Magnetorheological Characterization of Blood Analogues Seeded with Paramagnetic Particles

TL;DR

This study provides a first magnetorheological characterization of blood analogues seeded with paramagnetic particles under uniform magnetic fields. By combining steady and oscillatory shear tests on Newtonian and viscoelastic carrier fluids with two particle types and several loadings, the work reveals a pronounced MR-induced structuring and shear-thinning behavior, well described by a Casson-type framework and collapsed onto a Mason-number master curve. The analysis leverages FT-Chebyshev decomposition to quantify nonlinear viscoelasticity in LAOS, highlighting strain-rate-driven elastic softening and complex viscous non-linearities, while numerical simulations corroborate a critical strain for chain subdivision. Although oscillatory measurements face substantial experimental challenges and geometry-imposed limitations, the results establish a robust framework for extending MR characterization to real blood and for designing magnetically responsive biomedical systems.

Abstract

Magnetic particle under external fields can be useful in various medical applications, gaining access to the whole body if deployed in the bloodstream. Localised drug delivery, haemorrhage control, and cancer treatment are among the applications that have the potential to become revolutionary therapies. Despite this interest, a magnetorheological characterisation of particle-seeded blood has yet to be achieved. In this work, we evaluate the magnetorheological response of blood analogues seeded with paramagnetic particles in different concentrations, under the effects of a uniform, density-varying magnetic field. Through steady shear experiments, we encounter the usual magnetically-induced shear thinning response, and oscillatory shear results point toward significant alterations in the fluids' microstructure. However, experimental limitations make it difficult to accurately evaluate the oscillatory shear response of such rheologically subtle fluids, limiting both the quality and quantity of achievable information. Despite experimental limitations, our results demonstrate that magnetic fields can induce marked and quantifiable rheological changes in seeded blood analogues. The framework established here provides a foundation for future studies on real blood samples and for the design of magnetically responsive biomedical systems.

Figures (29)

• Figure 1: Viscosity curves obtained with the NBa (left column) and VBa (right column), seeded with MyOne particles at 15 wt% under the influence of 50 and 250 mT (top row), with MyOne particles at 5 and 15 wt% under 250 mT (middle row), and with MyOne and M270 particles at 15 wt% under 250 mT (bottom row). Adjusted low-torque and secondary flow limits are also shown in each graph.
• Figure 2: Flow curves obtained with the NBa (left column) and VBa (right column), seeded with MyOne particles at 15 wt% under the influence of 50 and 250 mT (top row), with MyOne particles at 5 and 15 wt% under 250 mT (middle row), and with MyOne and M270 particles at 15 wt% under 250 mT (bottom row). Adjusted low-torque and secondary flow limits are also shown in each graph.
• Figure 3: Flow curves with Casson model fits (top row) and dimensionless viscosity as a function of the reduced Mason number (bottom row), for each tested particle type, concentration and magnetic field density combination, for samples with the NBa (left) and VBa (right) as continuous phase (unseeded data not shown). Secondary flow limit is shown along with the flow curves (top row).
• Figure 4: Oscillatory shear data gathered with the unseeded NBa (left) and VBa (right), with the PP20 MRD P2. (Top) Pipkin diagrams depicting the Lissajous curves. The blue and red curves represent, respectively, the elastic (stress vs strain) and viscous (stress vs strain rate) Lissajous curves. The elastic and viscous stresses are also lightly plotted in the respective colours and the maximum measured stress is presented above each plot. (Bottom) First-harmonic loss ($G"_1$, in circular markers) and storage ($G'_1$, in triangular markers) moduli and experimental limits associated with low-torque issues and instrument and sample inertia (corrected for the geometry's gap-error).
• Figure 5: Oscillatory shear data gathered with the NBa (left) and VBa (right) seeded with 15 wt% of MyOne particles under a 250 mT magnetic field, with the PP20 MRD P2. (Top) Pipkin diagrams depicting the Lissajous curves. The blue and red curves represent, respectively, the elastic (stress vs strain) and viscous (stress vs strain rate) Lissajous curves. The elastic and viscous stresses are also lightly plotted in the respective colours and the maximum measured stress is presented above each plot. (Bottom) First-harmonic loss ($G"_1$, in circular markers) and storage ($G'_1$, in triangular markers) moduli and experimental limits associated with low-torque issues and instrument and sample inertia (corrected for the geometry's gap-error).