Tips and Tools

mRNA Vaccine Manufacturing: Responding Effectively to a Global Pandemic

Posted on by Ken Doyle

We’ve learned a few important lessons from the COVID-19 pandemic.

Perhaps the most significant one is the importance of an early and rapid global response to the initial outbreak. A coordinated response—including widespread use of masks and other personal protective equipment (PPE), travel restrictions, lockdowns and social distancing—could save lives and reduce long-term health effects (1). Widespread availability of effective vaccines goes hand in hand with these measures.

New Boosters to Fight Omicron

Last month, Pfizer/BioNTech announced the US Food and Drug Administration (FDA) had granted emergency use authorization (EUA) for a new adapted-bivalent COVID-19 booster vaccine for individuals 12 years and older. This vaccine combines mRNA encoding the wild-type Spike protein from the original vaccine with another mRNA encoding the Spike protein of the Omicron BA.4/BA.5 subvariants. Moderna also announced FDA EUA for its new Omicron-targeting COVID-19 booster vaccine. The Omicron variant of SARS-CoV-2 shows multiple mutations across its subvariants, and it is currently the dominant SARS-CoV-2 variant of concern across the world.

Genomic epidemiology of SARS-CoV-2 with subsampling focused globally over the past 6 months. This phylogenetic tree shows evolutionary relationships of SARS-CoV-2 viruses from the ongoing COVID-19 pandemic. Image from Nextstrain.org; generated September 20, 2022

Booster doses of vaccines have become a way of life, both due to declining effectiveness of the original vaccines especially in older adults (2), and the rapid mutation rate of SARS-CoV-2 (3). Clinical data for the new Pfizer/BioNTech booster vaccine showed superior effectiveness in eliciting an immune response against Omicron BA.1 compared to the original vaccine. Previously, Moderna published interim results from an ongoing phase 2-3 clinical trial, showing that the new bivalent booster vaccine elicited a superior neutralizing antibody response against Omicron, compared to its original COVID-19 vaccine (4).

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Using Databases to Find Scholarly Sources

Posted on by Promega

Today’s guest blog was written in collaboration with Melissa Martin, a former global marketing intern with Promega. She is a senior at the University of Wisconsin-Madison where she is double majoring in zoology and life sciences communication, with a certificate in environmental studies.

Peer-reviewed papers are considered the most technical and in-depth way to learn about research and scientific advances. As a student or scientist, you will not only want to read scholarly articles to learn about what others are doing in your field but also to expand your knowledge and learn about scientific advances in completely new areas of study. With countless disciplines of science covering wide-ranging topics such as cell biology, physical chemistry or human behavior, it can be overwhelming to do a general search and find articles and journals that will have the topics relevant to your interests.

Young woman searching databases for findingscholarly articles.
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Save Precious Time with Same-Well Multiplexing

Posted on by AnnaKay Kruger
Scientist performing a multi-well assay. Same-well multiplexing enables you to look at one event from several perspectives.

A graduate student believes he has mastered the art of “the assay”. No need to run duplicates, he knows exactly which one will get him the answers he needs right away.  

To challenge this, his PI proposes an exercise. He asks of the graduate student, “What happens when you treat cells with doxorubicin?”

The graduate student raises his cells, treats them accordingly, and decides to run a cell viability assay to determine their fate. He returns to the PI with the final verdict: his cells are dead.

The PI takes a look at the data and asks the graduate student to repeat the experiment with an additional assay for cytotoxicity―but the cytotoxicity assay shows that the cell membranes are intact, which only puzzles the graduate student. The PI asks him to run a third assay for apoptosis, and when the student does so, it becomes clear that the cells are dying.

The PI uses this opportunity to make his point: “Now do you see why I ask for more than one assay?”

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Inventory Managment and Onsite Stocking without the Headache

Posted on by Promega

The Helix on-site stocking program has been a resource for scientists for many years. With customized onsite stocking, inventory management and automated billing, losing precious time to a missing reagent is a thing of the past.

Helix freezers and cabinents provide seemless onsite stocking and inventory managment

To better understand the impact of Helix on our customers’ research, we spoke to Chris Thompson of Pro-GeneX, a clinical laboratory in Atlanta, GA. “Using the Helix system has been a game changer from the first day we got it,” Chris said.  “It was simple to set up and use from the start and has never let us down.  We routinely show it off to visitors to our lab because we are so impressed with it.  I only wish all my reagents used a system like this.  From an inventory perspective it is the best invention in our lab!”

Read our full Q&A with Chris below:

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Greening the Lab: Tips from Lab Manager’s Green Lab Digital Summit

Posted on by Promega

Today’s guest blog was written in collaboration with Melissa Martin, a former global marketing intern with Promega. She is a senior at the University of Wisconsin-Madison where she is double majoring in zoology and life sciences communication, with a certificate in environmental studies.

Infographic illustrating the places where simple actions can be taken to help build greener labs: greening the lab

Schools, businesses and organizations across the globe are increasingly implementing sustainable practices within their workspaces. From large-scale projects like installing solar arrays to behind-the-scenes initiatives like composting cafeteria food waste, “going green” is a reality of the modern workplace.

But one workspace otherwise known for being cutting edge and innovative is still struggling to implement the practices and culture of sustainability.

