University of Oulu Unveils New Nanoparticle Separation Method for Biotech

Precise control and separation of nanoscale particles have been a long-standing challenge in biotechnology. Researchers at the University of Oulu have developed a new method designed to improve particle separation and purification, potentially applicable in fields such as cancer research.

Separating nanosized particles is difficult because particles below a few hundred nanometers are primarily influenced by diffusion, which diminishes guiding forces and reduces separation accuracy.

A Breakthrough in Microfluidics

A microfluidics research group, led by Professor Caglar Elbuken at the University of Oulu, devised this new solution. The method significantly enhances the separation and purification of both small synthetic particles and nanoscale vesicles produced by living cells.

Particle separation is essential because numerous biological processes occur at the nanoscale. Extracellular vesicles from biological samples can indicate early changes in the body, but impurities must be removed to access valuable information. Therefore, an efficient and gentle purification method is critical for diagnostics and basic research.

The Innovative Technique Explained

The new technique integrates two physical phenomena: lift generated by electrophoretic slip and lateral forces arising in a viscoelastic fluid. In electrophoretic slip, an electric field initiates motion in the surrounding fluid rather than directly pulling the particle. A viscoelastic fluid exhibits properties of both a liquid and an elastic material, producing lateral forces not observed in water-based solutions.

Speed, Accuracy, and Scalability

The study was published in Analytical Chemistry. Seyedamirhosein Abdorahimzadeh, the lead author and a doctoral researcher from the University of Oulu, stated that controlled nanoparticle separation is crucial for biological research and clinical applications, noting that existing methods are often slow, complex, or unreliable.

"Our method allows efficient particle sorting in ordinary microchannels, unlike earlier techniques that required nanofluidic channels prone to clogging and high operating pressures."

He emphasized the new method's speed, accuracy, and scalability.

Promising Results Demonstrated

The research demonstrated improvements in the separation and purity of polystyrene particles by approximately 30–50%. Polystyrene particles serve as common model particles due to their precisely controllable size, shape, and surface properties. The method also increased the purity of vesicles secreted by cancer cells by more than one fifth.

Future Applications

Future applications for this method may include blood sample analysis, cancer research, studies of cellular communication, and broader nanomedicine applications. The research is part of Abdorahimzadeh’s doctoral thesis, focusing on electroviscoelastic and electroinertial methods for controlling and separating micro- and nanoscale particles.