Issue 4, 2025

Densimeter-on-chip (DoC): measuring a single-cell mass density by sedimentation in microchannel flows

Abstract

Intrinsic biophysical and morphological features are essential for the label-free identification of different cell types. Indeed, apart from object size, density could represent a key parameter for single-cell analysis. However, the measurement of such a parameter is challenging. Therefore, we present a straightforward and versatile microfluidic chip. The densimeter-on-chip (DoC) measures single-cell mass densities thanks to a hydrodynamically induced sedimentation process inside the microchannel. In detail, in-flow buoyant components become more relevant than viscoelastic alignment forces, leading to precise in-flow sedimentation. DoC is based on precise three-dimensional cell alignment, followed by an abrupt change in cross-section to induce calibrated sedimentation. Based on the balance of acting forces and tracking the in-flow cell trajectory, we have developed a self-written mathematical model to precisely measure the single-cell densities of multiple cell types of any shape. Both cell velocity and fall length define the resulting cell density. The working range of object diameters for which density can be estimated is 0.75–22.5 μm. As result, the minimum measured density is 998 kg m−3 and a sensitivity of 0.001 can be obtained. Great agreement between the computational and the literature findings about red blood cells (∼1159 ± 29.5 kg m−3), lymphocytes (∼1073 ± 49 kg m−3) and neutrophils (∼1093 ± 27 kg m−3) is obtained without chip modification. Indeed, the computational error between the mean density values is ∼1%. Thereby, DoC as an easy-to-use and reproducible solution for label-free single-cell density measurement, provides a universal approach for characterizing a wide range of cell types, independently of their size and shape.

Graphical abstract: Densimeter-on-chip (DoC): measuring a single-cell mass density by sedimentation in microchannel flows

Supplementary files

Transparent peer review

To support increased transparency, we offer authors the option to publish the peer review history alongside their article.

View this article’s peer review history

Article information

Article type
Paper
Submitted
31 Oct 2024
Accepted
20 Jan 2025
First published
21 Jan 2025
This article is Open Access
Creative Commons BY-NC license

Lab Chip, 2025,25, 673-685

Densimeter-on-chip (DoC): measuring a single-cell mass density by sedimentation in microchannel flows

D. Dannhauser, M. I. Maremonti, P. A. Netti and F. Causa, Lab Chip, 2025, 25, 673 DOI: 10.1039/D4LC00916A

This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence. You can use material from this article in other publications, without requesting further permission from the RSC, provided that the correct acknowledgement is given and it is not used for commercial purposes.

To request permission to reproduce material from this article in a commercial publication, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party commercial publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements