Skip to main content
Petri Dish

Petri Dish

By Petri Dish
Profane, insane, and 100% primo science, Petri Dish is a no-BS podcast that explores the wildest subjects in modern science with clarity and evil joy.

Hosted by Sean Allen, a Nanoparticle/Immunology Researcher, and Nathan Allen, his "screenwriter" brother, Petri Dish fuses hard science with a freewheeling and madcap conversational style.

Cannabinoids, Plague, Cats, the dreaded Candiru, and the even more dreaded Covid-19: all these and more are dissected with intellect and irreverence, dropping every week.

So reject ignorance. Join the Scientific Revolution. Join Petri Dish.
Listen on
Where to listen
Apple Podcasts Logo

Apple Podcasts

Breaker Logo


Castbox Logo


Google Podcasts Logo

Google Podcasts

Overcast Logo


Pocket Casts Logo

Pocket Casts

RadioPublic Logo


Spotify Logo


Stitcher Logo


Hiatus Announcement
Hey everyone! Hope you're all staying safe and healthy! We here at Petri Dish are taking a 2 week hiatus, but we'll be back with more science soon!
January 24, 2022
Ep. 132 Crustaceans Pt 2: Everybody Wants to Be a Crab
Hi everyone! In part 1 of crustaceans we laid down a lot of groundwork on what crustaceans even *are*. But here in part 2 we wanted to spend some time talking about a hot topic in crustacean-world: "carcinization" aka "stuff keeps evolving into crabs"! But not *all* crustaceans are yearning for crabdom -- there is a specific group called anomurans that really dig that crab vibe. Learn about them and what it takes to be a crab on this episode of Petri Dish! Real Ad! - Promo code is QUICKSTART References:
January 17, 2022
Ep. 131 Crustaceans Pt 1: What the F*** is a Shrimp?
Hey everyone! On this episode of Petri Dish we ask the question everyone has been asking since time immemorial -- what the fuck is a shrimp? Like seriously, what is that shit? No, I mean, I ask because there are so many things called shrimp -- fairy shrimp, mantis shrimp, seed shrimp, and so on... And while they look kind of similar to one another, they really aren't all that related, separated by hundreds of millions of years of evolution. But they all belong in the big group of animals called 'Crustaceans', along with crabs and lobsters! And insects. Wait, what? Yeah, this group of animals is a total mess, so let's talk about it! References:
January 10, 2022
Ep. 130 Kelp Pt 3: Chew on That
Our final episode on kelp! We've spent the last two episodes discussing natural kelp forests and some of the fun things we can use kelp to do like bioremediation. This episode, we talk about the nutritional value of kelp and some food uses, including in food for cows! Real ad for BetterHelp, check out their offer at References:
January 03, 2022
Ep. 129 Kelp Pt 2: Fixing, Farming, and Filtering
Part 2 of 3 of our series on Kelp! Part 1 was all about natural kelp forests and how cool they are, but part 2 is focused on how humans can EXPLOIT kelp for our own purposes, muahahaha! Can we use kelp to fix all that carbon we've been releasing into the atmosphere to help us reverse climate change? What about farming kelp for food and products? What about using kelp as a fancy filtration system to clean up water supplies? Find out about all that this week! Real ad for BetterHelp, check out their offer at References:
December 27, 2021
Ep. 128 Kelp Pt 1: Forests Au Naturale
Hey everyone! This next series of Petri Dish is about Kelp, due to strong demand from Nathan. Kelp are those big floaty plant-looking things (but they aren't plants, technically)! This episode, we dive into natural kelp forests and how they're both environmentally great and also at risk of shrinkage. In future episodes we'll cover kelp farming and the fun uses of kelp! Real ad for BetterHelp, check out their offer at References:
December 20, 2021
Ep. 127 Koji: A Fancy Fermenty Thing
This week we have a one-off episode for you on koji! Koji is a Japanese fermented ingredient with analogues in other East Asian cuisines -- basically it is a grain that has some mold growing on it. But oh, the fancy foods you can make with it! Soy sauce, miso, sake, and so many other delicious things! But how does koji get made? What is the deal with the mold? And what sorts of fun things could you make at home with this fuzzy stuff? References:
December 13, 2021
Ep. 126 Afforestation Pt 2: The Great Green Wall
