 patients who have seroconverted.

Weiss et al. developed an xMAP serological assay and used it to assess the presence of antibodies for two SARS-CoV-2 proteins in sera from COVID-19 infected and uninfected individuals. This assay is critical because it can identify patients who have been infected with SARS-CoV-2 and have seroconverted, which will help characterize the immune response to the disease.

Similarly, Randad et al. developed an xMAP-based ten-plex SARS-CoV-2 immunoassay for detecting salivary antibodies that demonstrated significant correlation with serum sample results. The assay had 100% sensitivity and specificity for detecting prior SARS-CoV-2 infection.

Dobaño et al. developed quantitative, xMAP-based multiplex assays for detecting IgG, IgM, and IgA against a panel of eight SARS-CoV-2 antigens. For the best-performing combination of Ig-isotypes and antigens, the assay demonstrated 100% specificity for SARS-CoV-2. Sensitivity was 94.94% for positive samples collected at ≥14 days following the onset of symptoms, and 96.08% for those collected at ≥21 days.

Additionally, the Wadsworth Center of the New York Department of Health developed an xMAP-based serological assay for the detection of total antibody (IgG, IgM, and IgA) to SARS-CoV-2 in human serum, which received Emergency Use Authorization from the Food and Drug Administration. The assay demonstrated a sensitivity of 88% and a specificity of 98.8%, and was implemented to detect reactive and non-reactive SARS-CoV-2 antibodies.

Flexible solutions to complex problems

If a ready-to-use solution works better for your workflow, Luminex was recently granted Emergency Use Authorization for our xMAP® SARS-CoV-2 Multi-Antigen IgG Assay, which is a multiplex, highly sensitive and specific assay that detects the presence or absence of antibodies against three different SARS-CoV-2 antigens. By using multiple antigens, this assay may provide earlier, more sensitive results.

The SARS-CoV-2 pandemic continues with a daily emergence of new cases, so the implementation of serological testing, in addition to nucleic acid tests, is increasingly important to understanding the pathology and impact of COVID-19. xMAP Technology is the established benchmark for running multiplex serology tests, and is actively being employed by academic research labs and healthcare facilities to help diagnose COVID-19, profile the immune response, support vaccine and therapeutic development, and much more.

Free White Paper: xMAP Technology: A Benchmark for Serological Testing

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