By Melvin Lye, Curiox Biosystems
For much of the history of flow cytometry, centrifugation has been treated as an accepted compromise. It is efficient, familiar, and deeply embedded in laboratory practice. At the same time, its limitations (cell loss, mechanical stress, and operator-dependent variability) have long been recognized, even if rarely interrogated explicitly in published work.
As long as experiments were short-lived, low-dimensional, or exploratory, these limitations were often tolerated. Increasingly, however, the field has moved beyond that regime. Longitudinal immune profiling, multimodal single-cell atlases, and fragile primary tissue studies now demand a level of consistency and preservation that exposes centrifugation as a structural constraint rather than a neutral step.
Over the past several years, this shift has begun to surface in the peer-reviewed literature. In a small but telling set of high-impact studies, centrifuge-free (C-FREE) laminar wash is not presented as an innovation to be evaluated, but as an enabling choice embedded directly into the methods. We selected where preparation-induced variability would otherwise undermine the biological claims being made¹–⁴.
The ladder below summarizes these increasing levels of consequence, from standardized protocols to fragile tissues, longitudinal designs, and clinical-grade cohorts where prep stability becomes prerequisite infrastructure rather than an evaluative variable.
Centrifugation introduces multiple sources of variability that are difficult to quantify or correct downstream: differential loss of fragile or activated cells, perturbation of surface protein expression, and operator-dependent handling effects during pellet aspiration. In isolation, each may seem modest. Aggregating across timepoints, donors, or conditions, they can shape the apparent structure of the data itself.
As cytometry has moved toward questions where subtle differences matter: persistence of immune memory, lineage relationships among progenitors, or native surface composition of primary tissues. Sample preparation has become inseparable from interpretation. The question is no longer whether centrifugation “works,” but whether it can be relied upon not to bias the conclusions.
A clear example appears in the 2023 Nature Communications study by Rydyznski Moderbacher and colleagues, which examined SARS-CoV-2–reactive B cells across longitudinal timepoints¹. The central claims of the work, persistence of early activated memory B cells, depend on the ability to compare low-frequency, antigen-specific populations across samples collected over time.
In this context, preparation-induced variability is not background noise; it is a direct threat to inference. The inclusion of centrifuge-free laminar wash in the sample preparation workflow reflects an implicit judgment that mechanical handling must be stabilized so that observed differences can be attributed to biology rather than processing artifacts. Notably, laminar wash is not highlighted or discussed in the results. It appears quietly in the methods, functioning as infrastructure rather than as a point of emphasis.
An even stronger signal comes from the 2024 study “An immunophenotype-coupled transcriptomic atlas of human hematopoietic progenitors” (PubMed ID: 38514887)². This work aims to construct a reference atlas integrating immunophenotyping with transcriptomic data across human hematopoietic progenitor populations.
Such atlases impose unusually stringent requirements on sample preparation. They must support comparability across donors, alignment across modalities, and reproducibility sufficient for reuse by the broader community. In this setting, variability introduced upstream cannot be averaged away; it becomes embedded in the atlas itself.
The authors’ use of centrifuge-free Laminar wash™ as part of their preparation pipeline reflects this reality. The wash step is treated not as a convenience, but as a means of controlling a physical variable that would otherwise complicate interpretation of lineage relationships and phenotypic structure. Again, laminar wash is not positioned as the scientific contribution. It is part of the scaffolding that allows the contribution to stand.
The limitations of centrifugation are even more pronounced in fragile primary tissues. In Nature Cardiovascular Research (2023), Luecke and colleagues describe surfaceome mapping of primary human heart cells³. Cardiomyocytes are highly sensitive to mechanical stress, and preservation of native surface protein expression is essential for meaningful surfaceome analysis.
In this context, centrifugation is not merely a source of loss, but a potential confounder that can distort the very features under study. The use of laminar wash reflects an explicit effort to minimize handling-induced perturbation so that surface signatures can be interpreted as biological rather than procedural. Here, centrifuge-free preparation expands not only robustness, but the scope of what can be credibly studied.
Perhaps the clearest indication that laminar wash has moved beyond niche adoption comes from methods codification. In Methods in Molecular Biology, Luecke and colleagues describe the GENTIL method for isolation of adult human cardiomyocytes⁴. Methods volumes occupy a distinct place in the scientific ecosystem: they do not highlight novelty, but define reproducible practice.
The explicit specification of laminar wash in this context signals that centrifuge-free handling is no longer viewed as optional optimization, but as part of a repeatable, teachable protocol. Once incorporated at this level, a technique ceases to be an experiment-by-experiment choice and becomes part of the methodological baseline.
Across these studies (spanning longitudinal immunology, multimodal atlases, and fragile primary tissues), a consistent pattern emerges. Laminar wash™ is selected not to improve throughput or convenience, but to remove a source of variability that would otherwise compromise trust in the data. It is used where failure is not an option, and where preparation artifacts would directly undermine the scientific claims.
Equally telling is how Laminar wash™ is presented: it is not promoted, justified at length, or framed as the focus of the work. It is trusted enough to disappear into the methods. That is characteristic of enabling technologies once they cross a certain threshold of acceptance.
Laminar wash does not generate biological insight on its own. What it does is reshape the boundary of what can be studied with confidence. The recent literature suggests that as flow cytometry and single-cell biology move toward longitudinal designs, atlas-level resources, and fragile primary tissues, centrifuge-free sample preparation is increasingly treated as a prerequisite rather than an enhancement.
In that sense, laminar wash marks a quiet transition point: not because it changes what scientists measure, but because it expands what they can trust, scale, and defend.
Talk with our team about removing the centrifuge from cell preparation to support harmonized automation workflows and more reliable assay transfer across sites and partners.
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