Hi folks! Welcome to part 2 on Afforestation/Reforestation! Last time, we discussed the Chinese effort to plant a ton of trees, both to combat desertification and to capture carbon, with complex results in terms of water availability and climate across the whole of China. This time, we discuss the Great Green Wall of Africa, an effort to stem the growth of the Sahara (whether it is growing or not is actually a matter of some debate...). We'll also talk some about Sargassum! Hop on in! Use the code POD at to get big discounts this holiday season! References:
December 06, 2021
Ep. 125 Afforestation Pt 1: Build a Forest Back Better
Hey everyone! On this week's episode of Petri Dish, Sean and Nathan start their two-part conversation on Afforestation and Reforestation! There's a lot of talk about how trees can help save the planet from climate change and make all kinds of fun biomes for critters, replenish aquifers, prevent desertification, and so on. But is it as simple as just planting a ton of trees? Tune in to find out about all the sciencey details! References:
November 29, 2021
Ep. 124 Beer Pt 3: The Beer of Future Past
On this, our last episode of our series on beer, we discuss the history of beer then talk about some of the cool ways synthetic biology and genetic engineering are being used to make the beer of the future! References:
November 22, 2021
Ep. 123 Beer Pt 2: So Many Wonderful Types
Last week we discussed how to make a beer. This week we use that knowledge to discuss the differences between different kinds of beers, from delicious stouts to stanky sours! Next week we'll talk about the past and future of beer, including genetic modification! References:
November 15, 2021
Ep. 122 Beer Pt 1: How to Make a Brew
Beer! One of humanity's oldest companions! Why are there so many kinds? How do we go about making beer? What is science doing to advance beer into the future? This is a three-parter on beer, with the first week focusing on the steps involved in beermaking, along with the science behind them! Next week we'll cover the different kinds of beer, followed by an episode on the future of beer! References:
November 08, 2021
Ep. 121 CoronaUpdate: Maybe Another Treatment
On this episode of Petri Dish, we have two updates on the ongoing COVID-19 pandemic! First, the FDA has approved the use of the Pfizer vaccine on children ages 5 and up! Second, there is a new promising small molecule drug coming out of clinical trials that seems to reduce severe COVID by 50% in high-risk patients AND it can be taken orally! Find out about the science behind these two topics this week on Petri Dish! References:
November 01, 2021
Ep. 120 Halloween: Macabre Mummies
It's the spooky season once again and this year on Petri Dish we explore the science and history of mummies! While ancient Egyptian mummies certainly have captivated the world, they aren't even close to the only culture that purposefully mummified the dead! Learn about other ancient mummies, and some much more modern ones as well, this week on Petri Dish! Warning! This episode mentions human remains and some stuff that is truly macabre -- that definitely is also true for the references! References:
October 25, 2021
Ep. 119 HIV/AIDS Pt 4: Bone Marrow and Genetic Engineering
In our final episode in our series on HIV/AIDS, we discuss the cutting edge treatments and vaccines that are currently being tested! One of the treatments discussed even aims to be about as close to a 'cure' as is possible for HIV infection -- learn how they plan to do it! References:
October 18, 2021
Ep. 118 HIV/AIDS Pt 3: Current Treatments
Welcome to part 3 of our series on HIV/AIDS! In the previous two episodes we covered the history of HIV/AIDS and how HIV/AIDS works on the cellular level. In this episode we use that information to understand how our current arsenal of anti-retroviral drugs work! Next week we'll be discussing the treatments on the horizon that may help us reach an end of the HIV/AIDS global epidemic! Ad Sponsor Info: Link: Code: HFAFF80 Offer: $80 Discount ($50 - $20 - $10) Including Free Shipping on First Box! References:
October 11, 2021
Ep. 117 HIV/AIDS Pt 2: Acute and Chronic
This week on Petri Dish we dive deeper into HIV/AIDS pathophysiology -- how does HIV do what it does to your body? How does the virus target specific cells? What does it do once it gets into your cells? Definitely an important episode to listen to in order to prep for our next two episodes on current and future treatments! Ad Sponsor Info: Link: Code: HFAFF80 Offer: $80 Discount ($50 - $20 - $10) Including Free Shipping on First Box! References:
