In the intricate world of nanoscale particle research, controlling and separating ultra-small particles has long posed formidable challenges for biotechnologists. These challenges stem from the particles’ size, which leads to unique physical behaviors, making traditional separation techniques inefficient or unreliable. Researchers at the University of Oulu have now unveiled an innovative microfluidic technique that promises to revolutionize nanoparticle separation and purification, opening exciting new avenues for applications in cancer diagnostics and beyond.
One of the fundamental difficulties when working with particles smaller than a few hundred nanometres is their behavior dominated by diffusion. At such a scale, particles no longer follow predictable trajectories under external forces. Instead, they engage in a stochastic movement often described as a “random walk.” This diffusive nature severely compromises the effectiveness of conventional separation methods, which rely on deterministic forces to sort particles according to size, density, or surface properties.
The pioneering solution developed by the microfluidics team, led by Professor Caglar Elbuken at the University of Oulu, harnesses the power of combining two distinct physical phenomena to achieve precise control over nanoscale particles. By intricately blending electrophoretic slip-induced lift forces with the lateral forces arising in viscoelastic fluids, the researchers have engineered a system capable of efficiently steering and separating nanoparticles with unprecedented accuracy.
Electrophoretic slip is a lesser-known but fascinating mechanism where an applied electric field does not directly move the particle itself; rather, it mobilizes the surrounding fluid, creating a “slip” effect that lifts the particles. This mechanism offers a gentler and more controllable means of manipulating particles compared to direct electrophoretic dragging, which can be harsh or unpredictable at the nanoscale. Meanwhile, viscoelastic fluids are complex materials exhibiting both viscous and elastic characteristics, unlike simple Newtonian fluids such as water. Flowing through these fluids exerts unusual lateral forces on embedded particles, which do not typically arise in standard aqueous environments.
By leveraging this dual-action system within ordinary microchannels—avoiding the need for technically demanding and clog-prone nanofluidic channels—the research group achieved separation performance far superior to previous methods. This breakthrough not only simplifies the microfluidic setup but also significantly improves separation speed, scalability, and reliability, crucial factors for translating laboratory techniques into real-world biomedical applications.
In their experimental investigations, the team tested their method on polystyrene particles, standard nano- and microscale proxy materials prized for their uniformity in size, shape, and surface chemistry. The results revealed an impressive 30 to 50 percent enhancement in separation efficiency and purity compared to existing microfluidic techniques. Polystyrene beads serve as a vital benchmark, and these improvements indicate promising applicability for a broad spectrum of nanoparticle separation tasks.
Equally compelling was the method’s effectiveness in purifying extracellular vesicles secreted by living cells, particularly those associated with cancer biology. Extracellular vesicles, tiny membrane-bound packets released by cells, carry valuable biomolecular information reflecting the physiological and pathological status of their source cells. Achieving over a 20 percent increase in vesicle purity at this minuscule scale marks a critical advancement, facilitating more sensitive and accurate downstream analysis for diagnostics and research.
This novel microfluidic electro-viscoelastic separation technique holds transformative potential for several biomedical fields. In cancer research, for example, the ability to cleanly isolate vesicles from blood or other biological fluids can enable early detection of tumors by revealing subtle biochemical changes. Similarly, the method offers new possibilities for studying cellular communication mechanisms, where vesicle-mediated signaling plays a crucial yet poorly understood role.
Moreover, the improved particle separation system promises to impact nanomedicine more broadly. The burgeoning field of nanotherapeutics relies heavily on precisely engineered particles for targeted drug delivery and diagnostics. Effective sorting and purification of these nanoscale carriers are essential to ensure safety, efficacy, and reproducibility in clinical applications. The University of Oulu’s technique provides a scalable, faster, and more reliable tool to meet this pressing need.
Published in the prestigious journal Analytical Chemistry, the research marks a significant milestone in microfluidic particle manipulation techniques. Lead author and doctoral researcher Seyedamirhosein Abdorahimzadeh emphasizes the practical advantages of the approach: the method operates in conventional microchannels, eliminating costly and fragile nanofluidic infrastructures. It also avoids high-pressure requirements and channel clogging that plague earlier technologies, making it more accessible to researchers and industry alike.
Abdorahimzadeh’s doctoral thesis delves deeper into electroviscoelastic and electroinertial microfluidics for particle separation, underscoring the broader scientific implications of this work. His defense scheduled for early 2026 at the University of Oulu is anticipated with interest by the microfluidics and nanobiotechnology communities, eager to see further insights and extensions of this innovative approach.
The researchers envision future integration of their technique into standard laboratory workflows for blood sample analysis, enhancing diagnostic accuracy and potentially enabling rapid point-of-care testing. As the technique evolves and scales, it may become a routine tool in nanobiotechnology research, clinical diagnostics, and drug development pipelines.
Conclusively, the microfluidic electro-viscoelastic method developed by the University of Oulu researchers represents a quantum leap in the capability to separate and purify submicron particles and extracellular vesicles. It addresses a long-standing bottleneck in nanoparticle research by marrying subtle physical principles to practical engineering, unraveling the complexity of nanoscale dynamics with elegance and utility.
This breakthrough is emblematic of the profound impact that interdisciplinary microfluidics research can have on health sciences and biotechnology. As the field continues to mature, such innovations are poised to not only deepen our fundamental understanding of nanoscale biological entities but also transform how we detect, monitor, and treat diseases at their earliest stages.
Subject of Research: Nanoscale particle separation and purification using combined electro-viscoelastic microfluidics.
Article Title: Microfluidic Electro-Viscoelastic Separation of Submicron Particles and Extracellular Vesicles.
News Publication Date: February 6, 2026.
Web References:
https://pubs.acs.org/doi/10.1021/acs.analchem.5c06727
References:
Seyedamirhosein Abdorahimzadeh, Zikrullah Bölükkaya, Éva Bozó, Artem Zhyvolozhnyi, Anatoliy Samoylenko, Feby W. Pratiwi, Henrikki Liimatainen, Seppo J. Vainio, and Caglar Elbuken. Microfluidic Electro-Viscoelastic Separation of Submicron Particles and Extracellular Vesicles. Analytical Chemistry, February 6, 2026. DOI: 10.1021/acs.analchem.5c06727.
Keywords:
Nanoparticle separation, microfluidics, electrophoretic slip, viscoelastic fluids, extracellular vesicles, nanoparticle purification, cancer diagnostics, electro-viscoelastic microfluidics, nanoscale particle control, biomedical applications, polystyrene particles, nanomedicine.
Tags: advancements in biotechnologychallenges in nanoscale particle researchelectrophoretic forces in particle sortinginnovative methods in cancer diagnosticsmedical applications of microfluidicsmicrofluidic technology in biomedicinenanoparticle separation techniquesprecision manipulation of microscopic particlespurification of ultra-small particlesstochastic behavior of nanoparticlesUniversity of Oulu research breakthroughsviscoelastic fluid applications