In her role as a teaching lab coordinator at the Johns Hopkins Institute for Nanobiotechnology (INTB), Christine Duke noticed a contrast between campus-wide sustainability initiatives and research labs:

“There is something missing here. Why aren’t we doing anything in the labs?”

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3D Cell Culture Models: Challenges for Cell-Based Assays

Posted on by Isobel Maciver
3D Cell Culture Spheroid
3D Cell Culture Spheroid

In 3D cell culture models, cells are grown under conditions that allow the formation of multicellular spheroids or microtissues. Instead of growing in a monolayer on a plate surface, cells in 3D culture grow within a support matrix that allows them to interact with each other, forming cell:cell connections and creating an environment that mimics the situation in the body more closely than traditional 2D systems. Although 3D cultures are designed to offer a more physiologically accurate environment, the added complexity of that environment can also present challenges to experimental design when performing cell-based assays. For example, it can be a challenge for assay reagents to penetrate to the center of larger microtissues and for lytic assays to disrupt all cells within the 3D system.

Earlier this week Terry Riss, a Senior Product Specialist at Promega, presented a Webinar on the challenges of performing cell-based assays on microtissues in 3D cell culture. During the Webinar, Terry gave an overview of the different methods available for 3D cell culture, providing a description of the advantages of each. He then discussed considerations for designing and optimizing cell-based  assays for use in 3D culture systems, providing several  recommendations to keep in mind when performing cell viability assays on larger microtissue samples.

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Monochromator vs Filter-Based Plate Reader: Which is Better?

Posted on by Johanna Lee

When it comes to purchasing a microplate reader for fluorescence detection, the most common question is whether to choose a monochromator-based reader or filter-based reader. In this blog, we’ll discuss how both types of plate readers work and factors to consider when determining the best plate reader for your need.

How do monochromator-based plate readers work?

Monochromators work by taking a light source and splitting the light to focus a particular wavelength on the sample. During excitation, the light passes through a narrow slit, directed by a series of mirrors and diffraction grating and then passes through a second narrow slit prior to reaching the sample. This ensures the desired wavelength is selected to excite the fluorophore. Once the fluorophore is excited, it emits light at a different, longer wavelength. This emission light is captured by another series of mirrors, grating and slits to limit the emission to a desired wavelength, which then enters a detector for signal readout.

Monochromator-based plate reader
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Just What Is an RLU (Relative Light Unit)?

Posted on by Promega

This post was contributed by guest blogger, Scott Messenger, Technical Support Scientist 2 at Promega Corporation.

It’s always an exciting time in the lab when you find a new assay to answer an important research question. Once you get your hands on the assay, it is always good to confirm it will work for your experimental setup. Repeating the control experiment shown in the technical manual is a great way to test the assay in your hands.

After running that first experiment of your assay, it looks pretty good. The trends of control and treatment are consistent. Time to get on with the experiments…but wait—the RLUs (Relative Light Units) are two orders of magnitude lower than the example data! I can’t show this data to my colleagues; it doesn’t match. What did I do wrong?

Relative Light Units, Measuring, Luminescence

This is a concern that we in Technical Services hear frequently. The concern is real, and I had this same thought when doing some of my first experiments using luminescence. When a question like this comes in, a Technical Service Scientist will make sure the experiment was performed as we described, and in most cases it is. We then start talking about RLUs (Relative Light Units).

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Maximize Your Time in the Lab: Improve Experimental Reproducibility with Thaw-and-Use Cells

Posted on by Michele Arduengo

Many cell biology researchers can name their department’s  or institutions’s “cell culture wizard”—the technician with 20+ years of experience whose cell cultures are always free from contamination, exhibit reliable doubling rates and show no phenotype or genotype weirdness. Cell culture takes skill and experience. Primary cell culture can be even more difficult still, and many research and pharmaceutical applications require primary cells.

Yet, among the many causes of failure to replicate study results, variability in cell culture stands out (1). Add to the normal challenges of cell culture a pandemic that shut down cell culture facilities and still limits when and how often researchers can monitor their cell culture lines, and the problem of cell culture variability is magnified further.

Treating Cells as Reagents

A good way to reduce variability in cell-based studies is to use the thaw-and-use frozen stock approach. This involves freezing a large batch of “stock” cells, then performing quality control tests to ensure they respond appropriately to treatment. Then whenever you need to perform an assay, just thaw another vial of cells from that batch and begin your assay—just like an assay reagent! This approach eliminates the need to grow your cells to a specific stage, which could take days and introduce more variability.

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Cloning Blunt-Ended DNA Fragments is Hard: pGEM®-T Vectors Can Make It Easier.

Posted on by Leah Cronan

PCR amplification with a proofreading polymerase, like Pfu DNA polymerase, will leave you with a blunt end. However, another thermostable DNA polymerase, like Taq DNA Polymerase, adds a single nucleotide base to the 3’ end of the DNA fragment, usually an adenine, creating an “A” overhang. This “A” overhang can create difficulties when cloning the fragment is your end goal. You might consider creating a blunt end with Klenow or adding restriction sites to the ends of your PCR fragment by designing them in your primers. But why go through all those extra steps, when that “A” overhang allows efficient cloning of these fragments into T-Vectors such as the pGEM®-T Vectors? Fewer steps? Who can argue with that?

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