GUEST EPISODE 05
Mycelium for Sustainable Packaging
4th August, 2025
Hemdeep Patel , Robin Boshoven , Alexandre LeBlond
How far can fungi take sustainable materials?
In this three-part series, we speak with Alexandre LeBlond, a master’s student in chemical engineering at McGill University, about his groundbreaking research using mycelium, the root-like structure of fungi, to create sustainable alternatives to traditional packaging and construction materials. In each episode, we cover:
Part 1
The environmental challenges posed by styrofoam and plastic, how mycelium could replace them, and the early experiments Alex and his fellow lab members are running to grow biodegradable packaging materials at scale.
Part 2
The innovative techniques Alex and his team use, from microfluidics to internal gelation to optimize mycelium growth, improve consistency, and speed up production for real-world applications.
Part 3
Future direction and topics of interest, such as: using SPG emulsification to create uniform mycelium beads; remote rehydration for on-site construction, and even probing the “intelligence” of brain-sized mycelium structures with EEG experiments.
So whether you’re passionate about sustainability, bioengineering, or the future of living materials, this series is for you.
Podcast Summary
McGill University chemical engineering master’s student Alexandre LeBlond, working in the Cellular Microenvironment Design Lab (Moraes Lab), is developing mycelium-based biomaterials as a biodegradable alternative to Styrofoam and polyurethane packaging. The project started as a classroom assignment and grew into a full master’s thesis focused on one specific bottleneck: production speed.
The core material is made by growing mycelium, the root-like network of a fungus, into a wood-waste substrate such as sawdust or straw. LeBlond’s lab uses white rot fungi, specifically Ganoderma lucidum (which forms a rigid mat) and oyster mushroom (which forms a fluffier mat). Once fully colonized, the resulting composite has density and insulation properties comparable to Styrofoam or polyurethane foam, but it biodegrades in a backyard in about 45 days, compared to roughly 500 years for conventional Styrofoam. The material is also self-regenerative: a piece of already-colonized mycelium can be transferred into fresh substrate and will restart growth. Production runs through four stages: substrate seeding, colonization, mold removal, and autoclaving (heat-killing the mycelium so it stops growing once shipped as packaging). Colonization is by far the slowest step, taking 5 to 20-plus days, versus minutes to hours for conventional plastic manufacturing.
Much of LeBlond’s research targets that colonization bottleneck. Drawing an analogy to plant propagation, where cuttings that are too small or too large both grow back slowly, the team hypothesized there might be an optimal starting fragment size for mycelium. Early 2D experiments on agar plates used biopsy punches to cut 1, 2, and 3-millimeter mycelium “plugs” at varying spacing. Plugs placed farther apart (up to 6 mm) produced patchy, non-uniform growth, while closer plugs fused into a single, homogeneous colony once they recognized shared DNA. Interestingly, 1-mm and 3-mm plugs covered the same fixed area despite very different starting biomass, suggesting smaller, more numerous fragments colonize more efficiently.
To push past the resolution limits of biopsy punches, the team moved into microfluidics, building PDMS channel devices (100 microns tall and wide, 8 mm long) loaded with agarose as a nutrient source. Both the PDMS molds and the agarose molds were made using 3D-printed molds on a CADWorks 3D printer, a workflow LeBlond described as immediately reliable once the lab had access to high-resolution resin printing. By cutting open chips after two days and measuring fragment size against biomass gained, the team identified a clear optimal starting volume of about 60,000 cubic microns, roughly a 50-micron sphere, that produced 10 to 15 times biomass growth within two days. Fragments below this threshold barely grew, and larger fragments grew only 1.5 to 2 times their starting size over the same period.
The next challenge is producing large quantities of these optimally sized fragments continuously. Mechanical blending damages the mycelium and produces inconsistent sizes, while standard external gelation (dripping alginate into calcium chloride) yields larger, poorly controlled particles that are hard to scale industrially. LeBlond’s team is instead adapting internal gelation, an oil-emulsion technique borrowed from a McGill lab that encapsulates mammalian cells for type 1 diabetes research, likening the process to shaking a vinaigrette until droplets shrink. Because that method still produces a wide size distribution, they are now testing SPG (Shirasu Porous Glass) emulsification, pushing the alginate–mycelium mixture through a porous membrane with roughly 50-micron pores to generate consistently sized particles (100–150 microns once in the oil phase). Bead gelation is then triggered chemically, producing a soft, porous alginate hydrogel that lets mycelium grow out easily. As LeBlond put it, describing the appeal of rapid, precise prototyping: “It was so satisfying to have something in mind, and just make it, exactly the size you need.”
Looking ahead, the lab is planning 3D “transparent soil” experiments to test how particle placement, including proximity to the air-solid interface where mycelium naturally forms its rigid outer coat, affects colonization speed. Other open questions include whether beads can be dehydrated, shipped, and rehydrated to trigger growth on-site for remote construction applications, and whether mycelium-based building materials could stay alive to enable self-repair. A more exploratory side project involves growing a brain-sized mycelium structure and recording its electrical activity with an EEG at the Montreal Neurological Institute, with future tests planned under chemical exposure to probe fungal responsiveness. Beyond packaging, LeBlond noted that mycelium is already used commercially in insulation panels and experimentally in leather-like and woven textile materials, though any application depends on the fungal strain’s ability to actually decay the chosen substrate.
Available on :
"When we make that material for packaging, we autoclave the mycelium. So we pass it into the oven to make sure it's fully cooked and killed. this way... Growing. Exactly. So it won't grow on your package, and likewise, it won't grow on the toilet. So that's some of the different horizons that we can get."
Transcripts
Part 1 Transcript
From Classroom Project to Sustainable Packaging Part 1
Hemdeep: Welcome to Big Ideas in Microscale, the podcast where we explore groundbreaking research happening at the microscale, where micro innovations make a big impact. We’re excited to showcase the incredible work being done by our users from around the world who are pushing the boundaries of microfluidics, lab-on-a-chip, organ-on-a-chip, and beyond. Through these conversations, we hope to learn from their experiences, uncover their insights, and bring their big ideas to a wider audience. So whether you’re in a lab, on the go, or just curious about the future of microtechnology, join us as we dive into big ideas at microscale.
Welcome back to Big Ideas in Microscale. Today we have a master’s student from McGill University; in our preliminary conversations with him, we dove deep into sustainable manufacturing, and I think this is going to be an extremely interesting conversation. My name is Hemdeep, and my co-host is…
Robin: That’s me.
Hemdeep: Today we’re joined by Alexandre, and I’m sure he’ll have a very interesting conversation with us; I’ve got a ton of questions for him too. Welcome to our little podcast here.
Alexandre: Well, thank you for having me. I’m very happy to be able to come and exchange ideas with you all.
Hemdeep: Let’s dive into who you are, the lab you work in, and how you got there, your pathway to where you are now.
Alexandre: Absolutely. I’m Alexandre, from Montreal, grew up there my whole life. I studied chemical engineering at McGill for my undergrad, and joined the Cellular Microenvironment Design Lab in 2023, right after I graduated. That’s a bit about where I am right now. It’s an interesting lab, with a lot of really different projects going on: people working on type 1 diabetes, breast cancer, air-liquid interface differentiation of epithelial cells, and a lot of other things. The whole lab studies the mechanobiology around how those different cell types differentiate.
My project is a bit different, though. It came out of a class I took with Chris, my supervisor, who was teaching it. One of our class projects was to make a sustainable mycelium composite, and I was really intrigued, since the way he framed it was: if you put the root-like part of a mushroom onto a wood waste byproduct, it forms a material with properties similar to polystyrene, but fully biodegradable. We had to do one of these projects for class, and I thought it was super interesting. When I was looking at what to do for my master’s, I thought this could be a great project, since I’ve always leaned toward sustainability, especially around materials, in chemical engineering. So I pitched it to Chris: “hey, could this be something interesting for you? I know it’s not exactly what the lab does, but I think it could be really interesting.” He said, “yeah, why not, let’s give it a try.” And here I am.
Hemdeep: That’s one of those unique moments where a classroom lesson turns into a possible commercial idea, solving a real problem. Was that the first time you’d seen that connection between a classroom lesson and a real-world application?
Alexandre: I’d say so. At McGill, especially in chemical engineering, it’s very theoretical; we barely even see a real pump, everything’s on paper. So being in the lab, actually building these prototypes and devices, I thought, this is really interesting, and it fits my values around sustainability. I thought this could be a really fun thing to develop further.
Robin: Is that normal? From what I understood, usually the PI assigns projects to students joining a lab. Here it’s the opposite: you approached Chris Moraes yourself and said, “I want to do this,” and he was willing to go for it.
Alexandre: I’d say it depends; our lab is also a bit different, with a lot of projects always coming in. When I emailed him, he said he really liked that it was me bringing the project, since that usually means the student is more motivated; they’re not just there because of a PI’s reputation, or the lab’s overall reputation, they’re there because they actually want to do this specific thing. I think that’s a bit special, a different kind of master’s experience. I’ve seen other labs that are very by-the-book, very “we’re a lab that only does this.” Here, it’s more “let’s take a different direction, let’s take some risks,” and that’s what I like about it.
Hemdeep: So with a number of disciplines all doing their own research in the lab, it sounds like there’s a lot of collaboration needed. For your project specifically, since you’re heading it, are you reaching out to people across the lab to help with the work?
Alexandre: Yes, definitely. Some of the techniques we’ve developed, whether with 3D printing or, say, agarose molds, have already been used in the lab by other people, so even though my project is a bit different, I can draw on ideas others have already developed and bring that into my research. Everyone’s collaborating together. Sometimes there’s real overlap, between different cell types and, in our case, mycelium; ideas come back around. Since people, postdocs, PhD students, come from different labs and backgrounds, we’re all able to come together and share ideas, even across pretty different projects.
Robin: Let’s talk more about your research specifically. Tell us about mycelium materials: what are they, what’s their purpose, just so our audience has a better sense of it.
Alexandre: To summarize the big picture: we’re taking the root-like part of the mushroom, called mycelium, not the fruiting body you’d buy at the grocery store and put in soup, but the part that grows underground. We put that into a substrate, sawdust or straw, for example, and slowly the mycelium grows and fully colonizes that substrate, forming a kind of brick with similar properties to Styrofoam or polyurethane: similar density, similar heat insulation, but it degrades in your backyard in about 45 days, compared to roughly 500 years for conventional Styrofoam.
The neat part is that it’s also self-regenerative: as long as it’s alive, you can take a piece of already-colonized mycelium, put it into fresh substrate, and it’ll restart and grow into a new colonized material. This is a really interesting application for packaging specifically, because currently, whenever you receive packaging, there’s usually a ton of Styrofoam involved, and that typically just ends up as waste almost immediately; you get a new appliance, say a new fridge for the lab, and it comes packed with Styrofoam that immediately goes to waste, taking around 500 years to degrade. If we replace that with a functional plastic alternative like this, we can put it in the backyard, and it degrades in about 45 days.
Robin: What does that process actually look like? Do you just dig a hole in your garden, put it in, and that’s it?
Alexandre: Pretty much, yeah. It’s fully compostable; you just put it in your backyard, and that’s basically it. It’s made entirely of natural material, mushroom and sawdust, so it takes up water, and the rest of the soil starts degrading it from there.
Hemdeep: Does the mycelium itself need to come from a specific type of fungus, or do you grow it in the lab? How does that work?
Alexandre: Within the fungal kingdom, there are a lot of different types of fungus, but we use one specific branch called white rot fungi, the type that degrades wood, the kind you’d see breaking down wood in a forest; that’s exactly what we need. In our lab, we use Ganoderma lucidum, one of the two main strains typically used; the other is oyster mushroom. Different strains form different types of mat as well: our Ganoderma strain forms a very rigid mycelium mat, whereas oyster mushroom forms a fluffier type of mat. So even within white rot fungi, there’s variation, but both can be used to make this kind of packaging material.
Hemdeep: So there’s a link between the type of mushroom used and the properties of the resulting composite. Could your research effectively help people identify new combinations of mushroom and available raw material?
Alexandre: I’d say my research isn’t really about finding new combinations; it’s more about how we can make these materials faster, at larger scale. But yes, different mushroom strains can be used to make different types of material, so we’re not limited to packaging; that’s just the most important application for me right now, and where I want to focus. But this can also help make larger materials for other applications. There’s already been development of leather-like materials from mycelium, coats made of mycelium leather, and people are starting to work on woven fabric too, so clothing is another interesting direction.
One of our collaborators at UBC, a postdoc in the architecture department named Nicholas Lin [name as transcribed; unconfirmed], has been working on large-scale mycelium building applications, and they developed a toilet meant to replace conventional composting toilets, made of mushroom material. The really interesting part is that when they tested it, it didn’t have that characteristic composting-toilet smell, which was a big surprise; the mycelium material, even though the mycelium itself is completely dead at that point, just a remaining structure, didn’t carry that odor. That was really interesting to see.
Robin: So the entire toilet was made out of mycelium? Sorry, I’m just trying to wrap my head around what that actually looks like.