October 04, 2021
Ep. 116 HIV/AIDS: The Present and the Past
Recent news has led to a lot of excitement with relation to HIV/AIDS -- approval for clinical trials using a new vaccine and a new treatment/potential cure has led to a lot of buzz! But what is the current state of the HIV/AIDS global epidemic? When did HIV first evolve into being? What even is HIV? Ad Sponsor Info: Link: Code: HFAFF80 Offer: $80 Discount ($50 - $20 - $10) Including Free Shipping on First Box! References:
September 27, 2021
Ep. 115 COVID Vaccine Booster Shots!
This week we have a short episode, a Q&A on COVID vaccine booster shots based on the latest info from 09/17/2021! Who can currently get a COVID booster shot? What happened with the FDA recently relating to booster shots? What even is a booster shot? Find out this week! Ad Sponsor Info: Link: Code: HFAFF80 Offer: $80 Discount ($50 - $20 - $10) Including Free Shipping on First Box!
September 20, 2021
Ep. 114 Strange Medieval Treatments Feat. The Microbe Moment Pt. 2
It's part 2 of our collaboration with The Microbe Moment (a podcast from The Microbigals!! We return to our discussion of some of the more ridiculous Medieval treatments for diseases that we could find in our research! Listen in for some of the odder things humans have done to other humans to try to treat a disease! Ad Sponsor: Hello Fresh (Canada) Link: Code: HFAFF80 Offer: $80 Discount ($50 - $20 - $10) Including Free Shipping on First Box!
September 13, 2021
Ep. 113 Strange Medieval Treatments Feat. The Microbe Moment Pt. 1
In the first episode of our collaboration with The Microbe Moment (a podcast from The Microbigals!, we discuss some of the more ridiculous Medieval treatments for diseases that we could find in our research! Listen in for some of the odder things humans have done to other humans to try to treat a disease! Ad Sponsor: Hello Fresh (Canada) Link: Code: HFAFF80 Offer: $80 Discount ($50 - $20 - $10) Including Free Shipping on First Box!
September 06, 2021
Ep. 112 Multiple Sclerosis Pt 3: Current and Future Treatments
In this final episode of our series on Multiple Sclerosis, we discuss the current treatments available for the disease, mainly for the relapsing/remitting form. We then discuss what some of the future treatments look like, including those currently in clinical trials, that may be able to help treat the progressive form of MS! Ad Sponsor: Hello Fresh (Canada) Link: Code: HFAFF80 Offer: $80 Discount ($50 - $20 - $10) Including Free Shipping on First Box! References:
August 30, 2021
Ep. 111 Multiple Sclerosis Pt 2: Missing Myelin
Last week we started our series on multiple sclerosis by discussing the history of the disease, the symptoms, and the various forms of the disease. This week we dive into the biological cause of the disease. What makes multiple sclerosis pop up? What sorts of genetic or environmental factors seem to play a role? We also recommend you check out Eps 63/64 on the blood brain barrier, Eps 56/57 on autoimmune disorders, and Ep 38 on the adaptive immune system for more background information! Ad Sponsor: Hello Fresh (Canada) Link: Code: HFAFF80 Offer: $80 Discount ($50 - $20 - $10) Including Free Shipping on First Box! References:
August 23, 2021
Ep. 110 Multiple Sclerosis Pt 1: Not Scoliosis
In this week's episode, Nathan and Sean start their discussion of multiple sclerosis, a progressive autoimmune neurodegenerative disorder with a ton of symptoms and freaky way of popping up and disappearing willy-nilly! Learn about Saint Ludwina, the patron saint of ice skaters! Find out what myelin is! Hear acronyms like RRMS! All on this week's episode of Petri Dish! Ad Sponsor: Hello Fresh (Canada) Link: Code: HFAFF80 Offer: $80 Discount ($50 - $20 - $10) Including Free Shipping on First Box! References:
August 16, 2021
Ep. 109 Artificial Sweeteners Pt 3: Rumors and Suspicions
This week on Petri Dish, Sean, Nathan, and special guest Andrei wrap up their discussion on non-nutritive sweeteners by looking at what evidence is out there on potential harmful impacts of these sweeteners. Do sweeteners cause cancer? Do they help you lose weight, or actually make you gain weight!? What about your microbiome, or the environment? Find out this week! References:
