Novel Vascular-Adaptive Liquid Metal Microspheres Enable Visualized Arterial Embolization Therapy

A CellScale MicroTester G2 was used to quantify the micro-scale mechanical behavior of the embolic microspheres and to compare X-MEN and unloaded gallium microspheres (GaMs) against the commercial embolic control Embosphere. Before testing, samples were filtered through a 70 µm cell strainer to obtain uniformly sized microspheres. The sample chamber was filled with deionized water and maintained at 37°C. For compression testing, a single microsphere was isolated on the iron sample stage and compressed with a 0.5588 mm diameter cylindrical probe to 20% of its original diameter while images, load, displacement, and diameter were recorded throughout loading and recovery. The resulting data were used to calculate compressive modulus with a spherical model, evaluate maximum compression ratio, and assess recovery behavior. For tensile/stretch testing, a single microsphere was first compressed to 20% of its original diameter and then the same 0.5588 mm probe was lifted vertically by 100 µm to initiate stretching; images and load-displacement data were collected during the deformation. These MicroTester G2 measurements showed that GaMs and X-MEN had markedly higher compressive modulus than Embosphere, exhibited hysteresis during compression-recovery, recovered rapidly after compression, and could be stretched under the probe whereas Embosphere could not. The CellScale data supported the authors’ core conclusion that the liquid-core gallium microspheres possess deformability, viscoelasticity, viscosity, and catheter-delivery-friendly mechanics that help them pack tightly and embolize vessels more effectively.