Alexandre: Yeah, me too, honestly, it’s an interesting thing to picture. The whole toilet is basically a substrate that’s been colonized by mycelium. I should also mention, when we make material for packaging, we autoclave the mycelium, basically run it through the equivalent of an oven, to make sure it’s fully cooked and killed. That way it won’t keep growing on your package, and the same goes for the toilet; that’s part of what makes these different applications work.
Robin: I’d imagine it’s also fairly waterproof, to some degree, in that case?
Alexandre: I’d say yes and no. What actually makes it biodegradable is that it can absorb water; the reason conventional plastics aren’t biodegradable is precisely because they’re not very water-permeable. So in our case, it’s not that waterproof, which is part of why it’s biodegradable. For the toilet, similarly, it’s probably not fully waterproof, but likely waterproof enough to hold up over a reasonable period; we’d need more detail on exactly how much it can withstand. It seems good enough for now; I believe they’re doing a demonstration in September.
Robin: I’m sure they’ve figured it out, because I don’t think anyone wants a disintegrating toilet while it’s actually in use.
Alexandre: Right, it won’t be instantaneous; over time it’ll degrade, but that’s the intended endpoint.
Robin: So degradation time is one property you compare between mycelium materials and polystyrene. What are some of the other properties you look at?
Alexandre: We’re not really doing a formal characteristics comparison ourselves; we’re mainly trying to speed up the growing process. But from the literature: cost is much lower, since it’s self-regenerative, and you don’t need much instrumentation or heating, you can just let it grow, say in an incubator at 30 degrees. That also makes it carbon-neutral, or even carbon-negative. What I mean is, conventional polymers are typically made from oil, and the process consumes a lot of energy and emits a lot of CO2. Here it’s the opposite; we’re almost capturing CO2 to make the material, or at least emitting very little. That’s a big difference from plastic polymers. There’s also density and insulation properties to consider.
But the main problem we’re trying to solve is production time. Plastics take minutes to hours to produce; mycelium composites take days to weeks. That means more time on the shelf, more overall production time, more cost, and more risk of contamination. Our real goal is to speed up that production process.
Robin: Let’s unpack that. Based on our earlier conversation, there are generally four stages to making these materials: substrate inoculation and seeding, mycelium colonization, removal from the mold, and then autoclaving, sterilizing the finished packaging so it’s ready to use. Which part of that process is causing the lengthy production time?
Alexandre: It’s really the colonization step. What’s great about this process is that we can make basically any packaging shape, as long as we have the right mold: put sawdust into a mold shaped, say, for a candle you want to ship, then add mycelium on top. That part doesn’t take long, we just make sure everything’s sterile. Then we let it grow, and that’s the long part, five to twenty days or more, depending on the substrate and how much mycelium you start with. Once it’s fully colonized, we simply take it out of the mold. So overall, the long part of the process really is just the colonization time, the mycelium fully covering the substrate.
Part 2 Transcript
From Agar Plates to Microfluidics Part 2
Robin: In today’s episode, we’re diving deeper into the groundbreaking work of Alexandre LeBlond, a master’s student in chemical engineering at McGill University.
Hemdeep: Last week, we explored how Alexandre is developing biodegradable packaging using mycelium, everything from mold design to the challenges of large-scale colonization, and why this fungus might be the key to sustainable packaging.
Robin: If you missed that episode, be sure to go back and check it out. This week, we’re looking at where Alexandre’s research began, on a 2D agar plate. We’ll explore how plug size and spacing affect mycelium growth, and how those results led the team toward microfluidics.
Hemdeep: We’ll also hear how Alexandre tackled scaling up, using a clever oil-based emulsion method to create optimally sized mycelium microbeads, and how accessible tools like 3D printing helped prototype and test everything along the way.
Robin: So let’s jump right back into big ideas in microscale.
Hemdeep: Taking one small step back, I think the work you did wasn’t originally on a three-dimensional mold, but on a 2D plate, correct? What did that work look like, what challenges did you face, and what did you find?
Alexandre: Right. The first question we had was, what’s causing this lengthy process, and our first guess was: is it about size? If you’ve ever tried propagating a plant, splitting it to start a new one, if the new piece you take is too small, it takes a long time to grow back, and if it’s too big, it also takes longer; there’s a sweet spot in between where it really thrives. We tried applying that idea to mycelium: is there an optimal size we can split it into, for these 2D agar plates, that makes a difference in overall colonization?
So we tested three sizes of plugs, using biopsy punches, basically fancy cookie cutters, at 3, 2, and 1 millimeter, to cut little agar-mycelium “cookies,” placed at different distances from each other. What we found was that when they were further apart, it resulted in patchy overall colonization, which isn’t what we want; we want a fully homogeneous material.
Robin: Sorry to pause you there, do you know what the actual distances were between these mycelium “cookies”?
Alexandre: A few millimeters apart; the closest were about two to three millimeters apart, and the furthest around six millimeters. When they were further apart, we saw that patchy growth, which we didn’t see when they were closer together. That was our first observation. We also defined a fixed area of agar, about 34 millimeters across, roughly the size of a well-plate well, and fit 18 plugs onto each disk, at different spacings. We found there wasn’t a big difference in coverage between the 1-millimeter and 3-millimeter plugs; both covered that same 34-millimeter area, which was interesting, since they started with very different amounts of initial biomass.
That’s when we realized size does seem to matter for overall colonization. If you applied this at equal biomass across a larger surface, the 1-millimeter plugs, which would mean about nine times as many plugs by area, would colonize much faster and further than the 3-millimeter plugs at the same total biomass. So smaller, more dispersed starting material colonizes faster than fewer, larger pieces. That’s roughly what we saw in this initial 2D assay.
Hemdeep: Was that a function of biomass, or actually the surface area of each plug, and its contact point with the material?
Alexandre: This particular test was just on agar, no wood involved, so it comes down to a balance between nutrients and surface area. I also think there’s likely some inhibition between separate pieces of mycelium early on, which limits their ability to expand and causes that patchy growth, even though, once they recognize they’re the same mycelium, genetically identical, they’re able to fuse and become one. That’s how we end up with a single, unified block, even starting from many separate pieces; once they recognize the same DNA, they fuse together. But it seems that when pieces are too far apart, they can’t fuse properly into uniform coverage, whereas closer together, they fuse well and form that uniform coverage.
Robin: Now that you understood how plug size and spacing worked, did you manage to identify an optimal size, is it 1 millimeter?
Alexandre: Good question. Unfortunately, we don’t have biopsy punches smaller than 1 millimeter, and it would’ve been very difficult to work with even tinier plugs at controlled spacing. So we changed our approach, and moved to microfluidics. We took a small piece of mycelium, placed it at the entrance of a microfluidic chip, and let it colonize tiny channels inside a PDMS chip. The design was simple: channels 100 microns tall, 100 microns wide, and 8 millimeters long, and we were able to load agarose, a nutrient source, into those channels too, so the mycelium had something to feed on as it grew.
We decided to cut the chip open after two days, once the mycelium had grown far enough in, and measure the size of the initial mycelium fragment inside. That let us isolate very small fractions of mycelium, and measure whether initial size affected colonization speed down the channel. Cutting the chips, we could identify small, medium, or larger initial fragments, and measure how much biomass each gained over one or two days, to see whether smaller pieces gained proportionally more biomass than bigger ones.
And we saw exactly what we’d seen with plants: when fragments were too small, there was almost no growth, as if there wasn’t enough cellular material to restart growth at all. Just above that threshold, there was a sharp peak, an optimal size that grew up to 10 to 15 times its starting biomass in just two days, which is remarkable. As we went to bigger and bigger starting sizes, growth dropped off, sometimes only doubling, or reaching 1.5 times the initial biomass, over the same period inside the chip. So we did identify an optimal starting size in our chip, an initial biomass around 60,000 cubic microns; that number doesn’t mean much on its own, but it’s roughly the volume that consistently produced very high rates of biomass growth.
Hemdeep: I know you used 3D printing to make your molds; how did you separate your final device from the mold itself? Was there a special process for getting agarose, or PDMS, off the mold?
Alexandre: For the mycelium chip, we used PDMS. With the CADWorks 3D printer, using the green resin, we could pour PDMS into the printed mold and just pull it out; that was it, very easy to work with. For the earlier 2D plug experiments, we used agarose: 3D-printed molds, pour agarose in, let it set, and remove it, no extra processing needed, it just came out cleanly.
Robin: So the process for agarose was basically the same as what you’d been doing for regular PDMS devices?
Alexandre: Exactly the same.
Robin: And for testing mycelium growth in the microfluidic device, since you used agar as the nutrient source, how did you actually get that into the channels?
Alexandre: That part took us a while to work out, trial and error. What we landed on: after building the full chip (PDMS bonded to PDMS via plasma bonding), we’d immediately fill it with liquid agarose, which fully entered and filled all the channels, and then let it solidify in place; that was it. The plasma bonding meant the agarose could really flow into every channel, and we didn’t have any issues integrating the nutrients.
Robin: Did you test other fabrication methods for this device, or go straight to 3D printing?
Alexandre: Straight to 3D printing. It was very easy for us; we were already in the lab, thought, let’s just try it, and it worked perfectly.
Hemdeep: Had you used a 3D printer before working with the ProFluidics?
Alexandre: Good question; yes, it was actually in Chris’s undergrad class, on another project before this one, where we first started using it, just standard resin 3D printing, and I absolutely loved it. It was so satisfying to have something in mind, and just make it, exactly the size you need. So once we had access to printers with really high resolution here, I was thrilled to keep going, and build even more ambitious devices.
Robin: So the main difficulty was obtaining those initial small fragments of biomass consistently. That leads into the second part of your research: how do you continuously produce these very small mycelium fragments?
Alexandre: Exactly. It’s good to know the ideal size, but if we want to scale up production, we need to generate a lot of these optimally sized particles to make a full batch of raw material. So, how do we do that? Taking that volume I mentioned earlier, it’s roughly equivalent to a sphere about 50 microns in diameter. We thought, could we encapsulate mycelium fragments of that optimal size in an alginate bead, a kind of protective shell?
In the literature, people have proposed various approaches to getting smaller particles. Some just use a blender, mechanically breaking up the mycelium, but that produces very inconsistent particle sizes, and damages the material a lot. Others have shown encapsulation is possible, using external gelation, dripping alginate into a solution, but that still produces fairly large particles. That’s the technique where you mix alginate, which forms the shell, and drip it into a calcium chloride solution, which gels the bead almost immediately; you get very poor control over size and shape, which isn’t what we want at scale, where we need consistency. It’s also a fairly slow, hard-to-industrialize process, given the dripping.
There are other encapsulation techniques, though. We actually have a lab here at McGill encapsulating mammalian cells for type 1 diabetes research, using internal gelation instead: rather than dripping into a solution directly, you mix the alginate into oil, essentially making a vinaigrette, a salad dressing. The more you mix, or shake, that dressing, the smaller the water droplets in the oil phase become. That’s exactly the effect we want, to make optimally sized, small mycelium particles: shake it enough, and the water particles just keep getting smaller and smaller, the same way your salad dressing separates less the more you shake it.
Part 3 Transcript
SPG Beads, Brain-Sized Mycelium, and What's Next Part 3
Robin: Over the last two episodes, we’ve been chatting with Alexandre LeBlond, a master’s student in chemical engineering at McGill University, exploring how he and his team are pushing the boundaries of sustainable material science using mycelium.
Hemdeep: First, we looked at the case for mycelium replacing Styrofoam packaging. Then we dove into optimizing mycelium growth using techniques like microfluidics and internal gelation.
Robin: If you missed those episodes, go back and check them out first. This week, we’re moving into the next phase of the research: Alexandre shares how the team is using SPG emulsification, sending liquid through a porous membrane, to produce highly uniform mycelium-alginate beads, boosting consistency and speeding up colonization.
Hemdeep: We’ll also get into some exciting new directions: testing 3D colonization environments, the possibility of rehydrating beads for remote construction use, and even brain-sized mycelium structures that might one day help explore fungal “intelligence.”
Robin: Let’s jump back into big ideas in microscale.
Hemdeep: Does the oil-emulsion approach fully solve the size-consistency issue, or do you still get varying particle sizes?
Alexandre: Unfortunately, it’s still not fully consistent. Even after shaking for a while, the size distribution stays fairly wide. So we’ve started using a technique called SPG emulsification, SPG standing for Shirasu Porous Glass; you push the liquid through this porous membrane, essentially a strainer, and that consistently produces particles at the target size. You can choose your pore size; ours are around 50 microns, close to our optimal mycelium fragment size. The resulting particles come out a bit bigger once in the oil phase, roughly two to three times larger, so between 100 and 150 microns. This way, we can continuously produce optimally sized particles when we make our alginate beads.
Robin: So it’s basically your vinaigrette being pushed through a fine mesh sieve?
Alexandre: In kitchen terms, not exactly, but close enough. We’re making that vinaigrette with the SPG system: the water phase, mycelium and alginate together, gets pushed through the SPG membrane, producing optimally sized particles with mycelium inside.
Hemdeep: This membrane you’re using to coat the mycelium, is it biocompatible? Is there a trigger that lets the mycelium activate and start growing? Does it need to break through the membrane once it’s placed into a material? Does the barrier restrict growth at all?
Alexandre: I should clarify what the SPG membrane actually does; it’s just the mesh used to form the emulsion, to make the optimally sized alginate particle in the first place, not something that stays around the finished bead. After that, the droplets sit in oil, we stir, and gel the beads: we add acid, and since there’s calcium carbonate distributed through the alginate solution, that reaction makes the alginate stiffen into a soft, quite porous hydrogel. So when mycelium is cultured inside these alginate beads, it’s able to get out of the alginate very quickly; it’s a porous material, and growing out into the surrounding substrate isn’t a problem at all.
Robin: Have you started testing seeding with these alginate beads yet?
Alexandre: Not yet; we’re still developing the SPG side of the technique, and that’s our next step, coming up in the next few weeks. A few other projects have come up that pushed this back a bit, so I can’t give an exact timeline yet, but preliminary tests suggest it could speed up overall colonization. We’re not there yet, but should have some interesting results soon, even just from the mechanical-mixing version, to see how fast we can produce this material.
Robin: How long does the SPG emulsion process itself take? Since you’re overall trying to reduce production time, is this an added complication that increases the time needed for that first stage, substrate seeding?
Alexandre: It does add a bit of time; for sure, it needs more time and resources. But the total time to fully produce the beads is only about a couple of hours, not very long at all. If that investment saves us days elsewhere, it’s a very good trade-off. Seeding mycelium directly into substrate is quick on its own, but a couple of extra hours to produce well-dispersed, optimally sized particles throughout the material, we think that’s a very good investment to speed up the overall colonization process.
Robin: So your next step is optimizing the SPG process. Are there other research questions you’re planning to explore?
Alexandre: Yes. We’re also thinking about running a similar experiment to the plug study, but in three dimensions: making a kind of transparent “soil” to see how size and spatial configuration, including location, affect growth. For instance, could we place particles closer to the outer surface specifically, since mycelium tends to want to grow toward the air-solid interface, forming this rigid outer coat? So the question becomes: if we place particles mainly near the exterior, does that speed up production, since that’s where the rigid structure forms anyway? That’s one of the questions we’re looking at right now.
Hemdeep: Do you foresee these beads eventually being manufactured in a factory, then shipped out, so people could transport them on-site, using locally available raw material, and make molds wherever they are?
Alexandre: That’s exactly one of the things we want to test: can we dehydrate these beads, ship them elsewhere, and have that work as a transport method for collaborators? Since the optimal-size fragments grow so rapidly, up to those 10-to-15-times increases within two days, we’d need a way to pause that growth in transit, and then trigger it again on rehydration. That’s one of the open questions we want to test with these beads.
Robin: Do you plan on doing all of this before you finish your master’s, in six months?
Alexandre: Yes, it’s a very ambitious plan, but a fun one. There’s a lot of work, and other projects going on too, so it’ll definitely be a busy stretch. One idea that came from Chris that we’re testing right now: could we make a mycelium structure about the size of a brain, and put an EEG, the little helmet used to measure brainwaves, on top of it, to see whether the fungus responds to stimuli in any measurable way? We have a collaborator at the Neuro, the Montreal Neurological Institute and Hospital at McGill, and we actually tested this: grew a brain-sized mushroom, put the EEG on top, and recorded electrical activity over a weekend. We’re planning to test responses to different stimuli next, and even things like putting it under chloroform, to see whether the equivalent of “brainwaves,” mycelium waves, I suppose, show something like anesthesia.
Robin: Have you ever seen or played The Last of Us?
Hemdeep: Imagine a brainwave readout that just says “get me a beer” or something.
Robin: If that ever happens, I’m blaming you two.
Alexandre: Yeah, I’ve seen it, the mini-series, yeah.
Hemdeep: In terms of other biomaterials, given that you’re using wood as the substrate here, could you use pretty much any biological material? In some countries, people build homes using dried dung, buffalo dung, formed into bricks. If you had mycelium beads of some kind, could that help people make actual structural bricks, rather than the flat dung patties typically used?
Alexandre: The main constraint is that the mycelium strain has to actually be able to decay whatever material you’re feeding it; ours is suited to wood. I’m sure other species can degrade other materials, but that gets more complicated. Even switching to straw instead of sawdust gives us more trouble, since straw is coated in waxes that are harder for our mycelium to break down.
In terms of other construction applications, though: companies are already making mycelium-based alternatives to polyurethane insulation panels, the blue foam panels used in home insulation, since mycelium also has quite good insulation properties. As long as the panel doesn’t take on a lot of water, we saw some serious flooding here in Montreal recently, that would be a real problem for mycelium panels, but assuming it stays dry, I saw on one company’s website that it can last up to 20 years in a home.
Robin: Following up on that: once you’ve autoclaved mycelium material, it can’t grow anymore. But if it’s exposed to a lot of water afterward, could it somehow come back to life and start growing again, or does it just fall apart?
Alexandre: I think you’d more likely just get mold growing on it, and it would start degrading that way. There is some research, I heard about this at a conference over the summer, into keeping mycelium alive within a building, so it retains that self-regenerative property: if there’s damage to a wall, it could actually repair itself, fusing back together over time. That would be a really interesting alternative to non-regenerative materials, where in this case, the mycelium itself stays self-regenerating.
Robin: Would it grow actual mushrooms on the wall, though?
Alexandre: I don’t think so; they’d likely try to limit fruiting, so you’re not getting spores everywhere. Though I suppose that could be an interesting feature too, especially with a rare mushroom variety.
Robin: Solve world hunger while we’re at it, right?
Alexandre: Exactly. Part of the broader vision for our research is optimizing this, and also increasing the resilience of the mushroom itself. There are real challenges bringing wild mushroom species into the lab; if we can find the optimal starting size for other mycelium types too, that could help colonize and adapt rare species to lab conditions, useful for cultivating rare mushrooms, but also for things like antibiotics; penicillin, after all, came from fungus. There are so many fungal species we simply can’t bring into a lab environment yet. Finding the right starting size and building resilience could be a good path toward making mycelium adaptable enough to survive that transition into a more hostile environment, the lab, and start growing there.
Hemdeep: Could you use any other plant with a root system for this kind of project, or is the fungal kingdom really the only option?
Alexandre: Good question. Other plants typically develop leaves and get most of their energy through photosynthesis, so I’m not sure this would translate directly; I’m not a plant biologist, so I can’t say for certain. Maybe if you supplied enough nutrients directly, that could support growth without needing full photosynthesis, but that’s a good question I don’t have a confident answer to.
Hemdeep: That crossed my mind too, since there are so many other root-based plants out there. But you’re right, I think the issue is that photosynthesis is the regenerative process driving those other plants, versus fungus.
Alexandre: I wonder if just feeding simple sugars directly, if the roots could absorb them, might let a plant get by without needing full photosynthesis. That’s a great question; I’d have to ask my dad about it.
Hemdeep: Is your dad a biologist?
Alexandre: He runs an orchid greenhouse; that’s where a lot of my ideas about plants come from, actually, you might’ve seen it in the background here. That’s also where I picked up this sustainability mindset in general, since he doesn’t use pesticides or anything like that. It’s an interesting issue right now too, with everything going on around glyphosate and so on; that’s part of what pulled me toward sustainability more broadly. Sometimes I’ll bring him a weird mushroom question, and he’ll have some useful insight, even outside his own field.
Hemdeep: That was extremely interesting and insightful, Alexandre. Thank you very much for joining us; you’ve given us a really good sense of what sustainable packaging looks like, now and going forward. Thank you.
Alexandre: Thank you for inviting me; it was a real pleasure to chat, and to meet you both. I really appreciate the opportunity to talk about my research.
Hemdeep: And with that, we’ve reached the end of our series with Alexandre LeBlond here on Big Ideas in Microscale. Over the past three episodes, we followed his research into sustainable materials, using mycelium to reimagine packaging as a green, biodegradable alternative.
Robin: We learned how early experiments led to real discoveries about optimizing mycelium colonization, then looked at techniques offering a more scalable path forward. We even looked beyond packaging, into construction and living architecture. Alexandre’s work is a great reminder that innovation often starts with curiosity, and grows from there, at the intersection of sustainability, creativity, and technology.
Hemdeep: Thank you, Alexandre, for joining us. Join us next time on Big Ideas in Microscale, when we’ll be speaking with Chen Li, a fellow PhD student at McGill University.
Robin: Thanks for tuning in to Big Ideas in Microscale. If you enjoyed the episode, follow us to stay up to date. You can listen on Apple Podcasts and Spotify, or watch the full video on YouTube. Follow us for updates and behind-the-scenes content on LinkedIn, Instagram, Bluesky, and X: we’re CADWorks 3D across the board. For show notes, paper references, and bonus resources, visit cadworks3d.com.
Hemdeep: Thank you for tuning in, and as always, stay curious, keep exploring, and never stop asking the big questions shaping our world.
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