August 09, 2021
Ep. 108 Artificial Sweeteners Pt 2: 'Natural'
Hey everyone! This week's episode continues our discussion on non-nutritive sweeteners! Last week we discussed synthetic sweeteners, the ones made in labs like Sweet N Low or Splenda. But there are sweeteners on the market that are 'natural', like stevia or monkfruit. What is up with those sweeteners? Are they just different kinds of sugars, or are they something else entirely? References:
August 02, 2021
Ep. 107 Artificial Sweeteners Pt 1: Finger Lickin' Sweet
This first episode in our three-parter on non-nutritive sweeteners is about the artificial stuff, the most-accidental discoveries that led to saccharin, aspartame, sucralose, all the big ones, all the hits! How do these synthetic sweeteners work? How do they differ from one another? Next week we'll cover 'natural' non-nutritive sweeteners and the week after that we'll cover whether there are any risks to their frequent use! Ad Link: References:
July 26, 2021
Ep. 106 Alzheimer's Disease Pt. 3: Alternate Hypotheses
In this final episode of our series on Alzheimer's Disease, we discuss some of the alternate hypotheses for what actually causes and drives progression of Alzheimer's Disease, if not amyloid beta. What other ideas are some scientists working through? Featuring a promo for Infectious Groove, a great podcast music podcast! Ad Link: References:
July 19, 2021
Ep. 105 Alzheimer's Disease Pt 2: FDA Approval
I don't know if y'all have heard or not, but a month ago the FDA approved a drug for the treatment of Alzheimer's Disease, the first one in a couple of decades. This approval was met with the resignation of some members of the FDA's own scientific advisory group, which had recommended that the drug not be approved. What is going on here? Let's get into the science behind this drug, how the approval process works, and what this whole situation means! Featuring a promo for Just the Zoo of Us, a great podcast about animal facts! Ad Link: References:
July 12, 2021
Ep. 104 Alzheimer's Disease Pt 1: Amyloid Hypothesis
One of the top killers of people over the age of 65, Alzheimer's Disease is the target of cutting edge pharmaceutical research and basic science. What do we already know about the symptoms and their biological causes? As it turns out, there is still a good amount of controversy when it comes to the fundamental mechanism of this disease! Ad Link: References:
July 05, 2021
Ep. 103 Cloning Pt 2: Why Would Anyone Do This?
Ad Link: Last week we discussed how someone could go about cloning something, but this week we dive into the WHY. Maybe there is no particularly good reason to do reproductive cloning for humans, but what about individuals of endangered species? What about trying to bring back recently extinct species? What about cloning to try to create new species? Featuring a promo for The Bald Scientist Podcast! References:
June 28, 2021
Ep. 102: How to Make a Clone Pt 1
Ad Link: Jurassic Park! Dolly the Sheep! Mammoths! Cloning went from science fiction to science, but maybe had fallen a bit out of vogue for a while? But some other concepts that can include cloning technology, like certain kinds of stem cell work and maybe bringing extinct species back to life! This episode, find out how reproductive cloning works! Next episode we'll talk about what it can be used for (and a little bit on whether we think it should be done at all). Feat. a promo for For Your Reference, a TV/Movie discussion podcast! References
June 21, 2021
Ep. 101 Allergies Pt. 4: Treatments and Future Cures
Ad link: Back from the brief interruption of our allergies series to celebrate our 100th episode, we're wrapping things up by talking about treatments for allergies and what scientists have been cooking up to help people get back to snorting cat dander. Don't worry, only one of the treatments involves getting purposefully infected with worms. Feat. a promo for Oz-9, a very funny science fiction/comedy podcast! References:
June 14, 2021
Ep. 100: The Big One Hundo
The 100th episode! Woo, we did it everyone! Thank you for listening to the podcast! This episode, Sean released his grip on the reins and let Nathan and Stacey pick topics to discuss, and so this episode is about: The History of the Number Zero Buttholes (Thanks, Nathan) Ad Link: Featuring a promo for Curiosity Kill the Rat, another great science podcast! References:
June 07, 2021
Ep. 99 Allergies Pt 3: Hygiene and Old Friends
Ad URL: Okay, so you have allergies, your friends have allergies, your enemies have allergies -- why does everyone seem to be allergic to stuff nowadays? Are we more allergic to things than we used to be? And if so, why? PROMO: Plants and Pipettes Podcast! References:
May 31, 2021
Ep. 98 Allergies Pt 2: Get Your Inhalers Ready
Ad URL: Asthma! Hives! Hay Fever! Such a wide variety of allergic responses -- what do they have in common? Surprisingly a huge amount! This episode we get into the biological details of the kinds of allergies we're all used to thinking about. PROMO: Thorndale Podcast! References:
May 24, 2021
Ep. 97 Allergies Pt 1: So Hypersensitive
Ad URL: Everyone knows about allergies! But, at the same time, hives seem very different from asthma, and both seem different from seasonal allergies. What is going on? On this first episode, we dive into one way of categorizing and describing allergies: the hypersensitivity type system! PROMO: Not Suitable for Adults Podcast! References:
May 17, 2021
Ep. 96 Spiciness Pt 2: The Return of the Burn
Ad URL: We’re back to discuss some more stuff about that spicy burny feeling! Our first spicy episode (Ep. 94) was focused on capsaicin, but that isn’t the only game in town! What are some of the other spicy molecules out there? Also, is there a scientifically approved method for cooling your mouth down after you’ve scarfed down too much Hot Chicken? Find out this week! Feat. a promo for Everything I Learned From Movies! References:
May 10, 2021
Ep. 95 Star Wars' LAZERSWORDS
Ad Link: Happy May the Fourth! Would it be possible to build a real lightsaber, just like what they have in the movies? Probably not! But the things keeping us from getting to have our very own bzzt bzzt blades might not be what you think they are! Listen in to find out potential ways scientists have been trying to come up with to make lightsabers a reality! Feat. a promo for Book Retorts! A winning combination of book recaps, reviews, and humor! References:
May 03, 2021
Ep. 94 Spicy Hotness Pt. 1 - Feel the Burn
Advertising Link: If you're like me, you love that burning sensation from a nice dose of capsaicin, maybe in a salsa or a tasty Thai dish. But what exactly is capsaicin, where does it come from, and how does it make your tongue feel like it is on fire? Find out this week on Petri Dish! Featuring a promo for Lit Gaming Arena, a podcast for all sorts of gaming news, reviews, and commentary! References:
April 26, 2021
Ep. 93 One in a Million: Adenovirus COVID Vaccines and Blood Clots  The AstraZeneca and Johnson & Johnson COVID vaccines have been in the news recently, suspected of causing a rare blood clotting issue in a small number of people who receive them. What is going on with these two vaccines, while the Moderna and Pfizer/BioNTech vaccines don't seem to have this problem? What are blot clots anyway and are the one in a million and on in one hundred thousand blood clots seen here just your average clot, or something more unusual? There is plenty that scientists don't know yet, but whatever we know, we want to share with you! Feat. a promo for Snark Tank, a pop culture podcast! References:
April 19, 2021
Ep. 92 Regeneration Part 3: Newt Eyes and Lizard Tails
Why can newts grow back part of their spine and brain while we're walking around unable to even heal a broken heart!? Even amongst us tetrapods, the ability to regenerate varies wildly! Learn how amphibians regenerate their body parts, how lizards regrow their tails, and how little human kids can regrow the tips of their fingers, apparently! Feat. a promo for Twisted and Uncorked, a true crime/paranormal podcast! Email us at petridishpod -at- On twitter @dishpodcast and instagram @petridishpodcast. References:
April 12, 2021
Ep. 91 Regeneration Part 2: Decapitating Sea Slugs
Last week we talked about hydra and planarians, which you can slice and dice into little bits and all the bits will regrow into new little jabronis! But they're pretty distant from us on the evolutionary tree, so how about we get a little closer! This week, we talk about sea slugs and zebrafish, two aquatic critters with pretty impressive regenerative abilities! Feat. a promo for I Said God Damn! A True Crime Podcast! Email us at petridishpod -at- On twitter @dishpodcast and instagram @petridishpodcast. References: