Hey there, fellow lab folks and lab techs! Let’s cut to the chase—if you’re a scientist, lab manager, or anyone who’s worked with lab equipment, you’ve probably stared at a pack of spacers and gone, “Wait, do I actually need to prime these things? Or is that just another unnecessary step my senior tech yells about?” As a spacer supplier, I hear this question every single week from new lab hires and even veteran researchers who’ve switched up their workflows. Today, we’re breaking this down straight—no jargon, no fluff, just the science and real-world stuff we see on our end. Spacers
First off, let’s get on the same page: what even are spacers here? We’re not talking about the ones for your laptop or phone case. These are thin, flat (usually) pieces, made from stuff like glass, plastic, or even silicone, that you put between two glass plates for gel electrophoresis—think Western blots, agarose gels, whatever your separation method is. Their whole job is to create a uniform gap so your gel’s thickenss is consistent, right? If that gap’s off, your lanes won’t run evenly, your bands will smudge, and you’ll end up wasting half your samples re-running gels.
Now, priming spacers. What’s that? Usually, it’s coating them with something—like ethanol, maybe a dilute agarose solution, or even just water—before assembling your gel cast. The old-school take from a lot of protocols is “yes, always prime,” but why? And is it actually mandatory, or just a holdover from when old spacer materials were way worse?
Let’s start with the science basics I’ve dug up (and also the stuff we’ve seen when customers send back feedback or issues). Spacers, even the “clean” ones fresh out of the packaging, have static, residue, or micro-texture that you can’t see with the naked eye. Back in the day, spacers were super basic—molded from cheap plastic that left tiny, irregular residues from the manufacturing process. Those residues would repel water (hydrophobic) so when you poured your agarose gel mix, it’d bead up or seep into tiny gaps between the spacer and glass plate. Priming with something hydrophilic (water-attracting) would make the surface even, so the gel adheres consistently. That makes sense for old, low-grade spacers.
But here’s the thing: we make spacers. Like, I work with our manufacturing team every week to adjust how these are made. The stuff we ship now? Most of our spacers are precision-cut from medical-grade plastic or borosilicate glass. We do a 2-step cleaning process during production: first a mild alkaline wash to strip manufacturing residues, then a rinse with filtered water and a final drying under low-static conditions. So when a customer opens a new pack from us, that residue is basically gone. But wait—static is still a thing. Even with our anti-static packaging, if you yank a spacer out of the pack in a dry lab, it builds up a tiny static charge. What does static do? It makes the spacer “stick” unevenly to the glass plate, or create a micro-gap that’s way too small or too big, and also makes your gel solution move weird when you pour it. That’s where a lot of people still prime—just to knock out that static. But is there a right way to do it, or are people overcomplicating?
Let’s talk about real-world test cases. Last month, I followed up with a customer in a biotech startup who’s been using our glass spacers for 6 months. They used to prime every single time with 70% ethanol, but they were noticing their assembly time was 10 minutes per gel, which slowed down their daily runs. We did a little trial: half their runs with primed spacers, half without. The ones without? No smudged bands, no uneven lanes, no leaks. The only difference? They skipped the 30-second ethanol wipe and just handled the spacers a little more gently to avoid static. But then, a different customer— a university lab, working with super low-concentration protein samples—had the opposite experience. They used our plastic spacers, skipped priming, and their gel had tiny “dry patches” in the lanes where the gel didn’t stick. Turns out, their lab was super humid? No, wait—wait, no, their lab was in a cold, dry basement, so static was way higher, and their plastic spacers had a little more micro-porosity than our glass ones. Priming them with a thin agarose coating fixed the dry patches instantly.
So here’s the nuance, which I swear is way more interesting than a yes/no answer: it depends on three things—what your spacers are made of, your lab’s environment, and what your experiment needs.
First, spacer material: Glass spacers? 9 times out of 10, you don’t need to prime them. They’re non-porous, have low residue from our manufacturing, and if you’re in a semi-humid lab, static isn’t a huge issue. The only time glass spacers might need it is if you’re running ultra-thin gels (like 0.5mm or thinner) where even a 0.1mm gap error messes up band resolution. For plastic spacers? This is where it’s a coin flip. Thin, flexible plastic spacers sometimes have a tiny amount of mold release agent (even our higher-grade ones—we’re not perfect) and they’re more porous than glass. If your lab is dry, plastic spacers need a quick prime (water or ethanol wipe) to cut static. If your lab is humid (like 50%+ humidity), plastic spacers might be fine straight out of the pack.
Second, lab environment: This is huge. I’ve seen labs in Arizona, where it’s dry as a bone most of the year, that have to prime spacers to avoid static-related issues. Same for labs with forced-air ventilation (like clean rooms) that blow dry air everywhere—static builds up faster. Labs in Seattle, where it rains 10 months a year, rarely have issues if they skip priming, because humidity naturally defuses static.
Third, experiment type: If you’re running a quick agarose gel for PCR product verification, you don’t need to prime. A tiny gap error won’t matter that much. But if you’re doing a Western blot where you need sharp, high-molecular-weight bands (those thin, tricky ones that barely move), or ultra-high-resolution gels for sequencing, that’s when priming can make a difference—even with good spacers. It’s not that skipping priming will ruin the experiment, but it can eliminate a small variable that might cause a weird, hard-to-troubleshoot smudge later.
Wait, but let’s address the common myths, because I hear these all the time. Myth #1: “Priming prevents leaks.” No—leaks almost always come from not clamping the gel assembly tight enough, or having a cracked glass plate. We’ve had customers send back spacers they claimed “caused leaks” and 9 times out of 10, it was a loose clamp, not the spacer. Myth #2: “All protocols say to prime.” A lot of old protocols—like 10+ years old—were written for way lower-quality spacers. If you look at newer protocols (post-2020), a lot of them skip the priming step for modern, high-grade spacers. That’s not a mistake, that’s a response to better manufacturing. Myth #3: “Priming takes too long.” If you’re wiping a spacer with ethanol and letting it air dry, that’s 10 seconds. But if you’re submerging it in a solution and waiting for it to coat, that’s more time. So it’s not the act itself, it’s how you do it.
Now, as a spacer supplier, I’m not here to tell you to always prime or never prime. That’d be dishonest—we’ve seen both work. But what I can tell you is this: if you’re skipping priming and running into issues, it’s not the spacer’s fault (usually)—it’s either a material mismatch or your lab environment. And if you are priming, you might be wasting time if your spacers are high-quality and your lab is humid.
Wait, let’s throw in a tip we give all our regular customers, because it’s saved them so much time: Test it for yourself. Pick 10 gels this month: 5 with primed spacers, 5 without. Keep track of lane evenness, smudges, run time, and how much time you spend prepping. I bet you’ll find a pattern that works for your setup, not a generic protocol. That’s way better than blindly following what someone else says.
Also, let’s talk about the hidden cost of over-priming. Wasting ethanol or agarose solution adds up over a year. For a 10-person lab, that’s like $50-$100 a year just in supplies they don’t need, not to mention the extra time spent priming each spacer. That time can be used for actual experiments, not wiping plastic.
Now, if you’re shopping around for spacers that work for your setup, here’s what to look for: If you’re in a dry lab, go for glass spacers (they’re way less prone to static) or anti-static plastic spacers (we make these, btw—they have a tiny coating that stops static without adding extra residue). If you’re doing ultra-thin gels, get precision-cut glass spacers with <0.05mm dimensional tolerance—they’ll hold their shape way better than cheaper plastic ones, so even if you skip priming, the gap stays consistent.
Wait, let’s make this relatable—last week, a grad student from a local university emailed me, panicking, because they’d been having smudged bands for 2 months. They were priming every spacer, using cheap plastic ones from a random brand, and their lab was in a cold, dry lab basement. We told them to switch to our anti-static glass spacers, skip priming, and adjust their clamp time (they were clamping too tight, which caused the spacers to warp). A week later, they emailed back saying no smudges, their assembly time was cut in half, and they got their first clean Western blot in 3 months. That’s the real stuff—this isn’t just a technical debate, it’s making people’s lab lives easier.
So, wrapping this up: Do spacers need to be primed? The answer is: It depends. For modern, high-grade glass spacers in a normal, semi-humid lab? Probably not. For thin plastic spacers in a dry, static-heavy lab? Yes, a quick prime will help. For ultra-high-resolution experiments? It can’t hurt, even if you don’t have to do it.
If you’re curious about which spacers would work best for your workflow, or want to ask more questions about priming, feel free to reach out to us to talk procurement or experiment needs. We’re here to help make your lab runs smoother, no guesswork required.
Suspension Stabilizers References
- Sambrook, J., & Russell, D. W. (2001). Molecular Cloning: A Laboratory Manual (3rd ed.). Cold Spring Harbor Laboratory Press.
- "Gel Electrophoresis Best Practices". Thermo Fisher Scientific Application Note, 2022.
- "Static Control in Laboratory Plasticware". Journal of Laboratory Automation, Vol. 18, No. 4, 2013, pp. 321-327.
- Manufacturer’s Technical Data Sheet: Precision Borosilicate Glass Spacers, Our Lab Supply Co., 2024.
Yantai Jiuyu Chemical Technology Co., Ltd.
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